You're right about trans fats - but high cholesterol needn't be bad

By Prof Rod Bilton and Dr Larry Booth, of the School of Biomolecular Sciences, Liverpool John Moores University, are authors of Get Healthy, Beat Disease (THE GUARDIAN, 03/10/06):

Alex Renton's article on trans fats was excellent, but further to his comments, we believe there is overwhelming evidence to support the case for banning plant derived trans fats from all foods (Grease is the word, September 27).

Trans fats can be considered cumulative poisons: they are only slowly broken down by the body and are difficult to excrete - this means they build up in our arteries and cell membranes.

A recent scientific study demonstrates this with the finding that up to two-thirds of fat found in arterial plaques at autopsy in heart attack sufferers is trans fat. Trans fats are also particularly harmful to diabetics as they interfere with insulin receptors that are responsible for control of blood sugar. It has also been proven that consumption of trans fats increases the ratio of "bad" cholesterol in the blood, which is associated with an increased risk of heart disease, diabetes and obesity. A worrying quality of trans fats is that their dangerous health effects take time to develop and are hard to detect until a disease condition arises - and we've all been eating these fats every day for years!

An extensive literature review for our book Get Healthy, Beat Disease, revealed some highly alarming misconceptions regarding the consumption of saturated fat.

Contrary to popular opinion, total blood cholesterol is no longer considered an accurate indicator of heart disease risk. The Framingham heart study, conducted over 50 years, was unable to establish a link between total blood cholesterol and heart disease. In fact, 40% of patients suffering heart attacks have "low" total blood cholesterol.

It is becoming apparent that the ratio of "good" cholesterol to "bad cholesterol" in the blood gives a far better indication of heart disease risk. And eating natural saturated fats, as part of a calorie-controlled diet and exercising regularly, can actually improve your good blood cholesterol.

Better still, a far more accurate indication of heart disease risk can be achieved by measuring Lipo protein A, homocysteine and C reactive protein levels in the blood. The Framingham study also revealed that Lipo protein A was the component of "bad" cholesterol which sticks to the artery walls.

Total blood cholesterol receives massive publicity and has become almost a national obsession. We have reached a stage where some physicians are recommending statin therapy for healthy middle-aged subjects. This is an extremely questionable alternative to healthy diet and exercise: some statins have very toxic side effects and have been withdrawn from the market; and other anecdotal evidence from statin users indicates a rapid loss of energy and disinclination to exercise.

Junk food is unhealthy, in fact, because of the high levels of sugar, refined carbohydrate and trans fat it contains. Sugar and refined carbohydrate have been found to raise blood cholesterol, particularly "bad" cholesterol, and trans fats have been seen to do the same. Eating this kind of rubbish and not exercising will really increase your chances of obesity, heart disease, diabetes and cancer.