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A CLOSER LOOK AT THE CHOLESTEROL ISSUE
Nita Bishop, Clinical Herbalist
More Cholesterol-Lowering Herbs
Milk thistle (Silybum marianum) is well known for its high hepatoprotective capabilities in xenobiotic injury (in amanita mushroom poisoning and carbon tetrachloride toxicity). It exerts antioxidant and membrane stabilizing activities, attributes important for liver secretion and uptake of plasma lipoproteins.
Inhibition of HMG CoA reductase in vitro has been demonstrated with therapeutic application of milk thistle, implying its possible direct influence on liver cholesterol metabolism. Milk thistle can be compared to probucol, an antioxidant hypocholesterolemic drug. In contrast to probucol, milk thistle caused an increase in high density lipoproteins and a decrease in liver cholesterol content, both additional benefits. In addition to its anticholesterolemic effect, milk thistle partially prevented the HCD-induced decrease in liver-reduced glutathione, an endogenous antioxidant.
The inhibition of ACAT (Acyl-CoA, cholesterol acyltransferase) has become important for the prevention and treatment of hypercholesterolemia and atherosclerosis. ACAT plays a role in the metabolism of cholesterol, including intestinal absorption of cholesterol, hepatic production of lipoproteins, and the deposition of cholesterol esters which accumulate as lipid droplets in macrophages and eventually form "foam cells" in atherosclerotic lesions. Although a large number of synthetic and microbial ACAT inhibitors have been reported, certain inhibitors have not yet been used clinically because of various side effects including hepatic toxicity. Safe and effective ACAT inhibitors have been isolated from the hairy roots of Panax ginseng and a Chinese herb known as Magnolia obovata. In one study, the extract leaves of Magnolia obovata inhibited rat liver ACAT by 62% ug/mL.
Highlight on Essential Fatty Acids (EFAs)
Fish oil is one of the few substances known to lower concentrations of triglycerides or fatty substances that pose a cardiovascular risk. Many physicians have been reluctant to advocate consuming fish oil in large quantities because it increases the proportion of cholesterol shuttled through the blood in LDLs, which contributes to heart disease. According to Edward Siguel, M.D., PhD, the principal author of EFA research applied to cholesterol, EFA abnormalities are a cause of acquired (not genetic) atherosclerotic disease through their effects on membrane function. He recommends "bringing the fatty acid profiles of patients with high cholesterol closer to those of healthy people preceding any decisions for drug therapy."
Dr. Siguel's research leads to a new treatment for abnormal cholesterol ratios, a treatment that is substantially different from the one proposed by the AHA and NIH. The NIH recommends decreasing intake of saturated fat and increasing intake of both carbohydrates and monounsaturated fat. Dr. Siguel recommends that people achieve ideal weight, if necessary by reducing caloric intake from all sources. He has stated that very low-fat diets may be counterproductive for many patients who have no EFA reserves stores in their bodies. EFAs are essential. Eating a diet that tends to correct fatty acid abnormalities may lead to substantial revisions in the way abnormal cholesterol ratios are treated today and may improve quality of life and life expectancy, as well as lowering health care costs. Increasing the rate at which cholesterol is degraded (converted into bile acids and steroid hormones) is key in understanding what represses cholesterol and LDL receptor synthesis when blood cholesterol levels are elevated. Consequently, a good blend of fish oil, evening primrose, flaxseed oil, and/or GLA is ideal.
Stress and High Cholesterol
Scientific research suggests that hormones created by stress impair cholesterol metabolism. Exercise, controlled breathing, meditation and other disciplines such as yoga can be of tremendous value in helping to lower stress levels. Lifestyle changes that reduce stress in the home, workplace and family life are therefore important considerations to lowering blood cholesterol counts.
A Multi-faceted Approach To Treat Multi-faceted Causes
Most recent findings indicate a multi-faceted cause to the problem of cardiovascular disease, including excessive intake of saturated fats, carbohydrate metabolism dysfunction, nutritional deficiencies, hormonal imbalance, and a high stress type lifestyle. Different people seem to oxidize cholesterol differently. In addition, certain mechanisms in the body may have gone awry, such as impaired liver LDL receptor uptake in Familial Hypercholesterolemia, requiring more information and monitoring. Lowering the intake of saturated fats is advisable-but not eliminating them. Nature has provided specific compounds capable of augmenting dietary and lifestyle changes for improved cardiovascular health and may afford a way to lower cholesterol without resorting to synthetic drug preparations and their potential side effects. |