Written by Greg Arnold, DC, CSCS. In a study of 37 severely obese women, all were deficient in selenium before the study and consumed one Brazil nut per day (one nut provides over 5 times the RDA of selenium). After 8 weeks all were sufficient in selenium and increased HDL (good) cholesterol by 18%.
Nuts are an energy dense food that have high amounts of monounsaturated fatty acids and polyunsaturated fatty acids (83-93% of total fat) and low saturated fat (7-17% total fat content). This unique fat profile is thought to be “an important contributing factor” to the beneficial health effects of frequent nut consumption (1).
Now a new study (5) suggests that Brazilian nuts may increase antioxidant levels in the body and improve fat profiles in obese women. In the study, 37 severely obese women (average body mass index 45 kg/m2) between the ages of 27 and 41 consumed one Brazilian nut per day for 8 weeks while filling out 3-day food assessments (6). They also gave blood samples to measure for levels of selenium, activity of an antioxidant enzyme called glutathione peroxidase (of which selenium plays an important role), and cholesterol. Selenium blood levels were specifically targeted because Brazilian nuts are extremely high in selenium. One Brazilian nut provides 290 micrograms of selenium per day, several times higher than the US RDA of 55 micrograms per day but well below the recommended upper intake of 400 mcg/d (7).
Before the study began, all of the patients’ blood levels had them classified as “deficient” in selenium, ranging from 38 to 82 micrograms per Liter. By the end of the study, all patients had “sufficient” selenium blood levels, ranging from 164 to 248 mcg/L (p < 0.001), an average increase of 240% per patient. There was also a 46% increase in Glutathione Peroxidase activity (36.6 to 53.6 micrograms per gram of Hemogloblin, p < 0.0001) and an 18% increase in HDL cholesterol levels (37.6 to 44.5 milligrams per deciliter, p <0.00001).
The significance of these results is that nutrient deficiencies like selenium (8), decreased activity of glutathione peroxidase (9), and low HDL levels are common among obese people and increase their risk of chronic illnesses like heart disease. For the researchers, “obese people who implement daily consumption of Brazilian nuts can improve both selenium status and lipid profile, especially HDL cholesterol levels, thereby reducing cardiovascular risks.”
Source: Cominetti, Cristiane, et al. “Brazilian nut consumption improves selenium status and glutathione peroxidase activity and reduces atherogenic risk in obese women.” Nutrition research 32.6 (2012): 403-407.
© 2012 Published by Elsevier Inc.
Posted September 28, 2012.
Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com
References:
- Sabate. J. Nuts, blood lipids and cardiovascular disease.AsiaPac J Clin Nutr 2010;19 (1):131-136.
- Kelly JH. Nuts and coronary heart disease: an epidemiological perspective. Br J Nutr 2006;96:S61–7.
- Tsai CJ. A prospective cohort study of nut consumption and the risk of gallstone disease in men. Am J Epidemiol 2004;160:961–8.
- Rajaram S. Nuts, body weight and insulin resistance. Br J Nutr2006;96:S79–86.
- Brazilian nut consumption improves selenium status and glutathione peroxidase activity and reduces atherogenic risk in obese women. Nutr Res 2012; 32(6): 403-407
- Basiotis PP, Welsh SO, Cronin FJ, Kelsay JL. Number of days of food intake records required to estimate individual and group nutrient intakes with defined confidence. J Nutr 1987;117: 1638–41.
- Selenium intake data obtained from the National Institutes of Health’s Office of Dietary Supplements website.
- García OP, Long KZ, Rosado JL. Impact of micronutrient deficiencies on obesity. Nutr Rev 2009;67(10):559–72.
- Vincent HK, Taylor AG. Biomarkers and potential mechanisms of obesity-induced oxidant stress in humans. Int J Obes 2006;30:400–18.
