Question to expert: Is it true that omega-3 supplements are useless?
Olga Lukinskaya
RESPONSES TO THE MAJORITY OF US QUESTIONS we used to search online. In the new series of materials we ask such questions: burning, unexpected or widespread - to professionals in various fields.
It seems that everyone has already learned that vitamin supplements just do not need to drink - they are useful only to fill the existing deficit. But there are exceptions: almost everyone needs vitamin D, and a large number of women have iron deficiency. Until recently, there was no doubt about the benefits of omega-3 and omega-6 fatty acids for the heart, but this year a refutation appeared - it turned out that supplements with these substances do not actually improve the health of the heart and blood vessels. We asked an expert to tell whether omega-acids are still needed and from what sources they should be ingested.
Evdokia Tsvetkova
endocrinologist
Everyone knows that fats are different, and fats rich in unsaturated fatty acids are beneficial for the heart. In general, fat molecules resemble jellyfish or tadpoles in form: “head” is glycerin, and “tail” is fatty acids. Fatty acid molecules are not the same and differ from each other in chemical bonds between atoms. These bonds can be single or double. Fatty acids are called unsaturated, if they have double bonds, and saturated, if they are not. Depending on where in the chain the double bond is located, a special name is assigned to the fatty acid. So, "omega-3" means that it is located after the third carbon atom from the end of the "tail" of fatty acid.
In 2015, a study was conducted at Harvard University, which showed that the replacement of saturated fats in the diet with unsaturated is favorable for heart health. It is the omega-3 and omega-6 fatty acids that are an important component of the Mediterranean diet, approved by the WHO nutrition system. Recall that it implies at least three servings of fish and seafood a week and regular consumption of olive oil.
The main sources of omega-6 fatty acids (and to a lesser extent omega-3) are seeds and vegetable oils. Flax seeds, walnuts and chia, like green leafy vegetables, contain omega-3, but the most significant sources of these fatty acids are fatty fish and other seafood (especially fish grown in the wild, and not on the farm). Omega-3 fatty acids are rich in cod liver and seaweed oil, and now there are other products enriched in omega-3 (for example, eggs or pasta).
The effectiveness of the Mediterranean diet has been demonstrated more than once: it reduces mortality from cardiovascular diseases and mortality in general, and also reduces the risk of hemorrhagic stroke. In an effort to understand why this is happening, scientists realized that unsaturated fatty acids play an important role - and, naturally, they thought that it could be useful to take these omega-acids in capsules.
Everyone still recommended a diet rich in unsaturated fatty acids, but supplements with omega-3 fatty acids have been ineffective
Initially, clinical experiments confirmed this: in many of them, it was shown that fish oil supplements reduce the incidence and progression of atherosclerosis, myocardial infarction, heart failure, stroke and arrhythmia. The unambiguous mechanism of how fish oil acts is not clear - it can be a combination of anti-inflammatory, antiarrhythmic and many other effects, including a decrease in the number of other fatty molecules (triglycerides) and a change in the properties of cell membranes. In international clinical guidelines, adults were advised to eat one or two servings of oily fish per week or take fish oil daily (about 1 gram of omega-3 fatty acids per day).
But in 2018, the results of large-scale studies were published, and they turned out to be unexpected: supplements with omega-3 fatty acids did not improve mortality and cardiovascular outcomes. A meta-analysis of 79 studies was conducted in more than 112 thousand people - and it turned out that taking omega-3 in the form of supplements did not reduce mortality (neither total nor cardiovascular).
At the same time, an increase in the share of omega-3 fatty acids in the diet still had a weak positive effect, reducing the frequency of arrhythmias, myocardial infarction and coronary death. But this effect did not apply to people with important risk factors - for example, those who have already suffered a myocardial infarction. They have an increase in the content of omega-3 in food did not help reduce the risk of recurrent myocardial infarction or stroke.
It turns out that early epidemiological and observational studies have noted the benefits of omega-3 supplements for the heart, but in recent studies this has been disproved. The difference in results may be due, for example, to the fact that effective treatment is available today (both medication and surgery), in comparison with which the use of omega-acids in already existing heart diseases becomes very weak.
So, based on current data, a diet rich in unsaturated fatty acids, including fatty fish and olive oil, is still recommended for everyone, but supplements with omega-3 fatty acids have been ineffective. People with high cardiovascular risks (after myocardial infarction, with diabetes, with disorders in the lipid profile of the blood or a regular increase in blood pressure more than 140/80 mm Hg) should think about the treatment and discuss it with your doctor.
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