Is cornstarch gluten free?
Yes. Plain cornstarch is naturally gluten free: it is not made from wheat, rye or barley, the grains FDA names as the sources of gluten.
What the gluten-free label means
A food labeled gluten free in the US must have less than 20 ppm gluten, whether the gluten comes from an ingredient or from contact during processing. Foods that are gluten free by nature, like fresh fruits and vegetables, can carry the label too (FDA).
For celiac disease, the risk with plain cornstarch is cross-contact in packing plants and kitchens, not the food itself. Pooled testing studies found more than 20 ppm gluten in 28% of foods that are gluten free by nature, against 9.5% of products labeled gluten free, so the label lowers that risk without removing it.
Cornstarch in place of wheat: what changes
If cornstarch replaces a gluten flour of the same kind, this is how the same amount compares, 1 tbsp (8 g) of each:
| Food | Calories | Protein | Fiber | Iron |
|---|---|---|---|---|
| Cornstarch | 30 calories | 0.02 g | 0.07 g | 0 mg |
| Semolina flour | 29 calories | 1.1 g | 0.29 g | 0.2 mg |
| Wheat flour | 29 calories | 0.78 g | 0.19 g | 0.4 mg |
| Spelt flour | 27 calories | 1.2 g | 0.75 g | 0.3 mg |
Values are for one USDA entry per food. An entry USDA labels enriched has added iron and B vitamins, which changes the iron column.
Cornstarch on other diets
| Diet | Fits? |
|---|---|
| Keto | Small portion only for 1 tbsp (8 g) |
| Gluten free | Yes, naturally |
| Vegan | Yes |
Who needs to avoid gluten, and what going gluten free costs
- Level E NIDDK states that people with celiac disease need a gluten-free diet for life to prevent symptoms and intestinal damage from returning. NIDDK (NIH), Eating, Diet, & Nutrition for Celiac Disease
- Level C A meta-analysis of 40 studies found gluten above 20 mg/kg in 9.52% of labeled gluten-free products, against 28.32% of naturally gluten-free foods. Br J Nutr, 2022
- Level B Two granola bars a day carrying 10 g of gluten caused no more gut symptoms than gluten-free bars in 33 young people who felt better off gluten, difference on a 100 mm scale -0.01. Aliment Pharmacol Ther, 2022
- Level C Children who went gluten free after a celiac diagnosis had four times more arsenic in their urine six months later, because rice is what replaces wheat. American Journal of Gastroenterology, 2025
Levels: A systematic review or meta-analysis, B randomized trial, C observational, D lab or animal, E expert body. How we grade evidence.
Keep exploring
Sources
- USDA FoodData Central (SR Legacy), Cornstarch, FDC ID 169698, accessed 2026-10-12 · full nutrition facts
- FDA, Questions and Answers on the Gluten-Free Food Labeling Final Rule, www.fda.gov (content current as of June 30, 2022), accessed 2026-10-12
Numbers are USDA values scaled to the serving shown. Serving sizes are USDA household measures. % DV uses FDA Daily Values for adults. Checked 2026-10-12 · How we verify. Information, not medical advice.