Nutritional Deficiencies Among the
From publishers of The New England Journal of
when healthy, people 90 and older can develop deficiencies in the vital micronutrients
zinc, selenium and vitamin B6, reports the February American Journal of Clinical
Nutrition. Such deficiencies may affect the abundance and efficacy of natural killer
cells, immune cells that seek out and destroy cancerous cells or infectious invaders.
Italian researchers examined the nutritional status of
62 healthy people aged 90 to 106 who were not taking nutritional supplements or drugs.
Deficiencies in zinc, selenium or vitamin B6 were found in approximately half of the
participants, while smaller percentages had deficiencies in vitamins A, E, B12 and folate.
People with the highest levels of zinc and women with the highest levels of selenium had
the highest percentage of natural killer cells in their blood. When placed in a test tube,
the natural killer cells of women with high levels of vitamin E were better at defeating
tumor cells than were the natural killer cells of women with low levels of vitamin E.
Though this study suggests that zinc, selenium and
vitamin E protect immune function, HealthNews associate editor George Blackburn,
M.D., says that there is no hard evidence that differences in the number of natural killer
cells influence our ability to fight infections and cancer. Still, he acknowledges that
because of poor dietary absorption as we age, elderly people sometimes develop nutritional
deficiencies. Nutrient-fortified food or a multiple vitamin and mineral supplement may
help ensure adequate amounts of micronutrients, says Dr. Blackburn.