Cholesterol levels are at the heart of cardiovascular disease research, and opinions within the field of health care remain divided on this important issue. New information continues to emerge, illuminating the causes of high cholesterol and treatment options. As a result, "normal" levels of cholesterol are being redefined to take into account current understanding about genetic factors and lifestyle habits.
Total Cholesterol
The American Heart Association recommends that total cholesterol, the combined sum of HDL and LDL levels, be kept under 200 mg/dL as a preventive measure for cardiovascular disease. Levels between 200 mg/dL and 239 mg/dL are considered borderline and, according to statistics, levels above 240 mg/dL pose twice the risk of cardiovascular events, such as heart attack and stroke. While total cholesterol is one value that is calculated, it is by no means the only number to consider when forming an opinion on risk, or on which to base a treatment plan.
LDL
A recent study of more than 136,000 heart attack patients, as reported by UCLA Newsroom, showed that over 70 percent had levels of LDL—the "bad" cholesterol—within normal range of 130 mg/dL or below; and nearly 18 percent had LDL levels below 70 mg/dL, putting this group in the lowest risk category by current standards. Based on these numbers alone, none of these individuals would have been targeted for preventive intervention with diet or exercise modifications or medications, and, indeed, only 21 percent were taking lipid lowering medications prior to hospitalization, while nearly 50 percent had prior history of cardiovascular events.
HDL
Levels of HDL—the "good" cholesterol—by contrast, were found in the UCLA study to be lower than normal by current standards, with almost half of participants having HDL levels that put them in the high risk category. Guidelines for desirable HDL levels are set at 60 mg/dL and above, according the the website ExRx. Almost 55 percent of patients had HDL levels 40 mg/dL or under and the researchers noted an overall trend toward more people having low HDL levels, attributing the finding to increasing obesity and insulin resistance.
Triglycerides
Triglycerides are lipid molecules that the body uses as ready sources of energy and to build cell membranes via their contribution to the production of cholesterol. The American Heart Association recommends triglyceride levels in the blood be limited to under 150 mg/dL. Triglycerides levels are effected by fat in the diet and also by dietary carbohydrates, especially highly processed carbohydrates. In fact, a study reported on the website Epoch Times showed that lowering carbohydrate intake lowered triglycerides even when saturated fat consumption was not changed and without weight reduction.
Ratios
Ratios of "good" and "bad" cholesterol are becoming more important in determining normal cholesterol levels, as statistics emerge that contradict the information on absolute values—the amounts of cholesterol and triglycerides reported on a screening test. Clearly, what may be normal and low risk for one person, may indicate a need for treatment in another individual. Commonly measured ratios include total cholesterol to HDL, with an ideal ratio of under 5.0:1.0 for men and under 4.5:1.0 for women; and HDL to LDL, with ideal values under 3.6:1.0 for men and under 3.2:1.0 for women, according ExRx.
