Tuna salad: the mayonnaise sets the calories, the tuna sets the cautions

Tuna salad is tuna plus a dressing, and nearly all the science sits with the tuna. In a randomized study of 40 healthy adults, adding plain tuna to a baked potato, pasta or toast lowered the glycemic index of the meal each time, although no topping differed significantly from the others and nobody tested tuna dressed in mayonnaise. The mayonnaise is where the calories move. In the US food survey, tuna salad made with regular mayonnaise has 194 calories and 15.8 g fat per 3.5 oz (100 g). A cup is coded as 238 g, which works out to about 462 calories and 995 mg sodium, figures recalculated from the 100 g values. Made with light mayonnaise, the same 100 g drops to 106 calories and 5.4 g fat, with sodium slightly higher at 464 mg. Homemade salads vary with how much mayonnaise goes in. Portions also run large. When 147 Americans aged 18 to 30 served themselves in a 1984 study, their tuna salad portions came out above the accepted standard, and the abstract does not say by how much.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• Under US law, anything sold as mayonnaise must be made with egg yolk or whole egg and contain at least 65% vegetable oil, so a tuna salad made with real mayonnaise contains egg. — foods sold as mayonnaise in the US Evidence E source
  Mayonnaise must contain egg yolk-containing ingredients and at least 65% vegetable oil by weight
• Iranian canned tuna averaged 77.9 mg/kg histamine across 693 samples, below the FDA limit of 200 mg/kg. — 693 canned tuna samples from 11 Iranian studies (n = 693 samples) Evidence C source
  Mean 77.86 mg/kg (95% CI 47.51-108.21); target hazard quotient 0.10
• Pooling 1295 canned tuna samples from Iran, mean mercury was 0.11 ug/g and selenium 2.23 ug/g wet weight, with hazard quotients at or below 1 for adults and children. — 1295 canned tuna samples from 23 Iranian articles, 1983-2017 (n = 1295 samples) Evidence C source
  Se 2.23, Hg 0.11, Cd 0.14 ug/g wet weight; THQ and TTHQ <=1.0
• Swapping regular for light mayonnaise cuts US survey tuna salad from 194 to 106 calories and from 15.8 to 5.4 g fat per 3.5 oz (100 g), while sodium is slightly higher at 464 mg. — USDA FNDDS, Tuna salad, made with light mayonnaise (code 27450061, fdc_id 2706829) vs 27450060 Evidence E source
  106 vs 194 calories; fat 5.4 vs 15.84 g; sodium 464 vs 418 mg; protein 9.78 vs 10.07 g per 3.5 oz (100 g)

What a real portion looks like

• FDA and EPA size a child's fish serving at about 1 ounce at ages 1 to 3, 2 ounces at 4 to 7, 3 ounces at 8 to 10 and 4 ounces at 11. Children should have 2 servings a week from the Best Choices list, which includes canned light tuna. — children aged 1 to 11 Evidence E source
  A serving is about 1 oz at 1 to 3 years, 2 oz at 4 to 7, 3 oz at 8 to 10, 4 oz at 11; 2 servings a week from Best Choices; canned light tuna is a Best Choice
• When 147 young adults served themselves an average portion, their tuna salad portion was larger than the accepted standard, and few could estimate amounts accurately. — 147 adults aged 18-30 (n = 147) Evidence C source
  Tuna salad portions above standard; 8% to 68% estimated items within 25%
• US survey tuna salad made with mayonnaise has 194 calories, 15.8 g fat and 418 mg sodium per 3.5 oz (100 g), and one cup is coded as 238 g. — USDA FNDDS, Tuna salad, made with mayonnaise (code 27450060, fdc_id 2706828) Evidence E source
  Per 100 g: 194 calories, fat 15.84 g, protein 10.07 g, sodium 418 mg, selenium 35.2 ug; 1 cup 238 g = about 462 calories, 995 mg sodium

What your body absorbs

• In a crossover trial where 14 women aged 51-70 ate each diet for 7 weeks, a high-meat diet that included tuna increased zinc absorption and retention compared with a low-meat diet. — 14 postmenopausal women aged 51-70, three diets of 7 weeks each in random order (n = 14) Evidence B source
  Higher zinc absorption and retention on the high-meat diet; lower iron status indexes

What cooking and storage change

• Canning appears to strip much of tuna's allergenicity: all 45 oral challenges with canned tuna were negative, including in 18 patients with IgE-mediated fish allergy. — 45 children and young adults with food allergies, 18 with IgE-mediated fish allergy (n = 45) Evidence C source
  0 of 45 positive challenges with canned tuna

What it does to your health

• In a randomized study of 40 healthy adults, adding tuna and other toppings to baked potato, pasta or toast consistently lowered the meal's glycemic index, though differences among toppings were not significant. — 40 healthy adults (11 men, 29 women), Oxford Brookes University staff and students (n = 40) Evidence B source
  Consistent GI lowering with toppings; no significant difference among toppings (P=0.06, 0.06, 0.39)

Safety, limits and interactions

• In a double-blind crossover trial, 75 mg of oral histamine, a dose found in normal meals, provoked symptoms in 5 of 10 healthy women, and tuna is among foods that can hold up to 500 mg/kg. — 10 healthy females aged 22-36, hospitalized, histamine-free diet (n = 10) Evidence B source
  Symptoms in 5 of 10 after 75 mg histamine; none after placebo
• In a hospital norovirus-type outbreak that hit 81 patients and 114 staff, eating tuna salad was linked to illness with an odds ratio of 6.6. — patients and staff of four hospitals served by one central kitchen (n = 195) Evidence C source
  OR 6.6 (95% CI 1.0-71.6) for tuna salad
• Across 103 histamine poisoning incidents from 55 reports, the implicated food held a mean 1107 mg/kg histamine, and the fish involved was mainly tuna or marlin-type species. — 55 outbreak reports, 103 incidents, 1959-2013 (n = 103 incidents) Evidence C source
  Mean 1107.21 mg/kg (95% CI 422.62-2900.78)

Who this works differently for

• CDC tells pregnant women and other higher-risk groups to avoid premade deli salads such as tuna or chicken salad because of Listeria, and names homemade deli salads as the safer choice. — people at higher risk of Listeria infection: pregnant women, newborns, adults 65 and over, people with weakened immunity Evidence E source
  Avoid premade deli salads such as tuna or chicken salad; homemade deli salads are the safer choice
• Among 108 Singaporean children with IgE-mediated fish allergy, 75.9% tolerated another fish species, and tuna was tolerated by 24.1%. — 108 children with IgE-mediated fish allergy, tertiary pediatric hospital, Singapore, 2015-2020 (n = 108) Evidence C source
  75.9% tolerated another species; tuna 24.1%; anaphylaxis 6.5%
• A global review of canned tuna found methylmercury hazard quotients above 1 for children in 12 countries, but only for adults in Tunisia. — published canned tuna surveys from many countries, risk modeled for adults and children Evidence C source
  MeHg THQ >1 for children in 12 countries, adults in 1
• Among 700 three-year-olds, eating non-fried fish including tuna was linked to 120% higher toenail mercury than eating no fish. — 700 three-year-old children, New Hampshire Birth Cohort Study (n = 700) Evidence C source
  +120% toenail Hg (95% CI 82% to 164%) vs no fish
• The FDA and EPA state that albacore (white) tuna typically contains three times more mercury than canned light tuna, so people who are or may become pregnant should limit albacore to one serving a week with no other fish. — people who might become or are pregnant or breastfeeding, and children aged 1-11 Evidence E source
  Albacore about 3 times the mercury of canned light tuna; albacore 1 serving and no other fish that week

The bottom line

Tuna counts as meat for minerals. In a crossover trial of 14 postmenopausal women eating each diet for 7 weeks, a high-meat diet raised zinc absorption and retention compared with a low-meat one, with tuna only one of four meats in it. Mercury is the question most people bring to tuna. The FDA and EPA say albacore, sold as white tuna, typically holds three times the mercury of canned light tuna. Their advice for people who are or may become pregnant, people who are breastfeeding and children aged 1 to 11 is that a week with albacore should hold only 1 serving of it and no other fish. For children the same advice sizes a fish serving at about 1 ounce at ages 1 to 3, 2 ounces at 4 to 7, 3 ounces at 8 to 10 and 4 ounces at 11. It sets 2 servings a week from its Best Choices list, which includes canned light tuna. Those sizes are for the fish, not for a salad with mayonnaise. A global review of canned tuna surveys found modeled methylmercury hazard quotients above 1 for children in 12 countries and for adults only in Tunisia, figures built on local consumption assumptions. Among 700 three-year-olds in New Hampshire, eating non-fried fish including tuna went with 120 percent higher toenail mercury than eating no fish (95% CI 82 to 164 percent). What that level means for their health is unknown. In Iran, 1295 canned tuna samples from one market averaged 0.11 micrograms of mercury per gram, with hazard quotients at or below 1 for adults and children. Histamine is the second concern. Across 103 histamine poisoning incidents from 55 outbreak reports, the fish involved was mainly tuna or marlin-type species, and the implicated food held a mean of 1107 mg/kg histamine, with reports so varied that heterogeneity reached 100 percent. Iranian canned tuna averaged 77.9 mg/kg across 693 samples, under the FDA limit of 200 mg/kg, in that one market. In a trial of 10 healthy women, 75 mg of pure liquid histamine, a dose found in normal meals, gave symptoms to half of them. That trial used histamine alone, with no tuna served. A prepared salad can also carry an infection. In one hospital outbreak of gastroenteritis that hit 81 patients and 114 staff, eating tuna salad went with 6.6 times the odds of illness, with a confidence interval from 1.0 to 71.6 in that single outbreak. For pregnant women, newborns, adults 65 and over and people with weakened immunity, CDC advises avoiding premade deli salads such as tuna or chicken salad because of Listeria, and names homemade deli salads as the safer choice. It gives no risk figure for tuna salad itself. For fish allergy the evidence points two ways. In one older study, all 45 challenges with canned tuna were negative, including 18 patients with IgE-mediated fish allergy, and the challenges were not described as randomized. Among 108 Singaporean children with fish allergy, 24.1 percent tolerated tuna. Neither result makes tuna safe for someone with a fish allergy. That decision belongs with an allergist. The dressing adds egg. Under US law anything sold as mayonnaise must be made with egg yolk or whole egg, so a tuna salad made with real mayonnaise contains egg, which matters to anyone who avoids it. Salad dressings and mayo-style spreads fall outside that standard and may be egg-free, so the label is what tells you.

Sources

1. hf2-tsd-2 · US federal regulation
   Mayonnaise is the emulsified semisolid food prepared from vegetable oil(s), one or both of the acidifying ingredients specified in paragraph (b) of this section, and one or more of the egg yolk-containing ingredients specified in paragraph (c) of this section. ... Mayonnaise contains not less than 65 percent by weight of vegetable oil. ... Liquid egg yolks, frozen egg yolks, dried egg yolks, liquid whole eggs, frozen whole eggs, dried whole eggs, or any one or more of the foregoing ingredients listed in this paragraph with liquid egg white or frozen egg white.
   21 CFR 169.140 Mayonnaise (eCFR, current) · checked 2026-10-08
2. tsd-daily-r6-08 · systematic review of sample surveys
   The mean concentration was calculated as 77.86 mg kg−1 (95% confidence interval [CI], 47.51 to 108.21 mg kg−1), which was lower than the 200 mg kg−1 recommended limit by the U.S. Food and Drug Administration (FDA).
   J Food Prot, 2018 · checked 2026-09-29
3. tsd-daily-r6-09 · systematic review of sample surveys
   Data from 23 articles and 1295 samples were assessed and extracted. The ranking order of metals based on mean concentrations (μg/g wet weight) were Fe (13.17) > Zn (9.31) > Se (2.23) > Al (1.8) > Cr (1.63) > Cu (1.52) > As (0.38) > Ni (0.33) > Pb (0.24) > Cd (0.14) > Hg (0.11) > Sn (0.1). ... THQ, and total target hazard quotient (TTHQ) were ≤1.0 for adult and children consumers.
   Food Chem Toxicol, 2018 · checked 2026-09-29
4. tsd-daily-r6-14 · reference dataset
   FNDDS 27450061 Tuna salad, made with light mayonnaise (fdc 2706829): Energy 106 kcal | Total lipid (fat) 5.4 g | Protein 9.78 g | Sodium 464 mg | Selenium 34.7 ug per 100 g
   USDA FNDDS 2021-2023 (FoodData Central), code 27450061 · checked 2026-09-29
5. hf2-tsd-3 · agency guidance
   Childhood: On average, a serving is about: 1 ounce at age 1 to 3 2 ounces at age 4 to 7 3 ounces at age 8 to 10 4 ounces at age 11 Eat 2 servings a week from the “Best Choices” list. ... Tuna, canned light (includes skipjack) Best Choice
   FDA/EPA, Advice about Eating Fish (content current as of 03/05/2024) · checked 2026-10-08
6. tsd-daily-r6-12 · cross-sectional
   For dry cereal, orange juice, tuna salad, and fruit salad, selected portions were above accepted standards, but the portion for salad dressing was below the standard.
   J Am Diet Assoc, 1984 · checked 2026-09-29
7. tsd-daily-r6-13 · reference dataset
   FNDDS 27450060 Tuna salad, made with mayonnaise (fdc 2706828): Energy 194 kcal | Total lipid (fat) 15.84 g | Protein 10.07 g | Sodium 418 mg | Selenium 35.2 ug per 100 g || 1 cup 238 g | Quantity not specified 119 g
   USDA FNDDS 2021-2023 (FoodData Central), code 27450060 · checked 2026-09-29
8. tsd-daily-r6-01 · randomized crossover trial
   The women ate each of the three diets for 7 wk in random order. Lean beef, chicken, ham, and tuna in the HM diet replaced foods with a low mineral content in the LM diet. ... Compared with the other diets, the HM diet increased zinc absorption and retention, and slightly increased urinary zinc.
   Am J Clin Nutr, 1995 · checked 2026-09-29
9. tsd-daily-r6-04 · food challenge study
   Altered fish allergenicity as a result of food processing was examined with canned tuna and salmon. Forty-five children and young adults with food allergies, including 18 patients with IgE-mediated hypersensitivity to fish, were challenged with canned tuna. All 45 challenges with canned tuna were negative.
   J Allergy Clin Immunol, 1992 · checked 2026-09-29
10. tsd-daily-r6-02 · randomized repeated measures trial
    Cheddar cheese, chilli con carne, baked beans and tuna were added to baked potatoes, cooked pasta and toast to determine the effect on glycaemic response. RESULTS: No significant difference was found among the various toppings and baked potato (P=0.06), pasta (P=0.06) and toast (P=0.39). However, the addition of toppings to a carbohydrate-rich food had a consistent lowering effect on glycaemic index (GI).
    Eur J Clin Nutr, 2006 · checked 2026-09-29
11. tsd-daily-r6-03 · randomized crossover trial
    Histamine-rich foods such as cheese, sausages, sauerkraut, tuna, tomatoes, and alcoholic beverages may contain histamine up to 500 mg/kg. ... We conclude that 75 mg of pure liquid oral histamine--a dose found in normal meals--can provoke immediate as well as delayed symptoms in 50% of healthy females without a history of food intolerance.
    Allergy Asthma Proc, 2004 · checked 2026-09-29
12. tsd-daily-r6-06 · case-control
    A common source outbreak of small round structure virus (SRSV) gastroenteritis affected 81 patients and 114 staff in four hospitals served by one central hospital kitchen. ... a case control study of patients in one hospital showed an odds ratio of 6.6 (95% CI = 1.0-71.6; P = 0.04) for eating tuna salad and becoming ill.
    Epidemiol Infect, 1994 · checked 2026-09-29
13. tsd-daily-r6-07 · systematic review of outbreak reports
    Fifty-five (55) reports were included, these studies reported 103 incidents. ... histamine mean concentration in poisoning samples was 1107.21 mg/kg with confidence interval for the meta-mean of 422.62-2900.78 mg/kg ... Fish involved in histamine poisoning was mainly tuna or Istiophoridae species.
    Crit Rev Food Sci Nutr, 2018 · checked 2026-09-29
14. hf2-tsd-1 · agency guidance
    If you are in any of these groups, choose safer foods to protect your health or your pregnancy. ... Premade deli salads, such as coleslaw and potato, tuna, or chicken salad ... Homemade deli salads
    CDC, Preventing Listeria Infection (Listeria prevention page) · checked 2026-10-08
15. tsd-daily-r6-05 · retrospective cohort
    Most can tolerate another species of fish (75.9%), most commonly salmon (37.0%), tuna (24.1%) and cod (22.2%).
    Asian Pac J Allergy Immunol, 2025 · checked 2026-09-29
16. tsd-daily-r6-10 · systematic review of sample surveys
    Moreover, the THQ value due to Me Hg for adult in Tunisia and for children in Tunisia, Malta, Portugal, Latvia, Cambogia, Peru, South Korea, Romania, Hong Kong, United Arab Emirates, Morocco, and Egypt was higher than 1 value.
    Int J Environ Health Res, 2024 · checked 2026-09-29
17. tsd-daily-r6-11 · cohort
    To a lesser extent, children consuming "other fish (not fried) including tuna" and "fried fish or fish sticks" had 120% (95% CI: 82%, 164%), and 23% (95% CI: 2%, 51%) higher toenail concentrations, respectively, than those consuming no fish.
    Environ Res, 2024 · checked 2026-09-29
18. tsd-daily-r6-15 · agency advice
    Albacore tuna, also known as white tuna, typically contains three times more mercury than canned light tuna. When you eat albacore or any of the other fish from the 'Good Choices' category, have only 1 serving and no other fish that week.
    US FDA and EPA, Questions and Answers from the FDA/EPA Advice about Eating Fish, 2022 · checked 2026-09-29