BREAST-FEEDING mothers on macrobiotic diets that avoid all animal produce may put their babies at risk of malnutrition, according to researchers in the Netherlands. They compared the milk of 10 omnivorous women with that of 21 breast-feeding women whose diets consisted mainly of organically grown, unrefined cereals, vegetables and pulses, and who generally avoided meat, fish, eggs and dairy produce.

Milk from the second group contained less zinc, magnesium and vitamin B6 and fewer saturated fatty acids than milk from the first group. This could adversely affect the development of small babies, the researchers write in the European Journal of Clinical Nutrition.

The omnivorous mothers' milk, however, contained significantly higher amounts of toxic substances such as PCBs, (polychlorinated biphenyls), DDT and other pesticides. Perhaps the answer lies in eating produce from animals reared on organic feed.