A Penn State study found that iron deficiency impaired levels of immunity from 28 to 50 per cent in a group of seemingly healthy, well-nourished, homebound, older women, aged 60 and above.
The research group leader, Dr. Namanjeet Ahluwalia, associate professor of nutrition at the university, said that women who are suffering what they believed to be the effects of aging, namely "being fatigued easily, breathlessness, attention problems, or frequent infections", should go to see their doctor and find out if rather than old age these complaints are related to undernutrition, specifically iron deficiency.
The study included 72 women, 60 or older, living in three rural Pennsylvania counties who were considered healthy, free of inflammation and generally well nourished. However, assessments of their iron stores found many of them iron deficient to a lesser or greater degree.
"Although half the iron-deficient women were anaemic, the rate of iron deficiency we found was moderate," said Ahluwalia. "The subjects ranged from a few who were severely deficient and had low hemoglobin, to those who had normal hemoglobin and whose other tests were subnormal."
The researchers then subjected the cells from the blood samples of the iron-sufficient and iron-deficient women to several immune response tests.
In one test, white cell, called T-cells, were stimulated with two chemicals that simulate response to infection in the body. T-cells normally respond by multiplying when faced with such a challenge. In the iron deficient women, the T-cells response was only 40 to 50 per cent that of the iron-sufficient women.
In another test, granulocytes, another type of white blood cell, were challenged with bacteria. Granulocytes usually ingest bacteria and kill them with an oxidative burst. While the extent to which granulocytes ingested the bacteria did not differ significantly by iron status, the magnitude of the oxidative burst was 28 per cent less in iron-deficient women suggesting a potentially reduced capacity of these cells to kill bacteria.
"We are conducting a follow-up project to study the effects on immunity of correcting iron deficiency via supplements," concluded Ahluwali, who will describe these findings at the 4th European Congress on Nutrition and Health in the Elderly in France in November.
A study published last month also drew attention to the potential importance of iron supplementation in the elderly. It stated that anaemia, a condition caused by vitamin and mineral deficiency particularly of iron, vitamin B12, and folic acid, doubles the risk of serious physical decline in the elderly.
This was the first study to find an association between physical decline in later life and anaemia, a blood condition that affects about 13 per cent of older Americans. It also found that older people who do not yet have anaemia, but whose blood levels show they could be close to developing the condition, are 1.5 times more likely to develop physical declines than those who have normal blood haemoglobin levels.
"This study suggests that even mild anaemia is a risk factor linked to reduced ability of older people to function at their fullest potential," said Dr Jack Guralnik, an epidemiologist who co-authored the study, published in the 1 August issue of the American Journal of Medicine .