Carotenoids are a group of pigments found mainly in plants, some of which can be converted into retinol, also known as vitamin A. It has been suggested that carotenoids, which are obtained solely in the diet, play a role in metabolic processes within the liver and adipose tissue. Carotenoids have been implicated in obesity, but it remains unclear whether lower concentrations of carotenoids in adipose tissue, liver, and muscle are associated with glucose dysregulation. A new study published in The Journal of Nutrition suggests that higher concentrations of carotenoids in the blood and adipose tissue are associated with more favorable metabolic traits, including insulin sensitivity in the liver and adipose tissue.
Blood and adipose tissue carotenoids in adult men and women were analyzed in samples collected in 2 separate studies conducted between 2008 and 2013. Retinol, 7 different carotenoids, body composition, and insulin resistance were measured. Subcutaneous, visceral, liver, and pancreatic fat were also measured. A subcutaneous fat biopsy was performed, and carotenoids and retinol measures were taken.
“Most carotenoids detected in blood and in adipose tissue correlated inversely with total body fat content and central adiposity.”Dr. Dorit Samocha-Bonet
This study reports, for the first time, associations between serum and adipose tissue carotenoids and adiposity as well as insulin resistance in humans. According to lead author Dorit Samocha-Bonet (Garvan Institute of Medical Research) and colleagues, “Most carotenoids detected in blood and in adipose tissue correlated inversely with total body fat content and central adiposity.”
Although many serum carotenoids were negatively correlated with insulin resistance in liver and adipose tissue, none of the carotenoids correlated with muscle insulin resistance. Although favorable relations between serum and adipose tissue carotenoids and metabolic health were found, tissue-specific roles of the various carotenoids should be further investigated.
Reference Harari A, Coster ACF, Jenkins A, Xu A, Greenfield JR, Harats D, Shaish A, Samocha-Bonet D. Obesity and insulin resistance are inversely associated with serum and adipose tissue carotenoid concentrations in adults. The Journal of Nutrition, nxz184, https://doi.org/10.1093/jn/nxz184.
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