VALUE OF VITAMIN A

Taranaki Daily News, 3 June 1935, Page 13

VALUE OF VITAMIN A

IMPORTANCE IN DIET INCREASED; DISEASE RESISTANCE. NECESSARY FOODSTUFFS FOR MAN. The importance of diet in preventing the onset of an infective process, not so much in reference to ordinary infectious disease, but to' Organisms already in contact with surfaces of the body, both external and internal, was Stressed oft Friday by Dr. Mary Champtaloup, medical officer of health at New Plymouth, in a lecture to members of the new subbrahch Of the Royal Sanitary Institute. Dr. Champtaloup spoke particularly of the value of vitamin A in diet. - Diet should Contain natural sources of vitamin A, milk, green vegetables, carrots, butter, and mammalian liver Once a week, said Dr. Champtaloup. A considerable amount of animal experiment had been Carried out to show the influence Of vitamin A deficiency on susceptibility to infection and it was found that an excess of A over and above requirements did not produce superior resistance, but a deficiency produced an increased susceptibility. i McCarHson did work in India on rats in two groups. The well-fed rats, on balanced diet Of natural foodstuffs, had no deaths from riatural causes. Clinically and post-mortem they were remarkably free from disease. The ill-fed rats had a high incidence of disease. The worst diet, from results, was, white bread, margarine, tea, sugar, jam, preserved meat and scanty or overcooked vegetables. Those deficient diets seemed capable of producing in rats a large proportion of ailments common to humans, especially diseases of the lung and gastrointestinal tract, . i

It appeared that vitamin A deficiency affected especially epithelial tissue. A marked deficiency produced xerophthalmia, a serious disease of the epithelium covering the eye. It was concluded that the function of vitamin A was to maintain the integrity of cells covering body surfaces, thereby preventing invasion .by microbic agents. Although the exact importance of vitamin A was not yet determined, it was undoubted that resistance to infection might be greatly reduced by dietary deficiencies, particularly during the early months and years of life. This was not on account of any decrease of antibodies or protecting substances in the blood, but was due to the influence pf vitamin A over the correct development of the tissue cells or epithelium and their maintenance in a condition to resist disease. - • ■ '''J EFFECT OF MILK DIET. Corry Mann experimented in a large boys’ school in which the ordinary diet was sufficient in itself to satisfy the appetite of growing boys. To the diet of one group was added one pint of raw milk daily. This practically doubled the annual increase in weight, and during the winter 1923-24 there was a# complete absence of illness among the ‘milk’ boys, although in other houses of the school village the tote of sickness was higher. This demonstrated the high nutritional value of raw milk and suggested an in-

crdase resistance tn infection. Five other groups had extra rations of water cress, sugar, casein, butter, margarine. "It is pleasing to note that the next highest gains in both height and weight, were in. groups with an extra ration of New Zealand butter,” added Dr. Champtaloup. Very extensive work over a number Of years was ddne under the Scottish Ministry of Health on school children in Lancashire. Four groups of children were given extra rations daily of milk, separated milk, biscuit and there was one control group. The milk groups showed an increase in' height and weight 20 per cent, greater than the ether two groups, both of which gave poor results. This confirmed the nutritional value of milk, and indicated an unexpected value in skimmed milk, aS there was little significant difference between. • The findings had a wide public' health significance indicating that milk was *a wonderful foodstuff and that the ordinary diets of children were not sufficient to produce the highest physical standard. “It is very frequently stated, that pasteurisation largely destroys the nutritive value of milk,” said Dr; Champtaloup. "It is undoubted that certain physical and chemical changes occur, and certain deterioration can be demonstrated by animal experiment. In 1929 experiments on the influence of pasteurisation on milk showed reduction Of Soluble calcium. Feeding experiments on calves showed a lessened increase in weight with pasteurised as compared with fresh milk. LANCASHIRE EXPERIMENT.

“Lancashire experiments in 1930 tested the effect of heated milk On humans. Large groups each of 5,000 children were given the extra ration of raw T.B. tested milk and two rations of the same milk pasteurised. There was no evidence of greater effect on growth in raw as compared with pasteurised milk, or vice versa, although with younger children increase in weight was less. From these experiments it appears that while animal experiment indicates a lessened nutritive value in pasteurised milk, for practical purposes in dealing with children-there is no significant difference between the two.”

The practical application pointed to the desirability of a liberal supply of milk for the growing child, continued the Speaker. Where this was of pure quality it was preferably taken raw, but where the purity was uncertain pasteurisation would give an added security'without materially reducing, its nutritive influence. Boiling destroyed its value, however. Where expense prohibited the use of whole milk, skimmed milk with the addition qf a little suet fat would make a valuable adjunct to the diet. Reiterated advice regarding the necessity for an abundant supply of milk and green vegetables, particularly for the growing child, was sound and to be stressed. With sufficient vitamin A in the early period of growth, full development and perfect formation was assured for the epithelial tissue which, was thus rendered more resistant to disease. Moreover it would appear that not only Was there an increased resistance to disease, but a positive health factor was built up.