|
Clinical Question
Does Fructose (fructose corn syrup) cause metabolic syndrome?
Bottom Line
Fructose may have a major role in the epidemic of metabolic syndrome and
obesity due to its ability to raise uric acid.
Reference
A Causal Role for Uric acid in Fructose-induced Metabolic Syndrome.Nakagawa
T, Hu H, Zharikov S, Tuttle KR, Short RA, Glushakova O, Ouyang X, Feig DI,
Block ER, Herrera-Acosta J, Patel JM, Johnson RJ.Am J Physiol Renal Physiol.
2005 Oct 18
Synopsis
The worldwide epidemic of the metabolic syndrome correlates with an
elevation in serum uric acid as well as a marked increase in total fructose
intake (in the form of table sugar and high fructose corn syrup). Fructose
raises uric acid, the latter which inhibits nitric oxide bioavailability.
Since insulin requires nitric oxide to stimulate glucose uptake, we
hypothesized that fructose-induced hyperuricemia may have a pathogenic role
in the metabolic syndrome. Four sets of experiments were performed. First,
pair feeding studies showed that fructose, and not dextrose, induced
features (hyperinsulinemia, hypertriglyceridemia, and hyperuricemia) of the
metabolic syndrome. Second, in rats receiving high fructose diet, the
lowering of uric acid with either allopurinol (a xanthine oxidase inhibitor)
or benzbromarone (a uricosuric agent) were able to prevent or reverse
features of the metabolic syndrome. In particular, the administration of
allopurinol prophylactically prevented fructose induced hyperinsulinemia
(272.3 vs.160.8 pmol/L, p<0.05), systolic hypertension (142 vs. 133 mmHg,
p<0.05), hypertriglyceridemia (233.7vs. 65.4 mg/dl, p<0.01) and weight gain
(455 vs. 425 g, p<0.05) at 8 weeks. Neither allopurinol nor benzbromarone
affected dietary intake of control diet in rats. Finally, uric acid
dose-dependently inhibited endothelial function as manifested by a reduced
vasodilatory response of aortic artery rings to acetylcholine. These data
provide the first evidence that uric acid may be a cause of the metabolic
syndrome, possibly due to its ability to inhibit endothelial function.
|