Birth defect-potato blight link

Press, Volume CXII, Issue 33060, 30 October 1972, Page 16

Birth defect-potato blight link

(N.Z.P.A.-Reuter —Copyright) LONDON, October 29.

A Christchurch surgeon now working in Britain has prompted an urgent study of the common potato—at least the discoloured one—as a possible cause of two of the most prevalent forms of birth defects.

Fresh laboratory evidence has just come forward that eating blighted potatoes during early pregnancy may lead to the birth of babies suffering from spina bifida or anencephaly. Spina bifida is a malformation at the base of the spinal cord which, even after an operation, leaves a child crippled for life and facing

an early death. Anencephaly is a skull and brain defect usually fatal within the first few days of birth.

“NATURE” ARTICLE

The alarm was raised by Dr James Renwick, a geneticist and biomedical researcher at the School of Hygiene and Tropical Medicine, London, after research based on an article in the science magazine “Nature” by Dr D. E. Poswillo, of the Royal College of Surgeons and formerly of Christchurch. Dr Poswillo reported an experiment in which a concentrate of diseased potatoes

was fed to six pregnant marmoset monkeys.

Four of the 11 foetuses taken from these monkeys showed gross abnormalities of the skull.

(Dr Poswillo, formerly senior oral surgeon with the North Canterbury Hospital Board, left Christchurch in 1969 to take a personal professorial chair at the Royal College. He did so with regret, he said at the time, but failing to go would have meant a s4m endowment for research being lost. (His special field is research into oral malformation and malignancy.) 18-MONTH GAP

Dr Renwick published his hypothesis on the link between diseased potatoes and birth defects in a medical journal, citing cases where the incidence of spina bifida and anencephaly had risen markedly some 18 months after potato blight had hit a given area.

Potato blight is usually caused by successive periods of damp and heat. It shows up as brown or purple patches on the skin of the potato. The Health Department in Britain at first scoffed at the idea, saying that Dr Renwick’s paper “does not contain convincing evidence.” Then, in Parliament on Monday, the Secretary for Health (Sir Keith Joseph) sounded a more cautious note when asked about the supposed link. Without supporting the theory, he warned that potatoes which were diseased, decayed or discoloured should be thrown away and damaged portions of other potatoes should be cut out.

Newspapers seized on the warning with a spate of mildly alarmed articles, and Dr Renwick weighed in with another article stressing that even if his theory proved wrong, the Government should take it seriously and investigate.

That, he said, was how the United States avoided a national disaster over the pregnancy drug thalidomide, which caused thousands of birth defects around the world.

Finally, late on Friday, the Government acted. The Health Department announced that it and its outside scientific advisers were making an urgent study of the suggested relationship between potato blight and birth defects.

The announcement stressed that the evidence so far did

no more than raise suspicion and “casts no doubt on healthy potatoes.” Few blighted potatoes reached the public, it said—an assertion that many housewives in Britain would dispute—but normal precautions in the home should be safeguard enough even if the link was confirmed.

This time, the department said that the safeguard was to throw away decayed, diseased and discoloured potatoes —and omitted Sir Keith Joseph’s advice to cut out damaged portions, a method Dr Renwick had challenged as “half-hearted.” RULES FOR MOTHERS

Dr Renwick has put forward a list of rules which he says all mothers-to-be should obey at least for the first three months of their pregnancy:

Throw away any damaged, diseased, decayed or green potatoes, as well as those that are sprouting shoots or have black or grey spots near the “eyes” . . . wear gloves when peeling potatoes to prevent any dangerous substance from being absorbed through the skin . . . and leave the kitchen when the potatoes are boiling to avoid inhaling the steam. The Health Department, anxious to stop any boycott of the potato, lauded it as “a valuable and important component of the British diet (in fact, the average British family consumes about 220 pounds—loo kilos —per person each year.) The value of such a component of the national diet must not be cast in doubt without firm evidence, it said.

The Potato Marketing Board, which was already stepping up quality safeguards, took the alarm more lightly. “We’ve been eating potatoes for 400 years now,” a board spokesman said, “so it seem a bit exaggerated to blame them for these serious diseases now.”