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Your genes may put you at risk of heart disease but a healthy diet will protect you

Peer Reviewed
Randomised Control Trials
Humans 

A healthy diet has been shown to reduce the risk of various forms of cardiovascular disease even in those who have a genetic risk, according to research from the University of Reading.

In two papers published by a team from the Institute of Cardiovascular and Metabolic Research (ICMR), geneticists and nutritionists looked at whether participants who had a genetic risk of cardiovascular disease (CVD) would benefit from a modified fat diet. In both studies, the researchers found that cholesterol was positively affected by the consumption of monounsaturated fatty acids compared to other types of fats.

The first study, published in Lipids in Health and Disease (https://doi.org/10.1186/s12944-017-0606-3), investigated the difference in cholesterol levels between participants following one of three diets, either rich in saturated fatty acids (SFA), monounsaturated (MUFA), or polyunsaturated fatty acids (PUFA).

Those with a genetic risk of CVD showed a significant reduction in total cholesterol when following a MUFA diet, compared to the other two diets.

Dr Vimal Karani, a lecturer in Nutrigenetics from the University of Reading, UK, said:

“There has been an assumption in the past that your genes have already determined whether you will suffer with heart disease. Through our work combining genetic expertise and nutrition (also called ‘Nutrigenetics’) we’ve found that this simply isn’t true.

“Even though there are a significant number of people for whom their genes put them at risk of heart disease, the good news is that by replacing saturated fat with foods with monounsaturated fats such as nuts and seeds, and olive oil will protect against that risk.”

Diabetes risk for Indian populations

In the second study published in PLOS ONE (https://doi.org/10.1371/journal.pone.0188382), the team found that Asian Indian participants in the study who, when following a low fat diet, had higher levels of good cholesterol (HDL) despite carrying a risky gene variant in TCF7L2, a gene that has been consistently shown to be associated with diabetes in several populations.

Dr Vimal Karani continued:

“Recent evidence suggests that lifestyle factors influence the relationship between genes and cardio-metabolic traits in several populations; however, the available research is limited among the Asian Indian population.

“We found that individuals who consumed a low fat diet had higher levels of good cholesterol despite carrying the risky gene variant. Likewise, those who consumed a low PUFA (polyunsaturated fatty acids) diet had higher levels of good cholesterol despite carrying the same TCF7L2 gene variant.

“These findings suggest that even if the individuals are genetically predisposed to a cardiometabolic disease, they can still overcome the genetic predisposition by consuming a healthy diet.

The study looked at a random sample of 861 diabetes patients and 821 controls from an Asian Indian population in Chennai, India from the Chennai Urban Rural Epidemiology Study led by Prof V Mohan, Director of Dr. Mohan’s Diabetes Specialities Centre, Chennai, India

Dr Karani said:

“What we need to look at now are ways to identify the effect of different fatty acids on good cholesterol, and whether high fat intake may reduce good cholesterol.

“Establishing these can lead to public health recommendations and personalised nutrition advice for this Asian Indian population in order to reduce the burden of CVD.”

Full citations:

Shatwan, I. M., Weech, M., Jackson, K. G., Lovegrove, J. A. and Vimaleswaran, K. S. (2017) Apolipoprotein E gene polymorphism modifies fasting total cholesterol concentrations in response to replacement of dietary saturated with monounsaturated fatty acids in adults at moderate cardiovascular disease risk. Lipids in Health and Disease, 16 (1). 222. ISSN 1476-511X doi: https://doi.org/10.1186/s12944-017-0606-3

Bodhini, D., Gaal, S., Shatwan, I., Ramya, K., Ellahi, B., Surendran, S., Sudha, V., Anjana, M. R., Mohan, V., Lovegrove, J. A., Radha, V. and Vimaleswaran, K. S. (2017) Interaction between TCF7L2 polymorphism and dietary fat intake on high density lipoprotein cholesterol. PLoS ONE, 12 (11). e0188382. ISSN 1932-6203 doi: https://doi.org/10.1371/journal.pone.0188382

Explainer on different kinds of fats

Saturated fats are those that are usually solid at room temperature. (for instance, bacon grease or a block of cheese). The less hydrogen than carbon, the more liquid it is. Saturated fats (such as margarine, butter, and coconut oil) are not healthy to use regularly because they have been shown to contribute to CVDs. Unlike saturated fats, unsaturated fats are healthier for the heart.

Monounsaturated Fats: MUFAs are fats that are usually liquid at room temperature, but when you chill them, they turn solid. MUFAs are high in vitamin E, a vitamin and antioxidant that keeps your body healthy by protecting your cells from damage.

Polyunsaturated Fats: Like monounsaturated fats, polyunsaturated fats are liquid at room temperature, but they also stay liquid when they are chilled. When eaten in moderation, polyunsaturated fats can lower your cholesterol levels and reduce your risk of heart disease.

Polyunsaturated fats can be divided into two categories: omega-3 fatty acids and omega-6 fatty acids. Omega-3 fatty acids play an important role in normal growth and development and brain function. They also reduce widespread inflammation and decrease the risk of chronic diseases such as CVDs, arthritis and cancer.

Like omega-3 fatty acids, omega-6 fatty acids play a role in growth, development and brain function, but they also regulate metabolism, stimulate hair growth and keep the reproductive system healthy.

However, omega-6 fatty acids have been shown to promote inflammation. The primary dietary sources of omega-3 fatty acids include salmon, mackerel, halibut, tuna, herring, flaxseeds, flaxseed oil, soybean oil, canola oil, walnuts, walnut oil and pumpkin seeds. The primary sources of omega-6 fatty acids include soybean oil, corn oil and safflower oil.

Examples of different kinds of fats: