Oatmeal or rice cereal: fiber, iron and the arsenic question

Rice cereal in a bedtime bottle is sometimes tried to help a baby sleep through, and one trial tested it. In 106 infants randomized to start it at 5 weeks or at 4 months, there was no significant difference in how many slept 8 hours, with sleep logged by caregivers one day a week. The trial measured sleep only. It does not show that cereal in a bottle, or cereal at 5 weeks, is safe, and this page holds no source that it is, so the trial is not a guide to doing it. The choice between the two cereals rests on plainer numbers. Per 3.5 oz (100 g) of dry infant cereal in USDA survey data, oatmeal carries 7.3 g of fiber and 10.99 g of protein, and rice carries 1.3 g and 6.65 g. Calories are almost level, 394 against 390 calories. Both are fortified with iron, about 2.4 mg and 2.0 mg per 4 g tablespoon, and that figure changes from brand to brand. Rice has one extra question. The FDA set an action level of 100 ppb inorganic arsenic for infant rice cereal because rice takes up more arsenic from soil and water than wheat or barley. It is guidance, not legally binding, and oatmeal cereal has no comparable level.

How much is actually in it

• Dry infant oatmeal cereal carries 7.3 g fiber and 10.99 g protein per 3.5 oz (100 g) against 1.3 g and 6.65 g for dry infant rice cereal, with similar calories. — US survey food codes for dry baby and toddler cereal, FNDDS (n = 2 food codes) Evidence E source
  Per 100 g oatmeal vs rice: fiber 7.3 vs 1.3 g, protein 10.99 vs 6.65 g, iron 64.1 vs 53.01 mg (fortified), energy 394 vs 390 calories; per tablespoon 4 g: iron 2.4 vs 2.0 mg

What a real portion looks like

• In a US national survey, 27.9% of infants aged 6 to 12 months ate infant cereal containing rice on a given day, averaging 3.3 g of rice a day from cereal. — 2635 US infants and toddlers 0 to 24 months, Feeding Infants and Toddlers Study 2016, 24-hour recalls (n = 2635) Evidence C source
  Rice or rice foods eaten by 58.2% at 6 to 11.9 months: snacks 32.1%, infant cereal 27.9%; per capita rice from infant cereal 3.3 g/day

What your body absorbs

• In 14 infants, mixing rice cereal into formula left calcium absorption at 57 to 58% and iron at about 6%, the same as formula alone. — 14 healthy infants, randomized order, formula alone or formula with 6.5 g/dl rice cereal, stable isotope tracers (n = 14) Evidence B source
  Calcium absorption 58% vs 57%; iron absorption 5.8% vs 6.3% (p = 0.06)
• In 69 breastfed infants eating fortified rice cereal daily from 4 to 9 months, electrolytic iron worked as well as ferrous fumarate, with 4.2% mild iron deficiency and no anemia. — 95 exclusively breastfed infants randomized at 4 months, 69 completed to 9 months, dry infant rice cereal with about 53 to 55 mg iron per 3.5 oz (100 g) (n = 69) Evidence B source
  No difference in iron status; mild iron deficiency 4.2% with each cereal; iron intake about 1.1 to 1.2 mg/kg/day
• In 40 adults, instant oatmeal needed 1.6 g extra oat beta-glucan to cut the blood glucose area by 20% against cream of rice, each gram lowering it by 7%. — 40 subjects, randomized crossover, 27 g instant oatmeal with milk plus 0 to 1.6 g added oat beta-glucan, or a matched portion of cream of rice (n = 40) Evidence B source
  IAUC 74 vs 93 mmol min/L with 1.6 g added beta-glucan vs cream of rice (p < 0.05); each gram lowered iAUC 7% and peak rise 15%

What cooking and storage change

• By the USDA retention table, cooking regular or quick oatmeal keeps about 70% of folate, 80% of thiamin and 95% of iron. — USDA Table of Nutrient Retention Factors, breakfast cereals group, oatmeal regular or quick, cooked (n = 1 method) Evidence E source
  Retained: folate 70%, vitamin C 80%, thiamin 80%, riboflavin, niacin and B6 90%, iron and potassium 95%, calcium, magnesium, zinc 100%

What it does to your health

• Among formula-weaned infants followed to 15 months, anemia exclusions were 8% with iron-fortified rice cereal against 24% with unfortified cereal. — 515 infants followed 4 to 15 months, double-blind as to iron in cereal or formula, rice cereal with 55 mg electrolytic iron per 3.5 oz (100 g) (n = 515) Evidence C source
  Cumulative anemia exclusions by 15 months: fortified cereal 8%, unfortified cereal 24%, fortified formula 4% (P < .01)
• In 43 breastfed infants given a single first food for a week, oatmeal cereal raised gut bacterial richness more than beef. — 43 vaginally delivered, exclusively breastfed infants randomized to oatmeal cereal, beef, carrot or prune for 1 week, then oatmeal cereal for 1 week (n = 43) Evidence B source
  Observed amplicon sequence variants higher with oatmeal cereal than beef (P = 0.024); Enterococcus raised
• In 56 adults with high cholesterol eating 2.8 oz (80 g) a day of oatmeal or white rice for 45 days, the LDL drop with oatmeal depended on a CYP7A1 gene variant. — 62 medication-naive hypercholesterolemic Chinese adults, 80 g/day oatmeal (n=31) or refined white rice (n=31) as staple, 45 days; 56 analyzed (n = 56) Evidence B source
  Genotype by diet interaction for LDL (p = 0.04); rs3808607-TT carriers responded more to oatmeal than G carriers (p = 0.02)
• Pooled meta-analyses link oats and oatmeal to 12% lower all-cause mortality, the same as breakfast cereal in general. — 16 reviews on foods and all-cause mortality, 17 on cardiovascular disease (n = 16 reviews) Evidence C source
  Oats/oatmeal RR 0.88 (95% CI 0.83 to 0.92); breakfast cereal RR 0.88; whole grain bread RR 0.85

Safety, limits and interactions

• The FDA sets an action level of 100 ppb inorganic arsenic for infant rice cereal, noting that rice takes up more arsenic than wheat or barley. — infant rice cereals sold in the US (white, brown, organic and conventional) Evidence E source
  Action level 100 micrograms per kilogram (100 ppb) inorganic arsenic; not legally binding
• Among 56 infants with reflux or swallowing problems, urinary arsenic did not differ between those thickening feeds with infant oatmeal or rice cereal and other thickeners. — 56 infants under 1 year with reflux or oropharyngeal dysphagia, single US center, 2021 to 2023; 10 on infant oatmeal or rice cereal (n = 56) Evidence C source
  Median urinary arsenic did not differ by thickener (p = 0.086), all below ATSDR limits; more servings of other arsenic sources linked to higher levels (p = 0.001)
• Across 75 studies of baby foods, 30% of rice-based mixes exceeded the international maximum level for arsenic. — 75 studies, 580 baby foods and 251 infant formulas worldwide (n = 75 studies) Evidence C source
  Arsenic median 0.048 mg/kg in rice mixes with 30% above the maximum level; cereals had the highest cadmium median, 0.013 mg/kg

What people believe that the data does not support

• In 106 infants, starting rice cereal in the bedtime bottle at 5 weeks rather than 4 months did not help them sleep through the night. — 106 infants randomized to bedtime rice cereal (1 tablespoon per ounce in a bottle) from 5 weeks or from 4 months, sleep logged 4 to 21 weeks (n = 106) Evidence B source
  No significant difference in the share sleeping 8 hours (or 6 hours) through the night

The bottom line

Iron fortification is where the infant evidence is clearest. Among 515 formula-weaned infants followed to 15 months, 8% on iron-fortified rice cereal were excluded for anemia against 24% on unfortified cereal, in a 1993 trial where feeding groups were not fully randomized. In 69 breastfed infants eating fortified rice cereal daily from 4 to 9 months, two kinds of added iron worked equally well, with 4.2% mild iron deficiency and no anemia. That trial had no unfortified arm. Mixing rice cereal into formula did not change absorption in 14 infants, with calcium at 57 to 58% and iron near 6%, measured on single test meals. For oatmeal the infant evidence is thinner. In a one-week pilot in 43 breastfed infants, oatmeal cereal as a first food raised gut bacterial richness more than beef (P = 0.024). That is a microbiome marker, with no clinical outcome, and rice cereal was not tested. We found no trial comparing infant oatmeal cereal with infant rice cereal on growth, health or arsenic exposure. Arsenic is the caution on this page, and it concerns babies. A review of 75 surveys found 30% of rice-based baby food mixes above the international maximum level for arsenic, with a median of 0.048 mg/kg, and gave no separate figure for oat cereals. Among 56 infants with reflux or swallowing problems at one US center, urinary arsenic did not differ by thickener (p = 0.086). Only 10 of them used oatmeal or rice cereal, pooled as one group. In a 2016 US survey, 27.9% of infants aged 6 to 12 months ate infant cereal with rice on a given day, averaging 3.3 g of rice a day from it. This page holds no card on how parents can lower that exposure. We have no data here on allergy to either grain, on pregnancy or on medicines. Adults choosing a hot breakfast face a smaller gap than the labels suggest. In 40 adults, plain instant oatmeal did not lower the 2 hour glucose area by 20% against cream of rice. That took 1.6 g of added oat beta-glucan (74 against 93 mmol min/L). In 56 Chinese adults with high cholesterol eating 2.8 oz (80 g) a day of oatmeal or white rice for 45 days, the LDL drop with oatmeal depended on a CYP7A1 gene variant, a small subgroup analysis done after the fact. Observational meta-analyses link oats and oatmeal to 12% lower all-cause mortality (RR 0.88, 95% CI 0.83 to 0.92), the same figure as breakfast cereal in general. That is an association and says nothing about rice cereal. Cooking oatmeal keeps about 70% of its folate, 80% of thiamin and 95% of iron, by a USDA group factor from 1975. There is no such factor for rice cereal.

Sources

1. orce-r7-01 · reference dataset
   FNDDS 2708492 Baby Toddler cereal, oatmeal, dry: Fiber 7.3 g, Protein 10.99 g, Iron 64.1 mg, Energy 394 kcal per 100 g; 1 tablespoon 4 g iron 2.4 mg · FNDDS 2708493 Baby Toddler cereal, rice, dry: Fiber 1.3 g, Protein 6.65 g, Iron 53.01 mg, Energy 390 kcal per 100 g; 1 tablespoon 4 g iron 2.0 mg
   USDA FNDDS 2021-2023 · checked 2026-09-30
2. orce-r7-06 · 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 2026-09-30
3. orce-r7-08 · RCT, crossover
   Mean (+/- SD) percent absorption of calcium from F was 58% (+/- 13) and from F + R 57% (+/- 18). Absorption of iron from F was 5.8% (+/- 7) and from F + R 6.3% (+/- 4) (p = 0.06).
   J Pediatr Gastroenterol Nutr, 1998 · checked 2026-09-30
4. orce-r7-09 · RCT
   With each cereal, 2 infants had mild ID, a prevalence of 4.2%, but no infant developed ID anemia. There were no differences in iron status between study groups.
   J Nutr, 2011 · checked 2026-09-30
5. orce-r7-13 · RCT, crossover
   Each gram of OBG reduced iAUC by 7% and peak-rise by 15%. Thus, to achieve a ≥20% reduction in iAUC relative to CR, 1.6 g OBG had to be added to IO (74 ± 7 vs. 93 ± 6 mmol min L-1, p < 0.05), but, to achieve a 20% reduction in peak-rise, only 0.4 g OBG was required (2.00 ± 0.1 vs. 2.40 ± 0.1 mmol, p < 0.05).
   Food Funct, 2018 · checked 2026-09-30
6. orce-r7-02 · reference dataset
   USDA-RETN-R6:352 OATMEAL,REG/QUICK,COOKED: folate_total 70% · thiamin 80% · riboflavin 90% · vitamin_b6 90% · iron 95% · zinc 100%
   USDA Table of Nutrient Retention Factors, Release 6, 2007, code 352 · checked 2026-09-30
7. orce-r7-10 · controlled trial
   Among infants weaned to formula before 4 months, the cumulative percentages of infants excluded for anemia by 15 months were 8%, 24%, and 4%, respectively, in the fortified cereal, unfortified cereal and formula, and fortified formula groups
   Pediatrics, 1993 · checked 2026-09-30
8. orce-r7-11 · RCT, pilot
   In phase 1, oatmeal cereal increased observed amplicon sequence variants compared with beef (P = 0.024).
   J Nutr, 2026 · checked 2026-09-30
9. orce-r7-12 · RCT, secondary analysis
   Genotype- diet interactions were observed between oatmeal consumption and SNP in the cytochrome P450 family 7 subfamily A member 1 gene rs3808607 in regulating LDL cholesterol (p=0.04); rs3808607-TT homozygotes exhibited significantly higher responsiveness to oatmeal (reduction in LDL cholesterol) than G allele carriers (GG/GT) (p=0.02).
   Asia Pac J Clin Nutr, 2020 · checked 2026-09-30
10. orce-r7-14 · umbrella review
    Carbohydrates were associated with a reduced risk of all-cause mortality (whole grain bread: relative risk (RR) 0.85, 95% confidence interval (CI) 0.82-0.89; breakfast cereal: RR 0.88, 95% CI 0.83-0.92; oats/oatmeal: RR 0.88, 95% CI 0.83-0.92).
    Eur J Prev Cardiol, 2019 · checked 2026-09-30
11. orce-r7-03 · 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 entitled "Inorganic Arsenic in Rice Cereals for Infants: Action Level."...Rice also tends to have higher arsenic concentrations than other cereal crops (such as wheat and barley) because of its ability to take up arsenic from soil and water and because it is typically grown under flooded conditions, which increase the potential for arsenic uptake
    US FDA, Supporting Document for Action Level for Inorganic Arsenic in Rice Cereals for Infants, 2020 · checked 2026-09-30
12. orce-r7-04 · cohort
    The median total urinary arsenic concentration did not differ between groups (p = 0.086) and levels between groups were well below the Agency for Toxic Substances and Disease Registry (ATSDR)'s toxicity limits.
    Sci Rep, 2025 · checked 2026-09-30
13. orce-r7-05 · 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
14. orce-r7-07 · RCT
    There was no statistically significant trend or a consistent tendency of one group to have a higher proportion of sleepers than the other. Therefore, feeding infants rice cereal in the bottle before bedtime does not appear to make much difference in their sleeping through the night.
    Am J Dis Child, 1989 · checked 2026-09-30