Re your report on essential fatty acids (WDDTY vol 14 no 2), we know that EFAs are fragile and easily oxidised, so people who consume oils need to have plenty of vitamin E, from a natural source, as this antioxidant is fat-soluble. Medical trials unfortunately tend to consider the action of one substance on its own. It is not surprising that fish oil given without vitamin E may ultimately prove harmful.

Oils should be processed with as little heat as possible to avoid removing their natural vitamin E content. Bottles of flax seeds and oil should be kept in the fridge and unopened bottles of flax oil are best kept frozen. Oils should not be used for frying. Most oils can be used for brief cooking so long as they are mixed with water or stock. This will stop the temperature rising above 100 degrees. Flax (linseed) oil should not be cooked, but may be put on salads or added to warm food. Fish should be cooked gently.

Converting linoleic acid and alpha-linolenic acid to prostaglandins requires magnesium, zinc, calcium, biotin, and vitamins B1, B2, B3, B6 and C. Doctors often assume that people with eczema have defective genes and are incapable of converting linoleic acid to gamma-linolenic acid. However, there is often too little linoleic acid in the diet, or a deficiency of at least one of the necessary vitamins and minerals. They may be on low-fat diets or only consume meat fat or olive oil, neither of which contains much linoleic acid. - Margaret Moss, DipION, Cheshire