Fish oil lowers the risk of cardiovascular disease and early death

– and the amount you consume matters

Fish oil contains the long-chained omega-3 fatty acids, EPA and DHA, that have a number of essential functions. Although it has been known for decades that fish oil lowers the risk of cardiovascular disease and early death, study results have been conflicting. Now, a large British population study of over 400,000 people confirms that regular consumption of fish oil supplements has a positive effect on the cardiovascular system and contributes to improved quality of longevity. The scientists also address that the quantity of fish oil may be determining for your health.

Omega-3 fatty acids are essential. Our cell membranes contain the two types called EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) that have a host of physiological functions. Oily fish and fish oil supplements contain these two types of omega-3 fatty acids, which are much easier for the body to utilize (than other omega-3 sources). The omega-3 fatty acids work in a biochemical interplay with the omega-6 fatty acids, and their type and the balance between them are vital. If we get too little omega-3, it sets the stage for cardiovascular diseases and many other lifestyle diseases by way of different mechanisms.

The design of studies is determining for their outcome

The new British study, which is published in British Medical Journal, refers to a number of studies of fish oil and cardiovascular disease, including the large VITAL study that showed that supplementation with fish oil and vitamin D is associated with a significantly lower risk of heart failure but failed to show a significant effect with regard to the risk of cardiovascular disease. The scientists behind the new study, however, criticize the design of the VITAL study and a number of other factors that could have affected the clinical outcome, for instance the amount of fish oil and other limiting factors.
For the new British study, the scientists recruited 427,648 people aged 40-69 years from different parts of England, Scotland, and Wales. None of the participants had been diagnosed with cardiovascular disease or cancer. Using touch-screen questionnaires and interviews, the scientist collected information about the participants’ fish oil consumption. Also, they took blood samples and measured other things. They adjusted for sociodemographic factors such as age, gender, ethnicity, place of residence, and income level. Furthermore, lifestyle factors like smoking and drinking habits, BMI, physical activity, diet, chronic diseases (including hypertension and diabetes), use of medicine and nutritional supplements were recorded. The new British study is therefore much more comprehensive than earlier studies.

Fish oil lowers the risk of cardiovascular disease by means of several mechanisms

Of the 427,648 people that took place in the new study, 133,438 of the participants (31.2%) reported to consume fish oil regularly. The study was conducted in the period between 2006 and 2010 and was followed up in 2018. It showed that regular consumption of fish oil supplements is significantly associated with a lower risk of cardiovascular disease, cardiac failure, and early death (all-cause mortality). This association was independent of risk factors like age, gender, ethnicity, income level, BMI, fruit and vegetable consumption, physical activity level, use of medicine and other factors that may skew the outcome. It also appeared that the intake of fish oil supplements had the largest effect on those participants who already had slightly elevated blood pressure.
The study supports earlier studies, and the scientists underpin that the quantity of fish oil consumed may have a determining effect on the prevention of cardiovascular disease and other lifestyle diseases. Also, they refer to other studies that take this into account. The scientists also address the different mechanisms through which fish oil improves the cardiovascular system and our health, including:

• Blood viscosity
• Anti-thrombotic effect
• Effect on blood pressure
• Effect on heart rhythm
• Triglyceride-lowering
• Effect on endothelial cells that line the blood vessels
• Anti-inflammatory effect

The scientists did point out that their study has certain limitations, as they have not looked into how much fish oil each participant has consumed and for how long they have been supplementing. It can also be difficult to determine if the results are the effect of healthy living or taking fish oil. Still, the study concludes that regular use of fish oil supplements lowers the risk of cardiovascular disease and early death in the general population.

Fish oil supplementation and finding the right dose

According to the health authorities, the intake of omega-3 fatty acids should be at least 2.5 – 3.0 grams daily. Look at the package and study the label to find out how much omega-3 and EPA/DHA each capsule contains. Fish oil based on free fatty acids has the highest bioavailability, and it is also important to choose a supplement that is within the threshold values for peroxide count and environmental toxins.

References:

Zhi-Hao Li et al. Associations of habitual fish oil supplementation with cardiovascular outcomes and all-cause mortality: evidence from large population based cohort study. BMJ 2020

Hemant Mahajan et al. Serum Long-chain n-3 polyunsaturated fatty acids and aortic calcification in middle-aged men: The population-based cross-sectional ERA-JUMP study. Nutrition, Metabolism & Cardiovascular Diseases. 2019

Magnus Bäck. Omega-3 fatty acids in atherosclerosis and coronary disease. Future Science OA. 2017

Tufts University, Health Sciences Campus. Consumption of omega-3s linked to lower risk of fatal heart disease. Science Daily 2016

https://www.sundhed.dk/sundhedsfaglig/laegehaandbogen/generelt/tilstande-og-sygdomme/diverse/omega-3-fedtsyrer/