Reduction of Obesity-Associated Oxidative Stress by Low-Fat Yogurt Consumption

Excess macronutrient intake leads to an increase in formation of reactive oxygen species (ROS). This causes an imbalance between ROS generation and the ability of the body to neutralize these radicals, a state known as oxidative stress. Previous research suggests the ability of dairy products to attenuate the postprandial response, which may reduce ROS formation. Therefore, this study aimed to elucidate the impact of low-fat yogurt consumption on fasting and postprandial oxidative stress in obese women. We hypothesized that co-consumption of low-fat yogurt and a high-calorie, high-fat meal would reduce postprandial elevations in oxidative stress in obese women. To test this hypothesis, healthy, lean and obese women co-consumed low-fat yogurt or soy pudding (control) and a high-calorie, high-fat meal on 2 occasions separated by 9-week daily yogurt or pudding consumption. Postprandial blood samples were collected for 4 h during meal challenges and fasting samples were collected at 3 week intervals throughout the duration of the intervention. Fasting and postprandial plasma samples were analyzed for malondialdehyde (MDA), total thiols (SH), and advanced glycation endproducts (AGEs). A secondary aim of this work was to classify changes in dietary intake associated with the intervention; data was based on 3-day self-reported dietary records. Low-fat yogurt consumption did not lead to changes in BMI, waist circumference, or blood pressure. Consumption of low-fat yogurt attenuated postprandial increases in MDA in obese women at both the initial and final meal challenges. However, 9-week yogurt consumption did not further attenuate the postprandial response and had no effect on fasting MDA concentrations in obese women. Yogurt and pudding prevented postprandial changes in SH and AGEs, while chronic plasma SH and AGEs were unaffected by 9-week yogurt or soy pudding intake. Daily consumption of low-fat yogurt and soy pudding increased calcium and vitamin D intake and yogurt increased dairy intake in lean and obese women. Therefore, the addition of low-fat yogurt to the diet may be a strategy to increase dairy, calcium, and vitamin D intake without inducing any unfavorable changes in body composition, blood pressure, and postprandial or chronic levels of oxidative stress