Neither coffee nor moderate use of alcohol causes heart attacks, and a few drinks a day may actually help protect against heart disease, according to the lead article in today's New England Journal of Medicine.

The conclusio is drawn from six years' study of heart disease among 7,705 men of Japanese descent in Hawaii. In an accompanying editorial, Dr. William Kannel - a leading authority on causes of heart disease - says several other American and European studies, studies cutting across racial lines, have found similar evidence.

Base on what doctors now know, adds Kannel, "It is encouraging to note that not everything one enjoys in life predisposes to cardiovascular disease. There is nothing to suggest, for the present, that we must give up either coffee or alcohol in moderation to avoid a heart attack."

"I am sure that many who read this editorial will be quite willing to drink to that statement," he concludes.

The examination of Hawaiian men was made by the federally funded Honolulu Heart Study, headed by Dr. Abraham Kagan. Drs. Katsuhiko Yano, George Rhoads and Kagan report that in the 294 men who developed coronary heart disease, there were fewer moderate drinkers and more nondrinkers than the group's average.

By moderate drinking, "we mean one, two, possibly three drinks a day," Kagan said by telephone yesterday. He defined a single drink as "a 1 1/2-ounce jugger of whiskey, a bottle of beer or" - with less certainty because of "so little evidence" on wire drinkers - "a four-ounce glass of table wine."

Kagan and Kannel cautioned that heavy drinking can severely harm the heart and other organs; that alcohol and coffee may have to be limited in some persons (for example, those subject to irregular heartbeat) and that doctors can base their recommendations only on current knowledge, not what someone might learn tomorrow.

"Alcohol isn't a completely innocuous beverage by any means" and "the evidence on coffee is perhaps not completely in yet," Kagan said.

Honolulu data now under development may show some connection between moderate alcohol consumption and some kinds of strokes, he reported.

In an unrelated study, doctors at the Kaiser Permante Medical Center in Oakland, Calif., have found that three or more drinks daily increase the risk of developing high blood pressure, which does increase the risk of both heart disease and strokes.

The just-published study of 102 largely professional and business men in Southern California found some "significant" loss of mental processes - specifically, "higher-ordered cognitive processes" like ability to adapt, form concepts and shift from one idea to another - in perfectly sober men who usually consumed only two drinks per occasion.

This study was made by Drs. Elizabeth Parker and Ernest Noble, who are both now at the government's National Institute of Alcohol Abuse and Alcoholism in Rockville, where Noble is the institute's director.

Another scientist, Dr. Floyd Bloom of the Salk Institute in San Diego, said he has not yet seen the Parker Noble study. But he disputed some past reports that even moderate alcohol use destroys brain cells. He called that "kind of an old wives' tale of neuropathology," but one not backed by good data.

Dr. Parker agreed, but said: "Our study shows we need to look at social drinking more carefully. We definitely shouldn't go around saying everything is hunky-dory for the social drinker. We just don't know."

"I drink," she reported, but evidence like the California study's "has made me more reflective about my drinking. The National Institute on Alcohol Abuse is planning more studies of social drinking.

As to alcohol and coffee, there have been some past reports linking both with heart disease. In today's New England Journal, Kannel says "all prospective studies" - studies which follow people through life rather than just looking back at possibly misleading statistics - have found coffee not guilty. He says studies that seemed to implicate coffee failed to take into account the fact that many coffee drinkers were also heavy cigarette smokers.

Kannel cited several reports that moderate alcohol use may protect the heart's blood vessels. One still "does not want to make too much" of this possibility, he said, but, at the least, past information "incriminating alcohol" in causing heart disease is unconvincing.

Kannel directs a medically famed "Framingham study" that seeks to identify heart disease "risk factors" in our lifestyles. So far, he says, only cigarette smoking, obesity and physical activity have been "firmly incriminated."