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Caffeine's Bad Rap With Heart Patients

April 20, 1989|DANIEL P. PUZO | Times Staff Writer

Heart disease patients have little to fear from moderate amounts of caffeine in their diets, according to Harvard University researchers.

In fact, a recent study, published in the Archives of Internal Medicine, found that there was no detectable change in heart rates among those who ingested the equivalent of two cups of coffee in a single sitting.

For years this group has been warned to avoid the compound because of potential harmful effects. But the results demonstrate, according to the report, that caffeine's ability to accelerate heart rhythms to dangerous levels is based more on folklore than fact.

Thomas B. Graboys MD and his colleagues in Harvard's School of Public Health designed the study to examine the effects moderate amounts of caffeine might have on the heart. Those selected for the research project suffered from arrhythmia, or irregular heartbeat patterns.

The researchers organized 50 subjects into two groups. Each of these were served decaffeinated coffee while being monitored by electrocardiographs. However, researchers added 200 milligrams of caffeine to the drinks served to half of the sample. (A regular cup of coffee contains approximately 100 milligrams of caffeine.)

The electrocardiograph detected no difference between the two groups' heart rates during the comparison, according to Archives of Internal Medicine.

The study's authors conclude that there is no evidence that modest amounts of caffeine disturb heart rhythms "even among patients with known, life-threatening arrhythmia," the article states.

A small number of people may be caffeine-sensitive, the researchers concede. And these individuals, if also considered arrhythmia patients, may experience an aggravation of their condition when exposed to the compound. However, this condition can be detected and avoided, according to the report.

For the record, caffeine is an alkaloid that stimulates the cortex of the brain, and in small doses can improve attention, concentration and coordination, according to Harold McGee's "On Food and Cooking" (Charles Scribner's Sons, New York: $29.95). It can also increase the contraction of skeletal muscles, making them less susceptible to fatigue. High doses, though, can cause a range of problems, the symptoms of which are compounded in children.

Bedtime Stories--Folklore was also at the heart of a recent report on the myths surrounding home-made sleep aids.

The article, in the UC Berkeley Wellness Letter, was skeptical of those who claim that warm milk will hasten sleep, for instance.

"No food eaten at bedtime will guarantee a good night's sleep," according to the newsletter, which is published by the university's School of Public Health.

High-proteins foods, such as meats and dairy items, may contribute to the sleep process, but only indirectly. These products contain large doses of tryptophan, an amino acid that helps the brain produce serotonin, a neurotransmitter, that brings on feelings of sleepiness and satisfaction. But the amounts of tryptophan found in foods is not sufficient enough to effect sleep habits, according to the Wellness Letter.

"Attempts to treat sleep disorders through diet alone have had inconclusive results," the article stated.

Another remedy that wilts under scientific scrutiny is the "nightcap" theory.

"Alcohol may help you fall asleep, but the sleep will probably be fragmented, light and unsettled, and you're likely to wake up suddenly," the newsletter reported.

Those who refrain from eating during the evening hours out of concern for their weight accomplish little from this device alone, the survey found.

"There's no evidence that calories consumed at night are stored more easily as fat than those taken in during the day," the Wellness Letter states.

If the food being consumed at night, however, is not part of a typical diet and is, instead, high-calorie snack products then there is likely to be weight gain. But the food choices would be the source of any waist-line expansion, not the time of consumption, according to the report.

The article also makes several sound suggestions for a good night's sleep. One logical step is to avoid caffeine within four hours of bedtime. Smoking at night is also ill-advised because the nicotine acts as a stimulant. And any strenuous exercises should be completed at least two hours before bedtime.

Concerned About Cleansing--Washing produce with solutions containing anything other than water may be compounding the residue problem on fruit and vegetables rather than solving it, according to federal officials.

In the public's rush to remove farm chemicals, many have begun cleansing produce in solutions of soapy water. Others have turned to diluted bleach and water rinses.

The U.S. Department of Agriculture is now advising consumers to wash fruit and vegetables only with fresh water as a means of removing surface chemicals, dirt and bacteria. In a recent statement on the issue the agency also warned about the use of soap and water on produce.

"Soap residues may be difficult to remove from some foods and soap is not intended to be consumed," the advisory stated.

Water is effective on removing surface residues and other debris, according to the agency. Brushes can be also used to scour thick-skinned produce.

The advisory did not, however, address the issue of commercial fruit and vegetables washes recently being marketed by several companies.

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