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This question from my peers arose at the breakfast buffet during a recent medical conference in the Rockies. From the smirking in the room, it became apparent how maligned the word "cholesterol" has become. Cholesterol is not synonymous with evil, but is in fact a vital part of our existence. It is often confused with triglycerides which refer to fats that store energy. Cholesterol is actually a steroid molecule that has a waxy feel to it. It is a basic building block of hormones, like testosterone and estrogen, used in cell membranes and bile salts. The sun can convert it to Vitamin D. Most of the cholesterol we need and use is manufactured in our own livers and not derived from food as is often thought. However, cholesterol in animal derived foods and saturated fats in other foods can significantly boost the amount of circulating cholesterol. Too much cholesterol floating around becomes deposited on the sides of arteries and is a component of plaques.
Cholesterol is oil-like and has a hard time floating in the water-based environment of our blood vessels, yet it needs to be delivered to our muscles and fat tissue. We come equipped with the ability to make cholesterol-carriers called apoproteins. When cholesterol is joined to its carrier and happily floating down our arteries these complexes are called lipoproteins. Lipoproteins come in three main types according to their weight. Low density lipoprotein (LDL) is associated with atherosclerosis. High density lipoprotein (HDL) complexes are good to have and seem to protect against artery blockage. Very low density lipoproteins (VLDL) become LDL apoproteins once they unload their cholesterol.
When your doctor sends you to have your cholesterol checked, we are checking all these parameters and expect that you have been fasting for twelve hours before this blood test. We generally measure total cholesterol, HDL, LDL, triglycerides and calculate VLDL as well as the cholesterol:HDL ratio. We tend to standardize these tests to only measure what is produced by the body. The results do not tell you that your diet is fine. Some people can tolerate boosting their natural levels by eating cholesterol-rich foods and still do fine. It is interesting to witness the games we play with our cholesterol tests. I have seen people live on water for three straight days before a test hoping that I would not be able to spot the effects of the last all-inclusive ten-meal-a-day cruise they embarked on. We are attempting to identify those people who naturally produce too much cholesterol. In these persons, it has become common practice to employ statin agents which block a cholesterol-producing enzyme in the liver. The rest of us need to watch what we eat.
Cholesterol levels increase with age and weight. Some people have genetic elevations while others see elevations produced by diseases such as diabetes and hypertension. Exercise and a low cholesterol diet can improve things. It is difficult to be a wise shopper given today's misleading environment. Beware of labels that state something is cholesterol free. The statement is misleading. The food item may not be from an animal source making the statement true, but it is probably packed full of harmful saturated fats. Become a label reader, or you may want to subscribe to an informative monthly newsletter called the Nutrition Action Healthletter.
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