Onions

Overview
Onions provide inulin (prebiotic fiber), quercetin (polyphenol), and sulfur compounds that support gut microbiome, antioxidant defenses, and glutathione synthesis. Prebiotic Fibres: Inulin (chicory, onions), GOS (legumes), resistant starch (cooled potatoes, green bananas), pectin (apples). Inulin (chicory, onions) supports Bifidobacterium, Akkermansia; ↑ butyrate production; improved gut barrier. Quercetin is abundant in capers, apples, onions, berries, kale and soybeans.
Food Context
Synergies
- Part of diverse prebiotic fiber strategy; prebiotic fibres including inulin (chicory, onions) support Bifidobacterium, Akkermansia; ↑ butyrate production; improved gut barrier
- Pair with other allium vegetables for synergistic effects
Preparation
- Can be consumed raw or cooked; cooking may enhance some compounds
- Sulphur-containing vegetables that provide glutathione precursors (e.g., broccoli, Brussels sprouts, garlic, onions) support antioxidant defenses
Recipes
Nutrient Tables (per 100 g)
Core nutrients
| Nutrient | Amount per 100 g | % RDA per 100 g |
|---|---|---|
| Energy | 44 kcal | — |
| Protein | 0.9 g | — |
| Total fat | 0.1 g | — |
| Carbohydrates | 9.9 g | — |
| Sugars | 5.8 g | — |
| Fibre | 2.2 g | — |
Key micronutrients
| Nutrient | Amount per 100 g | % RDA per 100 g |
|---|---|---|
| Iron | 0.2 mg | 1.3% |
| Zinc | 0.2 mg | 1.5% |
| Magnesium | 11.4 mg | 2.7% |
| Selenium | 0.5 µg | 0.9% |
| Calcium | 17 mg | 1.7% |
| Potassium | 197 mg | 5.8% |
Reference intakes: US Dietary Reference Intakes for adults (19–50 years; using the higher of male/female values where they differ).
Data provenance (core / micronutrient panel): USDA FoodData Central, Onions, red, raw, FDC ID 790577, API, per 100 g edible portion, last checked 2026-03-14
Substances
References
- Prebiotic Fibres: Inulin (chicory, onions), GOS (legumes), resistant starch (cooled potatoes, green bananas), pectin (apples)
- Sulphur-containing vegetables that provide glutathione precursors (e.g., broccoli, Brussels sprouts, garlic, onions)
- Quercetin is abundant in capers, apples, onions, berries, kale and soybeans
- Inulin (chicory, onions) supports Bifidobacterium, Akkermansia; ↑ butyrate production; improved gut barrier
- Prebiotic fibres including inulin (chicory, onions) support Bifidobacterium, Akkermansia; ↑ butyrate production; improved gut barrier










