Thiamin, riboflavin, and vitamins B-6 and C: impact of combined restricted intake on functional performance in man.
A double-blind study of combined restriction of thiamin, riboflavin, and vitamins B-6 and C was carried out with 23 healthy males. During 8 wk of low vitamin intake, 12 deficient subjects consumed daily a diet of normal food products, providing maximally 32.5% of the Dutch Recommended Dietary Allowances (RDA) for thiamin, riboflavin, vitamins B-6 and C. Other vitamins were supplemented at twice the RDA. Eleven control subjects consumed the same diet but with a supplementation of twice the RDA of all vitamins. In deficient subjects blood vitamin levels, urinary vitamin excretion, and erythrocytic enzyme activities decreased; in vitro enzyme stimulation increased. Vitamin depletion had no ill effects on health, physical activity, and mental performance. A significant decrease was observed in aerobic power (VO2max) and onset of blood lactate accumulation (p less than 0.001) of 9.8 and 19.6%, respectively. A combined restricted intake of thiamin, riboflavin, and vitamins B-6 and C causes a decrease in physical performance within a few weeks.
van der Beek
E J
EJ
Department of Human Nutrition, TNO-CIVO Toxicology and Nutrition Institute, Zeist, The Netherlands.
van Dokkum
W
W
Schrijver
J
J
Wedel
M
M
Gaillard
A W
AW
Wesstra
A
A
van de Weerd
H
H
Hermus
R J
RJ
D000328:Adult; D001206:Ascorbic Acid Deficiency / Q000503:physiopathology*; D001823:Body Composition; D004311:Double-Blind Method; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D009751:Nutritional Requirements; D011597:Psychomotor Performance; D012257:Riboflavin Deficiency / Q000503:physiopathology*; D013832:Thiamine Deficiency / Q000503:physiopathology*; D026681:Vitamin B 6 Deficiency / Q000503:physiopathology*
D007773:Lactates; D019344:Lactic Acid