Am J Clin Nutr. 2004 Jan; 79(1): 70-5.


Dietary iron intake and blood donations in relation to risk of type 2
diabetes in men: a prospective cohort study.

Jiang R, Ma J, Ascherio A, Stampfer MJ, Willett WC, Hu FB.

Departments of Nutrition and Epidemiology, Harvard School of Public Health,
Boston, MA 02115, USA.

BACKGROUND: Excessive iron stores may promote insulin resistance and lead
to the development of type 2 diabetes. However, prospective data relating
iron intake and blood donations (determinants of body iron stores) to
diabetes incidence are limited.
OBJECTIVE: We examined iron intake and blood donations in relation to the
incidence of type 2 diabetes.
DESIGN: We followed men aged 40-75 y who participated in the Health
Professionals' Follow-up Study; were free of diabetes, cardiovascular
disease, and cancer in 1986; and provided dietary data (n = 38 394). Of
those participants, 33 541 also provided a history of blood donation during
the past 30 y in 1992.
RESULTS: During 12 y of follow-up, we ascertained 1168 new cases of type 2
diabetes. After adjustment for age, body mass index, and other diabetes risk
factors, total iron intake was not associated with the risk of type 2
diabetes. Intakes of total heme iron [multivariate relative risk (RR) for
extreme quintiles: 1.28; 95% CI: 1.02, 1.61; P for trend = 0.045] and of
heme iron from red meat (RR: 1.63; 1.26, 2.10; P for trend < 0.001) were
associated with an increased risk. However, heme-iron intake from sources
other than red meat was not associated with diabetes risk (RR: 0.99; 0.81,
1.22). No significant associations were found between blood donation and the
risk of type 2 diabetes.
CONCLUSIONS: Heme-iron intake from red meat sources is positively
associated with the risk of type 2 diabetes. Total iron intake, heme-iron
intake from non-red meat sources, and blood donations are not related to the
risk of type 2 diabetes.

PMID: 14684399