Weight gain and obesity are increasingly being associated with inflammation, hormonal changes and metabolic dysfunction. Excess energy causes the accumulation of white adipose tissue, and this leads to an influx of macrophages to adipoctyes. This is followed by a release of C reactive protein, as well as pro-inflammatory cytokines (interleukin 1β, interleukin-6, interleukin-1 and tumour necrosis factor alpha) that lead to systemic inflammation. At the same time, levels of the cytokine adiponectin fall and this results in insulin resistance, and glucose and lipid metabolic dysfunction. The inflammatory conditions and the inability to regulate glucose and lipid metabolism lead to the development of atherosclerosis, hypertension, type II diabetes and cardiovascular disease. Weight reduction is known to significantly increase levels of adiponectin, which leads to increased insulin sensitivity and the restoration of proper glucose and lipid metabolism.
Data is growing that catalogues the factors than are associated with adiponectin plasma levels in humans. For example, researchers1 have investigated the dietary and compositional factors that are associated with adiponectin in a cross-sectional study involving 877 pairs of female twins. Studies involving twins are advantageous in that they allow pair matching of subjects based on genetic similarities as well as a range of factors in their shared environment. The results showed that adiponectin levels were influenced by magnesium intakes, non-starch polysaccharides (fibre) and there was a trend for an influence by fruit and vegetables. As expected adiponectin plasma concentrations were inversely associated with body mass index, as well as total and central fat mass. As has been shown in previous studies, alcohol intake was significantly positively associated with adiponectin levels in plasma, supporting data that shows a beneficial effect of body composition with modest drinking.
These results clarify some of the associations between dietary or compositional factors and adiponectin plasma concentrations. It is already widely accepted that fruit, vegetables and fibre are associated with weight loss and so it is no surprise that they are also associated with plasma adiponectin levels. This association gives further support for the incorporation of plant based foods in the diet in order to maintain recommended weight. The association between magnesium and adiponectin is supported by other data that shows an inverse association between magnesium intake, inflammation, diabetes and cardiovascular disease. Magnesium is an important co-factor in glucose metabolism and is also necessary for intracellular signalling, insulin receptor activity and phosphorylation reactions. Magnesium can also reduce platelet activity and dilate blood vessels due to an effect of muscle contraction.