Shallots: two tiny trials and a lot of borrowed onion data

The best human evidence on shallots comes from very small trials. In a randomized trial in 16 people with allergic rhinitis, 8 per group, adding 3 g of shallot a day to cetirizine for 4 weeks improved overall symptom scores in 62.5 percent of patients against 37.5 percent on cetirizine alone, with no interval reported. The nasal symptom score did not differ significantly between groups, so treat this as a hint from one small study. In a second trial, 9 volunteers took a single dose of shallot flesh or of the dry papery skin, and quercetin from the skin reached about twice the blood exposure of quercetin from the flesh. That measured absorption only, after one dose, and most cooks throw the skin away. Everything larger is observational and lumps shallots in with onions and garlic. A meta-analysis of 21 studies with 543,220 people linked the highest Allium intake with lower odds of stomach cancer, an odds ratio of 0.54 (95% CI 0.43 to 0.65), and the authors themselves name confounding and misclassified intake as limits. Shallots were never analyzed on their own.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• Raw shallot bulbs sampled for USDA Foundation Foods held 222 to 296 mg potassium and 2.0 to 2.5 g fiber per 3.5 oz (100 g), while calcium ranged from 17.2 to 40.0 mg across 8 samples. — 8 samples of raw peeled shallot bulbs, USDA FoodData Central Foundation Foods (FDC 2727586) (n = 8 samples) Evidence E source
  Potassium 251.5 mg (222-296); fiber 2.2 g (2.0-2.5); calcium 26.06 mg (17.2-40.0); vitamin B6 0.177 mg (0.164-0.189) per 3.5 oz (100 g)
• UK and US tables disagree on raw shallots: CoFID lists 0.80 mg iron and 0.05 mg copper per 3.5 oz (100 g), while USDA Foundation samples average 0.33 mg iron and 0.08 mg copper. — CoFID 2021 food 13-342 Shallots, raw, compared with USDA Foundation Foods FDC 2727586 (n = 1 UK record vs 8 US samples) Evidence E source
  Iron 0.80 vs 0.33 mg; copper 0.05 vs 0.08 mg; potassium 180 vs 251.5 mg per 3.5 oz (100 g)

What a real portion looks like

• No US survey portion, no US or EU health claim and no pregnancy, child, kidney or safety study names shallots, so serving size and safety in these groups remain unmeasured. — Layers searched on 2026-09-30 for shallots: FNDDS, 21 CFR 101, EU claim register, drug interaction layer, PubMed corpus version pubmed:469217 (n = 0 records) Evidence E source
  FNDDS 0 of 5,432 foods; 21 CFR 0; EU register 0 under the food name; interactions 0; corpus safety, pregnancy, children and kidney slices 0

What your body absorbs

• 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). — 9 volunteers given a single dose of shallot flesh or dry shallot skin providing 1.4 mg quercetin per kg body weight (n = 9) Evidence B source
  Peak plasma quercetin 3.95 vs 1.02 micromol/L; AUC 47.23 +/- 7.53 vs 22.23 +/- 2.32 micromol x h/L, skin vs flesh

What cooking and storage change

• 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, group Vegetables and Vegetable Products, method VEG,OTHER,FRIED (code 3780) Evidence E source
  Retained: folate 70%, vitamin C 85%, thiamin 85%, vitamin B6 90%, calcium, iron, potassium, copper 100%

What it does to your health

• 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. — 19 case-control and 2 cohort studies, 543,220 subjects (n = 543220) Evidence C source
  OR 0.54 (95% CI 0.43-0.65) highest vs lowest intake; OR 0.91 (0.88-0.94) per 20 g/day
• In a Shanghai case-control study, the food group of onions, garlic and shallots was associated with lower gallbladder cancer risk (odds ratio 0.81). — Population-based case-control study in urban Shanghai with 225 gallbladder, 190 extrahepatic bile duct and 68 ampulla of Vater cancer cases with food frequency data (n = 483 cases) Evidence C source
  OR 0.81 (95% CI 0.68-0.97) for gallbladder cancer
• In a hospital case-control study of 220 multiple myeloma cases in Northwest China, eating shallot and garlic was associated with lower myeloma risk (odds ratio 0.60). — 220 confirmed multiple myeloma cases and 220 matched hospital controls at 5 hospitals in Northwest China (n = 440) Evidence C source
  OR 0.60 (95% CI 0.43-0.85)

Safety, limits and interactions

• 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. — 16 allergic rhinitis patients, randomized equally to cetirizine 10 mg plus placebo or cetirizine plus 3 g oral shallot a day for 4 weeks (n = 16) Evidence B source
  VAS improvement 62.5% vs 37.5%; nasal symptom score no difference between groups (P = 0.18); ocular score improved only with shallot (P = 0.01); adverse events not different from placebo

Who this works differently for

• 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. — Patients with irritable bowel syndrome in South Asia, narrative review Evidence D source
  Shallots listed as a major high FODMAP source; no quantity given

The bottom line

Two smaller case-control studies point the same way and carry the same weakness. In Shanghai the onion, garlic and shallot group was associated with lower gallbladder cancer odds (0.81, 95% CI 0.68 to 0.97), and in Northwest China shallot and garlic together with lower myeloma odds (0.60, 95% CI 0.43 to 0.85). These are odds from food questionnaires, and neither separated shallots from the rest. On the plate, eight raw shallot samples tested by USDA averaged 251.5 mg potassium per 3.5 oz (100 g), ranging from 222 to 296, with 2.2 g of fiber. The UK table gives a different picture for the same raw vegetable, 180 mg potassium and 0.80 mg iron per 3.5 oz (100 g) against 0.33 mg iron in the US samples, a gap that may come from variety, soil or laboratory method. Frying costs some vitamins and no minerals. By the USDA retention factor for fried vegetables, set for the whole group and never measured on shallots, about 70 percent of folate, 85 percent of vitamin C and thiamin and 90 percent of vitamin B6 survive. Caution applies to one group we can name. For people with irritable bowel syndrome, shallots are listed with onion and garlic among the major high FODMAP foods that low FODMAP diets restrict, according to a review that gives no amount. In the rhinitis trial side effects were no more common than with placebo, across 16 people. We found no study on shallots in pregnancy, in children or in kidney disease, and no interaction data beyond the cetirizine trial above, which means those questions are unmeasured.

Compared with other foods

Sources

1. shal-daily-r3-07 · food composition data
   Shallots, bulb, peeled, root removed, raw: Potassium 251.5 MG range 222.0-296.0 n=8 · Fiber, total dietary 2.2 G range 2.0-2.5 n=8 · Calcium 26.06 MG range 17.2-40.0 n=8 · Vitamin B-6 0.1769 MG range 0.164-0.189 n=8
   USDA FoodData Central, Foundation Foods, release 2026-04-30, FDC 2727586 · checked 2026-09-30
2. shal-daily-r3-08 · food composition data
   CoFID 13-342 Shallots, raw: Iron 0.80 mg · Copper 0.05 mg · Potassium 180 mg | USDA FDC 2727586: Iron, Fe 0.3323 MG (0.0-0.481, n=8) · Copper, Cu 0.08025 MG (0.0561-0.112, n=8) · Potassium, K 251.5 MG (n=8)
   CoFID 2021, Public Health England / OGL v3.0, code 13-342; USDA FoodData Central Foundation Foods 2026-04-30 · checked 2026-09-30
3. shal-daily-r3-10 · search record
   shallots: FNDDS 0 of 5 432 · 21 CFR 101 0 · EU register 0 under food name · interactions 0 · corpus safety 0 · pregnancy 0 · children 0 · kidney 0
   Bioma research layers, snapshot 2026-09-30 · checked 2026-09-30
4. shal-daily-r3-01 · randomized crossover trial
   In a randomized crossover study, 9 volunteers took a single dose of either shallot flesh (99.2% quercetin glucosides and 0.8% quercetin aglycone) or dry shallot skin (83.3% quercetin aglycone and 16.7% quercetin glucosides), providing 1.4 mg quercetin per kg of body weight. ... The area under the concentration-time curve after dry skin consumption was 47.23 +/- 7.53 micromol x h(-1) x L(-1) and was significantly higher than that after shallot flesh intake (22.23 +/- 2.32 micromol x h(-1) x L(-1)).
   J Nutr, 2008 · checked 2026-09-30
5. shal-daily-r3-09 · retention factor data
   VEG,OTHER,FRIED (3780): folate_total_ug 70% · vitamin_c_mg 85% · thiamin_mg 85% · vitamin_b6_mg 90% · calcium_mg 100% · iron_mg 100% · potassium_mg 100% · copper_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 3780 · checked 2026-09-30
6. shal-daily-r3-03 · meta-analysis of observational studies
   We analyzed 19 case-control and 2 cohort studies, of 543,220 subjects. ... In a pooled analysis of all studies, consumption of large amounts of Allium vegetables (in a comparison of the highest and lowest consumption groups) reduced the risk for gastric cancer (odds ratio, 0.54; 95% confidence interval, 0.43-0.65).
   Gastroenterology, 2011 · checked 2026-09-30
7. shal-daily-r3-04 · case-control study
   The allium food group, consisting of onions, garlic, and shallots showed an inverse association with gallbladder cancer (OR: 0.81, 95% CI: 0.68-0.97).
   PLoS One, 2017 · checked 2026-09-30
8. shal-daily-r3-05 · case-control study
   Intake of shallot and garlic (OR=0.60, 95% CI: 0.43-0.85), soy food (OR=0.52, 95% CI: 0.36-0.75) and green tea (OR=0.38, 95% CI: 0.27-0.53) was significantly associated with a reduced risk of MM.
   Cancer Epidemiol, 2012 · checked 2026-09-30
9. shal-daily-r3-02 · randomized controlled trial
   Sixteen AR patients were randomized equally into the controls who received cetirizine 10 mg once daily and placebo capsules for 4 weeks, and the treatment who received 3g of oral shallot per day (equivalent to 1 ½ bulbs) and cetirizine. ... After 4-week of treatment, 62.5% of patients in shallot group and 37.5% of patients in control group showed improvement of post-treatment VAS. ... Adverse events from shallot were not different from placebo.
   Asian Pac J Allergy Immunol, 2022 · checked 2026-09-30
10. shal-daily-r3-06 · review
    However, major high FODMAP sources are frequently used and include onion, garlic, shallots, legumes/pulses, and wheat-based products, as well as coconut and milk products, offering an opportunity for dietary management to reduce the symptom load.
    J Gastroenterol Hepatol, 2018 · checked 2026-09-30