Banana: Potassium Content — Myth vs. Reality

Banana Potassium: What the Data Actually Says

🍌 The myth: Bananas are the ultimate potassium food. Doctors recommend them, athletes eat them, and the internet has cemented this as near-universal health knowledge.

The reality: A medium banana provides 422mg of potassium — approximately 9% of the 4,700mg adult daily value (DV). That is a meaningful contribution, but bananas are not even close to the highest-potassium foods per serving. Potatoes, spinach, avocado, and many other common foods contain more.

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USDA Full Nutritional Profile: Medium Banana (118g)

Source: USDA FoodData Central, ID 1105314

Nutrient	Amount	% Daily Value
Energy	105 kcal	5%
Total carbohydrate	27.0 g	10%
Dietary fiber	3.1 g	11%
Total sugars	14.4 g	—
Protein	1.3 g	3%
Total fat	0.4 g	1%
Potassium	422 mg	9%
Magnesium	32 mg	8%
Vitamin B6	0.43 mg	25%
Vitamin C	10.3 mg	11%
Folate	24 μg	6%
Vitamin A	4 μg	0%
Calcium	6 mg	0%
Iron	0.31 mg	2%
Sodium	1 mg	0%

🍌 The standout nutrient is actually Vitamin B6 — a banana provides 25% of the daily value. This is substantially more impressive than its potassium contribution, but vitamin B6 doesn’t get the marketing attention that potassium does.

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Potassium Comparison: How Bananas Stack Up

Food	Serving Size	Potassium	% Daily Value
Potato, baked with skin	1 medium (173g)	897 mg	19%
Spinach, cooked	1 cup (180g)	839 mg	18%
Sweet potato, baked	1 medium (114g)	542 mg	12%
Avocado, raw	1 half (68g)	345 mg	7%
Banana, raw	1 medium (118g)	422 mg	9%
Dried apricots	½ cup (65g)	755 mg	16%
White beans, cooked	½ cup (130g)	502 mg	11%
Salmon, cooked	3 oz (85g)	534 mg	11%
Milk, whole	1 cup (244g)	366 mg	8%
Orange juice	1 cup (248g)	496 mg	11%

A plain baked potato with skin contains more than twice the potassium of a banana and costs a fraction of the price. The banana’s potassium reputation vastly overperforms its actual nutritional ranking.

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Why Bananas Got the Potassium Reputation

Several factors explain how bananas became synonymous with potassium despite being outcompeted by potatoes, spinach, and many other foods:

1. Portability and branding — Bananas are self-packaged, portable, and widely marketed by Chiquita and Dole with health messaging. Potatoes are not marketed as a health food.
2. Athletic culture — Tennis tournaments began providing bananas courtside in the 1970s–80s; the association with electrolyte replenishment for cramps became deeply embedded.
3. Muscle cramps oversimplification — Potassium deficiency can cause muscle cramps, but sports-related cramps are more often caused by dehydration and electrolyte imbalances (sodium, magnesium), not potassium alone.
4. Consistent messaging — Decades of consistent “eat a banana for potassium” public health messaging created durable cultural memory.

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The Potassium Deficiency Context

Hypokalemia (potassium deficiency) is a clinical condition, but dietary potassium deficiency from normal eating patterns is uncommon in well-nourished adults. The much more common issue is inadequate potassium intake across populations, where chronic low intake contributes to hypertension risk.

Population	Average Potassium Intake	% Meeting DV (4,700mg)
US adults (NHANES)	~2,300–2,600 mg/day	~3%
UK adults (NDNS)	~2,800–3,000 mg/day	~8%
Recommended DV	4,700 mg/day	—

The takeaway: most people fall well short of potassium recommendations, and bananas alone cannot close that gap. A diverse diet including leafy greens, legumes, and root vegetables is required.

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Potassium Changes During Ripening

Potassium content does not change dramatically across ripening stages, but the dry-weight basis shifts as water content and sugars change:

Stage	Fresh weight basis (mg/100g)	Notes
Stage 1–2 (green)	~350–380 mg	Higher starch, lower sugar
Stage 4–5 (half-ripe)	~370–400 mg	Transition phase
Stage 6 (ripe)	~358–422 mg	USDA reference value
Stage 7 (overripe)	~350–380 mg	Slight concentration shift

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Related Pages

• Banana Radioactivity — K-40 in bananas, Banana Equivalent Dose
• Banana Ripening Stages — starch-to-sugar conversion across the 7-stage scale
• Banana Curvature Mathematics — why bananas are curved
• Global Banana Production — FAO production data, 120M tonne world total