Food/Health Salt’s enough to raise your Mood pressure

Press, 31 October 1981, Page 10

Food/Health Salt’s enough to raise your Mood pressure

It has long been argued that the study of Tokelau Islanders’ changing rates of blood pressure was unique. In this survey Dr lan Prior, and his research team, surveyed Tokelau Islanders from the central Pacific before the big hurricane in 1972. At five-yearly intervals after that they worked with Tokelau Islanders at home on their Central Pacific atolls, and also those who migrated to New Zealand. Salt

The migrants in New Zealand became much heavier and fatter, and changed their eating habits toward West-ern-style foods. In doing so, they ate four times as much salt as they had in the islands. This increase in calories, weight, and salt was associated with rising blood pressures as they grew older. Back in the islands, the older people were found to have much lower blood pressures. Culture Ten to 20 per cent of people in the major cities of developed countries have high blood pressure which inevitably leads to increasing heart attacks, and strokes. The latest ? figures show that more than half of us in New Zealand die from heart attacks or strokes. Is this tendency inherited or do we develop high blood pressure because we mostly become over-weight? Perhaps it is

Professor Beaven

Of course, kidney disease may be a cause of high blood pressure, but such people were excluded from the Qashqai study.

Stress of town living, stress of politics of responsibility, are not nearly as important as our level of salt intake. A trouble-free life without stress will not save us from blood pressure and strokes if we eat salty foods.

We all eat three or four times as much salt as we need in all our. traditional New Zealand foods — including our meat and vegetables,, and even in our daily bread and butter! Please don’t pass me the salt, ■ •? “ .

caused by something in our diet.

Doctors have argued about the causes, particularly since the advent of powerful and effective new drugs to keep blood pressure down to normal. Those of us interested in food and health are particularly concerned about any possible tie-up between what we eat and our rising blood pressures in the community. Unique study Dr Lot B. Page, from the Tufts University School of Medicine is well known for his blood pressure surveys in the Solomon Islands. He and a group of colleagues decided to study a tribal group of pastoral nomads. They felt that the Qashqai tribesmen from southern Iran had a continuing life style untouched by twentieth century civilisation. Indeed, these pastoral nomads lived as all our ancestors have lived for 95 per cent of our time on. earth.

About 260 Adult Qashqai tribesmen, originally of Turkish origin migrate semiannually up to 600 kilometres to meet the needs of their tribal animals.

Six campsites of one of these migrating groups were visited, and. free medical checks offered by the joint Iranian/American research group. Only at two campsites studied was regular access to markets'possible. The tribesmen’s account of

what they ate was carefully checked by local assistants, and certain blood tests and blood pressure recordings taken. In particular, all urine passed over 24 hours was collected. It is now accepted that sodium chloride or salt in such a 24-hour urine sample reflects the amount of salt eaten if the diet does not change. Careful analyses of such things as weight, height, and age were then undertaken.

Results To the surprise of the researchers these traditional nomadic groups showed that blood pressures rose steadily with age. Their most important finding was that increasing salt in the urine was significantly related to high blood pressure. The more salt in the urine, and presumably the more in the diet, the higher the blood pressure.

So it was concluded that a high intake overcame any protective effect of being nomadic.

Implications for N.Z.

In these columns we have reviewed evidence • that shows the danger of added salt to New Zealanders. This work by Dr Page's group is notable in suggesting that in our environment, salt is the most important identifiable factor related to blood pressure.