Lobster: plenty of selenium, almost no trials

Almost nothing on this page was measured on lobster itself. The strongest result here belongs to infancy. Across 4 trials with 3,295 babies, introducing several allergenic foods between 2 and 12 months of age halved the risk of IgE-mediated food allergy at ages 1 to 5, a risk ratio of 0.49 from 0.33 to 0.74, graded moderate certainty. Shellfish was one of eight foods in scope and the reviewers report no separate estimate for it. In adults the nearest thing to a feeding trial gave 18 men with normal blood lipids six shellfish species in turn. Crab, oyster and clam diets lowered LDL and total cholesterol, shrimp and squid changed nothing, and lobster was never on the menu. What the tables show is meat with a lot of selenium, 110 mg of cholesterol per 100 g in the British record, and a lot of variation. Six analysed samples of frozen lobster tail ran from 42 to 106 micrograms of selenium and from 235 to 933 mg of sodium per 100 g. The British record for boiled lobster carries three times the vitamin B12 of the American one, 3.0 against 0.995 micrograms, which is species, water loss and laboratory method rather than one of them being wrong.

The numbers, per 100 g

How much is actually in it

• In 177 fish and lobster samples from New York State markets the single highest cadmium reading, 511 ng/g, came from a lobster and exceeded the EU 500 ng/g limit, while all crustacean samples stayed below FDA action levels. — 177 retail fish and lobster samples, New York State, ICP-MS and combustion analysis (n = 177 samples) Evidence C source
  Highest Cd 511 ng/g (lobster) above EU 500 ng/g; As, Cd, Cr, Pb, Ni all below FDA action levels; 22 samples above 1000 ng/g Hg (fish)
• FDA monitoring found mean mercury of 0.107 ppm in American lobster (9 samples), 0.093 ppm in spiny lobster (13 samples) and 0.166 ppm in lobster of unknown species (71 samples). — FDA commercial fish and shellfish samples 1990-2012, mercury concentration mean in ppm (n = 9, 13 and 71 samples) Evidence E source
  Mean Hg ppm: lobster northern/American 0.107 (max 0.23), spiny 0.093 (max 0.27), species unknown 0.166 (max 0.451); crab 0.065
• Six USDA Foundation samples of lobster tail ranged from 42 to 106 micrograms of selenium and from 235 to 933 mg of sodium per 100 g. The British table gives boiled lobster three times the vitamin B12 (3.0 vs 0.995 micrograms) and five times the copper of the USDA record. — USDA FoodData Central Foundation Foods: Lobster, tail only, frozen, wild caught (6 samples); CoFID 2021: Lobster, boiled (16-332) (n = 6 analytical samples plus one CoFID record) Evidence E source
  Selenium 63.13 ug (42.1-105.5, spread 100%), sodium 508.8 mg (235-933), copper 0.2427 mg (0.134-0.395), B12 0.995 ug (0.85-1.2); CoFID boiled: B12 3.0 ug, copper 1.35 mg, selenium 54 ug, cholesterol 110 mg, protein 22.1 g

What a real portion looks like

• FDA and EPA list American and spiny lobster as a Best Choice, so children may eat it twice a week in age-sized servings from 1 ounce at age 1 to 3 up to 4 ounces at age 11. — children and pregnant or breastfeeding people, USA Evidence E source
  Lobster, American and spiny: Best Choice; children 2 servings a week; serving 1 oz (1-3 y), 2 oz (4-7 y), 3 oz (8-10 y), 4 oz (11 y)
• In FNDDS a whole lobster yields 200 g of meat, one tail 100 g, one claw 50 g and a cup of meat 135 g. — US household measures, FNDDS: Lobster (fdc_id 2706349, WWEIA Shellfish) (n = one FNDDS food) Evidence E source
  1 lobster 200 g, 1 tail 100 g, 1 claw 50 g, 1 cup 135 g, unspecified 85 g

What your body absorbs

• No study measured nutrient loss when lobster is cooked or how well its nutrients are absorbed, and the USDA group factor for frozen finfish heated predicts 5% loss of vitamin B12 and none of the minerals, with selenium absent from the table altogether. — Finfish and Shellfish Products (USDA group 15), frozen finfish heated (n = USDA R6 table, one group-by-method row) Evidence E source
  USDA-RETN-R6:2605 retained: vitamin B12 95%, vitamin B6 95%, folate 95%, thiamin 90%, vitamin C 90%, all minerals 100%; selenium not in R6

Safety, limits and interactions

• Across 61 population studies, self-reported shellfish allergy ranged from 0% to 10.3%, but where food challenges were used it fell to 0% to 0.9%, and it may be more common in Southeast Asia. — 61 population-based cross-sectional and cohort studies worldwide, all ages (n = 61 studies) Evidence C source
  Shellfish allergy 0-10.3% by self-report, 0-0.9% by food challenge; fish 0-7% and 0-0.3%
• Lobster is among the shellfish most often reported to cause allergy, and tropomyosin is the major allergen behind cross-reactions between lobster, shrimp, crab and even house dust mites. — general population, review of shellfish allergy literature Evidence E source
  Shellfish allergy prevalence estimated 0.5-2.5% of the general population; tropomyosin drives cross-reactivity
• Two lobster tails eaten 5 days before a urine test produced a total arsenic reading of 8880 micrograms per day that was entirely organic arsenobetaine, and the level fell to 50 micrograms per day after avoiding seafood. — one 54-year-old man evaluated for foot paresthesia, 24-hour urine arsenic (n = 1) Evidence D source
  Total arsenic 8880 ug/d, organic arsenic 4332 ug/L, no inorganic or methylated arsenic; 50 ug/d after seafood abstinence
• In NHANES 2003-2020, shellfish was the strongest dietary predictor of higher serum PFAS with a dose-response pattern, while fish showed weak or inconsistent associations. — US adults in NHANES 2003-2020, serum PFAS and food intake (n = NHANES 2003-2020) Evidence C source
  Shellfish: strongest positive predictor of total and individual PFAS; total PFAS fell about 75% over the period
• In a systematic review of microplastics in seafood, flathead lobster off Iran carried the heaviest load at 460 microplastic particles per animal, against a pooled shellfish mean of 1.43 particles per individual. — edible seafood species sampled worldwide, most studies from China (n = pooled species samples) Evidence C source
  Fish mean 1.11 MPs/individual (95% CI 0.3-1.92), shellfish 1.43 (CI -0.35-3.21); Thenus orientalis 460.2 MPs/individual

What people believe that the data does not support

• In 18 normolipidemic men fed six shellfish species in turn, crab, oyster, clam and mussel diets lowered LDL and total cholesterol while shrimp and squid did not, and lobster itself was never one of the test foods. — 18 normolipidemic men, controlled feeding of oyster, clam, crab, mussel, squid and shrimp diets with moderate fat restriction (n = 18) Evidence B source
  Crab, oyster, clam diets lowered VLDL triglycerides, LDL and total cholesterol; shrimp and squid no change; lobster not tested
• The EU register lists as authorised the claim that selenium contributes to normal thyroid function. The register snapshot does not state how much selenium a food must contain to carry the claim, and USDA gives a lobster tail 63 micrograms of selenium per 100 g. — EU food labelling, foods that are a source of selenium Evidence E source
  Authorised claim; threshold not in this snapshot

Who this works differently for

• Across 4 trials with 3295 infants, introducing several allergenic foods (shellfish among those studied) between 2 and 12 months halved the risk of IgE-mediated food allergy at 1 to 5 years (RR 0.49), with moderate certainty. — 13,794 randomised infants in 23 trials; shellfish was one of eight allergenic foods in scope; outcome at 1-5 years (n = 3295 (4 trials) for multiple-food introduction) Evidence A source
  RR 0.49 (95% CI 0.33-0.74), I2 49%; absolute -26 cases per 1000 at 5% incidence; withdrawal RR 2.29
• In Europe, pooled self-reported lifetime shellfish allergy is 0.4% and challenge-verified point prevalence 0.1%, the lowest of the eight big allergens after tree nuts and fish. — 93 European studies published up to 2021, all age groups (n = 93 studies) Evidence C source
  Shellfish self-reported 0.4% (95% CI 0.3-0.6); challenge-verified 0.1% (0.0-0.2)
• In 46 studies of shellfish eating in pregnancy, lactation and the first 2 years, higher intake tracked higher mercury biomarkers and better iodine status, was not linked to preterm birth, and gave mixed results on birth weight. — pregnant and lactating women and children 0-2 years, 46 articles 2000-2022 (n = 46 articles) Evidence C source
  Direction: higher contaminant biomarkers (mercury strongest), iodine status up, preterm birth null, birth weight mixed, child development null in few studies
• In cohort studies of gout, higher fish and shellfish intake carried a 36% higher risk in women (HR 1.36) but no measurable risk in men (HR 1.02), a difference the reviewers say rests on single studies. — 33 cohort articles on gout risk factors, general population and primary care (n = 33 articles) Evidence C source
  Fish and shellfish: HR men 1.02 (0.86-1.22), women 1.36 (1.12-1.65)

What is still unknown

• A review of 64 studies concludes shellfish carry mostly the less toxic organic arsenic yet remain a relevant dietary arsenic source, with contamination and geography as the main drivers of the level. — 64 articles on arsenic dynamics in marine shellfish (n = 64 studies) Evidence C source
  Direction only: organic arsenic dominates; anthropogenic contamination, location and species genetics set the level

The bottom line

A whole lobster yields about 200 g of meat in US survey measures, a tail 100 g, a claw 50 g and a cup of picked meat 135 g. The FDA and EPA put American and spiny lobster on their Best Choice list, where children can eat two servings a week, sized from 1 ounce at ages 1 to 3 up to 4 ounces at age 11. Mercury is the reason it sits there. FDA monitoring gives American lobster a mean of 0.107 ppm across 9 samples and spiny lobster 0.093 ppm across 13, with lobster of unknown species at 0.166 ppm. Those sample counts are small enough to keep in mind. The rest of the contaminant record is mixed. Among 177 retail fish and lobster samples from New York State, the single highest cadmium reading of 511 ng/g came from a lobster and passed the EU limit of 500 ng/g, while every crustacean sample stayed under the FDA action levels. Arsenic in shellfish is mostly the organic kind. One man who had eaten two lobster tails five days earlier tested at 8880 micrograms of total arsenic a day, all of it arsenobetaine with no inorganic or methylated arsenic, and he was down to 50 after avoiding seafood. That is a single case, and a lesson about how urine tests are read rather than about poisoning. A review of 64 studies still calls shellfish a relevant dietary source of arsenic, without separating lobster from the rest. In US national survey data from 2003 to 2020, shellfish eating was the strongest dietary predictor of higher serum PFAS, with a dose-response pattern, in a survey that cannot say which came first. Microplastics depend entirely on where the animal lived, and flathead lobster off Iran carried 460 particles per animal against a pooled shellfish mean of 1.43. Allergy is the caution that sends people to hospital. Self-reported shellfish allergy across 61 population studies ran from 0 to 10.3 percent, and where food challenges were used it fell to 0 to 0.9 percent. In Europe the pooled figures are 0.4 percent self-reported and 0.1 percent confirmed by challenge. Lobster is among the shellfish most often named in allergy reports, and tropomyosin is the protein behind cross-reaction with shrimp, crab and house dust mite. Two smaller groups carry their own numbers. In cohort studies of gout, higher fish and shellfish intake went with 36 percent higher risk in women, HR 1.36 from 1.12 to 1.65, and nothing measurable in men, HR 1.02 from 0.86 to 1.22, a split the reviewers say rests on single studies. For pregnancy, lactation and the first two years, a scoping review of 46 articles found shellfish intake tracking higher mercury biomarkers and better iodine status, with no link to preterm birth and mixed results for birth weight. Nobody has measured what boiling does to lobster, or how much of its selenium a person absorbs. The USDA group factor for heated frozen finfish, a row dated 1975, keeps 95 percent of the B12 and all of the minerals, and selenium is not in that table at all. The EU register authorises the wording that selenium contributes to normal thyroid function. That is a judgement that the evidence was sufficient, not a measure of what a lobster dinner does to anyone.

Sources

1. lobs-c4-06 · cross-sectional analytical survey
   A total of 177 fish and lobster samples were initially analyzed using combustion for Hg...The highest Cd concentration (511 ng/g) was found in a lobster. This level is greater than the 500 ng/g limit set by the Commission of the European Communities. All levels of As, Cd, Cr, Pb, and Ni were below the U.S. Food and Drug Administration action levels for these metals in crustaceans and shellfish.
   J Food Prot, 2010 · checked 2026-09-23
2. lobs-c4-13 · agency monitoring table
   LOBSTER (Spiny) | 0.093 | 0.062 | 0.097 | ND | 0.27 | 13...LOBSTER (NORTHERN / AMERICAN) | 0.107 | 0.086 | 0.076 | ND | 0.23 | 9...LOBSTER (Species Unknown) | 0.166 | 0.143 | 0.099 | ND | 0.451 | 71
   FDA, Mercury Levels in Commercial Fish and Shellfish (1990-2012), page updated 2022-02-25 · checked 2026-09-23
3. lobs-c4-17 · reference dataset
   Lobster, tail only, frozen, wild caught | Selenium, Se 63.13 UG range 42.1-105.5 n=6 | Sodium, Na 508.8 MG range 235.0-933.0 n=6 | Copper, Cu 0.2427 MG range 0.134-0.395 n=6 | Vitamin B-12 0.995 UG range 0.85-1.2 n=6 || CoFID 16-332 Lobster, boiled | Vitamin B12 3.0 ug | Copper 1.35 mg | Selenium 54 ug | Cholesterol 110 mg
   USDA FoodData Central, Foundation Foods, FDC 2747657; CoFID 2021 (Public Health England, OGL v3.0), code 16-332 · checked 2026-09-23
4. lobs-c4-14 · agency advice
   Lobster, American and spiny | Best Choice...Eat 2 servings a week from the 'Best Choices' list...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
   FDA/EPA, Advice about Eating Fish, page dated 2024-03-05 · checked 2026-09-23
5. lobs-c4-18 · reference dataset
   Lobster | 1 lobster 200 g | 1 tail 100 g | 1 claw 50 g | 1 cup 135 g | Quantity not specified 85 g
   USDA FNDDS (Food and Nutrient Database for Dietary Studies), fdc_id 2706349 · checked 2026-09-23
6. lobs-c4-16 · reference dataset
   USDA-RETN-R6:2605 FINFISH(FROZEN),HEATED | vitamin_b12_ug 95% | vitamin_b6_mg 95% | folate_total_ug 95% | thiamin_mg 90% | vitamin_c_mg 90% | zinc_mg 100% | copper_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007) · checked 2026-09-23
7. lobs-c4-03 · systematic review of observational studies
   The prevalence of fish allergy ranged from 0% to 7% and the prevalence of shellfish allergy from 0% to 10.3%, depending on the method of diagnosis. Where food challenges were used, the prevalence for fish allergy was found to be 0% to 0.3% and for shellfish allergy was 0% to 0.9%.
   Ann Allergy Asthma Immunol, 2016 · checked 2026-09-23
8. lobs-c4-05 · narrative review
   Globally, the most commonly causative shellfish are shrimps, crabs, lobsters, clams, oysters, and mussels. The prevalence of shellfish allergy is estimated to be 0.5-2.5% of the general population but higher in coastal Asian countries where shellfish constitute a large proportion of the diet...Tropomyosin is the major allergen and is responsible for cross-reactivity between shellfish and other invertebrates, within crustaceans, within molluskans, between crustaceans vs. molluskans as well as between shellfish and fish.
   Immunol Invest, 2016 · checked 2026-09-23
9. lobs-c4-07 · case report
   The total arsenic level was 8880 μg/d with concentrations of 4749 μg/L and 3769 μg/g creatinine...History revealed consumption of 2 lobster tails 5 days before the testing. Speciation was then performed on the original urine specimen and revealed an organic arsenic concentration of 4332 μg/L. No inorganic or methylated arsenic was detected. Repeat testing after abstaining from seafood demonstrated a total arsenic level of 50 μg/d
   Am J Ther, 2014 · checked 2026-09-23
10. lobs-c4-11 · cross-sectional survey
    Shellfish consumption was the strongest dietary predictor of higher total and individual PFAS concentrations, with dose-response relationships, while meat intake was modestly associated and fish intake showed weak or inconsistent associations.
    Chemosphere, 2026 · checked 2026-09-23
11. lobs-c4-12 · systematic review of sampling studies
    Crustacean species Thenus orientalis (flathead lobster) off the coasts of Iran were the most heavily loaded with 460.2 MPs/individual. Meta-analysis revealed high statistical and model heterogeneity of MP content in fish (mean 1.11 MPs/individual, 95 % confidence interval (CI)= 0.3-1.92) and shellfish (1.43 MPs/individual, 95 % CI= -0.35-3.21).
    J Hazard Mater, 2024 · checked 2026-09-23
12. lobs-c4-02 · controlled clinical trial
    Eighteen normolipidemic males were fed six different species of shellfish...Oyster, clam, crab, and mussel diets, low in cholesterol and high in n-3 fatty acids, lowered VLDL triglycerides and cholesterol and, except for the mussel diet, LDL and total cholesterol. Squid and shrimp diets, higher in cholesterol and lower in n-3 fatty acids, did not change the blood lipids.
    Am J Clin Nutr, 1990 · checked 2026-09-23
13. lobs-c4-15 · regulatory register
    POL-HC-6464 Selenium Selenium contributes to the normal thyroid function Authorised
    EU Register on nutrition and health claims, claim POL-HC-6464, snapshot 2026-09-21 · checked 2026-09-23
14. lobs-c4-01 · meta-analysis of RCTs
    Randomized clinical trials evaluating age at allergenic food introduction (milk, egg, fish, shellfish, tree nuts, wheat, peanuts, and soya) during infancy and immunoglobulin E (IgE)-mediated food allergy from 1 to 5 years of age were included...There was moderate-certainty evidence from 4 trials (3295 participants) that introduction of multiple allergenic foods from 2 to 12 months of age (median age, 3-4 months) was associated with reduced risk of food allergy (risk ratio [RR], 0.49; 95% CI, 0.33-0.74; I2 = 49%).
    JAMA Pediatr, 2023 · checked 2026-09-23
15. lobs-c4-04 · meta-analysis of prevalence studies
    The overall pooled estimates for all age groups of self-reported lifetime prevalence were as follows: cow's milk (5.7%, 95% confidence interval 4.4-6.9), egg (2.4%, 1.8-3.0), wheat (1.6%, 0.9-2.3), soy (0.5%, 0.3-0.7), peanut (1.5%, 1.0-2.1), tree nuts (0.9%, 0.6-1.2), fish (1.4%, 0.8-2.0) and shellfish (0.4%, 0.3-0.6)...fish (0.02%, 0.0-0.1) and shellfish (0.1%, 0.0-0.2).
    Allergy, 2023 · checked 2026-09-23
16. lobs-c4-09 · scoping review
    A total of forty-six articles were included in this review. Overall, shellfish consumption was associated with higher biomarkers of environmental contaminants, with mercury being the most studied and having the strongest evidence base. The limited research on nutritional biomarker status shows an association between shellfish consumption and iodine status. Preterm birth was not associated with shellfish consumption, but newborn anthropometry showed mixed results, with several studies reporting lower birth weight with higher shellfish consumption.
    Nutr Res Rev, 2025 · checked 2026-09-23
17. lobs-c4-10 · systematic review of cohorts
    Compared to men, women showed greater associated risk with higher consumption of fish and shellfish (HR (95% CI) Men: 1.02 (0.86-1.22); Women 1.36 (1.12-1.65))...Exceptions were metabolic syndrome in men and excessive seafood consumption in women, but these singular articles need further examination
    Adv Rheumatol, 2019 · checked 2026-09-23
18. lobs-c4-08 · systematic review of observational studies
    A total of 64 articles were considered from three databases. The key abiotic factor influencing the presence of arsenic in shellfish is anthropogenic contamination, followed by geographic location...Despite containing mostly less toxic organic arsenic, shellfish are a relevant source of arsenic in the human diet.
    Mar Pollut Bull, 2020 · checked 2026-09-23