Immunocompetence and oxidant defense during ascorbate depletion of healthy men.
To determine nonscorbutic effects of moderate vitamin C deficiency we measured immune function and oxidative damage in eight healthy men (25-43 y) who consumed 5-250 mg/d of ascorbic acid over 92 d on a metabolic unit. During ascorbic acid intakes of 5, 10, or 20 mg/d, subjects attained a state of moderate ascorbic acid deficiency as ascorbic acid concentrations in plasma, leucocytes, semen, and buccal cells dropped to less than 50% of baseline with no scorbutic symptoms observed. No changes in cell proliferation, erythrocyte antioxidant enzymes, and DNA strand breaks were observed; however, blood levels of glutathione and NAD(P) decreased during ascorbic acid deficiency, as did delayed hypersensitivity responsiveness. Concentrations of the oxidatively modified DNA base, 8-hydroxydeoxyguanosine in sperm DNA and fecapentaenes, ubiquitous fecal mutagens, were increased during ascorbic acid depletion. Moderate vitamin C deficiency, in the absence of scurvy, results in alteration of antioxidant chemistries and may permit increased oxidative damage.
Jacob
R A
RA
Western Human Nutrition Research Center, USDA Agricultural Research Service, Presidio of San Francisco, CA 94129.
Kelley
D S
DS
Pianalto
F S
FS
Swendseid
M E
ME
Henning
S M
SM
Zhang
J Z
JZ
Ames
B N
BN
Fraga
C G
CG
Peters
J H
JH
D000328:Adult; D001205:Ascorbic Acid / Q000378:metabolism; D001206:Ascorbic Acid Deficiency / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007121:Immunocompetence; D008297:Male; D016877:Oxidants / Q000378:metabolism*; D011090:Polyenes / Q000032:analysis
D016877:Oxidants; D011090:Polyenes; C037358:1-(1-glycero)tetradeca-1,3,5,7,9-pentaene; C037357:1-(1-glycero)dodeca-1,3,5,7,9-pentaene; D001205:Ascorbic Acid