Banana: Vitamin and Mineral Profile
Bananas are exceptional sources of vitamin B6 (0.37mg per 100g, 22% DV) and provide meaningful manganese (0.27mg, 13% DV) and vitamin C (8.7mg, 10% DV). The B6 content makes bananas one of the best fruit sources of this neurologically critical vitamin.
The banana’s micronutrient profile is dominated by one standout: vitamin B6. 🍌 While the fruit’s potassium content gets most of the cultural attention (examined in detail on the potassium page), B6 is the more nutritionally distinctive contribution bananas make — and one of the few micronutrient claims about bananas that holds up rigorously.
Vitamins Per 100g (Ripe Banana)
All values from USDA FoodData Central FDC ID 1105314. Daily Value (DV) based on FDA 2020 reference intakes for adults.
| Vitamin | Per 100g | % Daily Value |
|---|---|---|
| Vitamin B6 (Pyridoxine) | 0.367mg | 22% |
| Vitamin C (Ascorbic acid) | 8.7mg | 10% |
| Folate (B9) | 20mcg | 5% |
| Niacin (B3) | 0.665mg | 4% |
| Pantothenic Acid (B5) | 0.334mg | 7% |
| Riboflavin (B2) | 0.073mg | 6% |
| Thiamine (B1) | 0.031mg | 3% |
| Vitamin A (RAE) | 3mcg | < 1% |
| Vitamin E | 0.10mg | 1% |
| Vitamin K | 0.5mcg | < 1% |
Bananas are a meaningful source of B-complex vitamins, with B6 as the lead contributor. Vitamin C content is real but modest; a medium banana covers about 10% of daily needs compared to an orange’s ~116%.
Minerals Per 100g (Ripe Banana)
| Mineral | Per 100g | % Daily Value |
|---|---|---|
| Potassium | 358mg | 8% |
| Manganese | 0.270mg | 12% |
| Magnesium | 27mg | 6% |
| Phosphorus | 22mg | 2% |
| Copper | 0.078mg | 9% |
| Calcium | 5mg | < 1% |
| Iron | 0.26mg | 1% |
| Zinc | 0.15mg | 1% |
| Selenium | 1.0mcg | 2% |
The manganese content is underappreciated — at 12% DV per 100g, bananas rank among the better whole-food sources of this trace mineral, which functions as a cofactor for superoxide dismutase (the primary antioxidant enzyme in mitochondria).
Why Banana B6 Is Notable
Vitamin B6 appears across all food categories, but fruit sources are generally poor providers. Among commonly consumed fruits, banana is the richest B6 source in the Western diet by a substantial margin:
| Fruit | B6 (mg/100g) |
|---|---|
| Banana | 0.37 |
| Avocado | 0.26 |
| Jackfruit | 0.19 |
| Prune (dried) | 0.21 |
| Watermelon | 0.045 |
| Apple | 0.041 |
| Orange | 0.060 |
B6 is required for over 100 enzyme reactions, primarily involving amino acid metabolism. Clinically, B6 deficiency manifests as peripheral neuropathy, dermatitis, glossitis, and depression. The NIH RDA is 1.3–1.7mg/day for adults; one medium banana (118g) delivers roughly 0.43mg — about a third of daily needs from a single piece of fruit.
The Mood Food Claim: Tryptophan Reality Check
🍌 The popular claim that “bananas make you happy because they contain serotonin precursors” is technically true but practically misleading. Bananas do contain:
- Tryptophan: ~9mg per 100g
- Serotonin: ~15mcg per 100g (in the peel, negligible in flesh)
- Dopamine: ~2.5–10mcg per 100g
The problems with the mood claim are pharmacokinetic. Dietary tryptophan must cross the blood-brain barrier via a competitive transporter shared with other large neutral amino acids (LNAA). A meal with carbohydrates triggers insulin, which clears competing amino acids from plasma, giving tryptophan a relative advantage at the BBB — but the total tryptophan in one banana (approximately 11mg) is far below the 1–2g doses used in clinical tryptophan supplementation trials showing mood effects.
B6, however, is genuinely relevant: it is a cofactor for both tryptophan hydroxylase (converts tryptophan → serotonin) and aromatic L-amino acid decarboxylase (converts DOPA → dopamine). Adequate B6 status supports neurotransmitter synthesis, and banana is a legitimate dietary contributor to that status.
The macronutrient context for these values is covered on the macronutrients page. The way micronutrient content changes with ripeness closely tracks the starch-to-sugar conversion documented in sugar profile.
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