NEW YORK, Feb 02 (Reuters Health) -- Healthy diets may help women keep
their immune systems youthful as they age, researchers at Pennsylvania State
University report.
In a study of immune function in 75 well-nourished women aged 60 to 80,
the investigators found that the women's immune systems were nearly as strong as
those of women aged 20 to 40. This stands in contrast to previous research
suggesting that immune function normally declines with age -- but many of these
studies failed to take subjects' nutritional status into account, according to
Dr. Namanjeet Ahluwalia, an assistant professor of nutrition at Penn State in
University Park, and colleagues.
Their findings, published in the current issue of the journal Mechanisms
of Ageing and Development, suggest that healthy eating habits may offer a
"natural means" to maintain the body's ability to fight off infections and
reduce illness in old age, Ahluwalia said in a statement. She and her colleagues
note in their report that various vitamin and mineral deficiencies may impair
the immune system.
In the Penn State study, immune function in older women was compared with
that in 35 women aged 20 to 40. All women in the study were screened for
infections or chronic conditions that affect the immune system and for
deficiencies in protein, iron, vitamin B12, and folic acid. Such deficiencies
have been linked to impaired immune response. After determining that the women
were well nourished, the researchers judged their immune function by examining
particular immune-system cells in blood samples.
Ahluwalia's team found that regardless of age, the women showed similar
numbers of immune cells called T cells, including the "killer" T cells that are
key to warding off invading pathogens. They also had comparable numbers of
"natural killer" cells. When the researchers introduced two types of foreign
substances, however, T cells in the older women did show a lesser response than
those of the younger women.
Still, Ahluwalia and colleagues report, "most immune parameters were not
compromised with aging in this (group) of apparently healthy, well-nourished
women." This, according to Ahluwalia, shows that "when nutritional and health
status are maintained, the body's ability to defend itself against viruses,
bacteria, or tumor cells may not necessarily be affected with aging."
While the women in this study were tested for levels of protein, iron,
vitamin B12, and folic acid, the researchers note that future studies should
look at the importance of other nutrients in maintaining a healthy immune
response.
