Soya

Soya: what was it used for?

A food first: in China and Japan, Stuart writes, it made “bean oil,” “bean-curd,” and “soy,” three products of almost universal use in Eastern cooking. In medicine it was the black bean that counted. Its frequent use was thought to give “strength and vigor, albeit with heaviness”; it was taken for “an admirable counter-poison” against most of the vegetable poisons, aconite and croton among them, and the green beans chewed to a pulp were laid on smallpox ulcers and ulcers of the cornea, the bruised leaves on snake bite.

Soya: what does modern science say?

The European Medicines Agency’s herbal committee split the plant in three. Soya lecithin, a mixture of phospholipids in which phosphatidylcholine averages 76 per cent, it accepts as a traditional herbal medicine for the relief of temporary fatigue and a sense of weakness; refined soya-bean oil, about half linoleic acid, as a traditional bath additive for dry skin with mild recurrent eczema; both “exclusively based upon long-standing use” (monographs of 2017). For the isoflavone-rich extracts of the bean germ it adopted no monograph at all: neither a recognised efficacy nor the required period of traditional use was established (public statement of 2018). A Cochrane review of soy infant formula concluded in 2006 that it “cannot be recommended for prevention of allergy or food intolerance in infants at high risk of allergy or food intolerance.”

Soya: what did the older authorities say?

G. A. Stuart, Chinese Materia Medica

The Chinese distinguish the varieties by the colour of the seed, black, white, yellow, grey, azure, and spotted: “The black sort is used in medicine, and the yellow is specially valued in the preparation of bean-curd and soy.” The black kind was little eaten, “as it is thought to render the body heavy,” for the Chinese, he explains, favoured things that give lightness to the body over those that promote flesh and sluggishness. The beans went into prescriptions for difficulties after childbirth and for sexual disorders, but always with other active drugs, so that, he judged, “the beans play no very important part in these prescriptions.”