Cholesterol is a yellow fatty substance and a principal ingredient in the digestive juice bile, in the fatty sheaths that insulate nerves and in sex hormones, namely estrogen and androgen. It performs several functions such as transportation of fat, providing defense mechanism, protecting red blood cells and muscular membrane of the body. Most of the cholesterol found in the body is produced in the liver. However, about 20 to 30 per cent generally come from the foods we eat.
Some cholesterol is also secreted into the intestinal tract in bile and gets mixed with the dietary cholesterol. The percentage of ingested cholesterol absorbed seems to average 40 to 50 per cent of the intake. In blood, cholesterol is bound with certain proteins-lipoproteins, which have an affinity for blood fats, known as lipids. There are two main types of lipoproteins, a low density one (LDL) and a high density one (HDL).
The low-density lipoprotein is the one, which is considered harmful and is associated with cholesterol deposits in blood vessels. The higher the ratio of LDL to the total cholesterol, the greater will be the risk of arterial damage and heart disease. The HDL on the other hand plays a beneficial role by helping remove cholesterol from circulation and thereby reduce the risk of heart disease.
Foods can lower bad-type LDL cholesterol, raise good-type HDL cholesterol and help prevent the oxidation of LDL cholesterol that makes it more destructive to arteries. On the other hand, some foods, such as oats, are considered to reduce supplies of bile acids in the intestinal tract that otherwise would turn into cholesterol. Food antioxidants may also help keep bad-type LDL cholesterol from becoming oxidised and toxic to arteries.
Several years ago, scientists at the U.S Department of Agriculture’s laboratory at the University of Wisconsin in Madison, discovered that food substances called tocotrienols suppress an enzyme that hampers the liver’s manufacture of cholesterol. Cells needing cholesterol then suck it out of the bloodstream and cholesterol blood levels go down. Other foods create different chemicals that seem also to turn down internal cholesterol production. That is precisely how the potent cholesterol-reducing drug Mevacor (lovastatin) also works.
FOODS THAT LOWER LDL CHOLESTEROL
Almond, Apple, Avocado, Beans (dried), Carrot, Coriander seeds (dried), Fenugreek Seeds, Garlic, Grapefruit, Grape Seed OH, Ishabgul, Oats, Olive Oil, Onion, Safflower Oil, Soyabeans, Sunflower Seeds and Walnuts.
Almond, the most important of all nuts, is a highly nutritious food. It is high in monounsaturated fat, which is known to reduce cholesterol. In a research study, Dr. Gene Spiller made men and women with fairly high cholesterol, averaging around 6.24,eat lOOgrams of almonds a day for three to nine weeks. Others ate equal amounts of fat from cheese or olive oil. The average cholesterol of the almond eaters came down 10 to 15 per cent compared to that of the cheese eaters. Almonds and olive oil exercised beneficial effects, as most of the fat contained in both is chemically identical.
Apple, with its high soluble fibre called pectin, can help lower cholesterol. In a recent research, French scientists had a group of middle-aged healthy men and women add two or three apples a day to their ordinary diet for a month. LDL cholesterol fell in 80 per cent of them, and by more than 10 per cent in half of them. Good type HDL Cholesterol also went up. Interestingly, the apples benefited women more than men. One woman’s cholesterol came down by 30 per cent.
In another study, David Gee, Ph.D. at Central Washington University tested high-fibre apple waste left over from making apple juice. He had the apple fibre baked into cookies. When 26 men with fairly high cholesterol ate three apple cookies a day, instead of a placebo cookie, their cholesterol came down by seven per cent on an average. Each apple cookie had 15grams of fibre, equal to the amount in four or five apples, he says.
Most experts attribute cholesterol lowering quality in apple to pectin contained in it, although other components in this fruit also help lower cholesterol. As Dr. David Kritchevsky of the Wistar Institute in Philadelphia points out, a whole apple lowers cholesterol more than its pectin content predicts. “Something else is at work also”, he says.
Avocado is a valuable cholesterol lowering food. It has rich concentrations of the same type cholesterol lowering fat as almonds and olive oil. Research scientists in lsrail found that eating avocados, as well as almonds and olive oil for three months, cut detrimental LDL cholesterol by about 12 per cent in a group of men.
Australian cardiologists at the Wesley Medical Centre in Queensland also found recently that eating one half to one and a half avocados a day is more effective in reducing cholesterol than low-fat diet. In the test conducted by them, 15 women ate a high-carbohydrate, low-fat diet’with 20 per cent fat calories and an avocado high-fat diet with 37 per cent fat calories, each for three weeks.
The raw avocados were put in salads or spread on bread or crackers. The result was that average cholesterol came down by 4.9 per cent on the low-fat diet compared with nearly twice as much that is 8.2 per cent, on the avocado diet. Moreover, the low-fat diet also lowered good HDL cholesterol by as much as 14 per cent, but did not lower bad LDL cholesterol. Very-low-fat diets often do this. On the other hand, the avocados attacked only detrimental LDL cholesterol. Investigators noted that avocados also protected arteries against oxidative damage that makes cholesterol dangerous.