Cholesterol is part of many of the foods that omnivores eat. It is contained only in animal foods, such as meats, eggs, and milk products. The average daily intake in the United States is 500 mg. for men and about 350 mg. for women. Women are somewhat protected from CVD during their child-bearing years by their female hormones. The new suggested maximum for cholesterol intake is 300 mg., not much more than contained in one egg yolk (275 mg.). It is probably ideal, especially for those at risk for CVD, to consume less than 150 mg. of cholesterol daily. That is the reason for the big push to a more vegetarian diet. (A strict vegetarian diet, meaning no eggs or milk products, can sharply reduce an elevated cholesterol level in one month, possibly as much as 100 mg./dl. (deciliter), or 100 mg. percent.)

Cholesterol is easy to absorb and hard to eliminate. It appears that the higher our blood cholesterol level, the greater our risk of CVD. Below 180 mg. percent poses a low risk; 180?200 mg. percent is a good range; over 200 mg. percent clearly increases our CVD risk, while over 250 mg. percent gives us a high risk. (LDL and HDL levels are also important within the total cholesterol value; see discussion below.) The average adult has a blood cholesterol level between 200 and 220 mg. percent. So there is work to be done. There is no known deficiency disease with cholesterol; many people apparently do well with little or no cholesterol intake. The body still makes it, though with certain chronic illnesses or liver impairments, blood cholesterol levels may fall to very low and probably functionally deficient levels. Cholesterol helps in tissue repair and other important functions mentioned previously.

Many doctors feel comfortable working with the total cholesterol value alone. Reducing it through smoking cessation, control of diabetes, hypertension, or obesity, dietary changes, or exercise programs can offer some security in disease prevention. It is now known that even a small increase in cholesterol can lead to a marked increase in coronary disease and heart attacks; the main research studies suggest that every 1 percent we lower a high cholesterol, we reduce our heart disease risk by 2 percent. So even mild decreases in cholesterol are helpful.

In recent years, more practitioners are using the cholesterol subfractions?HDL and LDL (VLDL may also be significant). These represent lipoproteins, or fat-protein molecules, that carry the nonimmersible fats through the blood. The high-density lipoprotein (HDL) carries cholesterol back to the liver from the bloodstream and is thought to be protective by taking the extra cholesterol out of the blood. Low-density lipoproteins (LDLs) transport cholesterol through the blood to the cells and usually comprise most of the blood cholesterol. Very low density lipoproteins (VLDLs) also keep cholesterol in circulation and may contribute to atherosclerosis. The total cholesterol/HDL ratio and/or the LDL/HDL ratio can be observed as a relative measurement of CVD risks.

Smoking, being sedentary, and consuming saturated fats in the diet lower protective HDLs. Exercise, a high-fiber diet, and alcohol increase HDL, though alcohol also produces irritating effects on the liver and vascular system, and may increase total cholesterol. Increased LDL levels can be caused by increased consumption of saturated fats and sugar, deficient levels of vitamin C or chromium, and high copper or iron levels. The various fats have different effects on cholesterol. Saturated fats lead to more LDL and VLDL. The monounsaturated fats tend to have a neutral influence on cholesterol levels, while the polyunsaturated fats tend to lower total cholesterol but may also likewise lower the good HDLs.