Rice flour: a gluten-free swap with no blood sugar bonus

Rice flour is the usual stand-in for wheat in gluten-free baking, and in the one trial we have it did no better on blood sugar. In a randomized crossover trial on 12 healthy adults, muffins baked with refined rice flour had a glycemic index of 79, against 74 for wheat, 53 for oat and 55 for barley flour, and those were muffins in a small group. Which rice flour you buy matters more than the label suggests. US lab samples of brown rice flour held 124 mg magnesium and 5.99 mg niacin per 3.5 oz (100 g), about five times the 22.9 mg and 1.25 mg in unenriched white rice flour, from only 4 and 6 samples. UK tables list rice flour at 366 calories and 23 mg magnesium per 3.5 oz (100 g), in line with the white flour, without naming the type. An audit of 130 home-baking flours in four Sydney supermarkets found gluten-free products, the group rice flour belongs to, lower in protein and fiber than whole wheat flours, going by label data.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• US lab samples of brown rice flour held 124 mg magnesium and 5.99 mg niacin per 3.5 oz (100 g), about five times the 22.9 mg and 1.25 mg in unenriched white rice flour. — USDA Foundation Foods: Flour, rice, brown (4 samples) and Flour, rice, white, unenriched (6 samples) (n = 4 and 6 samples) Evidence E source
  Mg 124 mg (102-141) vs 22.9 mg (11.9-34.8); niacin 5.99 mg (5.48-6.89) vs 1.25 mg (0.34-1.89); iron 1.5 vs 0.22 mg per 3.5 oz (100 g)
• UK tables list rice flour at 366 calories, 6.4 g protein, 80.1 g starch, 1.9 mg iron and 23 mg magnesium per 3.5 oz (100 g), matching white rather than brown US flour. — CoFID 11-021 Flour, rice (n = 1 record) Evidence E source
  Per 100 g: 366 calories, protein 6.4 g, starch 80.1 g, iron 1.90 mg, magnesium 23 mg

What your body absorbs

• In a human trial, wheat noodles with 30% RD43 rice flour lowered blood glucose from 15 to 90 minutes after the meal. — healthy adults eating test noodles Evidence B source
  Lower postprandial glucose 15-90 min; higher GLP-1 and PYY at 30 min
• In an RCT on 53 Sri Lankan children only 2.2% of iron from iron-fortified rice flour was absorbed, rising to 4.7% with added Na2EDTA. — 53 schoolchildren aged 6-10 y, Sri Lanka, single meal with 25 g fortified rice flour (n = 53) Evidence B source
  Iron absorption 2.2 ± 1.3% vs 4.7 ± 3.6% with Na2EDTA; zinc 8.8% vs 13.5%

What it does to your health

• In a crossover RCT on 12 healthy adults a muffin made with refined rice flour had a glycemic index of 79, similar to wheat (74) and higher than oat (53) or barley (55). — 12 healthy adults, single test meals (n = 12) Evidence B source
  GI: rice 79, wheat 74, corn 74, oat 53, barley 55

Safety, limits and interactions

• A case report describes a 6-month-old girl with anaphylaxis to rice flour, confirmed by food challenge, showing rice flour is not always hypoallergenic. — one 6-month-old girl, Netherlands (n = 1) Evidence D source
  Anaphylaxis on provocation
• A case report describes a 14-year-old with exercise-induced anaphylaxis from rice who was advised to avoid rice flour too. — one 14-year-old girl, Japan (n = 1) Evidence D source
  Anaphylaxis with exercise after polished rice; IgE to 14-16 kDa rice protein
• In 35 children with celiac disease, median urinary arsenic rose from 3.3 to 13.6 mcg/L after 6 months on a gluten-free diet, where rice often replaces wheat. — 35 children aged 2-18 with newly diagnosed celiac disease, single US center (n = 35) Evidence C source
  Urinary arsenic median 3.3 to 13.6 mcg/L (P = 0.000004); below acutely toxic levels
• A review of 75 studies found rice-based baby food mixes had median arsenic of 0.048 mg/kg, with 30% of items above international maximum levels. — 580 baby foods and 251 infant formulas from 75 studies worldwide (n = 75 studies) Evidence C source
  Arsenic median 0.048 mg/kg in rice mixes, 30% above ML
• The FDA set an action level of 100 ppb inorganic arsenic for infant rice cereals, and about 47% of 2014 market samples would have met it. — infant rice cereals on the US market Evidence E source
  Action level 100 mcg/kg (100 ppb); 36% of 2011-2013 and 47% of 2014 samples met 100 ppb
• In the follow-up of the same celiac cohort, urinary arsenic in 21 children returned to baseline after 12 months on a gluten-free diet (3.42 vs 4.93 mcg/L). — 21 of 35 children aged 2-18 with celiac disease, 12 months on a gluten-free diet (n = 21) Evidence C source
  Urinary arsenic 3.42 vs 4.93 mcg/L, p = 0.17; nail arsenic unchanged

What people believe that the data does not support

• In a 12-week RCT in infants with atopic dermatitis, rice flour fermented with a heat-killed probiotic did not reduce eczema severity more than placebo (SCORAD difference -2.1). — infants aged 6-36 months with moderate to severe atopic dermatitis Evidence B source
  SCORAD change difference -2.1 (95% CI -5.5 to 1.3), below the 8.7 clinical threshold; less steroid use
• An audit of 130 supermarket flours in Sydney found gluten-free products, a category that includes rice flour, lower in protein and fiber than whole wheat flours. — 130 home-baking flour products in four Sydney supermarkets, 2020 (n = 130) Evidence C source
  Gluten-free products lower in protein and dietary fiber; whole wheat higher (p<0.001)

Who this works differently for

• In a trial on children aged 6 to 42 months with diarrhea, a rice flour oral rehydration solution supplied 152 calories and 3.6 g protein per liter. — children 6-42 months with mild to moderate dehydration, Ibadan, Nigeria (n = 88) Evidence B source
  Clinical improvement with both rice and maize ORS; rice-ORS 152.1 calories and 3.6 g protein per liter

The bottom line

The arsenic question comes up because rice takes up more of it than most grains, and we found no measurement of arsenic in rice flour itself. What exists is indirect. In 35 children newly diagnosed with celiac disease, median urinary arsenic rose from 3.3 to 13.6 mcg/L after 6 months on a gluten-free diet, below acutely toxic levels, and the study could not separate rice grain from rice flour. In the 21 of those children who gave a sample at 12 months, 40 percent having dropped out, urinary arsenic was back near baseline (3.42 vs 4.93 mcg/L, p = 0.17). A review of 75 studies found rice-based baby food mixes at a median 0.048 mg/kg arsenic, with 30% of items above international limits, and those were ready mixes. For infant rice cereal the FDA set an action level of 100 ppb inorganic arsenic, which about 47% of 2014 market samples would have met. That guidance applies to infant cereal only. Rice flour is often called hypoallergenic, and two case reports show it is not always. A 6-month-old girl in the Netherlands had anaphylaxis to rice flour on a supervised food challenge. A 14-year-old in Japan with exercise-induced anaphylaxis after rice was told to avoid rice flour as well. These are single cases, so they show the reaction can happen and say nothing about how often. Iron added to rice flour is poorly absorbed. In a stable isotope trial on 53 Sri Lankan schoolchildren eating 0.88 oz (25 g) of fortified rice flour in one meal, 2.2% of the iron was absorbed, and 4.7% when Na2EDTA was added. Some rice flours are engineered to act differently. Wheat noodles with 30% flour from RD43, a high-amylose rice cultivar, lowered blood glucose from 15 to 90 minutes in healthy adults, and the abstract does not say how many. In a 12 week trial in infants with atopic dermatitis, rice flour fermented with a heat-killed probiotic did not significantly reduce eczema severity against placebo (SCORAD difference -2.1, 95% CI -5.5 to 1.3), well short of the 8.7 point clinical threshold. A rice flour rehydration drink tested on 88 Nigerian children with diarrhea supplied 152 calories and 3.6 g protein per liter, in an old single-center trial that had no standard rehydration solution to compare against.

Sources

1. rf8-12 · food composition dataset
   Flour, rice, brown: Magnesium, Mg 124.0 MG (102.0-141.0, 4 samples), Niacin 5.99 MG (5.48-6.89), Iron, Fe 1.5 MG; Flour, rice, white, unenriched: Magnesium, Mg 22.9 MG (11.9-34.8, 6 samples), Niacin 1.25 MG (0.34-1.89), Iron, Fe 0.22 MG per 100 g
   USDA FoodData Central Foundation Foods, release 2026-04-30, Flour, rice, brown / white, unenriched · checked 2026-09-30
2. rf8-13 · food composition dataset
   Flour, rice, CoFID 11-021: Energy 366 kcal, Protein 6.4 g, Starch 80.1 g, Iron 1.90 mg, Magnesium 23 mg per 100 g
   CoFID 2021 (Public Health England), code 11-021, OGL v3.0 · checked 2026-09-30
3. rf8-02 · RCT
   In human studies, ingestion of 30% RD43 rice noodles significantly lowered postprandial plasma glucose at 15-90 min.
   Food Funct, 2021 · checked 2026-09-30
4. rf8-03 · RCT
   Absorption of (58)Fe from a meal was significantly greater (P < 0.01) in the groups administered FeSO(4) + Na(2)EDTA (4.7 +/- 3.6%) than in those administered FeSO(4) without Na(2)EDTA (2.2 +/- 1.3%).
   J Nutr, 2004 · checked 2026-09-30
5. rf8-01 · RCT
   Muffins baked with wheat, rice, corn, oat and barley flours gave rise to GI values of 74, 79, 74, 53 and 55, respectively.
   Eur J Nutr, 2015 · checked 2026-09-30
6. rf8-06 · case report
   A provocation test revealed an anaphylactic reaction to rice flour. Food allergy is a widespread problem within paediatrics; rice flour appears to be hypoallergenic, but can lead to immunological responses.
   Ned Tijdschr Geneeskd, 2001 · checked 2026-09-30
7. rf8-07 · case report
   As the patient may experience FDEIA after ingestion of no wash rice or rice flour, she was advised to eliminate these from her diet, treating them similarly to brown rice or polished rice.
   Arerugi, 2024 · checked 2026-09-30
8. rf8-08 · prospective cohort
   After 6 months on a GFD, there was a significant increase in the median urinary arsenic concentration (3.3 µg/L vs 13.6 µg/L, P = 0.000004).
   Am J Gastroenterol, 2025 · checked 2026-09-30
9. rf8-09 · scoping review
   For As, the highest median was found in mixed fish (0.165 mg/kg) and rice mixes (0.048 mg/kg), with 89% and 30% of items exceeding the As ML, respectively.
   Nutr Rev, 2026 · checked 2026-09-30
10. rf8-10 · agency guidance
    The 100 micrograms per kilogram (μg/kg) or 100 parts per billion (ppb) action level for inorganic arsenic in infant rice cereals is identified in the FDA Guidance for Industry ... These data suggest that approximately 47 percent of infant rice cereal samples on the market in 2014 would meet a 100 ppb hypothetical limit.
    FDA, Supporting Document for Action Level for Inorganic Arsenic in Rice Cereals for Infants, August 2020 · checked 2026-09-30
11. rf8-14 · prospective cohort
    Twenty-one of the 35 (60%) participants provided a follow-up sample. After 12 months on a GFD, total median urinary arsenic concentration returned to baseline (3.42 vs. 4.93 μg/L, p = 0.17).
    JPGN Reports, 2026, PMID 42110120 · checked 2026-09-30
12. rf8-04 · RCT
    The difference in the SCORAD change was -2.1 (-5.5 to 1.3; p = 0.223) for the experimental vs. the placebo group, not reaching the minimal clinical difference of 8.7 units.
    Pharmacol Res, 2021 · checked 2026-09-30
13. rf8-11 · cross-sectional
    Self-raising flours were significantly higher in sodium (p < 0.001) and gluten-free products were lower in protein and dietary fibre, making legume, buckwheat and quinoa flour a better choice.
    Nutrients, 2020 · checked 2026-09-30
14. rf8-05 · RCT
    The maize-ORS contains 4.3 g protein, 179.3 Kilocalories and rice-ORS contains 3.6 g protein and 152.1 Kilocalories per litre of the preparation, respectively.
    Afr J Med Med Sci, 2000 · checked 2026-09-30