Table 3.

Epidemiologic study outcomes related to iron status¹

Reference	Subjects, n	Intervention	Analysis	Tannin type	Conflation of phytates	Iron status affected?
53	173	Two 24-h recalls	Multiple regression	Dietary tannin including tea and other polyphenols	Yes	No IDA correlated with tannin intake. No significant effect in regression model.
54	143	24-h diet recall	Multiple regression	Dietary tannin including tea and other polyphenols	Yes	No significant IDA correlation with tannin intake.
55	1639	Three 24-h diet recalls, venous blood draw	Multiple regression	Black, green, and herbal tea	Yes	IDA or marginal iron status not correlated with tannin intake (ferritin 48, 50, and 49 vs. 50, 47, and 46 µg/L in control group and regular black, green, and herbal tea drinkers, respectively; P = 0.71, 0.34, and 0.36 in premenopausal women with green, black, and herbal tea, respectively).

¹IDA, iron-deficiency anemia.