According to scientists, unsaturated fatty acids from the omega-6 group promote mutations and facilitate the formation of cancer cells. Their negative impact is blocked by polyphenols contained, among others in blueberries and green tea. In the case of vegetable oils, the ratio of these acids to omega-3 fatty acids is important – the more omega-3 fatty acids, the better for the heart and blood vessels. The only exception to this is omega-6 arachidic acid.
Among the unsaturated fatty acids (EFAs), omega-6 has a poor reputation among scientists. Like other fatty acids of this type, omega-6 is essential for the proper functioning of the body. The omega-6 includes, among others acids: gamma linolenic, linoleic and arachidonic. These acids are found in corn, sesame (order freshly packed white and black sesame), sunflowers, grape seeds and grape seed oils. For about a decade, it has been believed that they can only be absorbed by the body together with essential fatty acids belonging to the omega-3 group, otherwise they will outweigh their negative qualities and omega-6 will harm them instead of helping them.
Omega-6 and vitamin E can cause cancer
A team of scientists from Georgetown University, led by Prof. oncology, Fung-Lung Chung. It turned out that theoretically healthy eating using vegetable oils may not be that way. In corn, grape seed and sunflower oil, the advantage of omega-6 EFAs over omega-3 is very large. Meanwhile, in some diets, especially those intended for women, it is advised to enhance the positive effect of vegetable oils with vitamin E. However, scientists from Georgetown University have found that vitamin E in combination with omega-6 increases the rate of formation of the so-called DNA in DNA. addition compounds. These compounds enable chemical damage to DNA, i.e. mutations that sometimes cause cancer. Adducts also start to form with an excess of omega-6; vitamin E only accelerates their production.
Scientists have started working to reverse this process. As it turned out, the formation of adducts could not be completely suppressed. However, the use of polyphenols – known antioxidants, contained, among others in green tea and berries, incl. blueberries and cranberries – this process slowed down significantly. Interestingly, another strong antioxidant, antitumor, which was alpha-lipoic acid contained mainly in broccoli and spinach, almost did not work at all, although in other conditions it showed a significant ability to destroy tumor complexes.
It turned out that an excess of omega-6 facilitates the formation of liver cancer cells in particular. Scientists have found that this is because it causes the formation of new, highly mutagenic DHHedA compounds, in addition to the already known ones, designated as ϒ-OHPdG. As noted by prof. Fung-Lung Chung, it is especially dangerous, because so far mutations caused by DHHedA have been found only in rodent and human cells. The team at Georgetown University found that the polyphenols in green tea almost completely eliminate the adducts of ϒ-OHPdG and significantly reduce the amount of DHHedA, which is generally difficult to eliminate. Scientists are currently working on plant polyphenols that will also act on these adducts. However, one should not think that once we discover these polyphenols, we will reduce the risk of cancer almost to zero. We are working on liver cancer, and what works in its case may not be true for other cancers, warns Prof. Fung-Lung Chung.
In turn, a team of scientists from the University of Toronto and Western University, led by Dr. Richard Bazinet and Michael Chu, investigated the effects of omega-6 unsaturated fatty acids in vegetable oils, including those labeled as cholesterol-reducing and preventing heart disease.
This wonderful linseed oil
Corn, palm and safflower oils (used in Asian and Indian cuisine), containing a large amount of linoleic acid and a small amount of linolenic acid, were found by researchers to have no beneficial effects on the heart and blood vessels. Similarly, sunflower oil. In his case, earlier publications indicated that this oil and margarine with its significant share mean that in the rat model, in the group fed with these fats, the amount of cholesterol in the blood decreases (from 8 to 13%), but the number of deaths due to heart disease and coronary artery disease is significantly higher than in the control group or groups fed with other vegetable oils.
Other oils, such as Canola or soybean, also contain significantly more omega-6 fatty acids than omega-3 fatty acids. It is unclear whether these oils reduce the risk of heart disease or coronary artery disease, the researchers said. But rapeseed oil, linseed oil and olive oil have been recognized as oils that certainly have a positive effect on the heart, reduce the amount of cholesterol in the blood and prevent coronary artery diseases. Linseed oil is very rarely used in cooking, due to its specific smell, it is usually used as a medicine.
Meanwhile, a team of scientists from the University of Cambridge, led by Dr. Rajiv Chowdhury, challenged the dietetics principle that had been used for several years, according to which the ratio of unsaturated fatty acids to saturated fatty acids is important. Only the maximum reduction in the amount of the latter was to keep cholesterol levels low and protect against heart and coronary diseases.
Meanwhile, the Cambridge team studied 72 collective analyzes covering 600 people. patients from 18 countries around the world (most of them came from Europe and North America). As an indicator element, scientists took dietary saturated fatty acid levels, monounsaturated fatty acid consumption, and omega-3 and omega-6 unsaturated fatty acids.
They found that there was a link between the levels of omega-3 unsaturated fatty acids and omega-6 arachidic acid consumed, and a lower incidence of coronary artery disease. However, no association was found between palmitic acid and stearic acid, contained in palm oil and animal fat, and an increased risk of coronary artery disease. On the other hand, margaric acid contained in dairy products, even though it was a saturated fatty acid, significantly reduced the risk of developing coronary diseases. In turn, the risk of coronary artery disease was not reduced by additional supplementation with omega-3 acids.
According to the authors, this proved that it is not the fatty acids that are important, but their source. Even saturated fatty acids, e.g. from dairy products, can have a positive effect on the heart and coronary vessels, reducing the risk of their diseases, while supplementation with unsaturated omega-3 fatty acids over the individual needs of the body no longer plays any significant pro-health role.
Tekst: Marek Mejssner