Oils: Cooking with vegetable oil can damage the heart

Oils: Cooking with vegetable oil can damage the heart

Omega-6 lowers cholesterol, but does not reduce heart disease
Animal fat is generally said to cause clogged arteries, heart attacks, and strokes. Can't we just replace the animal fat with vegetable oil to lower our risk of heart disease? Apparently not, because scientists have now found that vegetable oil does not lower the risk, but can actually increase it.

The researchers from the National Institutes of Health and the UNC School of Medicine found that switching from saturated to unsaturated omega-6 fatty acids resulted in lower blood cholesterol levels but no reduction in heart disease. The doctors published their study in the British Medical Journal (BMJ).

Scientists are examining data from around 10,000 subjects
The results of the new study question the cornerstones of nutritional advice. Vegetable oil does not lower the risk of heart disease, it can even increase it, the experts warn. The medical team had examined nearly 10,000 volunteers to determine the effects of a vegetable oil diet. For about 50 years, animal fat in meat, butter, cheese and cream has been considered a risk factor in human nutrition. The scientists explain that cholesterol clogs the arteries and thus leads to heart diseases.

In 1961, the American Hearth Association even recommended that vegetable oils should replace saturated fats in your diet. The World Health Organization (WHO) also recommends that saturated fats should make up less than ten percent of total energy intake. For example, full fat milk and bacon have been viewed with suspicion for decades. Pork was replaced by chicken and butter by margarine. In recent years, however, there have been more and more contradictions against the hypothesis, the researchers say.

Greater cholesterol reduction can increase your risk of heart disease
The new investigation analyzed data from a randomized controlled trial conducted 45 years ago at state psychiatric hospitals and nursing homes in Minnesota. Some of these subjects had replaced saturated fatty acids with corn oil in their diet, the doctors explain. The remaining participants had a high animal fat content, explains lead author Christopher Ramsden from the National Institutes of Health. Adding linoleic acid (a fatty acid found in vegetable oils) caused cholesterol levels to drop, the doctor adds. However, this does not increase life expectancy. A greater reduction in the level of cholesterol in the blood even increased the risk of death from heart disease.

The team also examined other studies, but was unable to find evidence to support the hypothesis that vegetable oils reduce the likelihood of heart disease.

More research is needed to design new nutrition guidelines
Further research must now determine whether similar results can be observed for all Omega-6 fats. The U.S. dietary guidelines, which were updated in January, confirmed that saturated fats should make up less than 10 percent of daily food intake. This recommendation must now be checked again, the doctors say. If blood cholesterol levels are not a reliable indicator of the risk of cardiovascular diseases, then a careful review of the evidence that substantiated nutritional recommendations is certainly justified, the scientists emphasize. (as)

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