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A CLOSER LOOK AT THE CHOLESTEROL ISSUE
Nita Bishop, Clinical Herbalist
Cholesterol levels have become the source of much national anxiety, even though cholesterol is one of the most valuable substances in the human body. Over the past few years the amount of cholesterol information bombarding the public has grown exponentially. New receptor proteins have been identified and research is opening doors to help us understand why "good" cholesterol is good and "bad" cholesterol is bad.
Cholesterol is a fat-like alcohol that travels through the bloodstream transported by the lipoproteins, LDL (Low-Density Lipoproteins) and HDL (High-Density Lipoproteins). Research suggests that high cholesterol levels interact with oxygen in the body to produce an excess of oxygen-free radicals. These free radicals interfere with the production of nitric oxide, a gas produced in the body which causes widening of the blood vessels. Less nitric oxide production results in less flexible blood vessels, or "hardening of the arteries."
The majority of information regarding cholesterol focuses on lowering serum cholesterol to "acceptable" levels by increasing HDL, the so-called "good" cholesterol, and diminishing the LDL, the so-called "bad" cholesterol, fraction.
Oxidative modifications of LDLs are also recognized as one of the major processes in atherogenesis. The concept of "good" and "bad" cholesterol arises from the way HDL removes LDL cholesterol from the tissues and transports it back to the liver for excretion as bile, thus eliminating the free radicals that inhibit nitric oxide production. In addition, some scientists theorize that HDL may actually prevent fatty deposits from clogging the blood vessels.
The standard definition of high blood cholesterol is anything in excess of 200 mg/dL, although many doctors are now citing 180 mg/dL as the maximum. An estimated 97.2 million, or 52.1%, of American adults have cholesterol levels over 200 mg/dL. There appears to be a connection in certain populations to high or low cholesterol. Norwegians with high cholesterol levels also report cardiovascular disease as the leading cause of death. Asians, in contrast, overall have inherently low cholesterol levels.
Longevity: Conflicting Reports
In a more recent study in LANCET there was a surprise finding: the higher an individual's cholesterol, the longer the person may survive. Starting in 1986, an ongoing study of 724 males and females aged 85 and older in the city of Leiden, Netherlands were monitored for ten years. By 1996, 88 percent of the participants in the study had died. However, the overall conclusion of this study shows that the lower cholesterol group experienced a higher death rate from cancer and infections. In a correlating and more recent study also done by another group in Netherlands, mice were injected with large quantities of pneumonia-causing bacteria and actually survived due to higher concentrations of low-density lipoprotein cholesterol. It appears that the so-called "bad" cholesterol bound up the poison produced by the bacteria, thus facilitating its "detoxification." This raises the question of whether increasing HDL and lowering LDL is perhaps too simplistic of an approach. Indeed, as Udo Erasmus states in the title of his book, there are "Fats that Kill and Fats that Heal." All fats are not bad. People who restrict their fat intake to 10 to 12 percent often deprive themselves of essential fatty acids, which are crucial to proper cellular metabolism and hormone synthesis. Obtaining the proper balance of HDL and LDL fats may be a more healthful approach than simple reduction of fat intake.
Where do free radicals come from?
Essential to understanding the chemistry of free radicals is the role played by oxygen. The simple act of breathing in oxygen to produce ATP (energy molecules) for use in our metabolism results in the production of free radicals. So, one source of free radical production is the oxidative metabolism involved in the body's production of energy. A second source of free radicals is found in certain types of white blood cells (phagocytic cells). These cells are responsible in part for destroying unwanted microbes and other infectious invaders. One way in which these cells achieve their destructive ability is by the production of free radicals. This demonstrates both the dangerous power of free radicals as well as their practical utility within the body.
There are two sources of cholesterol in the body, food and synthesis by the liver. The average American ingests between 300-500 mg of cholesterol per day from dietary eggs, dairy products, organ meats, beef, and pork. Even without the dietary intake of cholesterol containing foods, our bodies are sufficiently balancing the cholesterol ratios at the level of the liver. In fact, most of the cholesterol the body needs (2000 mg per day) is synthesized by the liver, which is used (in part) by the body for hormone production and lipid metabolism. For many years, epidemiological studies provided strong evidence that lowering elevated cholesterol levels reduced the risk of heart disease. However, recent evidence suggests other important factors are involved. |