Redox state is similar in subjects following omnivorous, vegan, vegetarian, and low-carbohydrate high-fat diet

Age-related noncommunicable diseases are a major health burden in developed countries, with oxidative stress being a key contributing factor. This cross-sectional study aimed to test the hypothesis that redox status among 88 participants with a particular interest in nutrition and habitually following 4 popular dietary patterns (vegan, vegetarian, low-carbohydrate high-fat, and omnivorous), is similar, but correlates with diet quality. Dietary intake was assessed using food diaries, and venous blood samples were collected to measure serum total antioxidative capacity (TAC), bilirubin, nicotinamide adenine dinucleotide (NAD⁺)/reduced form of nicotinamide adenine dinucleotide (NADH) ratio, and sirtuin 1 concentration, and the expression of antioxidative enzymes in leukocytes. TAC and the NAD⁺/NADH ratio were higher in the vegan group compared with the vegetarian group, whereas bilirubin concentration was higher in the omnivorous compared with the low-carbohydrate high-fat group. Other differences between the dietary groups were not significant. NAD⁺/NADH ratio and sirtuin 1 were positively correlated with diet quality, assessed with the Healthy Eating Index. Correlation analysis between dietary variables and redox markers revealed only a few weak to moderate associations. However, a hierarchical regression model including age, gender, and dietary variables explained 19.8% of the variance in TAC, 21.2% of the variance in the NAD⁺/NADH ratio, and 44.3% of the variance in sirtuin 1 concentration. Therefore, in healthy, relatively young participants with appropriate energy intakes, endogenous mechanisms are able to compensate for oxidative stress to a similar extent, regardless of dietary pattern. Nonetheless, overall diet quality and food selection appear to play a meaningful role in redox balance.