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Biomedical subjects

M L Yew

Publications and source records attributed to M L Yew.

6 recordsLinked to original sources
PubMed1973

The "trophic" value of foods.

Foods must furnish (i) calories, which can readily be measured, and (ii) raw materials necessary for the building and maintenance of metabolic machinery which makes possible fuel utilization. We have called this "beyond-calorie" quality of food its "trophic" value. This concept has more unity than appears on the surface, and is capable of approximate measurement by biological testing as our experiments show. The trophic value of a food cannot be ascertained from food composition tables because only a smattering of the necessary information is commonly furnished. A food cannot support life if it is missing, or deficient with respect to, any one of the necessary nutrients. A tabulation which includes only a few nutrients-e.g., calcium, thiamin, riboflavin, niacin, phosphorus, and iron-can be woefully misleading, especially if these individual nutrients have been added by way of fortification. THE MEASUREMENT WE HAVE APPLIED TO A NUMBER OF FOODS IS POTENTIALLY VALUABLE FOR COMPARING SIMILAR FOOD PRODUCTS: two grains, two breads, two milk products, or for comparison of the same food grown, processed, or preserved in different ways. By using essentially this method we have found that barnyard eggs are somewhat superior to battery eggs, but that whether they are fertile or infertile makes no difference. We are of the opinion that extensive biological testing of many commercial food products is highly desirable to help promote human health and better internal environments for our cells and tissues.

Animals↗
PubMed1973

"Recommended daily allowances" for vitamin C.

Although 41 years have elapsed since the identification of vitamin C, the amounts required for human health are far from established. Pauling's suggestion that human needs for this vitamin probably have been underestimated by a factor of 10 or more has frequently been ignored or refuted by rhetoric rather than by sound experimentation. In the present study young healthy guinea pigs were fed a scrobutic diet supplemented with ascorbic acid at four widely different levels (0.05, 0.5, 5.0, and 50 mg/100 g of body weight per day). Growth rates both before and after surgical stress, recovery times after anesthesia, scab formation, wound healing, and the production of hydroxyproline and hydroxylysine during wound healing all support the conclusion that young guinea pigs ordinarily need about 5.0 mg/100 g of body weight daily. This is far beyond what is needed to prevent scurvy. Under stress the needs are even higher. On a body-weight basis this amount is equivalent to a need on the part of a 30-kg human child of 1500 mg of ascorbic acid daily. While calculations on a body-weight basis are subject to some uncertainty, the enormous discrepancy (nearly 40-fold) between this amount and that recommended by the Food and Nutrition Board calls attention to the extreme uncertainty about human ascorbic-acid needs, and to an important public health problem related to the best development of young people.

Amino Acids↗