Plain language summary
Increasing numbers of the population are overweight or obese, which increases the risk of metabolic diseases such as diabetes and heart disease. Overweight/obese individuals have increased low grade inflammation, which is thought to be an underlying process in disease development. This double blinded randomised controlled trial (RCT) aimed to investigate if dietary supplements could reduce inflammation and oxidative stress. Dietary supplements contained six nutrients (fish oil, green tea extract, resveratrol, vitamin E, vitamin C, and tomato extract) that had evidence of anti-inflammatory properties. Supplements were taken by thirty-six overweight male subjects for five weeks, following a crossover study design. Blood, urine and fat tissue samples were taken as markers of inflammation, oxidative stress and nutrigenomics. Although the main inflammatory marker was unchanged, the study did show a decrease in other inflammatory and oxidative markers, and increase in antiinflammatory markers. The highly sensitive nutrigenomnic measures were able to detect an overall metabolic change. The authors suggested that greater changes might be seen with a longer intervention period. The study showed that supplementation with antiinflammatory food extracts had a beneficial effect on inflammatory and metabolic processes in overweight individuals.
Abstract
BACKGROUND Low-grade chronic inflammation in overweight subjects is thought to play an important role in disease development. OBJECTIVE It was hypothesized that specific dietary components are able to reduce low-grade inflammation as well as metabolic and oxidative stress. DESIGN Dietary products [resveratrol, green tea extract, alpha-tocopherol, vitamin C, n-3 (omega-3) polyunsaturated fatty acids, and tomato extract] selected for their evidence-based antiinflammatory properties were combined and given as supplements to 36 healthy overweight men with mildly elevated plasma C-reactive protein concentrations in a double-blind, placebo-controlled, crossover study with treatment periods of 5 wk. Inflammatory and oxidative stress defense markers were quantified in plasma and urine. Furthermore, 120 plasma proteins, 274 plasma metabolites (lipids, free fatty acids, and polar compounds), and the transcriptomes of peripheral blood mononuclear cells and adipose tissue were quantified. RESULTS Plasma adiponectin concentrations increased by 7%, whereas C-reactive protein (principal inflammation marker) was unchanged. However, a multitude of subtle changes were detected by an integrated analysis of the "omics" data, which indicated modulated inflammation of adipose tissue, improved endothelial function, affected oxidative stress, and increased liver fatty acid oxidation. CONCLUSION An intervention with selected dietary products affected inflammatory processes, oxidative stress, and metabolism in humans, as shown by large-scale profiling of genes, proteins, and metabolites in plasma, urine, and adipose tissue. This trial was registered at clinical trials.gov as NCT00655798.
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