Trans fats, not saturated fats, increase risk of death

Trans fats, not saturated fats raise the risk of death and coronary disease. Saturated fats come mostly from animal products such as butter, cows' milk, meat, salmon and egg yolks. Trans unsaturated fats, or trans fats, are made from plant oils and are used in margarine and various packaged backed and snack foods.

For years everyone has been advised to cut out fats. Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear. While no one is advocating an increase of the allowance for saturated fats in dietary guidelines, there is no evidence that higher limits would be specifically beneficial to health.

Researchers reviewed 50 observational studies to see the relationship between consumption of both forms of fat and health outcomes in adults. The researchers found that intake of trans fats increase the risk of dying by 34 percent, increase the risk of dying from congenital heart disease by 28 percent, and increase the chance of developing congenital heart disease by 21 percent.

Trans fats were not, however, linked to type 2 diabetes or stroke because of inconsistencies in the data, researchers said. Saturated fats were found by the researchers to generally not be associated with any of the diseases.

The lack of a link between saturated fat did not surprise researchers, as they write in the British Medical Journal, because previous studies have not found it to be linked to colon or breast cancer. Foods high in saturated fats have been found, however, to be associated with processed foods and meats with an increased risk for cancer.

If people are told to eat less saturated or trans fats,  a better choice must be offered. But not much evidence of the best replacement choice was available. These studies suggest replacing foods high in these fats, such as high-fat or processed meats and donuts, with vegetable oils, nuts, and whole grains.

While the study at McMaster University found that saturated fats are not associated with increased risk of death, the Danish Dairy Research Foundation found that moderate amounts of butter could result in increased levels of blood cholesterol.

That study, in the American Journal of Clinical Nutrition, found that olive oil was a better alternative to butter because, unlike butter, it was not seen to cause as great an increase in blood cholesterol.