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Dietary Intake of Manganese in the Japanese Diet and its Association with Cardiometabolic and Cardiovascular Diseases

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This two-page editorial summarizes dietary reference values and published estimates of manganese intake in Japan and comments on a Japanese cohort analysis linking higher manganese intake to lower cardiovascular mortality. It notes that green tea, unrefined cereals, legumes and vegetables are major manganese sources and that the main source can differ by assessment method. All numbers are secondary reports of other studies.

Key numbers

  • Adequate intake for adult men and women as summarized: 2.3 and 1.8 mg/day in North America, 4.0 and 3.5 mg/day in Japan (Dietary Reference Intakes for Japanese 2020); tolerable upper intake level 11 mg/day in both (p. 1421).
  • Japanese adult intake as summarized: 3.4 mg/day in 31 men from 31 prefectures in 1981 to 1982; 2.7 to 7.5 mg/day in duplicate-portion reports from the early 1960s to late 1980s; 5.1 and 4.9 mg/day in men and women from 16-day diet records in 2002 to 2003 (p. 1421).
  • In the cohort analysis discussed, estimated intake from a food frequency questionnaire was 5.3 mg/day, and green tea beverages, rice and oolong tea supplied 84%, 7% and 4% of intake (p. 1422).
  • Manganese is not assessed in the National Health and Nutrition Examination Survey Japan, according to the editorial (p. 1421).

Methods (brief)

Narrative editorial; no new data. The author cites dietary reference documents, duplicate-portion and diet-record studies, and a food frequency questionnaire cohort analysis.

Evidence fitness

The editorial supports citing the Japanese and North American adequate intake and upper level values as reported and the broad picture of Japanese manganese intake and sources. It is not primary evidence for any intake estimate or for a cardiovascular benefit.

Limitations

All values are second-hand and come from studies using different assessment methods, which the author notes are not directly comparable. The author raises the possibility that manganese intake is a proxy for plant-food intake.

Update history

No substantive edit history is available in this build. The full commit record is available in git.

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