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).
Within the BRAIN Diet framework, inulin (chicory, onions) supports Bifidobacterium, Akkermansia; ↑ butyrate production; improved gut barrier. Quercetin is abundant in capers, apples, onions, berries, kale and soybeans [1][2].
Key Nutritional Highlights
- Onions supply organosulfur compounds and quercetin glycosides with antioxidant relevance [1]
- Quercetin from alliums is studied for anti-inflammatory and cardiovascular mechanisms [2]
- Onions provide inulin (prebiotic fiber), quercetin (polyphenol), and sulfur compounds that support gut microbiome, antioxidant defenses, and glutathione synthesis. [1]
- Prebiotic Fibres: Inulin (chicory, onions), GOS (legumes), resistant starch (cooled potatoes, green bananas), pectin (apples). [2]
- 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
3 recipes containing this food
Black Bean & Sweet Potato Vegetable Chilli
A fibre-rich bean and vegetable chilli with warming spices and slow carbohydrates for steady energy and satiety.
Linguine alle vongole mantecate (Linguine with cockles in a silky emulsified sauce)
Whole-wheat linguine with cockles in a silky emulsified sauce; Italian emulsification technique without cream, supporting taurine, B12, and choline intake.
Turkey Wing Stew
A collagen-rich, glycine-heavy slow-cooked stew made from affordable turkey wings — rich in protein, tryptophan, and B vitamins.
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% |
Substances
Substances in this food: editorial (Overview / literature) plus analytical (nutrition table).
8 substances in this food
Quercetin (and Isoquercetin)
Polyphenol; antioxidant; mitochondrial support; bioavailability improved with vitamin C
Vitamin C (Ascorbate)
Antioxidant; supports iron absorption; neuronal SVCT2 transport
Iron
Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)
Zinc
Cofactor in neurotransmission and antioxidant enzymes; dopamine modulation
Magnesium
Enzymatic cofactor (>300 reactions); neurotransmitters; mitochondria; redox balance
Selenium
Antioxidant enzyme cofactor (GPx); supports redox balance
Calcium
Bone health; neurotransmission; interacts with vitamin D and K2
Potassium
Electrolyte for nerve transmission, muscle function, and blood pressure regulation
References
[1] Onions supply organosulfur compounds and quercetin glycosides with antioxidant relevance. Nicastro et al. 2015. Garlic and onions: their cancer prevention properties
[2] Quercetin from alliums is studied for anti-inflammatory and cardiovascular mechanisms. Davis et al. 2009. Quercetin increases brain and muscle mitochondrial biogenesis and exercise tolerance