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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #134122
Title: MODERATELY HIGH ZINC INTAKE IMPAIRS VERBAL MEMORY OF HEALTHY POSTMENOPAUSAL WOMEN ON A LOW COPPER DIET

Author
item Penland, James
item Milne, David
item DAVIS, CINDY - 5450-10-00

Submitted to: Trace Elements in Man and Animals International Symposium
Publication Type: Proceedings
Publication Acceptance Date: 11/30/1999
Publication Date: 2/1/2000
Citation: Penland, J.G., Milne, D.B., Davis, C.D. 2000. Moderately high zinc intake impairs verbal memory of healthy postmenopausal women on a low copper diet. In: Roussel, A.M., Favier, A.E., Anderson, R.A., editors. Trace Elements in Man and Animals 10. Kluwer Academic/Plenum Publishers, NY. p.1025-1030.

Interpretive Summary: Twenty-three healthy postmenopausal women aged 64.2±6.2 y (mean±SD) participated in a 200-d metabolic unit study consisting of 10 d of equilibration followed by 90 d of low zinc intake (3 mg/2000 kcal/d) followed by 10 d of equilibration, and concluding with 90 d of high zinc intake (53 mg/2000 kcal/d). Thirteen women were fed low copper (1 mg/2000 kcal/d) while 10 women were fed high copper (3 mg/2000 kcal/d) throughout both 90-d dietary periods. The equilibration diet contained 9 mg/2000 kcal/d zinc and 2 mg/2000 kcal/d copper. Diets consisted of conventional foods fed as a 3-day rotating menu, and were adequate in all other nutrients. The Memory Assessment Scales (MAS) (Williams, J.M., 1991, Memory Assessment Scales. Professional manual. Psychological Assessment Resources, Inc., Odessa, FL) test was used to assess verbal and visual memory at the end of each 90-d dietary period. The MAS yielded several subscale scores describing immediate recall of numbers presented verbally, immediate and delayed recall of words and prose presented verbally, and immediate and delayed recognition of face-name pairs and designs presented visually, as well as general scores summarizing short-term memory, verbal memory and visual memory, and a global memory score. Raw scores were standardized for age and level of education. Repeated measures analysis of variance showed that an interaction between zinc and copper significantly (p<0.05) affected the general measure of short-term memory and immediate recall of numbers presented verbally. Subsequent planned paired comparisons showed that short-term memory (p=0.007) and, in particular, immediate recall of numeric sequences presented verbally (p=0.005) were worse when women on the low copper diet were fed high zinc compared to low zinc diets. Contrasted with high copper intake, low copper intake was associated with increased intrusions during recall (p=0.003); this suggests difficulty in discriminating between relevant and irrelevant responses. The findings indicate exacerbation of negative effects of low copper intake by moderately high zinc intakes extend to cognitive function, specifically short-term memory for verbal material.

Technical Abstract: Twenty-three healthy postmenopausal women aged 64.2±6.2 y (mean±SD) participated in a 200-d metabolic unit study consisting of 10 d of equilibration followed by 90 d of low zinc intake (3 mg/2000 kcal/d) followed by 10 d of equilibration, and concluding with 90 d of high zinc intake (53 mg/2000 kcal/d). Thirteen women were fed low copper (1 mg/2000 kcal/d) while 10 women were fed high copper (3 mg/2000 kcal/d) throughout both 90-d dietary periods. The equilibration diet contained 9 mg/2000 kcal/d zinc and 2 mg/2000 kcal/d copper. Diets consisted of conventional foods fed as a 3-day rotating menu, and were adequate in all other nutrients. The Memory Assessment Scales (MAS) (Williams, J.M., 1991, Memory Assessment Scales. Professional manual. Psychological Assessment Resources, Inc., Odessa, FL) test was used to assess verbal and visual memory at the end of each 90-d dietary period. The MAS yielded several subscale scores describing immediate recall of numbers presented verbally, immediate and delayed recall of words and prose presented verbally, and immediate and delayed recognition of face-name pairs and designs presented visually, as well as general scores summarizing short-term memory, verbal memory and visual memory, and a global memory score. Raw scores were standardized for age and level of education. Repeated measures analysis of variance showed that an interaction between zinc and copper significantly (p<0.05) affected the general measure of short-term memory and immediate recall of numbers presented verbally. Subsequent planned paired comparisons showed that short-term memory (p=0.007) and, in particular, immediate recall of numeric sequences presented verbally (p=0.005) were worse when women on the low copper diet were fed high zinc compared to low zinc diets. Contrasted with high copper intake, low copper intake was associated with increased intrusions during recall (p=0.003); this suggests difficulty in discriminating between relevant and irrelevant responses. The findings indicate exacerbation of negative effects of low copper intake by moderately high zinc intakes extend to cognitive function, specifically short-term memory for verbal material.