Restricted riboflavin: within-subject behavioral effects in humans

Open Access
Publisher Website
Google Scholar
Abstract
Six male conscientious-objector volunteers served as subjects in an 84-day study of potential behavioral effects induced by severe hyporiboflavinosis. During 56-days of near total riboflavin restriction (i.e., two diets of 130-g/day and 65-g/day casein containing 0.5 µg riboflavin/g were used), significant changes were found in five personality subscales of the MMPI (hypochondriasis, depression, hysteria, psychopathic-deviate, and hypomania), as well as hand-grip strength. These effects were noted by the 39th and 52nd day of restriction, respectively, in the absence of any clinical symptomatology. Effects were not readily reversible during a 14-day repletion period. The MMPI data were viewed as reflecting subjective reports of somatic symptomatology and situational reactions associated with the stress of riboflavin restriction. Decreased hand-grip strength was viewed as a residual effect of reduced flavin proteins (i.e., oxidative phosphorylation) present in body musculature under riboflavin depletion. Incidental findings showed that an enzymatic erythrocyte glutathione reductase activity coefficient (AC) between 1.20 and 1.30 is a potentially conservative range unrelated to hyporiboflavinosis; and, select behavior measures afford improved means for assessing onset and recovery of specific vitamin deficiencies.