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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Dietary Prevention of Obesity-related Disease Research » Research » Publications at this Location » Publication #97659
Title: COGNITIVE EFFECTS OF ADAPTATION TO A LOW ZINC DIET IN HEALTHY MEN

Author
item KRETSCH, M - WESTERN HUMAN NUTR CTR
item FONG, K - WESTERN HUMAN NUTR CTR
item Penland, James

Submitted to: Trace Elements in Man and Animals (TEMA)
Publication Type: Abstract Only
Publication Acceptance Date: 5/2/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: This study examined the effects of low zinc intake on cognitive processing efficiency and psychomotor skills in men. Eight healthy men aged 37.8 yr +/-7.5 (mean +/-SD) participated in a 20 week metabolic unit study consisting of 34 d of baseline, 70 d of low zinc intake, and 37 d of repletion. A controlled, conventional foods diet (3 d rotating menu) containing 5 mg Zn/d was fed throughout the study. A 10 mg Zn gluconate supplement was administered daily during the baseline and repletion periods and a placebo during the intervention period. All other dietary nutrients were adequate. A standardized, computerized, battery of tests was used to assess a variety of cognitive and psychomotor skills after 25 days of baseline (B), after 19 and 61 d of low zinc intake (Zn1 and Zn2, respectively), and after 26 days of repletion (R). Tests included measures of fine and gross motor skills, eye-hand coordination, sustained attention, spatial and verbal memory, visual perception, and concept formation and abstract reasoning. The most pronounced finding was for short-term verbal memory. A highly significant effect (p<0.0001) was found for the reaction time (msec) needed for correct word recall (B=251.0+/- 20.0**a, Zn1=287.1+/-30.2**b; Zn2=226.2+/-9.2**c; R=271.6+/-21.2**ab). In contrast to baseline, reaction time slowed at Zn1 but was faster at Zn2. However, no significant effect was found for the percentage of words accurately recalled at the four timepoints (B=73.1+/-20.2; Zn1=68.8+/- 24.2; Zn2=66.9+/-28.3; R=68.1+/-26.0). These findings suggest that within the first weeks of adaptation to a low zinc diet, the latency of short- term verbal memory is slowed. However, given sufficient time, the body to low zinc intake and this cognitive impairment is no longer present.