So I was reading a bit about niacin, because of my efforts to lose a bit of stubborn belly fat without losing muscle (don't want to reduce calories too much more). In any case, the Wikipedia article on niacin seems to indicate that niacin blocks the break down of fat in the adipose tissue, which didn't exactly thrill me (though I couldn't find the study they were citing), so I did a little more looking and found these two studies that seemed to contradict one another:
"BACKGROUND: The lipid-lowering drug niacin has attracted renewed interest because it raises HDL-cholesterol and because it has recently been found to slow down the progression of intima media thickness in patients with coronary heart disease. Since niacin acts on adipocytes, we investigated its impact on adipokines and on some functions attributed to adipokines. METHODS AND RESULTS: In a randomized, placebo-controlled, double-blind study 30 men with the metabolic syndrome were treated for 6 weeks with 1500 mg extended-release niacin (n=20) or a placebo (n=10). Adiponectin increased by 56% (p<0.001) and leptin by 26.8% (p<0.012). Resistin, TNF-alpha, IL-6, and high sensitive CRP remained unchanged. In spite of the increase in adiponectin there was no improvement in endothelial function. The HOMA index actually deteriorated by 42% (p<0.014). CONCLUSION: Short-term treatment with extended-release niacin causes a pronounced increase in adiponectin but fails to improve atheroprotective functions attributed to adiponectin, such as insulin sensitivity, anti-inflammation and endothelial function."
So this is the extended-release niacin and while it causes a pronounced increase in adiponectin, it doesn't seem to translate into any of the positive effects usually associated with adiponectin. Odd. Also leptin increased. Is that good? Won't that further reduce leptin sensitivity?
"BACKGROUND: Leptin may play an important role in the development of atherosclerosis. Several transcription genes [including peroxisome proliferator-activated receptor gamma (PPARgamma) and CD36] involved in lipid and glucose metabolism and inflammatory processes may correlate to leptin expression. The aim of this study was to investigate the effect of niacin on serum leptin levels in hypercholesterolemic rabbits and the expression of leptin, PPARgamma, and CD36 in adipocytes from hypercholesterolemic rabbits. METHODS: Eighteen rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into two groups: (a) high-cholesterol group (n=6), which is maintained on high-cholesterol diet for 6 weeks, and (b) niacin group (n=6), which receives the same cholesterol diet plus niacin (200 mg/kg/day) for 6 weeks. The control group (n=6) was fed with normal diet for 14 weeks. Subcutaneous adipose was collected for RNA analysis. The direct effect of niacin on leptin release was assayed in hypercholesterolemic rabbit adipocytes. Leptin levels in serum and adipocyte culture supernatant were measured via enzyme-linked immunosorbent assay. RT-PCR was used to evaluate leptin, PPARgamma, and CD36 mRNA expression in adipose and adipocytes. RESULTS: Compared with the control group, rabbits fed with high-cholesterol diets showed higher levels of serum total cholesterol, low-density lipoprotein cholesterol, and leptin, all of which were significantly reduced by niacin treatment. After 6 weeks of treatment with niacin, the leptin level was significantly decreased by 21.8% (6.87+/-1.58 vs. 8.79+/-1.45, P<.05) and leptin mRNA expression of adipose was significantly lower in rabbits treated with niacin than in those fed with high-cholesterol diet continuously (0.58+/-0.11 vs. 0.73+/-0.15, P<.05). Niacin dose-dependently inhibited leptin secretion and increased CD36 and PPARgamma expression in cultured adipocytes. The reduction of leptin mRNA expression of hypercholesterolemic rabbits by niacin was negatively correlated with the up-regulation of PPARgamma and CD36 mRNA expression by niacin (r=-.69 and r=-.63, respectively, P<.01). CONCLUSION: Niacin can reduce serum level and adipose mRNA expression of leptin and up-regulate PPARgamma and CD36 mRNA expression in hypercholesterolemic rabbits."
On the flip side, in this study, it appears it reduced leptin, if I am understanding things correctly.
I'll readily admit, I am a poor layman at deciphering these sorts of studies, so perhaps more educated souls can make better sense of what the two mean. And is it not a good idea to include niacin in my diet (in supplemental form, that is), while trying to break down these last few stubborn pounds of belly fat?
Edited by suspire, 09 March 2009 - 10:48 PM.
