A fatty acid found in large amounts in rape and mustard seed oils, and widely (but mistakenly) thought to be toxic. As reported by nutritionist and oil expert Udo Erasmus PhD, the rat studies which showed fatty degeneration of heart, kidneys and glands after the consumption of erucic acid, were interpreted to mean that erucic acid is also toxic to humans. What was not considered was that sunflower seed oil, which contains no erucic acid, has the same effect on rats, because rats metabolize fats and oils poorly. Meanwhile a whole industry has grown up around the production of 'low erucic acid' rape seed oil.

Erucic acid has been used to treat a fatal degenerative disease known as adrenoleukodystrophy (ALD) and is sometimes known as 'Lorenzo's oil', after the boy who inspired the development of the treatment.

Essential amino acids (see Amino acids)

Essential oils

Volatile oils which can be distilled or extracted from plants and used for medicinal or cosmetic purposes or as aromatherapy oils. Examples are garlic oil, rosemary oil, peppermint oil and bergamot oil (the latter is used to flavour Earl Grey tea).

Essiac

A Native American herbal treatment for cancer discovered by a Canadian nurse René Caisse. (The letters Essiac are her surname spelled backwards). In 1938, after much public lobbying, Essiac came very close to being legalized by the Ontario government as a remedy for terminal cancer patients. Its ingredients are turkey rhubarb (Rheum palmatum), burdock root (Arctium lappa), the inner bark of slippery elm (Ulmus fulva), and sheep sorrel (Rumex acetosella). Campaigners who benefited from the treatment believe that organized medicine was responsible for marginalizing it.

Availability: Better known in the US than in the UK. Not widely available but may be made at home by combining the above herbs, or obtained from specialist practitioners and clinics.

Esters

Compounds formed between acids and alcohols.

Estrogen (see Oestrogen)

Ethanolamine phosphate (EAP)

A substance found within the body which can be used as a natural chelator to assist the absorption of minerals from food. (Also see Chelates.)

Evening primrose oil (Also see Fats)

The oil of seeds from the evening primrose plant, which yields about 8 to 10 per cent of its fatty acids as gamma linolenic acid (GLA). Evening primrose oil is also rich in linoleic acid.

Excipients

Also known as 'fillers and binders', excipients are additives used in tablet- and capsule-making, which help to bind the active ingredients together, to act as carrier substances, or to 'fill out' a capsule.