Obesity is a metabolic disorder characterized by increased body fat, oxidative stress, and chronic low-grade inflammation that can trigger problems such as hypertension, diabetes, and cardiovascular disease. Furthermore, this inflammatory state can affect intestinal permeability, further aggravating the inflammation.
To combat obesity, a healthy diet and calorie control are often recommended. Some foods, such as Brazil nuts, are known for their anti-inflammatory properties, thanks to their high content of selenium, a mineral essential for antioxidant defense and inflammation regulation. However, the full effects of these nuts on gut health are not fully known and require more research.
A new study carried out at the Federal University of Viçosa in Brazil between 2019 and 2021 has analyzed the effects of daily consumption of Brazil nuts on inflammatory markers and intestinal permeability in overweight or obese women who followed a calorie-restricted diet. .
Their results have been published in The Journal of Nutrition and reveal that daily consumption of Brazil nuts significantly reduced inflammatory markers and improved some aspects of intestinal permeability. These effects appear to be related to increased selenium levels, suggesting that selenium could be key in reducing inflammation and improving gut health in overweight or obese women.
High levels of selenium associated with better intestinal health
Researchers conducted an eight-week, nonrandomized dietary intervention study focusing on adult women with a body mass index (BMI) greater than 27. Participants had excess body fat and at least one cardiometabolic risk factor, such as an elevated waist circumference.
The women were divided into two groups: one that followed a diet without nuts (control group) and another that consumed 8 grams of Brazil nuts daily. Both groups were on a calorie-restricted diet with the goal of losing at least 4 kg of weight. During the study, fat intake was also controlled by using specific oils in their salads: canola oil for the Brazil nut group and soybean oil for the control group.
Various parameters were measured at the beginning and at the end of the study, such as body composition, dietary intake and inflammatory biomarkers in the blood. Intestinal permeability was evaluated through a test with lactulose and mannitol. Of the 56 women who began the study, 49 completed it, with a mean age of 34 years. 82% of the participants were obese to varying degrees. During the intervention, the Brazil nut group significantly increased their intake of selenium and fiber, while the control group reduced their intake of saturated fatty acids.
All of the women lost weight and reduced their waist circumference, but those who took Brazil nuts also experienced a significant reduction in inflammatory markers.
Although both groups lost weight similarly (about 2.4 to 3.2 kg) and also reduced their waist circumference, the group taking Brazil nuts showed a noticeable improvement in blood selenium levels, as well as reductions significant in inflammatory markers, such as C-reactive protein (CRP), tumor necrosis factor (TNF) and the interleukins IL-1β and IL-8. Likewise, more women in this group managed to normalize their CRP levels compared to the control group.
Regarding intestinal permeability, both groups showed similar changes, although the Brazil nut group presented a slight reduction in lactulose excretion, indicating an improvement in the intestinal barrier. Correlations were also observed between increased blood selenium and reduced levels of the interleukins IL-1β and IL-8, thus linking selenium intake with better intestinal health.
