Certain components in food can actually lower one's cholesterol. These include:
Dietary fibre can be regarded as a natural cholesterol-lowering agent as well as having other beneficial effects on bowel action and biology.
However, the effects on plasma lipids are relatively small and, used alone, fibre has little influence on the progression of atherosclerosis or coronary disease.
Other natural cholesterol-lowering agents include the plant sterols or phytosterols - natural plant products which closely resemble cholesterol chemically, but which are not absorbed from the small bowel.
The normal diet includes phytosterols, which are found in various seeds such as sesame seed. It has been shown that an increase in dietary phytosterols can reduce LDL cholesterol levels by 10%.
Antioxidants constitute a thriving health shop industry, despite absence of good evidence from well-designed clinical trials. Vitamin A trials have, in fact, been disappointing and have shown a possible increase in some malignancies and in congenital malformations in people in the trials.
Vitamins C and E are more promising but even here the direct clinical evidence is controversial.
Possibly more promising are non-vitamin antioxidants present in red wine, fruit, vegetables, teas and other herbal products. Besides the potentially beneficial effects on coronary artery disease, they seem to reduce the incidence of some cancers.
Despite the disappointing results of direct supplementation, there is stronger evidence for the protective effects of alcohol, especially red wine, and the consumption of fresh fruit and various plant products.
The relative antioxidant capacity of red wine is considerably higher than of most other natural sources. One glass of red wine (150ml) is equivalent to:
- 12 glasses of white wine
- 2 cups of tea
- 5 apples
- 100g portion of onions
- 7 glasses of orange juice
- 500ml beer
But it may not be simply the antioxidant properties of fruit and vegetables which are important since they contain many other substances such as:
- fibre
- agents which stimulate the immune system
- monounsaturated fatty acids
- agents which affect cholesterol synthesis
- B-vitamins
- folic acid
- agents affecting nitric oxide (a potent antioxidant) production and
- even alcohol itself
These may all have beneficial effects. Alcohol alone raises HDL concentrations in a predictable manner; high HDL levels being associated with decreased risk.
The optimum intake of red wine, and other alcoholic equivalents, is around two, but definitely less than four, glasses per day. Above that level, negative effects predominate: kidney disease, hypertension, certain cancers, hyperlipidaemias and damage to the nervous system may occur.