Fear and uncertainty have caused people to hesitate before reaching for a handful of delicious, creamy macadamia nuts. But should we really hesitate to put trust in one of nature's wondrous foods? Convincing scientific trials claim multiple health benefits from munching on a handful of macadamias a day. No trial is actually needed, but a nod from scientific studies can often clear up confusing information and reassure us about a food's health benefits.

Several studies since 2000 have proven that macadamia nuts CAN be included in a heart healthy diet. Macadamias, like all plant foods, have no cholesterol, but they do contain 75% total fat, 80% of which is monounsaturated. This high level of fat would naturally be a concern to anyone trying to avoid excess fat in his or her diet. But these nuts possess amazing properties that actually lower cholesterol in spite of their high fat levels.

Their high fat level also scares people who want to watch their weight or have a few pounds to lose. Several study authors expressed the same concern but found their study subjects actually lost a few pounds or stabilized their weight in macadamia trials.

In a study in the April 14, 2008 issue of Science Daily, lead researcher Dr. Amy E. Griel of Penn State conducted a five-week cholesterol-lowering trial on male and female subjects with mildly elevated cholesterol by comparing the standard American diet with a diet substituting 1.5 ounces of macadamias for some of the fat and protein. Researchers matched the diets for fat content and reported the macadamia diet significantly lowered total cholesterol by 9.4% and LDL cholesterol by 8.9% compared with the standard American diet. The results were defining and the researchers stated that including macadamias in the diet lowered overall cardiovascular disease risk.

Because macadamia orchards are cultivated in diverse locations, the macadamia nut became a natural study subject in those regions. The University of Hawaii conducted a macadamia study in 2001 and reported similar success showing their participants consuming the macadamias decreased their total and LDL cholesterol when compared with those in the control group who followed the American Heart Association Step 1 Diet.

Macadamia nuts were the subject of a recent study conducted at the University of Newcastle in Australia and reported in the journal Lipids in 2007. The four-week study of 17 male participants with elevated cholesterol included 40 to 90 grams a day of macadamias. Researchers were looking specifically at blood markers for inflammation, coagulation, and arterial oxidation. The study authors found significantly lower blood markers of inflammation and oxidation. At the conclusion, the researchers suggested that regular consumption of macadamia nuts may play a role in reducing the biomarkers of oxidative stress, thrombosis, and inflammation, the typical risk factors for coronary artery disease.

While the macadamia’s rich fats proved successful in reducing coronary artery risk, researchers felt there may be other bioactive factors aside from the monounsaturated fatty acids that were imparting impressive health benefits. Examining more closely, they found the monounsaturated fats contain oleic acid, known as Omega 9, a beneficial fat found in other foods like avocados, almonds, and olive oil. Oleic acid is a naturally heart protective fat that helps to maintain the function and flexibility of the cell structure.

Findings at a 2002 macadamia conference in Australia show that the nuts contain plant sterols, which are natural plant fats found in fruits, vegetables, grains, nuts, and seeds and play a role in lowering elevated blood cholesterol and reducing the risk of heart disease.

Macadamias also contain palmitoleic acid, which makes up almost one-third of the content of monounsaturated fat. According to cardiologist Dr. Ross Walker at Walker Health Resources in Australia, “The palmitoleic acid in macadamias works to stabilize, the rhythm in the heart. Omega 3 fatty acids and the palmitoleic acid in macadamias settles the heart down.” He also believes that if you are prone to heart disease or to irregular heartbeats, you would benefit from a daily dose of 10 to 15 macadamias and reduce the risk of sudden cardiac death.

In July 2003, the FDA issued the following health claim statement: “Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts (such as almonds, hazelnuts, pecans, pistachios, peanuts, some pine nuts, and walnuts) as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.”

The FDA’s list of approved nuts for this health claim does not presently include macadamias because they exceed the limit of 4 grams of saturated fat per 50 grams of nuts. Macadamias contain 6 grams of saturated fat for the 50 grams, but researchers studying macadamias suggested they should be included considering their significant health benefits.

Over the years several studies agree that macadamia nuts are effective in the prevention of coronary artery disease and stressed they should be included in the daily diet by substituting them for other saturated-fat-containing foods. Aside from their multiple heart-health advantages, macadamias are just plain good eating and are an excellent source of high protein, high fiber, and healthful plant fats that make them a nutritious food. Enjoy macadamia nuts and reap the benefits.

REFERENCES:
Altonn, Helen. “Like Macadamias? You Can Keep Eating Them.” Star Bulletin. May 14, 2007.