Date: Fri 21-Jul-1995

Publication: Hea

Author: CURT

Illustration: I

Quick Words:

vitamins-genetics-immunity

Full Text:

Building Immunity With Vitamins And Genetics

Maude English wasn't sick a single day in the winter of 1988-89. She didn't

even have a sniffle. Neither did her husband, William.

That was the year they took vitamin-and-mineral supplements in a pioneering

study to determine if enhanced nutrition can boost immunity in older people.

The answer was a dramatic yes.

Such discoveries, and others in immunology, could revolutionize the prevention

and treatment of illness, from colds to cancer.

By girding the body to fight its own biological battles - through nutrition,

vaccines and genetic engineering - scientists are opening a new world.

They are 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 were part of a year-long Canadian study involving 96 seniors.

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," says Mrs English, now

73, who lives with her 83-year-old husband in St. John's, Newfoundland. In

other years, when they haven't taken the supplements, they have been less

certain to avoid illness, she says.

The study was a "landmark" in research about diet and immunity, says Jeffrey

B. Blumberg, associate director of the US Department of Agriculture's Human

Nutrition Research Center on Aging.

Dr Blumberg did not take part in the work, led by Dr Ranjit Chandra, an

immunologist at Memorial University of Newfoundland, but he says related US

research supports it.

Diet is "fundamental" to healthy immune functioning, especially in the very

young and the elderly, says Dr Blumberg, a professor of nutrition at Tufts

University in Boston.

"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 says. "You have less resistance. You get

sicker more easily with any virus or bacteria."

John Bogden, a professor at New Jersey Medical School in Newark, found that a

standard over-the-counter multivitamin-and-mineral supplement made a

significant difference in immune response among seniors he studied, as

measured by skin tests.

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," Dr Bogden says. It often took a full year

for immune enhancement to develop, especially among women.

Other studies suggest nutrition can have powerful effects on immunity in

younger people.

HIV-positive men 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. But their

AIDS risk was three times higher if they had consumed excess zinc.

A recent follow-up of the original 281 subjects indicates that vitamins B-1,

B-2, B-6 and niacin were the most important, said Dr Neil N.M. Graham,

presenting updated findings in late April at the First International

Conference on Nutrition and HIV in Cannes, France.

Stimulating The

Immune System

In the AIDS fight, nutrition is only a tiny piece of the picture.

Frustrated by their failure to find a drug that will kill the fast-mutating

HIV, scientists are working on ways to boost immunity through gene therapy and

powerful immune stimulants such as interleukin-2.

Interleukin-2 also has shown promise in the fight against spreading tumors of

the kidney and skin.

About 5 percent of 283 patients receiving high doses of the genetically

engineered drug became cancer free and remained that way for seven months to

eight years, the longest any patient in the study was followed, a study

published last year in the Journal of the American Medical Association said.

The lead researcher, Dr Steven A. Rosenberg, chief of surgery at the National

Cancer Institute, says interleukin-2 continues to be promising.

But probably the most exciting recent development is the identification of

genetic coding for cancer cells that will trigger an immune response, he says.

"That opens a lot of new possibilities for the development of cancer

vaccines." A new genetically engineered cancer vaccine prevented tumors in

animals and shrank existing tumors without chemotherapy, researchers at the

University of Pennsylvania and Johns Hopkins University reported in May.

The researchers said the vaccine potentially could treat several human

cancers, including melanoma and cervical cancer.

Though not for cancer, new vaccines continue to be developed and marketed,

making the world of infectious diseases less threatening.

"The major new thing is the vaccine for hepatitis A," says Dr David A. Sack,

professor of international health at the Johns Hopkins School of Hygiene and

Public Health.

An improved vaccine for typhoid fever also is available, and a vaccine for the

most common type of traveler's diarrhea is expected within a couple of years,

he says.

With other diseases, travelers still must take their chances.

The flu vaccine you get in America in November may not protect you from the

flu strains roaming Australia in June, when it is winter there, Dr Sack says.

However, even the flu vaccine is undergoing improvements. Scientists from

Merck Research Laboratories in West Point, Pa., reported in May that they hope

to develop a flu vaccine that would protect against a wider variety of

strains.

Pfizer Inc. has announced that it will study traditional Chinese herbs to

determine whether they can be used for modern medicine. The study will be done

in conjunction with scientists at the Beijing Institute.