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Onions vs shallots: nutrition compared

Full comparison · Calories · Carbs · Healthier

Per 3.5 oz (100 g), onions has 40 calories and 1.1 g of protein; shallots has 72 calories and 2.5 g. Fiber: 1.7 g vs 3.2 g.

Where each one is ahead

Side by side, per 3.5 oz (100 g)

OnionsShallots
Calories40 calories72 calories
Protein1.1 g (2% DV)2.5 g (5% DV)
Fat0.1 g (0% DV)0.1 g (0% DV)
Saturated fat0.04 g (0% DV)0.02 g (0% DV)
Carbohydrate9.3 g (3% DV)16.8 g (6% DV)
Fiber1.7 g (6% DV)3.2 g (11% DV)
Total sugars4.2 g7.9 g
Sodium4 mg (0% DV)12 mg (1% DV)
Potassium146 mg (3% DV)334 mg (7% DV)
Calcium23 mg (2% DV)37 mg (3% DV)
Iron0.2 mg (1% DV)1.2 mg (7% DV)
Magnesium10 mg (2% DV)21 mg (5% DV)
Vitamin A0 mcg0 mcg
Vitamin C7.4 mg (8% DV)8 mg (9% DV)
Vitamin D0 mcg0 mcg
Vitamin K0.4 mcg (0% DV)0.8 mcg (1% DV)
Folate19 mcg (5% DV)34 mcg (8% DV)
Vitamin B120 mcg0 mcg
Cholesterol0 mg0 mg

— not reported by USDA for this food.

Per typical serving

Servings differ: 1 cup, chopped (5.6 oz, 160 g) of onions and 1 tbsp chopped (10 g) of shallots, the serving sizes we use for each (USDA household measures; 4 oz for meat and fish).

OnionsShallots
Calories64 calories7 calories
Protein1.8 g (4% DV)0.25 g (0% DV)
Fat0.16 g (0% DV)0.01 g (0% DV)
Saturated fat0.07 g (0% DV)0 g (0% DV)
Carbohydrate14.9 g (5% DV)1.7 g (1% DV)
Fiber2.7 g (10% DV)0.32 g (1% DV)
Total sugars6.8 g0.79 g
Sodium6.4 mg (0% DV)1.2 mg (0% DV)
Potassium234 mg (5% DV)33 mg (1% DV)

— not reported by USDA for this food.

What the numbers don't tell you

Most people comparing these two have a recipe that names one and a kitchen that holds the other. We found no study comparing them head to head, for flavor or health. Per 3.5 oz (100 g) shallots carry more than onions, 72 against 40 calories and 334 against 146 mg of potassium. But a tablespoon of chopped shallot weighs 0.35 oz (10 g) and holds about 7 calories and 33 mg of potassium, so the gap adds up to very little in a dish.

Pooled onion trials improved LDL cholesterol and blood pressure at onion supplement doses above 300 mg a day, not with onion eaten in food. The human trials on shallots enrolled 9 and 16 people. Observational data point two ways: no link with cancer overall in one meta-analysis, lower odds of stomach cancer at the highest intake in another, and neither looked at shallots alone.

One caution applies to both. If you have irritable bowel syndrome, a review lists onion and shallots together among the major high FODMAP foods (fermentable carbohydrates), without giving an amount, so swapping one for the other will not help.

Choose by taste. By USDA retention factors for fried vegetables in general, frying keeps the minerals and costs about 30% of the folate and 15% of the vitamin C in either.

Evidence behind this note

  1. Level A Pooled onion trials show metabolic benefit, and the dose where it appears is a supplement dose. Clin Nutr ESPEN, 2023
  2. Level A Pooling the studies, people who ate the most onions and garlic did not get less cancer. Front Nutr, 2021
  3. Level B In a randomized crossover trial in 9 volunteers, quercetin from dry shallot skin gave about twice the blood exposure of quercetin from shallot flesh (AUC 47.23 vs 22.23 micromol x h/L). J Nutr, 2008
  4. Level B In a randomized placebo-controlled trial in 16 people with allergic rhinitis, 3 g of shallot a day added to cetirizine for 4 weeks improved overall symptom scores in 62.5% vs 37.5% on cetirizine alone, with no excess of side effects. Asian Pac J Allergy Immunol, 2022
  5. Level C Observational data link high intake of Allium vegetables, a group that includes shallots, with lower gastric cancer risk: a meta-analysis of 21 studies found an odds ratio of 0.54 for highest vs lowest intake. Gastroenterology, 2011
  6. Level D For people with irritable bowel syndrome, shallots count among the major high FODMAP foods alongside onion and garlic, which is why low FODMAP diets restrict them. J Gastroenterol Hepatol, 2018
  7. Level E By the USDA retention table for Vegetables and Vegetable Products when fried, about 30% of folate, 15% of vitamin C and thiamin and 10% of vitamin B6 are lost, while minerals stay. USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 3780

Written from the studies and agency guidance we hold for both foods, reviewed by the Bioma editorial system. How we verify.

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Where the numbers come from

Each food is one USDA entry, chosen as it is usually eaten. Other cuts, brands and preparations differ; the links show them. % DV uses FDA Daily Values for adults. How we verify.