New Hope for a Nut With a Past : Nutrition: Hawaii’s macadamia growers are counting on a boon from preliminary research that points to health benefits.

Macadamia nut growers, a mainstay of Hawaii’s move to diversify its agricultural base, are pinning their hopes for new growth on preliminary research showing that the nuts with the sinfully rich image may contribute to a healthy heart.

Dr. J. David Curb, director of the Honolulu Heart Program at Kuakini Medical Center and research director of geriatric medicine at the University of Hawaii, says people laugh when he tells them he is trying to prove macadamia nuts can be good for you.

“Nobody takes you seriously,” he said. “But having gone into this as a skeptic myself, I’m convinced that we’re on to something.”

Early research suggests that macadamias are not detrimental and may even help prevent heart disease by improving cholesterol levels, according to Curb. The results of pilot studies have been intriguing enough to prompt the federal government to set aside more than $400,000 for a scientific study at the University of Hawaii.

However tenuous the evidence, Hawaii officials are ready to back just about any scheme that might boost the islands’ sagging agricultural sector. Sugar and pineapple, long the pillars of Hawaiian agriculture, are tottering. A century-old sugar plantation, the state’s second-largest, shut down last week, and the island of Lanai, dubbed the Pineapple Island, has abandoned its namesake in favor of resort hotels.

Macadamia nuts, first planted in earnest commercially in the early 1950s, have been one bright spot in Hawaii’s effort to diversify its crops. The state’s orchards now account for more than half the world’s production. But the nut’s image as fattening--and therefore unhealthy--takes a toll.

“Most people feel guilty when they eat macadamia nuts,” said Curb, who will head the Macadamia Nutrition Research Project. “But the nuts don’t deserve the reputation they’ve got.”

Among the preliminary research findings:

* A pilot study at the university found no change in weight or cholesterol levels for 74 subjects who ate as many as 50 dry-roasted macadamia nuts a day for four weeks. The rest of their diet was not strictly monitored, however.

* An eight-week study at Wesley Hospital in Brisbane, Australia, compared a macadamia-nut-enriched diet, totaling 40% fat, with a low-fat, complex-carbohydrate diet, totaling 20% fat. Cholesterol levels of the 14 subjects on both diets dropped 7%.

* Research by Yukio Yamori of Kyoto University in Japan found that rats prone to hypertension and stroke survived longer on a diet containing palmitoleic acid, which is derived from macadamia nuts.

“Given that heart disease is the No. 1 killer disease in the United States, it is important to conduct additional research to explore these possible benefits,” Curb said.

Dr. Henry Ginsberg, professor of medicine and chief of the Lipid Clinic at Columbia University, says none of the macadamia nut studies are solid enough to prove anything yet.

Controlled, long-term research is necessary before any conclusions can be reached. But macadamia nuts should not be written off as simply a high-fat food, he said. Because they contain mostly mono-unsaturated fat, a “good” fat, macadamias can be a good replacement for animal fats.

“You don’t want to put nuts on top of your ice cream,” he advised. “You want to cut the Haagen-Dazs in half and then add the nuts.”