Grain fortification with B vitamins (thiamin, riboflavin and niacin) and iron caused a significant increase in niacin and iron, which affect the body’s redox status and induce insulin resistance at high levels. The purpose of the present study was to investigate the correlation between the U.S. per capita niacin and iron consumption and the prevalence of type 2 diabetes by sex, age, and race.

The data on the per capita nutrient consumption in 1909-2010 were from the Economic Research Service (ERS) of the U.S. Department of Agriculture. The ERS data showed that the per capita consumption of niacin and iron has increased from 16 mg/d and 12.5 mg/d to 34 mg/d and 24.5 mg/d, respectively from 1930s to 1990s, and thereafter remained fairly constant. This increase was mainly contributed by fortified grains or refined grains.

The data of diabetes prevalence were from the Center for Disease Control (CDC). The data showed that the prevalence of diabetes begun to increase from 1960s, with two rapidly increasing periods: from 1960s to early-1970s, and from 1990 to the early-2010, especially in some Southern States (e.g., Mississippi, Alabama, and Louisiana, where grain fortification is mandatory), while the prevalence of diabetes remains relatively stable during the 1980s.

We found that the prevalence of diabetes in the U.S. was strongly correlated with the per capita niacin and iron consumption (both r > 9.0). We further analyzed the correlations by age, sex, and race, and also found close correlations between the nutrient consumption and the prevalence of diabetes among sex groups, different racial groups, and different age groups.

In conclusion, excess niacin and iron intake may play an important role in the increased prevalence of type 2 diabetes in the U.S.


Y. Zhou: None. N. Chen: None. D. Li: None. W. Sun: None. S. Zhou: None.

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