Older Americans Healthier Than Common Stereotypes

Americans over 65 are commonly thought to be frail and ill, but in fact most live vigorous, active, independent lives, a new study concludes.

"The truth is that most elderly live independently," epidemiologist Judith B. Cohen of the University of California at San Francisco told a recent conference of the American Association for the Advancement of Science. "In fact, only 5 percent are in institutions."

Even among the "old old," people over 85, three out of four can walk without help and 80 percent can dress and bathe themselves.

Among Cohen's other findings:

*Older people are more likely to retire because of company policies than ill health.

*Three out of four people over 65 own their home, and most have paid them off.

*Most men over 65 are married and live with their wives. Most women over 65 are widowed, and many live alone.

*Few older people want to live with their children, although most see them frequently.

*About 1 million Americans need "major assistance" in household chores to remain independent. Windsurfing on Polluted Waters

For nine days in August, Canadian windsurfers were falling off their boards and into polluted waters. The resulting sickness was enough to convince some public health experts that the same clean-water rules that apply to swimming should also apply to the increasingly popular surfboard sport.

Currently, windsurfing is "tolerated on waters judged unsafe for swimming," Dr. Eric Dewailly and colleagues at Universite' Laval in Quebec writes in the current American Journal of Public Health.

But in the 1983 competition in Beauport Bay, in which 84 people competed, the average windsurfer participated in seven three-hour races and fell 18 times. Concentrations of human waste bacteria in the bay are "frequently above acceptable limits," the journal reports.

About half of the competitors came down with symptoms including diarrhea, abdominal pain or infection of cuts. Everyone who fell more than 30 times was affected.

No one quit the tournament because of the illnesses, but some performed poorly and were eliminated from further competition, "which could have been a consequence of their illness," they write.

"Recreational windsurfers are at even higher risk," Dewailly writes, "as they fall more often than professionals." Pepper Bothers the Stomach, Mimicking Aspirin's Effect

Pepper causes slight bleeding of the stomach, researchers in Texas report.

But they don't know if this reaction is good, bad or simply unimportant.

The researchers at the Baylor College Veterans hospital in Houston examined the stomach contents of patients who had eaten meals with red or black pepper, looking for traces of blood and certain digestive chemicals. In all cases, the patients had excess acid and loss of potassium, the same reaction caused by aspirin.

Aspirin is known to irritate the stomach and cause damage to its lining with long-term use. But the effects of long-term use of spices is unclear.

It is possible that by irritating the stomach lining, pepper and other spices are actually good for the stomach lining by inducing a protective reaction in that is soothing and healing.

The research, conducted under a federal grant by Dr. David Graham, was presented recently to a meeting of the Gastroenterological Association in San Francisco. Magnesium Shortage Linked To Stroked in Alcoholics

Brain damage and strokes, common problems among chronic alcoholics, may be treatable or preventable with magnesium, new research suggests.

In experiments on rats, magnesium dilated blood vessels that had been constricted by alcohol, and also prevented blood vessel spasms, State University of New York researchers told a recent conference of the Federation of American Societies for Experimental Biology.

One of the effects of drinking large amounts of alcohol, according to Burton M. Altura and his colleagues, is depletion of magnesium from the body. When magnesium is restored, they have found, blood vessels relax and blood pressure improves.

In their experiments on rats, they found that when alcohol is injected into the brain, it caused blood vessels to burst, similar to what happens in alcohol-induced strokes in people. But if the rats were treated with magnesium first, then the strokes did not occur.

"Such findings suggest that alcohol makes us euphoric and lightheaded because it constricts blood vessels in the brain, thus reducing the blood flow to the point that some key neurons are starving for oxygen," Altura told the conference.

They said that alcoholics who do not eat enough magnesium may be especially at risk for brain hemorrhage. The mineral is found in leafy green vegetables, almonds and cashews, soybean seeds and whole grains. Ear Piercing Can Spark Allergy to Metals

Ear piercing can awaken a dormant allergy to metal, rendering a person unable to wear many kinds of jewelry, dermatologists warned recently.

"The allergy often becomes active after a trauma to the skin," Dr. Alexander Fisher of New York University told the American Academy of Dermatology at its May conference.

In most cases, nickel is responsible. The metal is often present in gold, silver and platinum objects, and is usually also in costume jewelry.

If the piercing needle contains nickel, Fisher said, it can spark a reaction in the earlobe, which in turn sensitizes the entire body. After that, a rash develops any time metal jewelry is worn, especially in summer, because perspiration reacts with the metal.

He said ears should be pierced only with a stainless steel needle. Although stainless steel contains nickel, it is bound so tightly that it does not react with the skin. While the ears heal, only earings with stainless steel posts should be worn.

People allergic to nickel might benefit by eating less of the mineral, some researchers believe. Foods high in nickel include apricots, chocolate, coffee, beer, tea and nuts.

And there are wardrobe alternatives, he said. Brass and copper, for example, do not contain nickel. But white gold almost always does. Dermatologists can provide test kits to test jewelry. On the Pulse

As of tomorrow, District motorists stopped for a traffic violation can be slapped with a $15 fine for not wearing a seat belt. (A similar law takes effect in Maryland July 1.) But there's an even better reason to buckle up: Of the 139 drivers and passengers killed in traffic accidents in the District in the past five years, 137 were not wearing seat belts . . . Six in 10 Americans say they wouldn't mind their organs being transplanted after death, "even if I have never given anyone permission," according to a Gallup poll commissioned by Dow Chemical. But only 19 percent have completed donor cards . . .