Evidence suggests that a number of foods are able to lower plasma cholesterol levels to a similar degree as cholesterol medication. In many cases, the effects of the foods are superior to the statins, the current gold standard in cholesterol lowering medication. The efficacy of certain foods at lowering cholesterol levels stems from the way that they are able to do this in comparison to medication. The statin drugs inhibit the HMG-CoA reductase enzyme in the liver, and this enzyme is the rate limiting step in cholesterol synthesis. As a result cholesterol levels in the plasma fall as the cholesterol synthesis rates decline. Food tend to work in two ways which makes dietary changes a more effective way of lowering cholesterol levels. Firstly, certain foods do inhibit cholesterol synthesising enzymes, but their effects tend to be more subtle, and as a result, side effects are mostly not seen with foods. In addition, food treat the cause of the raised cholesterol, which is development of insulin resistance and the metabolic syndrome.
Dietary flaxseed has been shown to have blood cholesterol lowering effects. These effects have been known to nutritionists for decades, and this is likely a result of the high fibre content of flaxseeds. For example, in one study1, researchers fed 30 grams of milled flaxseed for 12 months to a group of cardiovascular patients who had been diagnosed with coronary artery disease. A control group received 30 grams of whole wheat to provide a similar fibre content. Within 1 month the flaxseed group had experienced a 15 % reduction in low density lipoprotein (LDL) cholesterol, which is superior to anything a drug can produce. The whole wheat also caused a significant reduction in LDL cholesterol, although not as great as the flaxseed at 1 month. However, by 12 months the groups taking whole wheat and flaxseed showed no difference between the reductions of their LDL. Subjects taking cholesterol medication experienced further drops in plasma cholesterol when they had their diets supplemented with 30 grams of flaxseeds.
The observation that both flaxseed and whole wheat cause significant reductions in cholesterol levels, suggest that some common factor in the foods was responsible for the effects. Evidence suggests that fibre is effective at lowering plasma cholesterol levels, and both flaxseed and whole wheat are high in fibre. The general cholesterol lowering effect of fibre has been widely reported and is often superior to cholesterol lowering medication in this regard. The lack of side effects experienced in those that consume fibre further extends its advantages over cholesterol lowering drugs. The reason for the cholesterol lowering effects of fibre is not fully understood, but likely relates to the beneficial glycaemic effects it produces. By allowing better regulation of blood sugar levels, fibre may improve insulin sensitivity, and this in turn may decrease the lipid dysfunction that develops secondary to insulin resistance in the liver. The possibility therefore arises that high plasma cholesterol levels are a symptom of a fibre deficiency.
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