The ABCs of high blood pressure

In most cases, diagnosis of high BP and hypertension should be made only after a period of evaluation

I recently saw a gentleman, Mr A, who had a history of frequent dizzy spells which were so severe that it made him unsteady when he was performing his activities of daily living. Mr A has been on high blood pressure (BP) medication for more than 20 years. After evaluation, his BP medicine was stopped, his dizziness resolved and his blood pressure remained normal.

Criteria for diagnosis

How should one determine that a person truly has high BP? According to the latest guidelines, an upper or systolic blood pressure (SBP) of 140 mmHg, and/ or a lower or diastolic blood pressure (DBP) of 90 mmHg on repeated examination in the clinic would meet the criteria of a diagnosis of high blood pressure or hypertension. In some patients with isolated systolic hypertension, only the SBP is elevated (140 mmHg) and the DBP is 90 mmHg.

This is more commonly seen in the elderly where there is decreased elasticity of the major arterial vessels due to age-related changes. The BP value that is used by doctors to determine whether someone has hypertension is based on the measurement of the BP while the patient is in the clinic. It is recommended that there should be two to three clinic visits between one and four weeks’ interval before a person is determined to have high BP and the diagnosis of hypertension should not be made solely on the basis of one single visit to the clinic.

However, the exception to this is when the BP on a single visit is 180/110 mmHg and there is also evidence from other evaluation that there is underlying heart disease, then the diagnosis of hypertension can also be made on a single visit. Should you be considered to have high BP, it is recommended that this should also be confirmed by repeated BP measurements at home.

The correct way of measuring blood pressure

The BP recording used by doctors is measured in a manner which is consistently observed so that it will be comparable. The optimal way to measure BP is to have a person seated with his back supported, his feet firmly on the floor, using a validated BP measurement machine or device on a table with his arm resting, and with the device at the mid arm at about the level of the heart. In addition, the cuff size must not be too big or too small and must be able to fit comfortably over the arm.

The room should be quiet and there should be no talking during and between the measurements. The person should be relaxed for three to five minutes and should have the bladder emptied before measuring the BP. In addition, there should be no smoking or consumption of coffee or caffeinated foods or exercise for 30 minutes prior to the measurement of BP. Once all these conditions are met, the BP levels can be taken and there should be an average of three measurements taken at one-minute intervals. It is advised that the average of the last two measurements be used as the BP recorded.

In the initial evaluation, it will be ideal to measure the BP in both arms. If there is a consistent difference between the two arms of more than 10 mmHg in repeated measurements, use the arm with the higher BP as the arm for routine BP measurement. If the difference is more than 20 mmHg, further investigation should be considered to look for an underlying cause. Generally, out-of-clinic BP measurements by patients at home or 24-hour ambulatory BP recordings prescribed by the doctors are more reproducible than the routine clinic measurements and are more closely associated with organ damage and related to high BP.

Hence, if your BP is elevated upon the visit to the clinic, it does not mean that you definitely have hypertension. Before a diagnosis of hypertension is made, it is advised that repeated BP measurements should be performed, done in a manner as described above and the BP validated with home measurements.

Types of hypertension

In addition to sustained hypertension which is the elevation of BP throughout the day, there are also individuals who have elevated BP values in the clinic but have normal BP values when they are measured out of the office or at home. This is termed white coat hypertension. These patients routinely present with high BP values at the clinic and if they are prescribed BP lowering medication, they may feel light-headed or dizzy at home as the blood pressure values can drop very low with the medication.

If their risk factor profile is low and there is no evidence of organ damage related to hypertension, medication is not necessary. However, they should be advised to manage this white coat hypertension with lifestyle modification. There is another category of patients with normal BP values in the clinic but the BP values are elevated at home. This condition is called masked hypertension. Unlike white coat hypertension, those with masked hypertension are at similar risk of complications as those with sustained hypertension and hence, they may need drug treatment to normalise the home BP readings.


One of the most useful tests to determine whether there is evidence of organ damage by hypertension is the echocardiogram, an ultrasound assessment of the heart. In patients with hypertension, the presence of high pressure in the heart chambers can result in a dilatation of the left upper heart chamber as the thinned walled chamber gradually distends as the BP increases. In addition, the muscular left lower chamber has to work harder to pump the blood out of the heart chamber to the aorta.

As a result of constant stress on the muscular left lower chamber, the muscles will become thickened. This is analogous to the increase in your arm muscle if you have to carry heavier and heavier weights. If the BP is very high in the clinic and the echocardiogram is normal, it is very likely that this patient has white coat hypertension and medication is unnecessary in the majority of these patients. In Mr A’s case, his persistently elevated clinic BP as a result of white coat hypertension prompted his doctor to keep increasing his BP-lowering medication till he was on multiple drugs. At home, the BP-lowering drugs resulted in a low BP causing him to have severe dizzy spells whenever he tried to change his posture.

Despite being diagnosed to have hypertension and having been put on BP lowering drugs for more than 20 years, his echocardiogram did not support the diagnosis of long-standing hypertension. Hence, the decision to stop all his BP medication “cured” him of his symptoms and yet allowed his BP to remain normal.

The take-home message here is that if you are suspected to have high BP, measure your home BP according to the optimal protocols described above before you resign yourself to a fate of taking medication for the rest of your life.

Our Eyes, Our First Defence

As Singapore emerges from the “circuit breaker”, a measured approach and long-term plan for eye care to better prepare for possible future outbreaks should be considered

SGSecure, a national campaign launched in Singapore four years ago for crisis preparedness has been a success in informing residents of the need to be vigilant against terrorist attacks and other civic emergencies. It has a catchy tagline of “Our eyes are our first defence”, with eyeball mascots keeping an eye out for signs of trouble. I cannot agree more, since our sense of sight comprises 80 per cent of our senses.

2020, the year for good vision, has quickly degenerated into the worst public health and financial crisis in a generation, no thanks to Covid-19. As the world hunkers down to avoid what seems to be a threat worse than terrorism, local essential services like healthcare, transport, food supply and infrastructure have soldiered on these two months, including my specialist eye clinic, albeit on a much smaller scale.

Eye diseases are rarely life-threatening, even though they can blind one and affect one’s independence and livelihood. Yet the trickle of patients with eye problems, significant enough to leave home to see a doctor for, has told a sobering story of how prevention is truly many times better than cure. Apart from symptoms like seeing floaters and flashes which may be due to unavoidable retina tears that can cause detachment, most other acute eye diseases are arguably avoidable, either by early detection and preventive treatment, or careful management of general health problems that may give rise to eye diseases as a complication.

Flattening the curve
Very few would have predicted that a viral pandemic could bring human activities to such an abrupt halt. Deriving Singapore’s coping strategies from our Sars-hardened political leaders, public health and infectious diseases experts, themselves on a steep learning curve, we do our best to flatten the Covid-19 curve by staying home as much as possible.

Meanwhile, life goes on, and the usual urgent and emergent health problems happen as they normally would, with some exceptions such as reduction in influenza and air pollution-related allergies. On the other hand, as a result of the stay-home campaigns, health-seeking behaviours, other than pandemic-related, are altered and delayed by the healthcare bottlenecks worldwide. As such, there are emerging signs of increased disease severity at presentation in affected specialties, with possibly higher morbidity and mortality.

Even though I fully agree with and have operated by the Ministry of Health’s guidelines on appointments and social distancing during the past crucial weeks, my heart aches when I see otherwise able-bodied patients lose their vision. Chronic diseases like cataracts can sometimes progress faster than what conservative treatment plans for. This has resulted in some patients going from doctor to doctor, seeking surgical relief for functional restoration.

Furthermore, delays in seeking medical attention can cause one’s vision to be permanently damaged from common eye diseases like glaucoma, macular degeneration and diabetic retinopathy, all of which are usually symptomless in the early to moderate stages, where commencement of treatment to preserve sight is effective and strongly advised. In the worst scenarios, patients are unaware until they reach advanced stages of these eye diseases. By then, extensive treatment is indicated, unfortunately often unsuccessful in fully restoring vision. The consequent vision loss can render one unable to adequately manage activities of daily living and to work. It is my sincere wish that the eye care profession can satisfactorily manage the backlog of cases in the coming weeks.

As Singapore emerges from the “circuit breaker” and gradually resumes life as we knew it, my personal opinion is that a measured approach and long-term plan for eye care to better prepare for possible future outbreaks be considered. Ongoing management of acute cases aside, and while safe distancing and all applicable infection control measures are followed for protection of patients and doctors, emphasis should be on eye treatment to restore function as soon as possible for affected patients, so that breadwinners and families can get on with their lives.

Further to that, monitoring of previously diagnosed chronic eye diseases, particularly unstable cases, and eye screening for patients with risk factors should not be long-delayed, so that treatment outcome can be optimised. Efficient use of downtime As food for thought, in Hong Kong and South Korea where pandemic measures are reportedly balanced and infection control generally good, ophthalmologists, particularly those in non-hospital or privately-run settings, had continued to provide “compartmentalised” services for eye care including cataract and refractive laser surgeries.

Such practices, to my knowledge, had reportedly not contributed to a spread of Covid-19, is openly accepted locally and deemed an efficient use of enforced downtime, particularly by patients seeking laser refractive correction, who are typically young adults and more resilient to the pandemic. In other countries, Covid-19 swab tests are carried out as a screening prior to surgeries. In Hong Kong, eye specialists in different sectors seem to close ranks, with counterparts in the private sector proactively contributing to the care of public sector patients.

While practices differ from place to place, I opine that a universal principle should be to improve clinic infection control and time-efficiency so that eye service quality is not compromised. While we wait for sustained stabilization of the pandemic, clinical research, particularly commercial and unrelated to the pandemic, should continue to be scaled back. Certainly, in my practice, tests and procedures that are potentially aerosol-generating such as the airpuff eye pressure test, and that are invasive or prolonged, are currently avoided in favour of those that can achieve similar aims without the downsides.

Similar to how the pandemic forces us to hasten trends at the workplace, in retail and information technology, I believe in time to come, it will shape and perpetuate practice trends in healthcare and ophthalmology too. These trends may be the adoption of telemedicine, increasing use of non-invasive and contact-less diagnostic devices and embracing newer surgical approaches to reduce risks and improve long-term post-operative results, like using laser cataract and refractive laser lenticule techniques.

One thing is for sure, Zoom and webinars have resulted in unprecedentedly large participation in both public education and professional meetings I attended in the past two months, a trend that hopefully will stay for good. As for our first defence against the pandemic in the coming weeks, in addition to face masks, may I please suggest the anti-terrorist mentality of including eye protection, particularly in crowded places, since catching the virus through our eyes is not impossible – be it a wraparound eye shield, face shield or large-framed, close-fitting spectacles, all to be washed regularly. After all, Covid-19 is the most lethal terrorist to date!

How to live to 100

FROM 1960 till 2020, there has been a 28-fold increase in the number of centenarians. The path to longevity is strewn with false promises of expensive elixirs, exotic supplements, and stem cell rejuvenation. Human longevity is a complex interplay between the genes, the environment and lifestyle.

Genes and longevity
The study of human longevity genes is a developing science. Scientists estimate that between 15 and 30 per cent of the variation in human life span is determined by genes, but it is not clearly understood which genes are relevant, and how they contribute to longevity. In 2015, Ancestry, a genealogy and genetics company, partnered Calico, a Google spinoff, to study data from more than 54 million families and their family trees representing six billion ancestors, and were able to tease out a set of pedigrees that included over 400 million people. These individuals were connected to one another by either a parent-child or a spouse-spouse relationship.

In 2018, they published their results in Genetics, a journal of the Genetics Society of America. The study found that the lifespan of spouses were more similar and better correlated than in siblings of opposite gender. The study concluded that life span heritability is likely 7 per cent or less, and hence the contribution of genes to longevity is even lower.

Although genes seem to have only a small influence on lifespan, they appear to play a larger role in centenarians. Hence, there are a few genetic
factors that do give you a headstart in the journey to longevity. Being a first-degree relative of a centenarian makes it more likely for you to remain healthy longer and to live to an older age than your peers. First-degree relatives are less likely at age 70 years to have the age-related diseases that are common among older adults.

Women generally live longer than men, and the number of female centenarians is more than fourfold higher than that of male centenarians. It is
thought that this is due to a combination of social and biological factors. Studies on mammals and Korean eunuchs have shown that the removal of
testosterone at a young age was correlated with an increase in lifespan. Genetic studies show that centenarians have a lower genetic risk of having
heart disease, stroke, high blood pressure, high cholesterol, Alzheimer’s disease and decreased bone mineral density.

A study on Chinese centenarians published in 2013 showed that 55 per cent have normal systolic blood pressure, 82 per cent had normal diastolic blood pressure and less than 20 per cent were on long term medication. Hence, centenarians appear to have genes that reduce that risk of age-related chronic illnesses.

Biological clock
Epigenetics is the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself. One of the major mechanisms in which epigenetics manifest itself is by the process of DNA methylation, which involves the chemical modification of the DNA, thereby modifying the gene function and expression. Through this process, certain genes can be silenced or activated and potentially impact age-related diseases such as cancer, osteoarthritis, and neurodegeneration.

The biological or epigenetic lock in centenarians show a decrease in DNA methylation age, indicating that they are biologically younger than their chronological age. There is also data to suggest that although circadian rhythms deteriorate during ageing, they seem to be well preserved in centenarians, including preserved sleep quality.

Environment and longevity
Environmental factors have a large impact on longevity. Better living environment, clean food, clean water, good sanitation, reduction of infectious diseases, and access to better healthcare have resulted in significant improvement in human longevity. Using Italy as an example of the impact of a better living environment, the average life expectancy went up from 29 years in 1861 to 84 years in 2020.

The number of centenarians in Italy increased from 165 in 1951 to more than 15,000 in 2011, and the incidence of deaths occurring in those less than 60 years of age, decreased from 74 per cent in 1872 to less than 10 per cent in 2011. The continuous increase in lifespan in recent decades is mainly due to the advances in medical science. It is estimated that medical advances have allowed an increase in lifespan of five years in the last two decades and additional two years in the last decade.

When comparing two countries at different stages of development in 1950, the average life expectancy increase of 11 years from 68 years in 1950 to 79 years in 2020 in the USA, which was more developed in 1950, was much less remarkable than the increase of 3114 years in average life expectancy from 43 years in 1950 to 77  years in 2020 in China, which was less developed in 1950. The significant improvement in the living environment in China has contributed to the narrowing in the average life expectancy between those living in the US and China.

Lifestyle and longevity
In addition to environmental factors, lifestyle factors have an important impact on longevity. A study of more than 300,000 individuals over 7.5 years showed that individuals with social relationships have more than 50 per cent greater probability of survival compared with those with few and poor social interactions. A study on centenarians in Utah in the US between 2008 and 2015 suggested that sleep, life satisfaction and social attachment were significant predictors of days lived. There is an extricable linkage between lifestyle and socioeconomic status. The term  socioeconomic status as used in longevity studies encompass all the factors that can impact longevity including wealth, geography, education, occupation, ethnicity, cultural environment, neighbourhood environment, quality of healthcare and quality of diet. It is well established that the socioeconomic status of an individual will have a major impact on health and longevity.

A study on more than 120, 000 individuals by researchers from Harvard, published in the Circulation journal in April 2018, identified five low-risk lifestyle factors for increased life expectancy. They were: no smoking, non-obese ( body mass index of 18.5 to 24.9 kg/m2), exercise (at least 30 minutes per day of moderate to vigorous physical activity, including brisk walking), low-risk alcohol consumption (5 to 15 gm/day for women and 5 to 30 gm/day for men), and a high score for healthy diet.

In this study, the projected life expectancy at age 50 years was on average 14.0 years longer among female Americans with five low-risk factors
compared with those with zero low risk factors; for men, the difference was 12.2 years. These findings are consistent with a study on Chinese centenarians in which less than 20 per cent were smokers and less than 40 per cent drank alcohol. Hence, in general, most centenarians do not smoke, do not drink alcohol or are low-risk alcohol drinkers, are sociable, friendly, cope well with stress, are satisfied with life, have healthy diets and sleep well. In summary, the main drivers of longevity in the first eight decades of life are the socioeconomic environment and lifestyle choices.

Beyond the eighties, the inheritance of genes that defer age-related chronic diseases and a younger biological clock will help to propel these individuals beyond a hundred years.

Living through a once-in-a-lifetime event

It has been 14 weeks or so since the first case of Covid-19 virus landed on our shores. A lot has happened since, with a wave of returning citizens bringing home the virus from epicentres in the United Kingdom, Europe and the United States. These 579 imported cases unfortunately spawned community spread and the outbreak in our migrant worker dormitories.

The community spread led to unlinked cases that started from nine daily to as high as 31 daily before we had to impose “circuit breaker” measures. With the initial and further stricter measures, we have now brought the unlinked cases down to an average of 11 daily in the last week.

To date, Singapore has reported 21,707 Covid-19 cases in total, with more than 19,000 of those being migrant workers in the big dormitories and smaller factory converted dormitories. There are 200,000 workers in the big dormitories that can house up to 20,000 workers each, and 100,000 workers in the smaller factory dormitories that house as few as 20 workers.

The dormitory outbreak has challenged our nation in many ways. The logistics challenges are huge; agencies have had to deploy medical posts in the 43 big dormitories, impose restrictions on movements within these dormitories, swab huge numbers of sick migrant workers, move and house them in communal facilities to monitor them through their illness, and as they are recovering, move them to recovery facilities. The numbers in communal facilities total 10,000, a tally that is steadily rising and could soon double.

The agencies involved in such herculean efforts comprise both private organisations and public agencies. This private-public cooperation is heartwarming to see, as Singapore Inc mobilises under threat from this invisible enemy.  There has been criticism of the living conditions of the dormitories but I cannot think of any other nation that has mobilised in such a manner to look after their migrant-worker population.

The other challenge is the healthcare system and the effort to protect it from being overwhelmed. All the herculean effort on the dormitory scene is really to flatten the curve of the epidemic to prevent a massive surge of cases that may overwhelm the ICUs, high dependency units and oxygen points.

Though we have reduced the number of unlinked cases in the community, we are concerned that an outbreak in nursing homes will mimic that in the dormitories. The migrant workers are young and fit due to the nature of their job. The data shows that of those who are 30 years old and below, less than one per cent will need oxygen of any sort.

Hence the huge numbers of migrant workers who have caught the virus have not translated into huge demand on our ICU beds. But a sizeable outbreak in nursing homes will be of a different nature. On the testing front, the number of swabs has increased from 3,000 daily to 8,000 daily currently, and the number of swabs will be further increased five-fold. This is a huge ramp-up, with laboratory workers working non-stop at breakneck speed since January, and the shortage of reagents and disposables as there are limited suppliers globally.

The swab processing is a laborious process; it involves extracting and amplifying minute amounts of viral RNA and takes six to eight hours to execute. The antibody test that can be rapidly deployed and which is as simple as a pregnancy kit has been disappointing. The antibody test detects the viral antibody effectively only after 11 to 14 days of symptoms.

Good ICU care

On the ICU beds front, we have the capacity to double or triple the number needed. Our ICU care is good and we have a low mortality rate so far, although the 20 patients that have perished is one too many. Hence for a drug treatment to be effective, the drug has to perform much better than our ICU care or stop patients from entering ICU. There is a lot of hype around remdesivir.

Trials failed to show that it reduced mortality, but it did reduce the recovery period from 15 to 11 days. To find a drug off the shelf and then to repurpose it for a novel virus is a difficult ask. It is likely that we need to develop a new drug from scratch. As for the vaccine, there are three phases: the first involves 10 to 30 patients and you are looking for immune response and safety; the second phase is with larger numbers of 100 to 300 patients and you are still looking for safety and immune response. The third phase is real-world deployment with placebo-controlled randomised trials.

Realistically, this will take 12 to 18 months, and anything can go wrong during the three phases; then it is back to the drawing board. The race is on between the US and China for a vaccine, making this a geo-political race for prestige and prowess. This pandemic is a combination of health, economic and psychological crises all rolled into one. I would leave the economic aftermath to the economists and have a word about the psychological state of our globe. I like what author and public speaker David Kessler has said about this crisis – that it is a grief reaction.

Mr Kessler and his late collaborator Kubler Ross gave us the definitive stages of grief reaction.

The grief we feel is that of loss of normalcy, fear of economic loss and loss of connection to our social circles. The nature of the fear we feel is somewhat in the future; we dread the fear in anticipation. It is sort of like when a loved one is diagnosed with cancer – we dread the future of the disease and what it brings for us.

The stages of grief starts with denial, where we are sure the virus will never reach our shores and will go away. The next phase of anger results in us blaming that person for coming too close to us, or blaming another nation for the pandemic.  Bargaining makes us think if we take pills or supplements, it will not infect us. Sadness permeates us as we wonder when it will all end. The penultimate stage is acceptance where we decide we have to take control of the situation; we have to execute a series of actions of washing our hands, masking universally and working from home.

When we have a plan and execute it, we regain control and fulfil acceptance. There is an ultimate phase of grief reaction and that is to find meaning. We have encountered a once-in-a-lifetime event that has disrupted our lives, halted the economy dead in its tracks and left us hiding in our homes in a curfew-like situation. The virus has infected millions globally, killing a quarter of a million, decimated mighty economies and left the world in fear, grief and resignation.

Positive aspects

Yet there are silver linings. The skies are blue, the local PSI has halved, the dust on surfaces has reduced and wildlife and migratory birds have re-emerged. Our family life has become central, there is daily bonding over family meals, young children are amazed that parents are home daily, and exercising with children is a norm. Working from home has made workplace hierarchies less relevant, savings have accrued from reduction in transportation, meals and clothing; staff may actually need less renumeration with reduced costs, office space may shrink as most work can be done from home with today’s technology enablers. The need for helpers and the disincentive of the helper’s levy should be revisited.

That work is also a social need is important; offices may well become meeting places rather than workplaces. With the gradual reopening of the economy and the new normality we have to accept that there will be pain and loss of jobs, assets and destruction of value. This is a time to rally the nation round to face the hardships and the uncertainties the future holds. We have to form alliances, and we have to seek other nations to rebuild our economies together. Our leadership has to pull this off and navigate us through these uncharted waters.

The old adage is true – in the midst of crisis, there is opportunity to re-examine, realign and re-energise our values, our priorities and our prowess.

The race is on to seize the day.

Throat Cancer – Not Just A Smoker’s Disease

Throat cancer refers primarily to malignant tumours of the voice box and the lining of the muscular tube that lies behind it. The main risk factors are smoking and alcohol and these are synergistic when both factors are present. Throat cancer usually affects older males but it can also affect younger patients of any gender who are non-smokers and non-drinkers too. This article aims to inform the reader of the structure, disease process and management of this type of cancer and what to watch out for to avoid unnecessary delay in treatment.

Anatomy and physiology

The throat is a complex structure consisting of the muscular tube (pharynx) that connects the back of the nose and throat to the gullet (oesophagus) and voice box (larynx). It allows for the safe flow of food and fluids to the gullet and of air through the larynx into the lungs. The larynx consists of muscles, cartilage and nerves which are designed to safeguard the airway, protecting it from potential entry of food and drinks by “closing” itself off. This reflex is paramount in survival and is what allows us to thereafter generate immense force from our lungs to produce a cough to clear the airway. Failure to do so can result in choking and lead to chest infections such as pneumonia.

Other functions of the larynx include voicing and the capacity to strain and raise the abdominal pressure. There are three main parts of the larynx (Fig 1): the upper part is the supraglottis; the middle, the glottis – where the vocal folds/cords are located; and the lower part is the subglottis, where the voice box joins the windpipe (trachea). The lining of the throat is known as its mucosa. It is the toxic irritation of cigarettes and alcohol with their chemical compounds that alter the cells of the mucosa causing them to change their appearance and behaviour leading to an irreversible genetic alteration and to cancer. Genetic factors, exposure to certain chemicals and chronic exposure to acid, viral infections and other irritants have been postulated as causes in other patients.

Symptoms and signs

Patients with throat cancer present in several ways. Hoarseness in patients with no obvious precipitating cause exceeding a fortnight should be referred on for specialist investigation. Lesions on the true vocal folds affect their vibratory capacity and result in an abnormal rough voice. If the mass of the tumour or its extension reduce the mobility of either or both cords, the voice can sound breathy too. Swallowing difficulties and choking are also symptoms that can be present as signs of possible throat cancer.

Throat or ear pain on swallowing are also important complaints that warrant investigation. Blood in the saliva and increasing noise while breathing and shortness of breath can be later features of throat cancer and warrant rapid referral to an ENT surgeon. Patients with extension of their cancers may, rarely, present with disease that has spread to the lymph nodes in their neck which are often painless and hence should be seen urgently for further assessment.

History and examination

A full history is sought and risk factors ascertained. The state of the patient is appraised to assess the severity of the disease, especially in cases where the airway is either compromised physically, potentially leading to asphyxia, or in its inability to protect the lungs from aspiration of ingested solids and liquids. Thereafter, patients are examined with particular attention paid to their larynx, back of the tongue and side of their throats. This is achieved using a flexible fiberoptic endoscope known as a nasendoscope which is passed via the nostril, through the nose and above the voice box. Other methods of examining the larynx include using a laryngeal mirror and rigid endoscopes that are angled so they can visualise the throat through the mouth.


Imaging of the neck and throat are achieved using sophisticated cross-sectional imaging modalities such as an MRI or CT scan. Further investigation includes examining the patient’s upper aerodigestive tract under a general anaesthetic with concomitant biopsies of the lesion/s in question with analysis by the pathologist. Thereafter, the confirmed cancer is staged and treatment recommended after discussion in a multi-disciplinary tumour board made up of specialist oncologists in surgery, radio and chemotherapy, pathology, radiology and specialist nurses, speech therapists and dietitians.


Throat cancer may present at various stages, often divided into early or late. There are also pre-cancerous stages that if untreated may develop into cancer. Hence, treatment is tailored to the disease and patient along with risk factors such as persistent smoking, drinking etc. Early cancers can be treated with a single modality of treatment – that is, either by surgery alone or radiotherapy.

The decision to use a particular modality is made based on the site and accessibility of the  tumour, the ensuing risks to the voice and swallow and cost. Minimally invasive surgery utilising lasers (Figure 2A and 2B) has been well established as an effective method to treat laryngeal cancer. It is very accurate and can be repeated unlike radiotherapy that is often a one-off treatment and therefore rarely repeatable.

More advanced cancers require more aggressive treatment including the incorporation of chemotherapy where applicable to radiotherapy. Transoral robotic surgery has also been used to great success and in cases where patients may have already had radiotherapy and salvage surgery is advocated but carries higher risks of complications. Open surgery has become less common currently as “laryngeal preservation” is advocated to avoid what is generally a mutilating removal of the voice box with subsequent permanent changes to the patient. Total laryngectomy, however, in cases of advanced cancer is still a very oncologically sound and effective operation.

Voice rehabilitation

With the loss of the larynx comes the obvious loss of the capacity to speak. Along with this is the fact that the patient’s throat is no longer at the junction box between the airway (trachea) and food way (oesophagus). The patient therefore has a complete separation between the two tubes with the windpipe now attached to the skin of the neck below the removed voice box.

Various ways of voice rehabilitation have been developed including “oesophageal speech” where the patient swallows air and belches it out in a controlled manner causing vibration of the back of his tongue, mouth and lips while moving his tongue to speak. Other ways include the use of a speech valve – a purpose-built device that is inserted through the back wall of the windpipe into the oesophagus. This valve allows for the channelling of air from the lungs into the oesophagus and similarly out through the mouth causing vibrations that result in sound.

An electronic device that resembles a microphone known as an electrolarynx can be used and this transfers vibrations from the cheek to the device.

Finally, some patients rely on sign language and writing to communicate.


Laryngeal cancer is a cancer that can affect the young and old. It is seen in non-smokers and non-drinkers too. Symptoms that affect the voice box and throat that do not improve after a fortnight or so such as hoarseness, pain, swallowing problems, cough and shortness of breath should be referred on for specialist input quickly.

Singapore Medical Specialists Centre Breaks New Grounds In Vision Enhancement

One of the most common applications for lasers in the treatment of eye problems is in refractive correction. Due to its high safety and efficacy, laser vision correction for refractive errors has today become a mainstream approach. Providing freedom from glasses and contact lenses, it is sought after not just for convenience and cosmetic effect, but also for practical reasons, such as facilitating participation in sports, enhancing one’s career, and lifestyle pursuits. In many cases, quality of life is significantly improved following successful laser vision correction.

Compared to the first generation of laser vision correction treatments, such as the flapless Photorefractive Keratectomy (PRK) which is associated with post-op pain, longer recovery, and side effects of haze, the newer treatments, such as the flap-based Laser-assisted In Situ Keratomileusis (LASIK), are vastly more popular as they result in much shorter downtime and a higher satisfaction rate. While some patients may experience some degree of dry eyes, particularly in the treatment of higher eye power, they generally recover with proper post-operative care.

Third generation technology, such as the still-maturing Small Incision Lenticule Extraction (SMILE), a keyhole operation combining the flaplessness of PRK with the quick recovery of LASIK, can deliver even more stable results. Any small chance of eye power regression and cornea weakening (ectasia) can also now be prevented by corneal collagen cross-linking (XTRA).

Swiss Ziemer LDV™ Z8 Technology
A recent addition to the armamentarium in the refractive surgery world is the highly innovative and mobile FEMTO LDV™ Z8 Laser by Ziemer, an advanced technology that has brought a new level of accuracy, flexibility, speed, and mobility to laser eye surgeries. With its low energy (the lowest amongst all femtosecond lasers), it comes on the back of a highly respectable and continuous lineage. As an established FDA-approved femtosecond laser purpose-built for LASIK and corneal and lens surgeries, it has its roots in versions Z2, Z4, and Z6. The unique LASIK performed on the Ziemer platform is called Z-LASIK. Distinct from other makes of femtosecond lasers, the proprietary FEMTO LDV Z8 uses extremely fast, short pulses of low range pulsed light, which gives rise to a faster creation of the corneal flap (the first step of the Z-LASIK procedure) – within just 30 seconds.

The nanojoule laser allows for a gentle approach that produces an extremely smooth interface, reducing the stress on corneal tissue and post-treatment inflammation. As a result, patients can expect more rapid healing and improved vision in a shorter time frame. The laser’s small footprint and mobility also means that patients are not required to shift during different steps of the treatment, improving patient comfort and streamlining the surgical process. The flap creation is then followed by excimer laser treatment in the second step of LASIK (SMSC uses a proven NASA excimer technology, iDESIGN 2.0 VISX STAR S4, including wavefront-guided LASIK treatment).

What is interesting is that the FEMTO LDV™ Z8 does not just deliver bladeless all-laser LASIK for the treatment of refractive errors such as myopia, hyperopia, astigmatism, and presbyopia with high precision. Its adjustable 3D LASIK flap configuration is also versatile and customisable, like the Z6, with the additional advantage of an Optical Coherence Tomography (OCT) to visualise the Bowman membrane and previous LASIK interfaces, a feature of Z8 that enables finer precision work, such as LASIK retreatments or thinflap femtosecond LASIK (femtosecond sub-Bowman’s keratomileusis).

In lens surgeries, the Z8 laser delivers documented excellent results in Femtosecond-assisted Cataract Extraction Surgery. With its low energy levels, the
laser cuts are fine and precise, allowing for safe surgeries even in complex lens exchange and cataract operations. The mobility of the laser unit allows it to be positioned in the operating theatre right next to the patient, doing away with patient movement between equipment changes, creating a more comfortable experience. The Z8 is the only laser that is feasible when bilateral sequential femtosecond-laser assisted cataract surgery is opted for.

In addition to the above indications, the Z8 is able to perform femtosecond arcuate keratotomy for the treatment of astigmatism using a non-invasive method. Furthermore, Ziemer is on the cusp of releasing its Z-lenticule extraction treatment (yet to be formally named), its own version of SMILE, with added ability for centration, projected improvement in accuracy, and precision. Anticipated in the first quarter of 2020, it will be an attractive option for laser vision correction candidates seeking a flapless alternative.

Ziemer Z8 + Galilei G6
The breakthrough Z8 femtosecond laser can coordinate with the FDA-approved Galilei G6 scanner to create a complete Ziemer ecosystem. The Galilei G6, built on the G4 model, is a dual-Scheimpflug imaging/scanning device that captures up to 300,000 spots on the cornea on both its front and back surfaces and incorporates an optical biometer and Artificial Intelligence assessment technologies. It is precise for assessments for LASIK and SMILE/Zlenticule and for lens implant treatments like the Implantable contact lens (ICL), lens exchange, and cataract surgeries. The unique combination of the Galilei G6 scanner and Ziemer Z8 laser streamlines the application of pre-operative measurements, thereby improving LASIK and SMILE/Z-lenticule as well as ICL, lens exchange, and cataract surgery pre-planning, providing a clearer picture to achieve a safe and great visual outcome.

The Singapore Medical Specialists Centre is proud to be the first in Singapore to have the Ziemer Z8 combined with the Galilei G6. With OCT guidance for LASIK, we are confident we can enhance your vision with increased precision.

Children’s Ear, Nose and Throat Problems

Children commonly have issues with their ears, nose and throat. This is partly because of the natural physiological process of development which can make them prone to viral infections and allergies to name a few. While the common cold and ‘flu’ affect children and adults alike, the complications of these often ‘minor’ ailments can lead to more serious problems. An example would be tonsillitis which in the past when untreated could cause problems with the heart valves!

Thankfully this is very rare now. Nasal congestion and ‘sinus’ issues may spread to the eye (potentially causing blindness) through the thin bone that separates it from the nose. Commonly, children can have a blocked or painful ear which may affect their hearing, reducing their attention span, affecting speech and language and causing behavioural problems too. Allergy to dust mite, pets and different plant pollen is very common.

Sneezing, itching of the eyes and nose as well as a runny or blocked nose are typical symptoms. Referral to an ear, nose and throat (ENT) surgeon for an allergy test as well as treatment for their symptoms is highly recommended. Currently, treatment using a tablet placed daily under the tongue can help cure patients with some of these allergies and in many cases it helps avoid other conditions such as asthma later on in life.

Some pointers you can use to check on your child:
1. Does your child snore?
2. Does your child have recurring colds that progress into a sinus infection?
3. Does your child always complain of headache, and/or giddiness?
4. Does you child have a short attention span?
5. Does your child sneeze?
6. Does your child always feel tired and sleepy?

Ear, Nose & Throat Cancer
There are several types of cancers that an ENT and head and neck surgeon manages. They tend to affect adults and generally men who smoke and drink although this is not always the case. Cancers of the back of the nose (Nasopharyngeal cancer, NPC) tend to affect non-smokers and drinkers of Chinese ethnicity more than other populations. These cancers can be screened for in high risk groups. They present without much warning – with pain or bleeding being uncommon symptoms. A lump in the neck, blocked nose and blocked ears with some hearing loss may be the initial complaint. Quick referral to an ENT surgeon is strongly advised to assess the back of the nose with a special video telescope known as a nasendoscope.

Biopsies and scans may be necessary thereafter. Other cancers such as tonsillar (oropharyngeal) cancer are becoming more common partly due to a viral driven pathway – the human papilloma virus (HPV). Patients may present with an enlarged tonsil, swallowing issues or a neck lump. They tend to be younger and the condition is not caused by smoking and alcohol. Thyroid cancers are commoner amongst younger women and have a good prognosis usually. Surgery is the main treatment and in some cases it is done in combination with radio-iodine treatment.

Salivary tumours are rare. They are also treated surgically as the main management option. These tumours can affect the ‘major’ glands but are more aggressive in the minor ones that are dotted all over our oral cavity and throat. Any lump that is new within the mouth or neck should therefore be investigated if it does not regress or disappear after a fortnight or so.

Hearing Loss
Hearing loss affects the young and old. Childhood hearing loss can be due to genetic causes or birth issues. Certain drugs can also cause hearing loss. The commonest causes in children tend to be less serious and usually improve and disappear as the child develops. Often, the cause is a developing Eustachian tube which is short and less angled compared to an adult. Blockage or failure to clear mucus in the middle ear results in hearing loss which can also cause ear infections. Large adenoids (lymphoid structures similar to tonsils) can act as physical barriers to the opening of the Eustachian tubes and be a nidus for infection too. Surgery can help treat these conditions and is commonly performed in recalcitrant cases.

Age-related hearing loss is becoming a global concern as research continues to demonstrate its link with dementia. Many elderly patients become socially isolated and are not provided with the right recommendation for treatment – be it hearing aids or even cochlear implants. As the hearing begins to weaken, other functions take over the hearing centre in the brain creating a situation where the hearing areas of the brain do not ever recover from. Early referral to an audiologist and ENT surgeon is recommended.

Lower your blood pressure with right lifestyle choices

BLOOD pressure (BP) continues to be an important determinant of our health and has significant implications for many diseases including stroke, heart disease, kidney damage and eye disease. Understanding how our lifestyles impact our blood pressure can help us make the right decisions in maintaining a healthy range of BP.

Normal BP fluctuation
There is a diurnal physiological variation in BP, which rises on wakening in the early morning when the person gets up, reaches a plateau during the morning, decreases slightly in the early afternoon and rises again in the early evening. The BP then decreases gradually in the late evening, drops sharply after falling asleep and is lowest during sleep at about 3am. The BP increases again by about 20 per cent between 6am and 8am, around the time of awakening. If the sleep-time relative systolic blood pressure (SBP) decline is 10 per cent or more, this sleep pattern is considered a normal dipper pattern. In the majority of normotensive persons, the decrease in BP from daytime to night time is about 10 per cent to 20 per cent.

While many may think that this is due to your internal body clock, in truth, the variation associated with the sleep wake cycle is largely influenced by mental and physical factors. Hence, in shift workers, BP is high during work at night and low during sleep in the day.

Morning BP surge
The typical physiological morning elevation in BP is more a function of activity rather a function of the time of the day. Those who remain supine in bed after waking up do not show much change in their BP, which rises rapidly only when the person gets upright. The extent of BP elevation is related to the level of physical activity. In some patients with hypertension, an exaggerated increase in BP is seen and this is termed the morning surge.

Upon awakening and getting up and commencing activities of daily living, there is a large surge in your “fight or flight” hormones, namely the catecholamines (such as adrenaline). This results in increase in heart rate, increase in BP, greater pumping action of the heart, increase in your arterial vessel tone and decrease in the calibre of the arteries.

Other awakening changes include an increase in your body steroids (cortisol) level, and “thickening” of the blood (due to increased tendency of the platelets to stick together and an increase in blood viscosity). These changes result in an increased demand for oxygen by the heart, decrease in oxygen supply to the heart and “thickening” of the blood. These changes may help to explain the increase in heart and stroke events during the morning. Analysis of combined trial data has demonstrated an approximately 40 per cent increase in incidence of heart attacks, close to 30 per cent increase in incidence of heart-related deaths and close to 50 per cent increase in incidence of stroke, as compared to other periods of the day. In addition to the morning surge, hypertensive patients tend to have no dip in BP (non-dipping) at night. The nighttime non-dipping is associated with damage to key organs (such as the heart, brain and kidney) and heart disease.

Stress and BP
As everyone knows, stress increases BP. The stress of doing housework or rushing to work in the morning may cause an exaggerated surge in morning BP and even morning hypertension. Workplace stress can also cause daytime hypertension. A study reported that more than 20 per cent of civil servants who had workplace hypertension had normal BP during health examination. Interrupted sleep results in elevated BP and may contribute to the non-dipping of BP at night. It has been shown that hospitalisation can reduce stress, resulting in lower BP in the day and reduced difference between daytime and night-time BP in hypertensives. Activities such as meditation can also lower BP effectively.

Lifestyle and BP
There is little surprise that obese individuals have higher BP values than normal individuals. The good news is that weight loss in hypertensives can result in reduction in BP. Many obese individuals have obstruction of their upper airway resulting in snoring and a condition called obstructive sleep apnoea. This decrease in oxygen delivery to the body as a result of airway obstruction during sleep is associated with an increase in nighttime BP.

During exercise, BP increases and post-exercise, it decreases. This post exercise drop is due to a relaxation of the tone of the blood vessels and usually lasts for several hours. Several studies have also shown that regular exercise lowers BP in both normotensives and hypertensives. The impact of exercise on BP is  dependent on the time of exercise, with morning exercise resulting in decrease in daytime BP and evening exercise decreasing night-time BP in non-dippers (hypertensive pattern), but not dippers (normal pattern).

Taking a hot shower usually causes a rise in BP initially, but if you are immersed in a hot bath, BP will decrease with even further decrease immediately after the bath. It will gradually return to the baseline levels after about one hour. For smokers, studies using ambulatory BP monitoring have shown that only daytime BP is elevated, and it is higher on smoking than on nonsmoking days. Therefore, chronic smoking can cause daytime hypertension.

Food and BP
It has been observed that there is a mild increase in BP during meals as a result of increased physical activity, followed by a fall after meals as a result of dilatation of the vessels in the gut in response to food consumption. This post-prandial drop in BP is minor in the young but may be more pronounced in the elderly, in hypertensives, and following a high-carbohydrate meal (as compared to high-fat meal).

The peak of the post-prandial reduction in BP is at about one hour and persists for more than two hours. It is a well-known fact that a high sodium intake increases BP and a low sodium intake can decrease it. In contrast, dietary intake of potassium and magnesium is inversely related to BP. Hence, the consumption of fruits and vegetables that are rich in potassium and magnesium may decrease BP in hypertensives. Coffee lovers may be surprised to know that consumption of coffee can transiently increase the BP by up to 10 mm Hg for about one hour. Much of this is believed to be due to the effects of caffeine on the body. Conversely, the consumption of cocoa or dark chocolate appears to be associated with a significant reduction in 24 hours’ BP.

Shedding excess weight by exercising, followed by a hot bath immersion, consumption of dark chocolate, fruits and vegetables (high in magnesium and potassium) and ending the day with stress-relieving meditation is a perfect recipe for lowering the blood pressure. In addition, reducing salt, coffee, excessive weight, smoking and stress will certainly help you achieve the ideal BP and ultimately a healthy life.

Understanding the ‘cytokine storm’ that is Covid-19

I was on vacation in Japan around Christmas when I first heard the news on CNN, of a strange virus that was causing pneumonia in a cluster of patients in  Wuhan. On reading the report on my smartphone, I felt a shiver down my spine. This was because the description of the illness resembled the “cytokine storm” of the Sars virus. The shiver down my spine was prescient; as of current writing we are in Dorscon Orange with 86 patients diagnosed, 5 in intensive care and 47 patients discharged and well.

In China, despite the heroic and unprecedented actions of locking down an entire province, the epidemic rages on. The silver lining is that the heroic actions by the Chinese have bought us some time for our local actions to take effect. So what is this “cytokine storm” that you keep hearing about? In essence when a virus attacks a host, it is like an invasion. The virus lands on a beachhead – in humans it is usually in the throat – and starts multiplying in large numbers.

When there is a high viral concentration or viral load, the virus enters the blood stream or moves through lymphatic system or via secretions, and can spread to other organs. In the case of Covid-19, it spreads deeper into the lungs where it targets a receptor called the Angiotensin Converting Enzyme receptor. Why do some patients have a mild disease while others are warded in intensive care? This is because when there is a huge viral load, the body responds massively. In healthcare workers, our immune systems are constantly challenged as we meet lots of patients daily and are exposed to the viruses or bacteria that they carry.

Our immune system is primed to deliver an overwhelming response especially in the face of a huge viral load. It is precisely this overwhelming response that may make us very ill and be warded into intensive care. So, you may not realise that our healthcare workers are under a great deal of stress during this period as our risk is way higher than the average patient.

As for the public, what should they be aware of so that they can help themselves? We know the virus is spread via droplets. This means that when someone coughs, the droplets fly through the air for about 10 feet (three metres) and settle on surfaces. The mucus in the droplet protects the virus whilst the droplet is on a surface. The mucus usually dries up in 30 to 60 minutes and the virus dies. However, when an unsuspecting person touches the surface with his hands and  then proceeds to touch his eyes, face or hair, the virus can then be transmitted. The entry to a host is usually via mucus membranes; these line the inside of our mouth, nose and eyes. As for the hair, the droplet can cling onto hair and be protected by headgear. Hence, I tell my patients that hand hygiene is of the utmost importance and they must always wash their hands before they touch their eyes, face or flick their hair.

Do we really need to use hand sanitisers for hand hygiene? The reality is that soap and water will do. We also know that the coronavirus is quickly inactivated by plain tap water. However, we must get rid of the mucus envelope that protects the virus. Hence the soap is useful and for surfaces we need to ensure that the droplets with attendant load of mucus is cleaned off. We then come to masks. The current advice is that masks are useful for preventing those who are sick from infecting those who are well. The surgical mask is enough to stop droplet transmission.

There is no need to wear the N95 mask. In fact, when you wear the N95 mask for a period of time, you will get fatigue from breathing against resistance. Therefore, we do not encourage patients with chronic heart or lung diseases to wear N95 masks routinely. For healthcare workers who wear N95 masks for a long duration, we do feel the effects of that added work of breathing at the end of the day. For those who are well, should they wear masks? The perspective is that we have 30,000 to 35,000 patients daily in Singapore with upper respiratory infections of all sorts. Maybe a couple of hundred will be pneumonia cases and Covid-19 infections will probably number less than two handfuls. The idea is to avoid crowds as we cannot contact trace a crowd of people. However, I tell my patients that life must go on and if you are meeting your family members, friends and colleagues for a meal, contact tracing is simple as you know everyone.

As for fear of the virus, this is the stuff that epidemics are made of. The difference between Sars, H1N1 and the current situation is that the feed from social media is massive. We are constantly inundated by chats, videos and articles coming through our smartphones. The fear captures and amplifies the individual’s mind and soon he or she starts to think or say things in an illogical manner. This is so obvious when you are reading the feed from chatgroups.

When we are angered by a close shave, such as when an office colleague is ordered to be quarantined, we tend to think the worst of our colleagues. When we are fatigued and tired at the end of the day from our workload and our worries about the virus, and we read of the demise of the eye surgeon in Wuhan and his pregnant wife, you think of the safety of your family and are worried sick. When we receive news or read something that reflects our emotional state, our brain tends to amplify or exaggerate the pervasiveness, degree and severity of that situation.

It is important that we trust the experts, or make sure that our news comes from reliable sources and sieve out misinformation and fake news. Please do not believe claims that the virus is airborne, conspiracy theories on the origin of the virus, need for the whole population to wear masks or false claims about the competence of health authorities and governments. In Singapore, our leadership has the institutional memory of the Sars epidemic and the dress rehearsal of the H1N1 pandemic. We also have the logistics, preparation and the physical capability in terms of isolation rooms and intensive care. Most importantly, the leadership has the political will to take tough action when necessary and the people will listen, respond and act responsibly when we need to. As we speak, the Public Health Preparedness Clinics are being activated. Do spare a thought for our healthcare workers as they strive and struggle in the days ahead, often with their own burdens, fears and tensions pushed aside for the heroic task at hand.

Feasting or fasting in the festive season?

THE Christmas festivities are barely over and Chinese New Year is already rolling round. We have just recovered from the wine and dine of the Yuletide season and are trying to shed the extra kilogrammes. The gym instructors will tell you that there is a surge in the beginning of the year in gym attendance as people grapple with added body weight and the weight of their New Year resolutions! There has been a lot of interest in intermittent fasting and low carbohydrate diets. Intermittent fasting is practised in various ways. One is to fast on alternate days or to fast two to three days in a week, while an alternative way is to reduce the number of hours in a day for eating.

Hence you have regimens such as 5:2, where you fast for two days in a week, or fasting for 14 hours daily for five days in a week and gradually increasing it over months to 16 to 18 hours daily. The whole idea about intermittent fasting is to switch the body to use ketones as a fuel as opposed to glucose. The brain needs to use glucose to power itself and in fasting states, it uses ketones. The ketones comes from fat breakdown.

Caveman situation

The idea of intermittent fasting is to recreate the caveman situation where they did not cultivate crops and had to survive from hunt to hunt. The fasting state induces ketone production or ketosis and it takes only eight to 10 hours of fasting before ketones start to rise in the bloodstream. The rise is marked when the fasting period hits 24 hours. The ketones are not just a fuel; they are also powerful triggers of certain pathways that the body needs to overcome the challenge of fasting. These pathways allow the cells to mount antioxidant response, repair damaged DNA, increase number of mitochondria that are the powerhouses of the cell, remove damage structures inside the cell and reduce inflammation.

In short, the body conserves by shutting down growth and reproduction, enhancing response to stress, favouring repair mechanisms and ensuring cell survival. When the fast is broken and the patient starts to eat, the glucose levels rise, the ketones fall, the body starts to increase protein production resulting in growth and repair. Hence the intermittent fasting regimen together with exercise results in long-term adaptations that are useful. Is intermittent fasting the panacea to our growing obesity rates globally? There is a lot of research ongoing in different areas such as intermittent fasting in cancer, degenerating illnesses of the brain, asthma, autoimmune disease, diabetes, obesity and cardiac diseases.

A lot of data is in animal studies and we are still missing long-term, megasized trials. Other issues include gorging during the feeding states as you still have to restrict your calories when you break the fast; there is also irritability, hunger and “brain fog” when your brain starts using ketones as a fuel. Thankfully, these side effects resolve within a month of starting your regimen. The other popular strategy is the use of low carbohydrate diets. A healthy diet comprises of 45 to 65 per cent of carbohydrates. A moderate carbohydrate diet comprises 26 to 44 per cent, a “low” carbohydrate diet is 10 to 25 per cent and a “very low”  carbohydrate diet is 10 per cent or less. The remaining is either protein or fat. The diets that trigger ketosis are usually low or very low in carbohydrate and high in fat. High protein intake in a low carbohydrate diet can negate ketosis.

Does a low carbohydrate diet work? The data shows that such diets do work, and they can result in increased metabolism. We are not sure how this is achieved but it could be due to changes in stress and thyroid hormones. There is also remarkable initial weight loss due to loss of body water as ketones are diuretic in nature. The loss of water is also due to lower insulin levels and the depletion of the glycogen stores in your liver. The weight loss in the short term is much better than your normal low fat diet. In the longer term, that is, six months or more, the gains between low carbohydrate and low fat diet evens out. It is also very  difficult to sustain a very low carbohydrate diet. The other thing to note is that your muscle mass may also deteriorate with low carbohydrate diets and so it is important to make sure you eat enough protein and not just fat.

I am often asked if cholesterols will be affected by a low carbohydrate diet. The response of cholesterols levels may be quite varied. If the patients eats a lot of saturated fat, the LDL or bad cholesterol will rise. Hence we usually tell patients on such diets to monitor their cholesterol profiles. The triglycerides are heavily influenced by glucose and hence such diets do lower triglycerides. In diabetic patients, the triglycerides and blood glucose levels are reduced by such diets.

Not all diets are equal

Among the low carbohydrate diets, not all are equal. For example, they found the diets that were more Mediterranean and Paleolithic in nature were useful in diabetics. Those with higher protein and lower fat were also useful. Is there a down side to such low carbohydrate diets? Well, they found that it was not helpful in blood pressure patients, it may produce changes in the gut bacteria and it is not helpful with inflammation. We believe that the arteries are inflamed, therefore triggering blockages. Is there increase in longevity if we partake in such diets? The data shows that if we substitute the carbohydrates that we forego in such diets with animal fat or protein, longevity is reduced.

However, if we use plant-based fat or protein, longevity is enhanced. In the final analysis, we have found that patients do lose weight with low carbohydrate diets and intermittent fasting. We have to be aware that such diets are not fads or trick diets. One can lose weight by cutting off a leg; “trick diets” try to get you to reduce your calorie intake by making you consume too much of one item, be it pineapples or apples or whatever. Ultimately, as we leave one festive season and move into the next, be mindful of what you eat, try to eat in moderation, control your portion sizes, maintain your exercise and enjoy the goodwill and fellowship of kin, friends and colleagues.

Dr Chong Yeh Woei
Senior Physician (Internal Medicine)
MBBS (S’pore), MRCP (UK) Internal Medicine