Effects of natto intake habits on uric acid metabolism

Abstract

Soybeans are considered a high-purine vegetable, and excessive intake of natto, a processed product of soybeans, can lead to gout flares. Purines contained in commercially available natto were measured using two HPLC methods (total purine-based analysis and molecular type purine simultaneous analysis methods). The total amount of purines contained in natto was 56.6 mg/100 g, bring about 50% of the previously reported content. It has been revealed that natto has a low content of polymeric nucleic acids and a high content of nucleosides and purine bases, which are easily absorbed in the intestinal tract. A registered dietitian interviewed 63 patients with gout and hyperuricemia who were able to achieve a serum uric acid level of 6 mg/dL or less on treatment with dotinurad, regarding their habits of cating purine-containing foods and natto. On comparing serum uric acid levels and urinary uric acid excretion among subjects divided into four groups based on their dietary habits of natto intake, there were no significant differences between patients who had a dietary habit of eating 1 pack (40 g) of natto 5 or more days a week (11 cases) and those who did not eat natto (26 cases). The amount of purines derived from natto as a percentage of the daily purine intake was only 6.9±2.8% in patients who had the habit of eating natto five or more days a week. The dietary habit of consuming up to 1 pack (40 g) of natto per day has little effect on uric acid metabolism; therefore, it is considered that natto, which is of marked health value, can be recommended even to patients with gout and hyperuricemia.