Abstract
Objectives
Systemic low-grade inflammation mechanistically links obesity to impairments in the metabolic processes central to the development of type 2 diabetes and cardiovascular disease. This phenomenon is promoted by digestion of a high-fat meal, whereas whole foods with proposed anti-inflammatory actions, such as apples, may be beneficial. Thus, the current studies aimed to assess the effects of acute and chronic consumption of whole apples on biomarkers of inflammation in overweight and obese adults.
Methods
Overweight or obese adults in otherwise good health were recruited. With n = 26 (17 female/9 male; mean age 45.5 ± 3.1 y; mean BMI 34.1 ± 0.2 kg/m2), a randomized, crossover trial was conducted to assess the effects of acute (one time) consumption of 3 whole Gala apples (∼200 g) on the 6 h postprandial inflammatory response (e.g., plasma gut-derived lipopolysaccharide (LPS), cytokines) to an oral fat tolerance test (1 g fat/kg body weight). Fasting and 4 h postprandial peripheral blood mononuclear cells (PBMCs) were also isolated from whole blood and stimulated with 10 ng/mL LPS for 24 h to measure secreted cytokines. With n = 46 (32 female/14 male; mean age, 46.2 ± 2.2 y; mean BMI 33.5 ± 0.8 kg/m2), a parallel-arm, randomized, controlled trial was conducted to assess the effects of chronic (6 week) consumption of 3 whole Gala apples per day (∼200 g) on fasting inflammatory markers.
Results
Acute apple consumption decreased 4 h postprandial unstimulated (IL-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage inflammatory protein (MIP)-1β, TNF-α) and LPS-stimulated (IL-6, TNF-α) PBMC-secreted inflammatory cytokines (P < 0.05, n = 18). Similarly, chronic apple consumption decreased fasting unstimulated (IL-6) and LPS-stimulated (IL-6, INF-γ, TNF-α) PBMC-secreted inflammatory cytokines (P < 0.05; n = 16–18/group), as well as plasma IL-6 (P < 0.05, n = 22/group).
Conclusions
Both acute and chronic whole apple consumption may be an effective dietary strategy to mitigate the obesity-associated inflammation that precedes and exacerbates metabolic disease risk.
Funding Sources
Ontario Ministry of Agriculture, Food & Rural Affairs; Ontario Apple Growers.