I want to understand how caffeine (1,3,7-trimethylxanthine) can be easily oxidized to uric acid.

Is it safe to conclude that caffeine may increase the uric acid level in blood?


I doubt caffeine can be so easily oxidized to uric acid. I'd propose a way by demethylation via cytochrome P450 to the corresponding xanthines and oxidation via xanthine oxidase (but these are enzymatic reactions).

From a synthetic perspective, one will start with guanine (-> guanine deaminase followed by oxidation; or oxidative deamination of Guanine followed by another oxidation)

It's not safe to conclude that caffeine increase uric acid blood level.

Long story short: Coffee consumption seems to lower uric acid blood levels. Decaf coffee consumption also seems to lower uric acid blood levels. Tea consumption seems to have no effect on uric acid blood levels.

Serum uric acid level tended to decrease with increasing coffee intake (Figure 1). After adjusting for age and sex, serum uric acid level in individuals with coffee intake 6 cups daily was lower than in those with no use by 0.43 mg/dl (95% CI 0.22, 0.65; P for trend 0.001). After adjusting for other covariates, the differences were attenuated but remained significant (P for trend 0.001) (Table 2).

"Coffee, Tea, and Caffeine Consumption and Serum Uric Acid Level: The Third National Health and Nutrition Examination Survey", Choi HK, Curhan G., 2007 DOI 10.1002/art.22762

It has to be noted this was the first study I found on the fly and there may be other results out there

  • $\begingroup$ now I understand that Caffeine is not easily oxidized to uric acid. On the quote provided, I researched that "Coffee may also contain substances which inhibit xanthine oxidase, an enzyme converting xanthine to uric acid..."source: hindawi.com/journals/jnme/2010/930757. Coffee has a component that inhibits Caffeine to be converted to uric acid. So I may still conclude that Caffeine may increase UA level on the blood after being metabolized in the body. $\endgroup$
    – rahstame
    Feb 2 '17 at 21:01
  • $\begingroup$ I don't think so. The conclusion that Caffeine may increase UA level is contrary to both publications provided here. As statet in your source: "Age-adjusted and multivariate-adjusted means of serum UA were progressively lower with increasing consumption of coffee..." and later "However, caffeine was found to be unrelated to serum concentrations of UA" and also in the study I provided there is no evidence for an increase in UA level. The opposite is shown. $\endgroup$
    – Immo
    Feb 3 '17 at 10:12

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