Millet flour: a high-GI drink and iron that depends on the seed

Is millet flour a slow carbohydrate? In a crossover trial in 14 healthy adults, a drink made from extruded whole-grain pearl millet flour came out high on the glycemic index and gave 2-hour glucose and insulin responses similar to a maltodextrin drink. That was one serving of one processed drink, and the abstract gives no GI number. The iron story depends on the seed. In 40 two-year-olds in Karnataka, India, eating about 3 oz (84 g) of pearl millet flour a day, flour from an iron-biofortified variety tripled absorbed iron to 0.67 mg a day against 0.23 mg, measured over test meals on 2 days rather than as iron status. In 20 Beninese women with marginal iron status, biofortified millet meals eaten with leaf and okra sauces over 5 days gave 1125 micrograms of absorbed iron against 527. The share absorbed stayed at 7.5% for both, so the gain came from the extra iron in the bred grain, and the regular flour in the same trials gave less than half as much.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• The US reference entry for millet flour lists 32.7 micrograms of selenium, 0.535 mg of copper and 6.02 mg of niacin per 3.5 oz (100 g), from a single record without sample ranges. — USDA FoodData Central, SR Legacy, Millet flour, FDC 172023 (n = 1 record) Evidence E source
  Per 100 g: selenium 32.7 micrograms, copper 0.535 mg, niacin 6.02 mg
• UK tables list foxtail millet flour at 1.6 mg niacin per 3.5 oz (100 g) against 6.02 mg in the US millet flour entry, a gap of about 73 percent. — CoFID 2021 code 11-016 vs USDA SR Legacy FDC 172023 (n = 2 records) Evidence E source
  Niacin CoFID 1.6 mg vs USDA 6.02 mg per 3.5 oz (100 g); CoFID also 354 calories, 5.8 g protein, 0.68 mg thiamin, 260 mg phosphorus

What your body absorbs

• In an RCT in 40 Indian 2-year-olds fed about 3 oz (84 g) of pearl millet flour a day, iron-biofortified flour tripled absorbed iron to 0.67 mg/d and raised absorbed zinc to 0.95 mg/d. — 40 children aged 2 y in Karnataka, India (21 test, 19 control); test meals on 1 day for zinc and 2 days for iron (n = 40) Evidence B source
  Iron absorbed 0.67 +/- 0.48 vs 0.23 +/- 0.15 mg/d (P < 0.001); zinc 0.95 +/- 0.47 vs 0.67 +/- 0.24 mg/d (P = 0.03)
• In a crossover trial in 20 Beninese women with marginal iron status, meals of iron-biofortified pearl millet flour gave 1125 vs 527 micrograms of absorbed iron, with fractional absorption 7.5% for both. — 20 Beninese women with marginal iron status, multiple millet paste meals for 5 d (n = 20) Evidence B source
  Total iron absorbed 1125 vs 527 micrograms (P < 0.0001); fractional absorption 7.5% vs 7.5%; post-harvest fortified flour 10.4%, 1500 micrograms

What it does to your health

• In a crossover RCT in 14 healthy adults, a drink made from extruded whole-grain pearl millet flour was high-GI and gave 2-hour glucose and insulin responses similar to a maltodextrin drink. — 14 euglycemic and eutrophic adults, four acute sessions, 2-h follow-up plus 24-h food intake (n = 14) Evidence B source
  Glycemic index classified high; glycemic, insulinemic, appetite and 24-h intake responses similar to maltodextrin control
• Survey data from 18,090 Indian adults link swapping refined cereals for whole wheat or millet flour, at the same carbohydrate intake, with no lower odds of type 2 diabetes (OR 0.94). — 18,090 adults, national ICMR-INDIAB survey, India (n = 18090) Evidence C source
  Type 2 diabetes OR 0.94 (95% CI 0.57 to 1.56); abdominal obesity OR 1.08 (95% CI 0.66 to 1.76)

Safety, limits and interactions

• A survey of dried foods found the heat-tolerant bacterium Bacillus cytotoxicus in millet flour as well as in potato products, with 57 isolates typed. — dried food products including potato flakes and millet flour; 57 B. cytotoxicus isolates (n = 57 isolates) Evidence C source
  Presence detected in millet flour; loads given only for potato flakes (below 10^2 CFU/g)

The bottom line

On paper the US reference entry looks generous, with 32.7 micrograms of selenium, 0.535 mg of copper and 6.02 mg of niacin per 3.5 oz (100 g). That is a single record with no sample range, and it does not name the millet species. The UK table lists foxtail millet flour at 1.6 mg of niacin per 3.5 oz (100 g), about 73 percent less, and the two entries may well be different species. In a national survey of 18,090 Indian adults, swapping refined cereals for whole wheat or millet flour while keeping total carbohydrate the same was not linked to lower odds of type 2 diabetes (OR 0.94, 95% CI 0.57 to 1.56). That cross-sectional model pools wheat with millet, so it cannot speak for millet alone. On safety, a survey of dried foods found the heat-tolerant bacterium Bacillus cytotoxicus in millet flour, with no count given for the flour. The survey did not look at illness in people, so it can neither show harm nor rule it out, and heat tolerance means cooking cannot be assumed to remove it. We found no card on how long cooked millet porridge or baby food can safely stand, on eating the flour raw, or on allergy, pregnancy, medicines or limits for children. If you cook millet flour for a young child, this page cannot tell you it is safe to keep, so ask your pediatrician or local food safety service.

Sources

1. mlf-daily-r5-01 · composition dataset
   Millet flour (FDC 172023, SR Legacy): Selenium 32.7 µg; Copper 0.535 mg; Niacin 6.02 mg per 100 g
   USDA FoodData Central, SR Legacy, Millet flour, FDC 172023 · checked 2026-10-02
2. mlf-daily-r5-02 · composition dataset
   Flour, millet, foxtail, CoFID 11-016: Niacin 1.6 mg, Energy 354 kcal, Protein 5.8 g, Thiamin 0.68 mg, Phosphorus 260 mg; Millet flour (USDA FDC 172023): Niacin 6.02 mg
   CoFID 2021 (Public Health England), code 11-016; USDA FoodData Central SR Legacy FDC 172023 · checked 2026-10-02
3. mlf-daily-r5-03 · RCT
   The study was undertaken in 40 children aged 2 y in Karnataka, India (n = 21 test/19 controls). Three test meals providing ∼84 ± 17 g dry pearl millet flour were fed on a single day for zinc and 2 d for iron between 0900 and 1600 h. ... The mean (± SD) quantities of iron absorbed from test and control groups were 0.67 ± 0.48 and 0.23 ± 0.15 mg/d, respectively (P < 0.001). The quantities of zinc absorbed were 0.95 ± 0.47 and 0.67 ± 0.24 mg/d, respectively (P = 0.03).
   J Nutr, 2013 · checked 2026-10-02
4. mlf-daily-r5-04 · RCT
   an iron absorption study was conducted in 20 Beninese women with marginal iron status. ... Fractional iron absorption from test meals based on regular-iron millet (7.5%) did not differ from iron-biofortified millet meals (7.5%; P = 1.0), resulting in a higher quantity of total iron absorbed from the meals based on iron-biofortified millet (1125 vs. 527 μg; P < 0.0001).
   J Nutr, 2013 · checked 2026-10-02
5. mlf-daily-r5-05 · RCT
   This is an acute, single-blind, randomized, controlled, cross-over clinical study comprising 14 euglycemic and eutrophic adults. ... The extruded millet flour strawberry-flavored beverage had the best sensory acceptance and was classified as having as high GI. Consumption of the extruded millet beverage showed similar glycemic and insulinemic responses, as well as appetite control and food intake of the subjects, when compared with consumption of the maltodextrin control beverage.
   Nutrition, 2024 · checked 2026-10-02
6. mlf-daily-r5-06 · cross-sectional
   Using data from the national Indian Council of Medical Research-India Diabetes survey (18,090 adults), we examined India's dietary profile and the effect of isocaloric substitution of carbohydrates with other macronutrients on metabolic risk. ... Replacing refined cereals with whole wheat or millet flour without decreasing overall carbohydrate quantity was not associated with lower risk for T2D (OR = 0.94, 95% CI = 0.57, 1.56) or abdominal obesity (OR = 1.08, 95% CI = 0.66, 1.76).
   Nat Med, 2025 · checked 2026-10-02
7. mlf-daily-r5-07 · prevalence survey
   B. cytotoxicus was observed in other potato-containing products and in millet flour. B. cytotoxicus isolates (n = 57) fell into six RAPD patterns and 11 plasmid profiles.
   J Food Prot, 2019 · checked 2026-10-02