Quinoa and rice: more fiber and iron, thinner proof

By a meta-analysis of 5 small randomized trials in 206 adults, quinoa seed lowered triglycerides by 7.20 mg/dl and total cholesterol by 6.86 mg/dl, with confidence intervals clear of zero (4.87 to 9.52 and 3.08 to 10.64 mg/dl lower). Those trials compared quinoa with wheat or corn, and none used rice as the control. A second meta-analysis, of 7 trials in 258 adults eating 0.53 to 1.8 oz (15 to 50 g) a day for 28 to 180 days, found no significant change in body weight or BMI against placebo. The first analysis reported a drop in weight, so the two disagree, and the larger one found nothing. The nutrient gap is plain. Per 3.5 oz (100 g) of dry grain in the UK food tables, quinoa has 13.8 g protein, 7.0 g fiber and 7.8 mg iron, against 6.7 g, 1.1 g and 0.26 mg for white long grain rice. Brown rice sits between them at 7.7 g, 3.0 g and 1.05 mg.

How much is actually in it

• Per 100 g raw in UK food tables, quinoa has 13.8 g protein, 7.0 g fiber and 7.8 mg iron, versus 6.7 g, 1.1 g and 0.26 mg for white long grain rice and 7.7 g, 3.0 g and 1.05 mg for brown rice. — UK composition tables, raw grain Evidence E source
  Quinoa 309 calories, magnesium 210 mg; white rice 355 calories, magnesium 25 mg; brown rice 333 calories, magnesium 116 mg
• USDA lab samples show quinoa flour iron ranging 3.55 to 6.6 mg per 3.5 oz (100 g), while unenriched white long grain rice ranged 0 to 0.51 mg and brown rice 0.87 to 1.73 mg. — USDA Foundation Foods analytical samples, 8 per food Evidence E source
  Fiber: quinoa flour 4.35-8.24 g, white rice 0-1.19 g, brown rice 2.6-3.4 g; magnesium: quinoa flour 130-177 mg, white rice 12.9-38.7 mg, brown rice 110-121 mg

What a real portion looks like

• In the US dietary survey one cup of cooked quinoa weighs 6 oz (170 g) and one cup of cooked white rice weighs 5.6 oz (158 g). — US food survey portion weights Evidence E source
  1 cup cooked: quinoa 170 g (FNDDS 56204005); white rice 158 g (FNDDS 56205008); quantity not specified 170 g vs 118 g

What your body absorbs

• In young women, iron absorption from coated iron-fortified rice was 4.0 percent versus 6.6 percent from the reference meal, and cooking two fortified rice types in excess water lost 25 percent of their added iron. — 41 young women in two stable-isotope studies (n = 41) Evidence B source
  FAFe coated 4.0% (2.9-5.4) vs reference 6.6% (4.9-9.0); 1:2 water ratio kept over 80% of iron and zinc

What cooking and storage change

• A systematic review found the glycemic index of rice varieties ranged from 48 to 93, with brown rice lower than white only when both are cooked for the same time. — published glycemic response studies of rice Evidence A source
  GI 48 to 93; insulinemic index 39 to 95
• Laboratory data across 15 studies suggest cooking lowers arsenic in rice by about 0.04 mg/kg, with rinsing and parboiling the most effective methods. — 15 food analysis studies of cooked rice Evidence D source
  Arsenic WMD -0.04 mg/kg (95% CI -0.05 to -0.03); lead and cadmium -0.01 mg/kg

What it does to your health

• A meta-analysis of 7 randomized trials in 258 adults found 0.53 to 1.8 oz (15 to 50 g) of quinoa a day for 28 to 180 days did not change BMI or body weight versus placebo. — 258 adults aged 31 to 64, 7 trials, 28 to 180 days (n = 258) Evidence A source
  BMI MD -0.25 (95% CI -0.98 to 0.47); body weight MD -1.2 lb (95% CI -6.7 to 4.3; metric: -0.54 kg, -3.05 to 1.97)
• A meta-analysis of 5 randomized trials in 206 adults found quinoa seed lowered triglycerides by about 7 mg/dl and total cholesterol by about 7 mg/dl. — 206 adults, 5 RCTs (n = 206) Evidence A source
  TG WMD -7.20 mg/dl (95% CI -9.52 to -4.87); TC WMD -6.86 mg/dl (95% CI -10.64 to -3.08); LDL WMD -3.08 mg/dl (95% CI -5.13 to -1.03)
• In a one-year randomized trial in 207 adults with impaired glucose tolerance, 3.5 oz (100 g) of quinoa a day replacing about half the staple food lowered 2-hour post-meal glucose more than mixed whole grains. — 207 adults with impaired glucose tolerance, China, 1 year (n = 207) Evidence B source
  Lower 2hPG, fasting insulin, HOMA-IR and 14-day mean glucose vs multigrain and control (P < 0.05); absolute differences not given in abstract
• In a crossover trial in 40 adults aged 50 to 75, 15 g of quinoa biscuits daily for 4 weeks lowered total cholesterol by 12 mg/dL (0.30 mmol/L) more than wheat biscuits. — 40 healthy adults aged 50-75, 4 weeks per arm (n = 40) Evidence B source
  TC -0.30 ± 0.58 mmol/L, LDL -0.25 ± 15 mg/dL (0.38 mmol/L), weight -0.61 ± 0.89 kg vs control (P < 0.05)
• In a 4-week crossover trial in 37 overweight men, bread providing 20 g quinoa flour a day did not lower LDL or fasting glucose more than refined wheat bread. — 37 overweight men aged 35-70, 4 weeks per arm (n = 37) Evidence B source
  No difference vs control in glucose or LDL; cumulative glucose AUC lower vs wheat period (p = 0.039)
• Cohort data link the highest white rice intake to a 55 percent higher risk of type 2 diabetes in Asian populations, with no significant link in Western populations. — 352,384 participants in 7 prospective cohorts, follow-up 4 to 22 years (n = 352384) Evidence C source
  Asian RR 1.55 (95% CI 1.20 to 2.01); Western RR 1.12 (0.94 to 1.33); per daily serving RR 1.11 (1.08 to 1.14)
• Pooled cohort data link high rice intake to more chronic disease in women but not in men, and not to higher overall mortality. — 12 cohort studies, highest vs lowest rice intake Evidence C source
  Women RR 1.40 (1.13 to 1.73); men RR 0.95 (0.72 to 1.24); mortality RR 0.97 (0.88 to 1.06)

Safety, limits and interactions

• In 19 treated celiac patients, 1.8 oz (50 g) of quinoa a day for 6 weeks was well tolerated and did not worsen the disease. — 19 adults with treated celiac disease, 6 weeks (n = 19) Evidence C source
  Gastrointestinal parameters normal; villus height to crypt depth 2.8:1 to 3:1
• Across 75 studies of baby foods, rice mixes had a median arsenic level of 0.048 mg/kg and 30 percent of them exceeded the international maximum level. — 580 baby foods and 251 infant formulas in 75 studies (n = 831) Evidence C source
  Rice mixes: As median 0.048 mg/kg, 30% above ML; Pb median 0.008 mg/kg, over 20% above ML
• In a US survey of 2,635 infants and toddlers, 58 percent of infants aged 6 to 12 months ate rice or rice-containing foods on a given day. — US infants and toddlers 0-24 months, FITS 2016 (n = 2635) Evidence C source
  58.2% of infants 6-11.9 months; mean 11.9 g rice per day among consumers
• The US FDA set an action level of 100 parts per billion for inorganic arsenic in infant rice cereals in 2020. — infant rice cereals sold in the US Evidence E source
  Action level 100 ug/kg (100 ppb), final guidance August 2020

What people believe that the data does not support

• The EU did not authorize a claim that quinoa stimulates the hair bulb and favors hair growth. — EU health claim application Evidence E source
  Non-authorized
• The EU did not authorize a claim that germinated brown rice helps maintain normal blood glucose. — EU health claim application Evidence E source
  Non-authorized

What is still unknown

• USDA retention factors for rice cooked with the water absorbed keep 70 percent of folate and 80 percent of thiamin, while quinoa has no retention row at all. — Cereal grains group, white and brown rice Evidence E source
  Code 432: folate 70%, thiamin 80%, riboflavin 90%, iron 95%, magnesium 100%, zinc 100%

The bottom line

Single trials point in mixed directions. In 40 healthy adults aged 50 to 75, 15 g of quinoa a day baked into biscuits for four weeks lowered total cholesterol by 12 mg/dL (0.30 mmol/L) more than wheat biscuits, and biscuits are a product, not cooked grain. In 37 overweight men, bread with 20 g of quinoa flour a day for four weeks did not lower LDL or fasting glucose more than refined wheat bread. For rice, a systematic review of glycemic tests found the glycemic index of rice varieties ranged from 48 to 93, without pooling the studies. Brown rice gave a lower blood sugar response than white only when both were cooked for the same time. At the longer times brown rice normally needs, the difference was smaller and inconsistent. Observational data link white rice to type 2 diabetes mainly where people eat a lot of it. Across 7 cohorts of 352,384 people, the highest intake carried a relative risk of 1.55 (95% CI 1.20 to 2.01) in Asian populations, who eat three to four servings a day. In Western populations it was 1.12 (0.94 to 1.33), which did not reach significance. Pooled cohorts also link high rice intake to more chronic disease in women (RR 1.40, 1.13 to 1.73) and not in men, with no link to overall mortality (RR 0.97, 0.88 to 1.06), though the studies varied a lot. One cup of cooked quinoa weighs 6 oz (170 g) in US survey tables, and one cup of cooked white rice weighs 5.6 oz (158 g). Who should be careful. The arsenic question sits with rice and with babies. Across 75 studies of baby foods, rice mixes had a median arsenic level of 0.048 mg/kg and 30 percent were above the international maximum, measured in the products rather than in children. In a one-day US survey, 58.2 percent of infants aged 6 to 12 months ate rice or rice-containing foods. The US FDA has set an action level of 100 parts per billion of inorganic arsenic for infant rice cereals. Laboratory data from 15 food studies suggest cooking lowers arsenic in rice by about 0.04 mg/kg, with rinsing ranked most effective and parboiling next. For people with celiac disease, 19 treated patients ate 1.8 oz (50 g) of quinoa a day for six weeks without the disease getting worse, in a small study with no control group. We have no cards on pregnancy or medicines for either grain. Iron added to fortified rice can be lost in the pot. In 41 young women, iron from coated fortified rice was absorbed at 4.0 percent against 6.6 percent from the reference meal. Cooking two of the fortified types in excess water lost 25 percent of their added iron, while a 1 to 2 rice to water ratio kept more than 80 percent. These figures apply to fortified rice only. We could not find a trial that put quinoa directly against rice, and the USDA cooking retention table has no row for quinoa. The EU refused a claim that quinoa helps hair grow and a claim that one germinated brown rice product helps maintain normal blood glucose.

Sources

1. qnrc-daily-r8-01 · reference dataset
   CoFID 14-843 Quinoa, raw: Protein 13.8 g · AOAC fibre 7.0 g · Iron 7.80 mg · Magnesium 210 mg · Energy 309 kcal; CoFID 11-861 Rice, white, long grain, raw: Protein 6.7 g · AOAC fibre 1.1 g · Iron 0.26 mg · Magnesium 25 mg · Energy 355 kcal; CoFID 11-868 Rice, brown, wholegrain, raw: Protein 7.7 g · AOAC fibre 3.0 g · Iron 1.05 mg · Magnesium 116 mg · Energy 333 kcal
   CoFID 2021 (Public Health England), codes 14-843, 11-861, 11-868 · checked 2026-10-02
2. qnrc-daily-r8-02 · reference dataset
   FDC Foundation Flour, quinoa: Iron, Fe 4.528 MG, range 3.55-6.6, 8 samples · Fiber, total dietary 6.295 G, range 4.35-8.24 · Magnesium, Mg 163.8 MG, range 130.0-177.0; Rice, white, long grain, unenriched, raw: Iron, Fe 0.1405 MG, range 0.0-0.511 · Fiber 0.1488 G, range 0.0-1.19 · Magnesium 26.53 MG, range 12.9-38.7; Rice, brown, long grain, unenriched, raw: Iron, Fe 1.242 MG, range 0.87-1.73 · Fiber 3.021 G, range 2.6-3.4 · Magnesium 115.0 MG, range 110.0-121.0
   USDA FoodData Central, Foundation Foods, release 2026-04-30 · checked 2026-10-02
3. qnrc-daily-r8-03 · reference dataset
   FNDDS 2708400 Quinoa, no added fat: 1 cup, cooked 170 g · Quantity not specified 170 g; FNDDS 2708408 Rice, white, cooked, no added fat: 1 cup, cooked 158 g · Quantity not specified 118 g
   USDA FNDDS (FoodData Central), fdc_id 2708400 and 2708408 · checked 2026-10-02
4. qnrc-daily-r8-18 · RCT
   There was no difference in FAFe between HER2 [5.1% (3.7%, 7.1%)] and COR [4.0% (2.9%, 5.4%)] (P = 0.14), but FAFe from COR was lower than that from the reference meal [6.6% (4.9%, 9.0%)] (P = 0.003) ... Cooking in a rice-to-water ratio of 1:2 resulted in iron and zinc retentions >80%, and cooking in excess water did not affect iron retention from hot-extruded rice but caused iron losses of 25% from CER and COR.
   J Nutr, 2017 · checked 2026-10-02
5. qnrc-daily-r8-13 · systematic review
   Based on a glucose reference value of 100, the observed glycaemic index values for rice varieties ranged from 48 to 93, while the insulinaemic index ranged from 39 to 95. ... The milling process shows a clear effect when compared at identical cooking times, with brown rice always producing a lower PPG and PPI response than white rice. However, at longer cooking times normally used for the preparation of brown rice, smaller and inconsistent differences are observed between brown and white rice.
   Br J Nutr, 2015 · checked 2026-10-02
6. qnrc-daily-r8-14 · meta-analysis of lab studies
   Our results showed a significant decrease in the content of arsenic, lead, and cadmium following the cooking rice (WMD= -0.04 mg/kg, 95% CI: -0.05, -0.03, P = 0.000) ... Furthermore, based on the subgroup analysis the overall rank order of cooking methods in the rice was rinsed > parboiling > Kateh > high-pressure, microwave, and steaming.
   Int J Environ Health Res, 2024 · checked 2026-10-02
7. qnrc-daily-r8-05 · meta-analysis of RCTs
   Seven trials comprising 258 adults with mean ages of 31 to 64 years were included in this review. Studies used 15 to 50 grams of quinoa/per day as an intervention, and the intervention was between 28 to 180 days. ... our findings showed that quinoa seed supplementation did not have a significant effect on BMI (MD: -0.25; 95% CI: -0.98, 0.47; I2=0%, P = 0.998) and BW (MD: -0.54; 95% CI: -3.05, 1.97; I2=0%, P = 0.99), when compared with placebo.
   Curr Med Chem, 2024 · checked 2026-10-02
8. qnrc-daily-r8-06 · meta-analysis of RCTs
   Five eligible RCTs representing 206 subjects were enrolled. The pooled result showed that quinoa seed supplementation significantly lowered the body weight ... triglyceride (TG) (WMD: -7.20 mg/dl, 95% CI: -9.52, -4.87, p < .001), total cholesterol (TC) (WMD: -6.86 mg/dl, 95% CI: -10.64, -3.08, p < .001)
   Phytother Res, 2021 · checked 2026-10-02
9. qnrc-daily-r8-07 · RCT
   In total, 207 participants diagnosed with IGT were randomly assigned to the quinoa group (QG; 100 g day-1, replacing about half of the total daily staple food), multiple whole grain group (WGG; 100 g day-1), or control group (CG) and followed for one year.
   Food Funct, 2025 · checked 2026-10-02
10. qnrc-daily-r8-08 · RCT
    Significantly greater decreases in total and LDL cholesterol concentrations (- 0.30 ± 0.58 and - 0.25 ± 0.38 mmol/L, respectively), TC: HDL ratio (- 0.11 ± 0.30), weight (- 0.61 ± 0.89 kg) and BMI (- 0.22 ± 0.34 kg/m2) were apparent following consumption of the quinoa versus control biscuits (all P < 0.05).
    Eur J Nutr, 2020 · checked 2026-10-02
11. qnrc-daily-r8-09 · RCT
    After 4 weeks of intervention, blood glucose and low density lipoprotein (LDL) cholesterol were significantly lower than baseline in both groups but there was no difference between quinoa and control.
    Nutrients, 2018 · checked 2026-10-02
12. qnrc-daily-r8-11 · meta-analysis of cohorts
    The pooled relative risk was 1.55 (95% confidence interval 1.20 to 2.01) comparing the highest with the lowest category of white rice intake in Asian populations, whereas the corresponding relative risk was 1.12 (0.94 to 1.33) in Western populations (P for interaction=0.038).
    BMJ, 2012 · checked 2026-10-02
13. qnrc-daily-r8-12 · meta-analysis of cohorts
    Stratified analysis by gender showed a significant positive association between rice consumption and risk of chronic diseases in women (1·40; 1·13, 1·73), but not in men (0·95; 0·72, 1·24). Combining ten effect sizes from five studies showed that high consumption of rice was not significantly associated with mortality (0·97; 0·88, 1·06).
    Public Health Nutr, 2017 · checked 2026-10-02
14. qnrc-daily-r8-10 · cohort
    Nineteen treated celiac patients consumed 50 g of quinoa every day for 6 weeks as part of their usual GFD. ... Addition of quinoa to the GFD of celiac patients was well tolerated and did not exacerbate the condition.
    Am J Gastroenterol, 2014 · checked 2026-10-02
15. qnrc-daily-r8-15 · 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 2026-10-02
16. qnrc-daily-r8-16 · cross-sectional
    Percentage consuming rice or rice-containing foods was highest for infants aged 6-11.9 months (58.2%), including snacks (32.1%), infant cereal (27.9%), baby food purees (11.1%), and cooked rice (7.7%).
    J Acad Nutr Diet, 2025 · checked 2026-10-02
17. qnrc-daily-r8-17 · agency guidance
    The guidance identifies an action level of 100 micrograms per kilogram (µg/kg) or 100 parts per billion (ppb) which protects public health by reducing infants' dietary exposure to inorganic arsenic and is achievable by industry.
    US FDA, Final guidance on action level for inorganic arsenic in infant rice cereals, 2020 · checked 2026-10-02
18. qnrc-daily-r8-19 · EU claim register
    POL-HC-7865 Quinoa (Chenopodium quinoa) Stimulation of the hair bulb, favouring the growth of the hair Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7865, snapshot 2026-09-21 · checked 2026-10-02
19. qnrc-daily-r8-20 · EU claim register
    POL-HC-8510 Vibigaba (germinated brown rice) Contributes to the maintenance of normal blood glucose levels. -/- Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-8510, snapshot 2026-09-21 · checked 2026-10-02
20. qnrc-daily-r8-04 · reference dataset
    USDA-RETN-R6:432 RICE,WHITE/BROWN,COOKED,WATER USED: folate 70% · thiamin 80% · riboflavin 90% · iron 95% · magnesium 100% · zinc 100%
    USDA Table of Nutrient Retention Factors, Release 6 (2007), code 432 · checked 2026-10-02