New Evidence on Link Between Fatty Acids and Heart Disease

Current nutritional guidelines restrict the consumption of saturated fats, such as those found in butter, cream, fatty cuts of meat, among others and encourage the consumption of polyunsaturated fats (found in fish and plant sources), since the former were thought to be linked to increased risk of heart disease.

A new study conducted in March 2014 challenges this theory and finds that the evidence for these guidelines may not be definitive. It does not support high consumption of polyunsaturated fats such as omega 3 or omega 6 fatty acids in order to reduce coronary heart disease. The study results were published in the journal Annals of Internal Medicine.

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The study was led by the University of Cambridge, which analyzed the existing studies and randomized trials on fatty acid intake and risk of coronary heart disease. The results of the research do not support the guidelines, which restrict the consumption of saturated fats in order to prevent heart disease.

For the purpose of the study, fatty acid exposure included levels of fatty acid biomarkers and amount of fatty acid intake, which was estimated by diet questionnaires. Coronary disease was defined as fatal or non-fatal heart attack, angina, coronary insufficiency and sudden cardiac death.

The researchers studied data from 72 unique studies with over 600,000 participants from 18 countries. These studies considered the intake of total saturated fatty acid, total monounsaturated fatty acid, total long-chain-3 polyunsaturated fatty acid, total-6 polyunsaturated fatty acid and total trans-fatty acid intake.

Risk of Coronary Heart Disease Reduced by Dietary Polyunsaturated Fatty Acids
Dietary polyunsaturated fatty acids may reduce the risk of coronary heart disease.

They concluded that the total saturated fatty acid was not associated with coronary disease risk in the observational studies both when measured in the diet or in the bloodstream as a biomarker. They also did not find any significant relation between consumption of total monounsaturated fatty acids and increase in coronary risk. However, they found that individual subtypes of polyunsaturated fatty acids, such as long-chain omega 3 and omega 6 fatty acids were linked to heart risk differently.

When researchers looked at studies with saturated fatty acids, they found weak links between bloodstream levels of palmitic acid and stearic acid and heart disease, but it was seen that blood levels of the dairy fat margaric acid could significantly reduce heart risk.

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They also studied trials, which tested the effects of adding omega 3 and omega 6 supplements to diets. These trials reportedly did not see any benefit in reducing risk of coronary disease.

The following were reported to be some limitations to this study:

For the studies based on dietary intake, the period of assessment of diet time was unclear.
The amount of fat consumption i.e., fat consumption per day between people in the top third as compared with people in the bottom third was unclear.
The results may not be applicable to healthy subjects, since some of the studies involved people with a pre-existing health condition.

Dr. Rajiv Chowdhury from Cambridge University, who is the lead researcher said: "These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines. Cardiovascular disease, in which the principal manifestation is coronary heart disease, remains the single leading cause of death and disability worldwide. In 2008, more than 17 million people died from a cardiovascular cause globally. With so many affected by this illness, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence."

Quiz on Healthy Heart
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Thus even though the current NHS guidelines suggest that men should not consume more than 30g of saturated fat per day and women not more than 20g, the above study has shown that diets which are low in saturated fat do not lower cholesterol or prevent heart disease.

Dr. Frank Hu, a professor of nutrition and epidemiology at the Harvard School of Public Health, said the results of the study should not be mistaken as a means to eat more butter, cream and other foods, which are rich in saturated fat. He added “Looking at individual fats and other nutrient groups in isolation could be misleading, because when people cut down on fats they tend to eat more bread, cold cereal and other refined carbohydrates that can also be bad for cardiovascular health.”

Science is constantly changing. For years, we believed that saturated fat is a nutritional demon, but the current study just shows us otherwise. Till more studies are conducted to present conclusive evidence in this favor, choose what you put on your plate wisely. Remember a healthy outside starts from the inside. Eat to nourish your body. After all you are worth more than you realize!