Taking two alcoholic drinks a day, eating vegetables and anything that lives in the ocean, but not meat, are some of the best ways to avoid heart disease, or to reverse it if you have it, said one of the nation's leading heart experts yesterday.

Dr. William P. Castelli, director of a Framingham, Mass., study on heart disease, gave this prescription for a healthy cardiovascular system at a seafood luncheon hosted by Sen. Ted Stevens (R-Alaska). Both were promoting seafood, one for hometown interests and the other for health.

Complaining that machines get more preventive maintenance than people in the United States, Castelli warned that heart disease is still the big killer, striking every fifth man over 50. But he said better eating habits could reverse the deadly tide of heart disease.

"Eskimos don't have heart attacks," said Castelli, "but if you live in this country you ought to be thinking about ways to hedge your bet" against contracting heart disease. One way to do this, he said, is to eat like the Eskimos, meaning passing up steaks for fish, clams, crabs, shrimp, lobster or anything else that lives in the sea.

"Anything (edible) in the sea is good for you," he said. Doctors were acting on flawed research when they advised people against eating shrimp, clams or lobsters. It turns out, he said, that the cholesterol in those delicacies is good for you, not bad as doctors thought.

There are five kinds of cholesterol, he said. The good one is high density lipoprotein, or HDL. Seafood is high in HDL, he said. Better yet, he said, an acid found in seafood, especially oily fish, lowers the four kinds of bad cholesterol and makes the fat-like substances in the blood so they do not build up within the arteries like rust in pipes.

As for alcohol, Castelli said two drinks a day, but no more, are better than none at all as far as keeping the arteries free of blockages. The doctor said this bit of good news about drinking was the most popular moment in his lectures.

However, the doctor warned that even two drinks can be dangerous for some people because they can lead to a craving for more. He said there is a growing body of evidence linking alcoholism to the way alcohol affects a person's metabolism. An orphan of alcoholic parents is more likely to become addicted to alcohol than one whose parents were teetotalers, Castelli said.

"We used to think it was psyco-social," Castelli said of alcoholism. "We're only beginning to understand that chronic alcoholism may be due to the fact that people are metabolically different" in the way their systems react to alcohol.