stock up on calcium and lessen chances of getting osteoporosis later in life, a Purdue University study has found.

Purdue researchers discovered that calcium absorption in young women peaks near the onset of menses and declines for the rest of their lives. Low calcium intake during adolescence has been associated with osteoporosis in later years, the study said.

"One of the key findings of our study was that young girls retain more than four times as much calcium as women just a few years older,'' said Connie M.

Weaver, a principal investigator for the study, whose findings appeared in the American Journal of Clinical Nutrition. The study suggests that young girls may be able to absorb higher levels of calcium than previously thought.

Ms. Weaver, the head of Purdue's foods and nutrition department, conducted the study in 1990 with 14 girls between 11 and 14 and 11 women aged 19 to 32. They stayed at a Purdue sorority house, dubbed "Camp Calcium,'' where calcium intake, diet and eliminations were regularly monitored and measured.

*** Neither Maude English nor her husband William was sick a single day in the winter of 1988-89.

That was the year they took vitamin-and-mineral supplements in a pioneering Canadian study to determine if enhanced nutrition can boost immunity in older people -- and the answer was a dramatic yes.

Such discoveries in immunology could, the study seemed to prove, revolutionise the prevention and treatment of illnesses from colds to cancer.

By girding the body to fight its own biological battles through nutrition, vaccines and genetic engineering, it further showed, scientists are opening up a whole new world, giving people better odds of staying healthier later in life, avoiding a wider variety of diseases at every age and prevailing over the illnesses they get.

The Englishes, of St. John's, Newfoundland, were participants in a year-long study that involved 96 seniors. Among the study's findings was the discovery that those who took specially formulated supplements got about half as many infections, needed about half as many antibiotics and had more disease-fighting cells in their bodies than those who took placebos.

"We never had a cough or a cold for the whole winter,'' Mrs. English, now 73, told the Associated Press. In other years, when they hadn't taken the supplements, they had been less certain to avoid illnesses, she added.

The study, which was led by Memorial University immunologist Dr. Ranjit Chandra, was a "landmark'' in research about diet and immunity, said Jeffrey B. Blumberg, the associate director of the U.S. Department of Agriculture's Human Nutrition Research Center on Aging.

Blumberg did not take part in the work, but he said that related US research supported it.

"Infectious disease is the fourth leading cause of death among older people, and a lot of that has to do with the fact that there seems to be a decline in the immune system with age,'' he said. "You have less resistance.

You get sicker more easily with any virus or bacteria.'' Using a battery of skin tests, John Bogden, a professor at New Jersey Medical School in Newark, similarly found that a standard over-the-counter multivitamin-and-mineral supplement made a significant difference in immune response among the seniors that he studied.

Edibles ...

His findings among 56 subjects ages 59 to 85 were published in the American Journal of Clinical Nutrition in September.

"These improvements are not rapid,'' Bogden said. It often took a full year for immune enhancement to develop, especially among women.

Other studies, including some that involved HIV-positive men, suggest that nutrition can have powerful effects on immunity in younger people.

The HIV-positive men, for example, had a 40-percent to 48-percent reduced risk of developing AIDS over seven years if they had been consuming moderate to large doses of vitamins A, C, B-1 and niacin, a 1993 Johns Hopkins study found.

The same research concluded, however, that the AIDS risk was three times higher if the men had consumed an excess of zinc.