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.

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.

Watch that hidden poison in your rice

Besides seafood, rice products have the highest arsenic content. Long-term exposure to arsenic is linked to cancer

Many may be surprised that the large majority of cancers are related to environmental causes and genetic causes comprise a minority. Hence, the air we breathe, the food we eat and the water we drink – they all have a bearing on our health. Rice is a major food staple in this part of the world. Just recently, one of my patients, Mdm A, who had been eating a brand of rice which is less commonly consumed by the public but is available in high end supermarkets, was surprised that after consuming it for one year, her blood arsenic level was significantly elevated.

Arsenic in food: seafood and rice. Arsenic is a naturally occurring metal element that is present in water, air and soil, and is absorbed by some food crops as they grow. The forms of arsenic can be broadly divided into two categories; inorganic and organic. The term organic here refers to the chemical form and not the method of growing rice. While inorganic arsenic is the main toxic form of arsenic, the common form of organic arsenic (predominantly DMA) can also be toxic though organic arsenic compounds are generally considered to be of little toxicological significance.

The highest levels of arsenic are found in fish, crustaceans, and seaweed, but the arsenic is mainly organic and hence considered to have relatively minimal toxicological effect. Seafood aside, rice products have the highest arsenic content. Rice, being grown in flooded soils, is exposed to higher arsenic content in the soil and rice plants have evolved efficient mechanisms of capturing arsenic from soil solution. Hence, rice has higher levels of inorganic arsenic than other cereal foods.

Permissible levels of arsenic

Arsenic is classified by The International Agency for Research on Cancer, the European Food Safety Authority and the United States Food and Drug Administration (FDA) as a carcinogen based on the association between long-term exposure to arsenic with skin, lung and bladder cancers. Studies have linked high chronic (prolonged or long-term) exposure with adverse health effects in multiple organ systems including the stomach, kidneys, liver, and in coronary heart disease and diabetes.

Hence, in April 2016, the FDA proposed a limit of 100 parts per billion (ppb) for inorganic arsenic in infant rice cereal to reduce infant exposure to inorganic arsenic. In January 2016, the European Commission implemented regulations controlling the level of inorganic arsenic in rice products. For example, the inorganic arsenic content in rice destined for the production of food for infants and young children should not exceed 0.1 mg/kg wet weight.

Arsenic content in rice: high levels in rice bran and rice milk

The arsenic content in rice varies according to the type of soil where it is grown, the processing of the rice and the way of cooking the rice. In terms of the source of rice, in a publication in October 2015 in Environmental Science and Pollution Research journal, comparison of arsenic content from different sources of rice grains showed that on the whole, rice grains from United States of America had twice the level of arsenic of rice from Asian countries.

Generally, basmati rice is lower in arsenic than other kinds of rice whereas brown rice has a higher content of arsenic than white. Brown rice is higher in inorganic arsenic than white rice as arsenic is concentrated in the bran that is removed by milling to produce white rice. The amount of arsenic present in rice products also depends on the way the rice product is processed. Rice bran is  composed of the hard outer layers of the rice grain and it contains a large amount of fibre. Although often thought of as a healthy fibre food product, one may be surprised to know that among the rice products, the highest arsenic concentration has been found in rice bran.

Rice cakes and rice crackers are popular snacks but the arsenic content can be higher than that in cooked rice. While consuming rice milk, be aware the arsenic content is higher than the amount that is generally allowed in drinking water. In the United Kingdom, children younger than 4½ years are advised against having rice milk because of arsenic concerns. The US Environmental Protection Agency, the European Union and the World Health Organization have set a level of 10 μg per litre for total arsenic concentrations in drinking water.

Reducing arsenic in rice by soaking

Studies by Mosley and Meharg from the United Kingdom showed that by soaking the rice overnight before cooking, using a ratio of 5 times as much water as rice, only 18 per cent of the arsenic remained in the rice. The time the rice is soaked in water allows the arsenic to leave the rice into the water. The following day, drain the water and rinse the rice thoroughly with fresh water. Add 5 parts of water to each part of rice and cook till the rice is tender. Do not boil the rice till it is dry. Drain the water again and rinse the rice with hot water to get rid of the cooking residual water.

However, if the rice is cooked till there is no more water or it is cooked with a rice cooker, the arsenic is reabsorbed into the rice. If the same ratio is used for cooking but not soaked overnight, 43 per cent of the arsenic remained in the rice.

Putting arsenic in rice in perspective

Before you decide to change to a no rice diet, you should know that the lung cancer and bladder cancer risk attributable to lifetime exposure to all rice products is a small portion of all cases of these cancers, at 39 cases per million people (10 cases/million bladder cancer and 29 cases/million lung cancer). This additional 39 cases are a small fraction of the 90,000 per million people who develop lung and bladder cancer over a lifetime from all causes.

Rice is not the only source of arsenic in food. A 2014 European Food Safety Authority (EFSA) report stated that the main contributor of inorganic arsenic, except for infants and toddlers, was grain-based processed products (nonrice-based). In the ESFA report, other important contributors to the overall intake in all age classes were rice, milk and dairy products and drinking water. Food experts do not consider the consumption of rice products a few times a week a health risk, and rice continues to be a part of the international recommendations on food.

Things to note

Remember the following when making decisions on rice:

  • Do not be fooled by “organic” rice labels – they have no bearing on the arsenic content.
  • White rice has a lower content of arsenic compared to brown rice.
  • Asian sources of rice have lower arsenic content.
  • Young children below 5 years should avoid rice milk and reduce rice-based snacks.
  • Apparently “healthy” rice bran has the highest arsenic content among rice products.
  • Cooking rice the right way can minimise the arsenic to negligible levels.
  • Eating the “right” rice will have no significant adverse impact on your health. Hence, there is no need to give up your chicken rice, nasi biryani and nasi lemak!

Dr Michael Lim
Medical Director
MWH Heart Stroke and Cancer Centre
MBBS, MRCP (UK), M Med (Int Med), FAMS (Cardiology), FRCP (Edin)


Should I Eat More Fish?

Beyond just eating fish, it is also important to understand what fish to take, how it should be cooked and the quantity that should be consumed. Among the fatty acids that are present in seafood, the long-chain n-3 polyunsaturated fatty acids (P3UFAs), namely, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are the PUFAs most closely associated with heart health. The content of these 3PUFAs vary with the type of seafood, the highest content being seen in coldwater fatty fish such as salmon, anchovies, herring, mackerel, tuna and sardines. One fatty fish serving of about 100 gm per week provides the recommended daily intake of 3PUFAs. Other types of seafood such as shrimp, lobster, scallops, tilapia, and cod have lower levels of 3PUFA.

Currently, supermarkets stock a wide variety of foods enriched with 3PUFAs including eggs, peanut butter, orange juice, margarine, bread, yogurt, and milk. However, seafood remains the only class of food which has been researched extensively. Presently, the 2015-2020 Dietary Guidelines for Americans and the Scientific Report of the 2015 US Dietary Guidelines Advisory Committee recommend at least two servings per week to provide a daily average of 250 mg of 3PUFAs per day in place of other animal sources of protein.

Effect of 3PUFAS in studies

Ingested seafood-derived 3PUFAs eventually become part of the cell membranes and have been shown to have favourable physiological effects on the electrical activity of the heart cell membrane which make the cell “less irritable” and more electrically stable. Hence, adequate consumption of seafood has also been associated with positive clinical findings such as lower heart rate, slower conduction of electrical impulses between the upper and lower heart chambers, lower likelihood of abnormal recovery of the electrical activity of the heart muscle cell and less heart rate variability.

The combined effects contribute to more stable heart muscle cell electrical activity and have been associated with a lower risk of developing life-threatening heart rhythms and sudden heart-related deaths. Studies have shown that 3PUFA intake is associated with improvement in the elasticity of arterial walls and lower arterial stiffness. Seafood-derived 3PUFAs have been shown to reduce serum triglycerides (TG) concentrations in those with high serum triglycerides, most likely by increased liver removal of TG and reduced liver production of TG rich protein particles VLDL (or very low-density lipoprotein).

Preventing sudden heart death

Many studies including the Physicians’ Health Study have shown that while diets high in seafood 3PUFA have not been associated with prevention of heart attacks, there is a strong inverse association with sudden cardiac death. A possible explanation of this is the association of 3PUFA intake with reduction in life-threatening heart rhythms which can occur after a heart attack. Higher seafood intakes have been associated with greater electrical stability of the heart muscle cell, decreased risk of fatal and non-fatal ventricular arrhythmias (abnormal heart rhythm originating from the lower heart chambers), lower heart rate, and improved heart rate variability, each of which is a risk factor for sudden heart death.

It does not mean that the higher the intake of seafood 3PUFA, the lower the risk of sudden cardiac death. While there is an incremental risk reduction benefit seen in those with increasing intake of seafood, this risk reduction plateaus. Hence, while consuming up to 2 fatty fish meals per week is associated with a 50 per cent lower risk of sudden heart death compared with little or no seafood intake, no further reduction was seen with higher intake. Beyond the quantity of seafood consumed, the method of cooking also affects the benefits. While seafood 3 PUFA intake was associated with reduction in sudden cardiac death, this benefit was not seen when the fish was fried. While the studies showing a reduction of sudden heart death with seafood 3PUFA intake were mainly studies conducted in the United States, other studies done in Japanese populations have failed to demonstrate this benefit. One explanation could be that the baseline dietary seafood intake is much higher and 95 per cent of adults eat seafood more than once weekly.

Coronary heart disease

Many large studies reported that increased seafood and dietary 3PUFAs intake was associated with a lower risk of heart artery disease in a healthy cohort. In studies in which all participants in the study reported on their seafood intake, participants who consumed seafood at least four times a week had a 22 per cent lower risk of heart artery disease, compared with those who consumed seafood less than once a month. In addition, the risk reduction could potentially be greater if the seafood intake replaced processed meat. This is illustrated in two large US cohorts, where substitution of 3 per cent of total protein calories in processed meat with 3 per cent of total protein calories from seafood was associated with 31 per cent lower risk of cardiovascular death.


Results from the various prospective studies which examined the relationship between seafood 3PUFA intake and stroke have shown that intake of seafood was associated with a lower risk of thrombotic (due to occlusion of artery) stroke but has no association with haemorrhagic (due to bleeding)  stroke. One study which examined the way the fish was cooked, Cardiovascular Health Study, found that while intake of broiled and baked fish was associated with a 40 per cent lower risk of ischaemic stroke, intake of fried fish or fish sandwiches was associated with a higher risk of ischemic stroke. Recent analysis of combined studies has suggested that consumption of one serving of seafood a week was associated with a 14 per cent lower risk of ischaemic stroke compared with no or infrequent consumption of seafood.


Large fish such as shark, swordfish, golden bass, king mackerel, tuna, marlin, and orange roughy are a significant source of methylmercury. While current evidence does not show any adverse impact on heart disease, it is possible that high mercury levels can negate the effect of seafood 3PUFAs intake. In a Finnish study of 1,857 men, a 0.5 per cent increase in blood 3PUFAs was associated with a 23 per cent lower risk of sudden heart death among men with low hair mercury but this did not translate to any benefit for men with high hair mercury.

The current evidence suggests that the benefits of one to two servings a week outweigh the risks of methylmercury, especially if a variety of seafood is consumed. However, caution should be exercised against consuming multiple servings of seafood which may potentially contain mercury, as higher fish intake does not translate to further risk reduction as the benefits plateau and have a threshold beyond which there is no incremental benefit.


Current evidence supports the following conclusions:

* Consumption of non-fried seafood with high 3PUFA, one to two times per week is associated with a reduction in the risk of sudden heart death, heart artery disease and ischaemic stroke;

* The beneficial effects of seafood 3PUFA peaks at about 250mg of seafood intake per week and higher intakes are generally not beneficial or harmful.

* There may be further beneficial risk reduction if the seafood is substituted for unhealthy meats such as processed meats.

Coldwater fatty fish such as salmon, anchovies, herring, mackerel, tuna and sardines have distinct benefits Should I eat more fish? The long-chain n-3 polyunsaturated fatty acids (P3UFAs), namely, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are the PUFAs most closely associated with heart health.


Dr Michael Lim

Medical Director, MWH
Heart Stroke and Cancer Centre
MBBS, MRCP (UK), M Med (Int Med), FAMS (Cardiology), FRCP (Edin)


Are fish oil supplements good for heart?

Are fish oil supplements good for the heart?

Their role in today’s medical context is still not clear

A very common question asked of me by patients is, “Should I consume fish oil supplements?” The fish oil supplements referred to are those containing the omega-3 poly unsaturated fatty acids (PUFA), namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

In this article, recent scientific data will be reviewed to help shed some light on this topic. The scientific data in this article refers to studies on fish oil supplements in the form of capsules and not fish oils from dietary seafood. Firstly, is fish oil supplementation useful for those with no pre-existing heart disease? In the general population for those without pre-existing heart disease, there is presently no evidence that consumption of omega-3 PUFA supplements is beneficial. Even for those with diabetes mellitus or prediabetes, none of the well-designed randomized controlled trials (RCTs) have been able to demonstrate that consumption of omega-3 PUFA supplements can prevent cardiovascular events (heart attacks and strokes).

Secondly, is fish oil supplementation useful for those with no known heart disease, but who were considered at high risk of heart disease on the basis of the presence of disease in other arterial sites such as stroke, limb arterial disease, diabetes mellitus, or hypercholesterolemia?

Overall, the data from RCTs is mixed although the majority of co-authors of the April Omega-3 Polyunsaturated Fatty Acid (Fish Oil) Supplementation and the Prevention of Clinical Cardiovascular Disease Science Advisory from the American Heart Association concluded that treatment is not indicated, a minority of co-authors concluded that treatment of these patients is reasonable.

Can fish oil supplements prevent heart disease and sudden death in patients with heart artery disease?

There are five large RCTs and other smaller RCTs which have been performed to evaluate the effects of omega-3 PUFA supplementation on clinical cardiovascular events in patients with pre-existing heart artery disease. Taken together, the cumulative findings from RCTs suggest that omega-3 PUFA supplements may reduce incidents of heart artery disease death, possibly through a reduction in sudden death during a heart attack. However, fish oil supplementation does not prevent future heart attacks. Hence, it is considered that treatment with omega-3 PUFA supplements is reasonable for secondary prevention of death from heart artery disease.

If your heart pump is weak, current data suggests that omega-3 PUFA supplementation may reduce heart failure-related hospitalizations and death. This conclusion is based on one RCT, and more studies will help to provide more understanding in the future.

However, before you start loading yourself up with large amounts of fish oils, you should be aware that the benefit of fish oil supplementation have decreased over time.

While earlier studies have shown a large reduction in sudden cardiac death, later studies have shown no benefit. This discrepancy may be due to a few factors. Firstly, the relationship between fish oil supplementation and sudden cardiac death is not a linear relationship. In other words, it does not mean that the higher the quantity of fish oils consumed, the lower the risk of sudden cardiac death.

Therefore, in more recent years with more public educations, there has been increasing intake of fish oils. It may be possible that patients included in the more recent trials have already been consuming sufficient amount of dietary fish oils (for, example, at least one to two weekly servings of fatty fish) so that additional fish oil supplementation would produce little or no incremental reduction in cardiac death.

Secondly, medical treatment of heart disease has improved significantly over the years and with optimal medical treatment with current drugs, it may be possible that fish oil supplementation has little benefit whereas fewer patients in earlier trials received cholesterol-lowering medication or had angioplasty or surgery after a heart attack.

Thirdly, given the improvement in medical treatment of heart disease over the last two decades, it has required a much larger cohort of patients to be included in trials to be able to detect the lower incidence of death from heart artery disease. Compared to post-heart attack patients 20 years ago, the likelihood of sudden cardiac death following a heart attack in present day patients is very much lower.

Hence, it is difficult to have a large trial, given the much lower incidence of sudden cardiac death presently, which is able to detect any potential effect of fish oil supplementation on sudden cardiac death.

What this means is that for those patients with heart artery disease who received optimal medical therapy in today’s medical context, the role of fish oil supplements is not entirely clear. However, results of ongoing trials may provide an answer in the near future.

Can fish oil supplements prevent stroke?

For healthy individuals with no prior stroke, there is currently no evidence that the consumption of omega-3 PUFA supplements can prevent strokes. There is currently also no RCT that has examined the effects of omega-3 PUFA supplements on cardiovascular events, either stroke or heart disease, among patients with a  previous stroke.


The benefits of omega-3 PUFAs in reducing sudden cardiac death is seen in those with a recent heart attack. It is believed that the mechanism is mainly through stabilizing the electrical milieu of the heart muscle cells in the context of a recent heart attack and hence reducing the likelihood of life-threatening heart rhythms.

In a heart attack, there is damaged heart muscle and also heart muscle which is not getting adequate blood flow as a result of occlusion of the heart artery. This causes the affected heart muscle cells to be electrically unstable and this may result in the occurrence of life-threatening heart rhythms originating from the damaged muscle.

It is believed that fish oils work by making the covering membrane of the affected heart muscle cells less irritable and decreases the likelihood that life-threatening heart rhythms may develop. The mechanism of reducing cardiac death by fish oil consumption is not due to effects on atherosclerotic (vascular degeneration) progression of the heart artery, plaque (cholesterol deposits in the wall of the artery causing narrowing) stability, plaque rupture, or the development of a blood clot which occludes the narrowed heart artery segment.

Practical measures

If you are healthy, there is no benefit in fish oil omega-3 PUFA supplements. Even if you have pre-existing diabetes or prediabetes but have no known heart disease, there is no evidence that consumption of fish oil omega-3 PUFA supplements can help.

For those with no known heart disease but are considered at high risk for heart disease on the basis of the presence of disease in other arterial sites such as stroke, limb arterial disease, diabetes mellitus, or hypercholesterolemia, although the majority view is that it is not indicated, there is a small dissenting minority which holds the view that it is reasonable to consume fish oils.

If you had a recent heart attack or have heart failure with reduced heart pump function, omega-3 PUFA supplementation may be reasonable. However, if you are taking omega-3 PUFA supplementation to prevent a future stroke, there is currently no evidence to support it.

If you should decide to take fish oil omega-3 PUFA supplements, it is best to take those with high EPA and DHA content.

Business Times
31 August 2019

Self-Assessment for Heart Disease Test

Early detection prevents complication such as heart failure, stroke, kidney disease and artery disease. Heart disease is 1 of the top leading cause of death worldwide and affects not only the heart but other major parts of the body. Early detection prevents complication such as heart failure, stroke, kidney disease and artery disease.

Heart (Cardiovascular) Screening

Heart disease is a broad term that uses to describe a range of diseases of the heart and blood vessels. Heart disease is often used interchangeably with cardiovascular disease.

Why is cardiovascular screening important?

Cardiovascular disease begins with damage to the body from lifestyle factors like smoking, physical inactivity and an unhealthy diet. This progresses to the development of high-risk diseases such as obesity, high blood pressure and diabetes.

Screening identifies those at risk of future cardiovascular events of the heart and other major body organs. It also identifies those with modifiable risk factors, which are reversible and reduce one’ s risk of developing cardiovascular disease.

Who should go for the screening of cardiovascular risk factors?

  • Every adults aged 18 years and above should go for the screening of cardiovascular risk factor
  • Patients with diabetes, high blood pressure
  • Long-standing kidney disease patients

the above are those who are having a higher risk for cardiovascular disease and should be screened regularly based on their doctor’s advice.

Cardiovascular Risk Assessment

What is the global cardiovascular risk assessment?

Global cardiovascular risk assessment involves assessing a patient’s total cardiovascular risk rather than just assessing risk factors (high cholesterol, blood pressure, diabetes or obesity) in isolation.

The best known global cardiovascular risk assessment tool is the Framingham Risk Score (FRS). Based on the FRS adapted for local use, the risk for an asymptomatic individual is classified as:

  • Low-risk corresponding to <10% risk of vascular events* over a ten-year period
  • Intermediate-risk corresponding to 10-20% risk of vascular events over a ten-year period
  • High-risk corresponding to >20% risk of vascular events over a ten-year period

*These vascular events include heart attack and coronary death.

It should be done every five years starting from the age of 18 years. For individuals at risk but who have no symptoms, the assessment is followed by advice on making certain lifestyle changes such as cutting back on cigarettes, eating healthy foods and exercising regularly and, where appropriate, medicines are given to treat high blood pressure, high lipids and diabetes. Individuals at low risk should continue to lead a healthy lifestyle. More frequent assessment is recommended for those who are diabetic, chronic smokers or obese.

How to calculate the ten-year coronary artery disease risk?

It is calculated based on:

Smoking status
Total and High-Density Lipoprotein (HDL) or good cholesterol level
Systolic blood pressure

Additional Screening Tests

What additional screening tests may be needed following global cardiovascular risk screening?

These additional tests may be needed for cardiovascular evaluation of individuals moderate and high risk without any symptoms.

  • Resting Electrocardiogram (ECG)
  • Exercise Treadmill Test
  • Coronary artery calcium score
  • Cardiac stress imaging (Stress Echocardiology)
  • CT Coronary angiography
  • Carotid intima-media thickness

When should screening for body mass index (BMI), waist circumference, high blood and high cholesterol be done?

Pre-exercise Screening

It helps identify those at risk for the cardiovascular event during exercise. The questionnaire below recommended for safety reasons before participating in any physical activity.

Physical Activity Questionnaire (PAR Q) can be obtained from HPB (

Follow-up on the Results of Screening for Cardiovascular Disease and Risk Factors

Discuss the result of your screening with your doctor and know what you can do to live a healthy lifestyle as well as ways to prevent and treat your medical conditions.

Table of reference – Live a healthy lifestyle

What you can do Recommendations
Healthy eating Eat five to seven servings of rice and alternatives daily (of which two to three servings should be wholegrain products)

Eat two servings of fruits and two servings of vegetables daily

Eat two to three servings of meat and alternatives daily (of which half a serving should come from dairy or other high calcium products)

Use fats, oils and salt sparingly to flavour food

Drink six to eight glasses of fluid (1.5 to 2.0 litres) daily

Maintain a healthy weight Target to have your BMI between 18.3 to 22.9 kg/m2

Keep your waist circumference equal or less than

80 cm for women

90 cm for men

If you are overweight, aim to lose only 0.5 kg per week.

A slow and steady weight management is healthier and easier on the body

Engage in regular physical activity If you are not exercising regularly, start today with ten minutes of brisk walking and build up as your physical fitness improves. You will enjoy the better health that comes with regular exercise

Target to exercise regularly e.g. brisk walking 30 minutes a day five days a week, or a pedometer reading of 10,000 steps a day

If you enjoy doing other exercises, be regular in doing them

Cut back on cigarettes See your doctor if you need help to quit smoking or to discuss more about it
 Limit alcohol use Avoid alcohol bingeing

Ask your doctor s advice on setting the limits on alcohol consumption

Table of Reference – Prevent your medical conditions

What you can do Recommendations
Keep your cholesterol levels in check Desirable levels are:

Total Cholesterol Less than 5.2 mmol/L (200 mg/dL)
HDL-cholesterol Equal or greater than 1.0 mmol/L (40 mg/dL)
LDL-cholesterol Less than 3.4 mmol/L (130 mg/dL)
Triglycerides Less than 2.3 mmol/L (200 mg/dL)

Check with your doctor the levels to set for yourself

Keep your blood pressure levels in check Normal blood pressure levels are:

Systolic BP Less than 130 mm Hg
Diastolic BP Less than 80 mm HgCheck with your doctor the levels to set for yourself

Keep your blood sugar levels in check Optimal (target goal for majority of patients) are:

HbA1c 6.5 7.0%
Pre-meal glucose 6.1 8.0 mmol/L
Two-hour post-meal glucose 7.1 10.0 mmol/L

Check with your doctor the levels to set for yourself

Take your medications regularly Take your medicines regularly even if you feel well

Check with your doctor on the targets of control if they are not optimal

Go for regular monitoring if you have chronic medical conditions You need regular monitoring if you have high cholesterol levels, high blood pressure or diabetes


Keep up to date on your screening appointments for you and your family using our MWH Medical Mobile Apps.

Download MWH Mobile Apps through Apple or Android Store.

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