Studies on the causes of folic acid deficiency Part 2. Folic acid contents of various foods and loss of food folate by boiling

Folic acid contents of various foods (147 items) were estimated by the microbioassay using Lactobacillus casei as the test organism. Folic acid were abundant in vegetables, fruits, fishes and the liver of animals. Nineteen foods were examined for loss of folic acid during boiling. Leaching out into the water was also examined. 20-70% of free folate was destroyed after 5 minutes and 20-90% after 15 minutes. Destruction of total folate was less than that of free folate i.e., 30% after 5 minutes and 40-60% after 15 minutes. Pteroylglutamic acid was not destroyed by boiling for 15 minutes. So the folate destroyed during boiling was considered to be other forms of folate except pteroylglutamic acid. Folic acid contents of two hospital diet in Okayayma city was estimated. Mean daily folic acid amount in the diet of hospital A was 205μg of free folate and 839.8μg of total folate. In the diet of hospital B, 305.5μg of free folate and 738.1μg total folate were present. These amounts were much more than those reported in USA and England. As to the reason why megaloblastic anemia is rare and folic acid defi ciency is so mild in Japan, abundant folic acid intake from diets, uniformity of dietary habits i.e. boiled rice as basic food, were discussed.