Cooking oils with vegetable oil can damage the heart

Although lowering the level of cholesterol, omega-6 does not reduce heart disease
Animal fat is generally said to cause clogged arteries, heart attacks and strokes. Can not we simply replace the animal fat with vegetable oil to reduce our risk of heart disease? Apparently not, because scientists have now found out that vegetable oil does not lower the risk but can even increase it.

The researchers from the National Institutes of Health and the UNC School of Medicine found in their study that although the change from saturated to unsaturated omega-6 fatty acids leads to a lower blood cholesterol level, no reduction in heart disease is observed. The physicians published their study in the journal British Medical Journal (BMJ).

It has long been claimed that animal fats are very unhealthy and should be replaced as much as possible with vegetable oils. Physicians have now discovered that while plant oils lower cholesterol levels, they can also increase the likelihood of heart disease. (Image: fovito / fotolia.com)

Scientists examine data from about 10,000 subjects
The findings of the new study challenge the cornerstones of nutritional counseling. Vegetable oil does not reduce the risk of heart disease, it can even increase it, the experts warn. The physicians had studied nearly 10,000 subjects 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. It has been suggested that cholesterol clogs the arteries and causes heart disease, the researchers explain.

In 1961, even the American Hearth Association recommended that plant oils should replace saturated fats in the diet. The World Health Organization (WHO) also recommends that saturated fats should account for less than 10 percent of total energy intake. For decades, for example, full-fat milk and bacon were viewed with suspicion. So pork was replaced by chicken and butter by margarine. In recent years, however, there were more and more contradictions to the hypothesis, say the researchers.

Greater cholesterol reduction can increase risk of heart disease
The new study analyzed data from a randomized controlled trial that was conducted 45 years ago at state mental hospitals and nursing homes in Minnesota. Some of these subjects had replaced saturated fatty acids with corn oil in their diet, explain the physicians. The rest of the participants fed on high levels of animal fat, explains lead author Christopher Ramsden of the National Institutes of Health. The diet of linoleic acid (a fatty acid found in vegetable oils) caused cholesterol levels to drop, the physician adds. But that does not increase life expectancy. A greater reduction in blood cholesterol even increased the risk of death from heart disease.

The team also looked at other studies, but could find no evidence to support the hypothesis that plant oils reduce the likelihood of heart disease.

Further research is needed to design new dietary guidelines
Further research is now required to determine whether similar results can be observed for all Omega-6 fats. Updated US dietary guidelines in January affirmed that saturated fats should account for less than 10 percent of daily food intake. This recommendation must now be controlled again, say the doctors. If blood cholesterol is not a reliable indicator of the risk of cardiovascular disease, then a careful review of the evidence supporting dietary recommendations is warranted, scientists point out. (As)