Written by Jessica Patella, ND. Study shows that daily consumption of 1.5 ounces of macadamia nuts significantly reduced total cholesterol and LDL cholesterol levels.
Cardiovascular disease is the leading cause of death in the United States and is largely preventable (1). A major cardiovascular disease risk factor is elevated LDL or “bad” cholesterol (2,3). Diet is the first line of therapy that is used to improve cholesterol levels (2). Recently, nuts have gained favor for lowering cholesterol because they are low in saturated fatty acids and help reduce cardiovascular disease risk (2,4). Current research has shown that macadamia nuts significantly lower LDL cholesterol levels (2).
The research study included 25 participants with moderately high levels of cholesterol (LDL 2.64-4.53 mmol/L) who were not taking cholesterol-lowering medications (2). Two experimental diets were used: the average American diet (AAD), and a macadamia nut-rich diet (MAC) that included 1.5 oz of macadamia nuts per day (about 15 nuts) (2). The AAD was based on the typical American diet as defined by the Continuing Survey of Food Intakes by Individuals via the National Health and Nutrition Examination Survey (NHANES) (2).
Participants were randomly assigned to consume one of the two experimental diets during a 5-week period. This was followed by a 2-week washout period, during which they ate their typical diet. They then finished with a second 5-week period during which they consumed the other experimental diet.
Breakfast, lunch and dinner were prepared for the participants at the Metabolic Diet Study Center at Pennsylvania State University (2). Six different caloric levels of meals were designed by the University to maintain body weight of individuals during the study. For example, a participant in the study weighing 150 pounds versus one weighing 250 pounds were given calorie-adjusted meals so their weights would stay stable (2).
Previous studies have suggested that for every 1 unit decrease in the TC:HDL ratio, there is a 53% decrease in the risk of heart attack (5). In the current study, the TC:HDL ratio was lower after the MAC diet compared to after the ADD diet (4.26 +/- 0.25 vs. 4.95 +/- 0.25; P<0.01), which correlates to about a 17% reduction in the risk of a heart attack (2).
In conclusion, 1.5 ounces of macadamia nuts daily significantly reduce total cholesterol and LDL cholesterol levels (2). This study adds to the evidence that nuts have beneficial effects on the cardiovascular system and should be recommended in a heart healthy diet (2). Further research with more participants should still be done in the future.
Source: Griel, Amy E., et al. “A macadamia nut-rich diet reduces total and LDL-cholesterol in mildly hypercholesterolemic men and women.” The Journal of nutrition 138.4 (2008): 761-767.
© 2008 American Society for Nutrition.
Posted December 5, 2011.
References:
- Prevalence of Heart Disease – posted on the Centers for Disease Control and Prevention website.
- Griel A, et al. A Macadamia Nut-Rich Diet Reduces Total and LDL-Cholesterol in Mildly Hypercholesterolemic Men and Women. 2008. J Nutr 138: 761-767.
- National Cholesterol and Education Program. Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III); 2001 May 16.
- Kris-Etherton PM, et al. The effects of nuts on coronary heart disease risk. Nutr Rev. 2001;59:103–11.
- Stampfer MJ, et al. Prospective study of cholesterol, apolipoproteins, and the risk of myocardial infarction. N Engl J Med. 1991;325:373–81.
