POISONOUS FOOD

One of the most remarkable discoveries of modern food science has been that for the majority of the adult human beings on earth and for a significant minority of children, milk may be actively harmful. By milk, I mean cows' milk, the beverage which has been esteemed and praised, claimed from its analysis to be the “perfect” food, shown by Sir Frederick Gowland Hopkins in 1912 by its dramatic effect on the growth of young white rats to be the vehicle of undiscovered vitamins, and demonstrated by Corry Mann in 1926 to improve the health of orphan boys given a diet otherwise calculated to be adequate. Yet during the last few years a number of cases have come to light of a condition in infants of severe diarrhoea and malnutrition which is found to improve when milk is withdrawn from the babies' diet. This has since been shown to be due to the presence in milk of an ingredient toxic to these infants. Nor was the toxic ingredient which produced these effects an adventitious poisonous contaminant, the result of bacterial infection or, indeed, a trace component present in low concentration or measured in parts per million at the lower limits of analytical detection. The toxic agent was lactose, the naturally‐occurring sugar of milk constituting 5 per cent of its total weight and making up 39·7 per cent of the total milk solids.