ALL OUR IF'S

New Zealand Listener, Volume 10, Issue 255, 12 May 1944, Page 22

ALL OUR IF'S

(Written for "The Listener’ by DR.

MURIEL

BELL

Nutritionist to the

Department of Health),

HE action of one foodstuff on another is a matter that needs some consideration. The movies tell us that Popeye’s addiction to spinach gives him great muscular powers. Does Popeye drink his milk with equal devotion? If not, where does he get his calcium? Perhaps by chewing bones, assuming that the strength of his jaw is also equal to the task! We can say that spinach is all right if we take our milk. The same may be said, and for the same reason, with regard to silver beet and rhubarb; it has been found by. workers at the Middlesex Hospital that the oxalic acid that is present in these vegetables is not absorbed, provided there is enough milk in the diet. The calcium in the milk combines with the oxalic acid to form insoluble calcium oxalate. There are points against absorbing too much oxalic acid-certain people tend to be unable to deal with oxalic acid, and it is then excreted in the form of calcium oxalate, a substance that forms a nasty kind of stone in the kidney. Though these are rare, they are worth avoiding. Mofeover, it is desirable, especially in the growing child, to keep up the absorption of calcium. When milk is: taken, efiough should be included each day to overcome the losses that occur from the unexpected agencies in our foods. When studies are made on human béings, the retention of calcium even from milk, in which food the calcium is best available for absorption, is néver 100 per cent-it varies in different individuals, from about 12 to 50 per cent of the dietary calcium. We have thus to take a surplus in order to meet cut tequirements, and perhaps this surplus takes care of the chemical substances like oxalic acid that precipitate the calcium. It is certainly undesir able to condemn spinach or silver beet because they contain oxalic acid; they often have enough calcium themselves to take care of their own oxalic acid. All green vegetables ate good for supplying us with Vitamin C. Moreover, spinach is a very good source of some of the newer components of the Vitamin B complex, as well as being a vegetable that is easily puréed; it is thus suitable for infants — if they are getting their calcium in the form of milk. The same thing holds for wholemeal bread which is good if milk figures latgely in the food, But it is actually a bad thing to eat wholemeal bread if at the same time there are not adequate sources of calcium in the diet. The explanation required would take tod many wofds for my allotted space, and will theréfore be deferred. Cabbage is good, if we take our iodised salt. Phosphates are good, if the diet has enough calcium, but to put moré of them into a diet already deficient in calcium may upsét the calciumphosphate ratio-and fickets may result. Magnesium is good, if theré is not too much of it. Fluorine is good, if there is neither too little nor too much, especially the latter. Thus we afe learning more about "balancing" the diet-keeping our foods in their proper proportions.