Is cholesterol’s bad reputation deserved?

Press, 30 May 1981, Page 10

Is cholesterol’s bad reputation deserved?

Good eating

Janice Bremer

What has happened to cholesterol? r A few years ago popular opinion led us to believe that we would be better off without it if we wanted to improve the odds against developing heart disease. Cholesterol doesn't seem to be in the news any more.

Cholesterol is not an essential nutrient because it is manufactured in our bodies, or not we eat foods which contain a lot of it. ■

However it does have important functions, and can indicate how our bodies deal with fats, including some of those that we eat.

A high level of cholesterol in the blood is an important indicator of risk for coronary heart disease — New Zealand’s number-one cause of death.

Cholesterol has a reputation for clogging up the arteries. Extensive studies in the United States, Britain and some European countries agree that cigarette smoking, high blood cholesterol levels, high blood pressure, poor physical fitness, and stress, are major contributors to heart disease.

However, some populations have some of these risk factors present, but not a high rate of heart disease. The Japanese are smokers; they have high blood pressure (because of . their highsalt diet); they have stress (because they are an industrialised society);, but they have low blood cholesterol levels and a low incidence of heart disease. Those who move, from Japan to the United States develop a higher rate of heart disease.

This finding is consistent with studies from other countries, and with Professor Don Beaven’s report from Singapore last week. There he has found that an increase of heart disease, was concurrent with an'increase of fat and a reduction of starchy food in. the local diet.

Unless your cholesterol consumption is very high, normal cholesterol levels are not significantly lowered just ' by a low cholesterol diet. But high cholesterol levels can be lowered by certain diet changes. •

DIETITIAN

The balance of the dif- • ferent types of fats that we eat, and the levels of the proteins that carry these fats in the bloodstream are possibly the more important dietary factors. ‘Essential’ fats Current studies now point to a deficiency of “essential” fat as a cause of heart disease, even in those who may not have a high blood , cholesterol. People who have heart attacks have a low level of “essential” fat in their bodies, and a greater tendency for blood clotting. “Essential” fat is not manufactured in the body so it must be supplied by the diet: It comes in foods high in polyunsaturated fats. The requirements for this “essential” fat are increased by a high consumption of saturated fats, which are also usually high in cholesterol. See table I and II for the dietary sources of these -different fats.

TABLE 1 Foods with Polyunsaturated Fats (high “essential” fat) Vegetable - Amount o 1 origin fat as polyunsaturate! Cooking oil 40%.-75%. Margarine ,60% French dressing 127) Walnuts 72%. Almonds ‘ 20% Whole Wheat 65% Soyabeans 60%

TABLE 2 Foods with Saturated Fats (high cholesterol) Animal Amount-of fat as polyunsaturated Lard ‘ 10% Butter -3% Coconut 2% Cream 3% Meat fat 4% Cheddar cheese 3% . Eggs 13% If we eat less saturated fat our blood cholesterol will be lowered more than if we eat more polyunsaturated fat. As our requirement for “essential” fat is very small, the simple replacement of some saturated fat by wholegrain cereals or vegetables in our diets, will give a higher proportion of our fat as polyunsaturated. This change will cover both our need for “essential" fat and will reduce our consumption of saturated fat. Nezc’ routines Changes we need to make to increase essential fats: • Change from butter to margarine. © Use vegetable oils in place of cooking fat. © Eat less meat, but more wholegrain cereals. © Have copious fruits and vegetables. © Include legumes (dried beans) or fish regularly in place of meat. © Have nuts in place of confectionary. Changes in our arteries usually begin in 'childhood. A woman, who is breast feeding and ' has a high polyunsaturated fat diet,, produces milk which has a 'higher "essential”; fat . con-, tent. This- 'factor /'may be protective for her child. Human milk has’four to five Times the “essential”- fat content of cow’s milk. Unmodified cow's milk may be unsuitable.for infants with a : family history• of heart disease. Just as the fats, in our bodies reflect our diet, so do the bodies of animals reflect their diet.

Poultry and rabbits (and fish) eat small amounts of

plant food (therefore the fats are polyunsaturated and higher in essential fatty acids). However, when they are domesticated and fat-tened-upi the excessive food eaten is changed to saturated fat.

As farming has become more intensive, the carcases of cattle and sheep have changed because they are kept in closed paddocks, with little exercise and the available food easily digested. They become well fattened willi saturated fat. One third of the fat in wild animals is “essential” fat, whereas in domestic animals it is less than one fifth of the fat:

Once all the visible fat has been removed, and the meat is cooked without fat, most meats have a similar total fat content. The leanest meat contains about 1 teaspoon of fat in 2 medium slices (lOOgrams). This includes ham. beef, veal, pork, chicken, turkey, venison and silverside. Marbled beef and mutton have 60 to 70 per cent more fat. .

These meats all have a similar cholesterol content. The highest cholesterol-con-taining foods are organ meats, eggs, shrimps and prawns. Scientists have been able to develop meat, dairy products, and eggs of higher polyunsaturated fat content by altering the diet of animals. But it is more efficient if we feed ourselves with more plant- foods and bypass reliance on animals for our polyunsaturated fats. Other dietary factors reported to inhibit the onset of heart disease, include: eating high-fibre foods, especially legumes; vegetable protein, a daily glass of wine; less use of salt; eating garlic; hard water (contains calcium); .other; ’trace minerals; and avoidance of excessive weight.. Regular exercise is also believed to be beneficial.

A diet with' little animal fat. and largely of plant foods will ensure a low cholesterol consumption, maximal cholesterol excretion from the body, and it will have a high:? efficiency of "essential', fats