Selenium and Zinc Status Are Suboptimal in a Sample of Older New Zealand Women in a Community-Based Study

Abstract

The importance of selenium and zinc in the immune functioning of the aged is widely recognized. Seniors in New Zealand are at particularly high risk of low selenium status because of the low selenium soil environment. The zinc status of the New Zealand elderly has never been assessed. In this cross-sectional study, the biochemical selenium, zinc and lipid levels, physical functional capacity and dietary intakes of 103 randomly selected free-living New Zealand women (mean age +/- SD, 75 +/- 3 y) were assessed. Among nonusers of selenium supplements (n = 80), 80% [95% confidence interval (CI): 70; 88%] had plasma selenium levels (0.85 +/- 0.23 micromol/L) below 1.00 micromol/L [ approximately 10% below mean plasma selenium necessary for full expression of glutathione peroxidase (GPx) activity in New Zealand subjects]. Plasma selenium was strongly correlated with GPx: r = 0.56; P < 0.0001. For nonusers of zinc supplements (n = 88), serum zinc concentrations were 12.4 +/- 1.4 micromol/L, with 12% (95% CI: 6; 21%) having levels below the cut-off value (10.7 micromol/L). Estimated mean daily selenium and zinc intakes were 34 +/- 10 microg and 8.7 +/- 2.0 mg, respectively. Subjects in the highest tertile of a functional capacity index had higher biochemical zinc and selenium values than those in the lowest tertile (P < 0.05). The correlation between plasma selenium and GPx indicates that selenium intake in these women is still insufficient for full expression of GPx activity. Lower serum zinc levels also appear to be prevalent. Because a suboptimal trace element status may be more common among those with a poor physical functioning, promotion of the consumption of nutrient dense foods or supplements to improve selenium and zinc status of elderly women in New Zealand may be beneficial.

Prevalencia de las deficiencias de zinc y cobre en adultos mayores de la Región Metropolitana de Santiago

“…Estudios realizados en distintos países muestran que los adultos mayores constituyen un grupo que presenta una elevada prevalencia de defi ciencia de zinc, especialmente en los grupos más pobres, en aquellos que se encuentran institucionalizados u hospitalizados y en los países en vías de desarrollo [11][12][13][14][15][26][27][28] . Sin embargo, la información referente a la prevalencia de la defi ciencia de cobre es prácticamente inexistente.…”

“…Diversos estudios nacionales 19,30,31 , regionales 13,15 , otros países en vías de desarrollo 27 e incluso de países desarrollados 26,28,32,33 han mostrado una ingesta inadecuada de zinc en los adultos mayores, acentuándose la reducción de la ingesta con la edad 5 . Por otra parte, una ingesta insufi ciente de cobre en este grupo etario ha sido demostrada en estudios nacionales 19,29 y algunos realizados en países desarrollados 32,34 .…”

Environmental Exposure to Trace Elements and Prostate Cancer in Three New Zealand Ethnic Groups

“…Intake estimates from the 1997 National Nutrition Survey were only two-thirds the Australian recommended daily intake. More recent studies in younger New Zealand adults still indicate an insufficient Se intake for full expression of glutathione peroxidase (GPx) and do not confirm the earlier findings of 1996 [22].…”

“…Therefore, the older the person the higher the blood Cd level is likely to be. It has also been suggested that, as populations age, their intake of Se and Zn decreases due to age-related changes in diet [22]. As prostate cancer risk increases with age, these changes in trace element exposure may further increase prostate cancer risk.…”

“…Furthermore, in the South Island, 100% New Zealand grown wheat is used in bread making, whereas in the North Island, between 50 and 100% imported wheat is used [22]. As older people are prone to low Se status and because intakes of Se are strongly correlated with those of total energy and protein [40], de Jong et al [22] conclude that this places the elderly living in the South Island of New Zealand at particular risk.…”