Effect of short-term folic acid supplementation on insulin sensitivity and inflammatory markers in overweight subjects

Objective: Inflammation plays a pivotal role in the atherosclerotic process, and some chemokines seem to be crucial in the pathogenesis of vascular damage. High-serum homocysteine, recently recognized as an independent risk factor for vascular disease might increase cytokine and chemokine levels, thus amplifying endothelial damage; moreover, it might worse insulin resistance, thus further contributing to enhance cardiovascular risk. The effect of folic acid supplementation in improving in vivo endothelial function is still debated. In this study, we investigated the effect of folic acid supplementation on insulin sensitivity and peripheral markers of inflammation in overweight healthy subjects.

Design: The study was performed as an unmasked randomized placebo-controlled trial of 12 weeks duration.

Subjects: Sixty healthy volunteers with normal glucose tolerance and BMI between 25 and 29 kg/m² were enrolled.

Measurements: Biochemical parameters and plasma concentrations of homocysteine and of some inflammatory molecules were measured at baseline and at the end of the study, together with an estimation of insulin sensitivity.

Results: Subjects receiving folic acid supplementation showed a decrement of homocysteine and an amelioration of insulin sensitivity; this treatment was also associated with a significant drop in the circulating concentration of monocyte chemoattractant protein-1, interleukin-8 and C-reactive protein, in the absence of any significant variation of BMI or fat mass.

Conclusions: In healthy overweight subjects a short-term folic acid supplementation reduces the circulating level of some inflammatory mediators independently of weight change, thus suggesting a potential therapeutic role for folic acid in the protection from atherogenesis and cardiovascular diseases.

Researchers: A Solini¹, E Santini¹ and E Ferrannini^1,2

1. ¹Department of Internal Medicine, University of Pisa School of Medicine, Pisa, Italy

2. ²CNR Institute of Clinical Physiology, Pisa, Italy

Correspondence: Dr A Solini, Department of Internal Medicine University of Pisa, Section of Internal Medicine III, Via Roma 67, I-56100 Pisa, Italy.

Reprinted with permission by Nature Publishing Group's: http://www.nature.com/ijo/journal/v30/n8/abs/0803265a.html#top#top

Received 27 May 2005; Revised 8 October 2005; Accepted 18 December 2005; Published online 21 February 2006.

Reprinted by permission from Macmillan Publishers Ltd: International Journal of Obesity Original Article.

International Journal of Obesity (2006) 30, 1197–1202. doi:10.1038/sj.ijo.0803265; published online 21 February 2006

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