Folic acid supplementation on insulin sensitivity and inflammatory markers

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.
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.
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.

International Journal of Obesity (2006) 30, 1197–1202.

On the other hand it has been shown that increased folic acid supplementation can increase the chance of colorectal and prostate cancer. Specially if a person already has a precancerous lesion, folic acid supplementation would increase the chance of malignancy in these lesions.
For this study, I think, we can't just tell people to consume more folic acid. We already know about the increase of the risk of cancer, which is a big problem and most of the breads and cereals are already fortified with folic acid in U.S. So we can't have people increase their folic acid intake.