PREVENTIVE MEDECINE: CHOLESTEROL: HIGH BLOOD LEVELS
Cholesterol is thought to be important in producing heart disease. Here we look at ways of lowering blood cholesterol levels, and of preventing a high level from arising in the first place.
Prevention:
• Eat more fibre. This has an effect on cholesterol metabolism. Eating wheat bran produces bile that is less saturated with cholesterol (which is good because it tends to reduce the formation of gallstones). In a study involving men eating rolled oats (l 1/2 cupful a day), their cholesterol levels fell by 8 per cent after only three weeks. In another study cholesterol falls of 11 per cent were produced in men fed about 2 cupful of oats a day. Italian researchers took thirty-three volunteers and found that a typical meal took seven hours to pass through the small bowel, absorbing as it went 43 per cent of available cholesterol. When seven of the volunteers were given a substance that speeded up transit through the bowel (to 41/2 hours) cholesterol absorption fell to 27 per cent.
Pectin is a particularly good type of fibre for reducing transit time through the small intestine. It is found in fruit and vegetables and especially apples. Research in Maryland suggests that pectin helps lower cholesterol levels by slowing down the digestion of cholesterol-rich fatty foods. Also, there is a suggestion that pectin converts cholesterol into a form that is poorly absorbed by the body.
• Aubergines (eggplants) also reduce the amount of cholesterol absorbed from foods. An Austrian scientist fed a high-cholesterol diet to laboratory animals. If they also received aubergines they were protected from the build-up of fatty plaques in their blood vessels. The results were best when the aubergine was eaten with the fatty meal.
• Garlic has a long history of being useful in heart disease. An Indian research team looked at blood cholesterol levels in ten people who ate garlic along with a meal of bread and butter. Those, who ate the bread and butter alone had a 20 per cent rise in cholesterol but those who ate it with garlic had no such rise. Another Indian research group found that garlic prevented coronary artery disease in rabbits fed on a high-cholesterol diet. The rabbits’ cholesterol rose, but only the ‘helpful’ HDL fraction which might even be protective against atherosclerosis (narrowing of the arteries) and heart disease.
• Beans lower the dangerous LDL portion of cholesterol. A study of eight men with high blood cholesterol found that half a cupful of beans a day for three weeks reduced their cholesterol by 20 per cent. The dangerous LDL fraction went down by 24 per cent yet the protective HDL fraction was not altered. Soya beans appear to be especially valuable. A study in the Netherlands found that rabbits fed soya protein were much less likely to develop atherosclerosis than were those fed animal protein. There were dramatic reductions in their blood cholesterols in only one day. Similar findings have been reported with humans, particularly in vegetarians, who experienced significant rises in total cholesterol after eating beef for four weeks. Other researchers have found that vegetarians who don’t eat eggs or dairy products have lower LDL and total cholesterol levels than do meat eaters or vegetarians who do eat eggs and dairy products.
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