The effect of thiamin supplementation on the health and general well-being of 80 randomly selected healthy elderly Irish women, from a population with marginal thiamin deficiency, was studied. Key variables affecting thiamin status were controlled. Weekly dietary intakes, subjective feelings, and activity assessments were measured during a 4-week baseline and 6-week double blind treatment period. Clinical assessments were performed during the last week of each period. For treatment, subjects were randomly assigned to either thiamin (10 mg daily) or placebo groups. Compared to baseline and placebo supplemented values, thiamin-supplemented women experienced significantly increased appetite, energy intake, body weight and general well-being, and decreased fatigue. Thiamin supplementation also tended to reduce daytime sleep time, improve sleep patterns, and increase activity. These data suggest that evaluation of thiamin status is indicated when nonspecific conditions such as anorexia, weight loss, fatigue, depression, and sleep disorders are present in elderly persons.

Unlike severe zinc deficiency, marginal Zn deficiency is difficult to identify in rats because no reliable indicator of suboptimal Zn status is currently available. We have previously observed reduced pancreatic γ-glutamyl hydrolase (EC3.4.22.12) activity and impaired pteroylpolyglutamate absorption in Zn-deficient rats. In the present study the effect of Zn depletion and repletion on the Zn concentration of various tissues and on the activity of this enzyme was investigated. The objective was to determine the sensitivity of these variables to Zn depletion and to evaluate their usefulness as indices of Zn status. Male Wistar rats (about 180 g), maintained from weanling on a purified Zn-adequate diet, were randomly allocated into twelve groups. A pretreatment control group was killed immediately. The remaining eleven groups were fed on a Zn-deficient diet and a group killed daily for 7 d (Zn-depleted groups). The remaining four groups were re-fed the Zn-adequate diet and a group killed daily (Zn-repleted groups). On analysis, pancreas and spleen Zn levels responded most rapidly to reduced Zn intake, followed by tibia, liver, kidney and plasma. Zn concentration was maintained in testes. Reduced plasma folate levels were also observed. A significant reduction in pancreatic γ-glutamyl hydrolase activity before the depletion of many tissue Zn stores confirms the Zn sensitivity of the enzyme. It was concluded that future investigation into the inter-relationship between Zn and folate metabolism may be useful in identifying a sensitive, biochemical index of Zn status.

~Two studies were conducted to investigate the possibility that pteroylmonoglutamic acid supplementation would alleviate teratogenesis in zinc-deficient rats. Pregnant rats of the Wistar strain were fed on Zndeficient ( < 0.5 mg Zn/kg) or Zn-supplemented (75 or 95 mg Zn/kg) diets from mating until day 18.5 of gestation. The basal level of pteroylmonoglutamic acid added to all diets (056mglkg) was supplemented with 30-200 mg/kg in selected diets. Dietary Zn deprivation resulted in fetal resorption, fetal growth retardation and reduced concentrations of Zn in fetuses and maternal plasma and tibia. Low maternal body-weight at conception emerged as an important determinant of risk of resorption in Zndeficient rats. Dietary Zn deficiency resulted in reduced maternal plasma folate concentrations and these values were inversely correlated with litter size or weight in Zn-deficient rats. Pteroylmonoglutamic acid supplementation increased maternal plasma folate concentrations, but did not reduce the high incidence of teratogenesis which occurred in Zn-deficient rats. Supplementation of Zn-deficient rats with pteroylmonoglutamic acid significantly increased the incidence of clubbed foot and tended to increase the incidence of brain or meningeal abnormalities, or both, and cleft palate, but did not reduce maternal or fetal Zn status. Pteroylmonoglutamic acid supplementation also increased the weights of Znsupplemented control fetuses.

The relationship of folate status and polyphenol intake to thiamin status was studied in 80 randomly selected elderly and young Irish women, with key variables affecting thiamin nutrition controlled for. Folate, thiamin, and polyphenol intakes were measured during a 4-wk baseline (elderly and young) and 6-wk double-blind (elderly) supplementation period. Only elderly subjects were randomly assigned to placebo, folic acid (400 micrograms), thiamin (10 mg), or folic-acid-plus-thiamin groups. Thiamin status (TPP effect) was not affected by folate status (plasma and erythrocyte folate) during the baseline period or with folic acid supplementation alone. Polyphenol intake was not correlated with thiamin status. Only thiamin intake and thiamin supplementation significantly affected thiamin status. Because the majority of subjects (102 of 160) were initially thiamin deficient, enrichment of Irish grain products with thiamin is recommended.

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