Red meat, cooking oil and high heat pose risks

Red meat, cooking oil and high heat pose risks

Disease culprits include heat-created compounds

MONTREAL - The wienerschnitzel was so large it hung off the plate. Topped with a sprinkling of chopped parsley and lemon juice, it was an absolute treat.

To this day, my mouth waters whenever I recall my first schnitzel experience. My aunt, who had arranged for us to come to Montreal after we'd fled Hungary during the 1956 uprising, owned the Riviera, a European style restaurant. It was there that I was introduced to the delights of a serving of veal, pounded almost paper thin, battered in flour, eggs and breadcrumbs, and quickly fried to a golden brown.

I just loved it. The Riviera is long gone, but I have learned to make a pretty acceptable schnitzel myself. But science has entered the picture and my enjoyment is now tainted by nutritional concerns. Some pretty dark clouds hang over the frequent consumption of red meat, and fried foods in particular.

The words "red meat" and "cancer" now appear in the same sentence in the scientific literature with alarming frequency and articles commonly conclude that many cancer cases can be prevented by dietary modification.

The suggested changes usually involve increasing fruit and vegetable consumption while curbing the intake of red meat and foods cooked at a high temperature. A huge European study, which enrolled almost half a million healthy men and women in the 1990s followed their health status. After about five years, about 1,300 cases of colorectal cancer had been detected and the lifestyles of these patients were then compared with those free of the disease.

The major finding was that bowel cancer was associated with an intake of red meats and processed meats. People who ate more than 160 grams of red or processed meat a day were 35-per-cent more likely to develop bowel cancer than those who ate less than 20 grams a day.

And 160 grams is not a lot. Eat a "quarter pounder" and you've got it. Chicken was not implicated and fish was associated with a lower risk of bowel cancer.

Exactly what the problem is with red and processed meats is hard to say, but it's a good bet that heterocyclic amines (HCAs) are involved.

Heating food unleashes a host of chemical changes. High temperatures allow compounds such as creatinine in meat to combine with aldehydes (glucose for example) to form heterocyclic amines, recognized carcinogens.

The higher the temperature, the longer the cooking time, the more HCAs form. Red meat consumption is also associated with prostate, stomach and pancreatic cancer, and researchers have found that women who routinely eat very well done meat face a five-fold increase in breast cancer risk when compared with women who eat meat rare or medium.

I don't know what the cooks in the Riviera used to fry my schnitzel, but it was probably some sort of animal fat. As scientists learned more about the cholesterol-raising properties of saturated fats, they pushed to replace them with polyunsaturated fats found in vegetable oils. These degraded more easily when heated and couldn't be reused as often. A remedy was found in the form of "partially hydrogenated" vegetable oils which had better keeping qualities.

But hydrogenation converted some unsaturated fats into the now notorious "trans fats," which were as bad for the heart as the animal fats.

Frying in unsaturated vegetable oils eliminates the trans fat problem but there is the emerging issue of trans-4-hydroxy-2-nonenal, or HNE.

HNE forms when polyunsaturated fats react with oxygen. Such fats are present in cell membranes and can give rise to HNE, which then can travel through the bloodstream. The bad news is that HNE has been linked with cardiovascular disease, Parkinson's, Alzheimer's, liver and kidney ailments, and even cancer.

HNE forms when polyunsaturated oils, including corn, soy and canola, are heated, especially if heated repeatedly. Those restaurant fries may be laden with HNE!

Monounsaturated fats like peanut oil or olive oil are less prone to such contamination.These aren't commonly used in restaurants so limiting fried foods when eating out is really important.

Montreal Gazette