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Oysters are one of the most nutrient-dense foods in USDA data: a 3-ounce serving of raw farmed eastern oysters, about six medium oysters, has only around 50 calories yet supplies close to three times the Daily Value for zinc, more than five times the Daily Value for B12, and nearly all of the Daily Value for selenium. The main catch is safety. CDC names raw or undercooked oysters as the leading way people get Vibrio infections, which can be severe for some groups. Below are the USDA oyster nutrition facts, how preparation changes them, the raw oysters question, and who should be careful.
Peptide Labs does not sell oysters or oyster products. This article is general nutrition information, not medical advice.
Key Takeaways
- Three ounces of raw farmed eastern oysters have about 50 calories and 4 grams of protein in USDA data.
- NIH says oysters contain more zinc per serving than any other food; one serving tops the Daily Value.
- Oysters are also rich in B12, copper and selenium, with values that vary by species and habitat.
- CDC advises against eating raw or undercooked oysters; cooking is the step that kills Vibrio.
- FDA and EPA place oyster in their lowest-mercury group. Mollusks are not a labeled major allergen.
Oyster nutrition per 3 ounces
The table uses three USDA FoodData Central SR Legacy entries (FDC 175172, 171978 and 174250), each converted to the 3-ounce (85 gram) serving USDA lists for them. The percent Daily Value (%DV) uses the FDA Daily Values printed on Nutrition Facts labels. Raw oysters are mostly water, so the cooked Pacific entry looks richer partly because cooking concentrates the same nutrients into less weight.
| Per 3 oz (85 g) | Eastern, farmed, raw | Eastern, wild, raw | Pacific, cooked (moist heat) |
|---|---|---|---|
| Calories | 50 | 43 | 139 |
| Protein | 4.4 g (9%) | 4.9 g (10%) | 16.1 g (32%) |
| Fat | 1.3 g (2%) | 1.5 g (2%) | 3.9 g (5%) |
| Carbohydrate | 4.7 g (2%) | 2.3 g (1%) | 8.4 g (3%) |
| Cholesterol | 21 mg (7%) | 34 mg (11%) | 85 mg (28%) |
| Sodium | 151 mg (7%) | 72 mg (3%) | 180 mg (8%) |
| Vitamin B12 | 13.8 mcg (574%) | 7.4 mcg (310%) | 24.5 mcg (1,020%) |
| Zinc | 32.2 mg (293%) | 33.4 mg (304%) | 28.3 mg (257%) |
| Copper | 0.63 mg (70%) | 2.43 mg (270%) | 2.28 mg (253%) |
| Selenium | 54.2 mcg (98%) | 16.8 mcg (30%) | 130.9 mcg (238%) |
| Iron | 4.9 mg (27%) | 3.9 mg (22%) | 7.8 mg (43%) |
| EPA plus DHA (omega-3) | 0.33 g | 0.27 g | 1.17 g |
Three patterns stand out. First, oyster calories are low for the amount of nutrition: even the cooked Pacific serving is under 140 calories. Second, the zinc numbers are extraordinary. The NIH Office of Dietary Supplements (ODS) states that oysters contain more zinc per serving than any other food, and its own table matches these USDA values within rounding. Our guide to foods high in zinc puts oysters in context against beef, crab and seeds. Third, the numbers swing widely between entries. Wild eastern oysters carry about four times the copper of the farmed entry, while the farmed entry has about three times the selenium. Species and habitat both play a part, so read any single figure as an estimate.
B12, copper, selenium and iron
Oysters belong on most lists of B12 foods, and the ODS copper fact sheet names shellfish among the richest dietary copper sources, listing cooked wild eastern oysters at 539% of the Daily Value per 3 ounces. Oysters also supply heme iron, the form found in animal foods that our foods high in iron guide explains is absorbed well. If you already take a zinc or copper supplement, it is worth mentioning shellfish meals to your clinician, since our copper supplement guide covers how the two minerals interact.
How preparation changes oyster nutrition
How oysters are prepared matters as much as the oyster itself. The comparison below uses USDA entries for eastern oysters, again per 3 ounces.
| Eastern oysters, 3 oz (85 g) | Calories | Fat | Sodium | Zinc |
|---|---|---|---|---|
| Farmed, raw (FDC 175172) | 50 | 1.3 g (2%) | 151 mg (7%) | 32.2 mg (293%) |
| Wild, cooked, moist heat (FDC 171980) | 87 | 2.9 g (4%) | 141 mg (6%) | 66.8 mg (607%) |
| Canned (FDC 171981) | 58 | 2.1 g (3%) | 95 mg (4%) | 77.3 mg (703%) |
| Breaded and fried (FDC 171979) | 169 | 10.7 g (14%) | 354 mg (15%) | 74.1 mg (673%) |
Breading and frying roughly triples the calories of a raw serving and adds saturated fat (2.7 grams, 14% of the Daily Value, in the USDA entry) and sodium. The 2025-2030 Dietary Guidelines for Americans suggest swapping deep-fried cooking for baked, broiled, roasted, stir-fried or grilled methods, which applies neatly to oysters. Canned oysters are cooked during canning, which makes them a shelf-stable way to get oysters without the raw-shellfish risk. Sauces add sodium too, so check labels on anything bottled; our low sodium foods guide has label-reading tips.
Raw oysters and Vibrio: what CDC and FDA say
Raw oysters on the half shell are popular, but public health agencies are clear about the risk. CDC estimates about 80,000 cases of vibriosis each year in the US, roughly 52,000 of them from eating contaminated food, and says most people get infected by eating raw or undercooked shellfish, particularly oysters. Vibrio bacteria live naturally in coastal water, so an oyster that looks, smells and tastes normal can still carry them. One species, Vibrio vulnificus, is especially dangerous: CDC reports that about 1 in 5 people with that infection die, sometimes within a day or two of becoming ill.
- Higher risk: CDC lists liver disease, cancer, diabetes, HIV, thalassemia, a weakened immune system and medicines that lower stomach acid as factors that raise the risk of serious illness.
- FDA advice: pregnant women, young children, older adults and people with weakened immune systems should avoid raw oysters, even oysters processed after harvest to reduce bacteria.
- Cooking: CDC’s message is simple: do not eat raw or undercooked oysters or other seafood, and cook them before eating. For oysters in the shell, CDC suggests boiling until the shells open and then boiling another 3 to 5 minutes, or steaming another 4 to 9 minutes.
- Handling: wash hands with soap and water after handling raw shellfish, and keep open cuts away from raw seafood and seawater.
If you develop fever, vomiting, diarrhea or a skin wound that worsens after eating raw shellfish or after seawater exposure, contact a clinician promptly and mention the shellfish.
Choosing and cooking oysters safely
FDA’s seafood safety page gives practical checks. Look for tags on sacks or containers of live shellfish and labels on packages of shucked oysters. Throw away oysters with cracked or broken shells; live ones close when the shell is tapped. During cooking the shells open, and FDA says to discard any that stay closed. Most seafood should reach an internal temperature of 145°F.
Are oysters good for you? Mercury, allergies and purines
For most people who enjoy them cooked, yes: oysters are a low-calorie source of protein, zinc, B12 and other minerals, and the Dietary Guidelines encourage a variety of protein foods that includes seafood. A few points help put that in perspective.
- Mercury: the FDA and EPA fish advice, written for people who are or may become pregnant, breastfeeding parents and children, lists oyster in its lowest-mercury group, alongside clam, scallop, shrimp and sardines.
- Allergy: FDA guidance says crustacean shellfish such as crab, lobster and shrimp are major food allergens, but molluscan shellfish such as oysters, clams, mussels and scallops are not. That means a package’s Contains statement is not required to flag oyster, so read the full ingredient list (oyster sauce is a common hidden source) and ask an allergist whether mollusks are safe for you.
- Purines and cholesterol: shellfish appear in our foods high in purines guide, so people with gout should ask their clinician how seafood fits. Cooked oysters carry moderate cholesterol; see foods high in cholesterol for context.
- Omega-3: oysters contribute some EPA and DHA, about 1.2 grams per cooked Pacific serving in USDA data, but fatty fish usually supply more; our omega-3 guide compares sources.
Oysters share many of these traits with their filter-feeding cousins; our sibling guide to mussels compares the two side by side.
Frequently Asked Questions
How many calories are in oysters?
USDA lists about 50 calories for 3 ounces of raw farmed eastern oysters, about six medium oysters. Cooked Pacific oysters are about 139 calories per 3 ounces, and breaded fried oysters about 169.
Are oysters high in zinc?
Yes. NIH says oysters contain more zinc per serving than any other food. A 3-ounce serving supplies roughly two and a half to six times the Daily Value, depending on the type and cooking.
Are raw oysters safe to eat?
CDC advises against eating raw or undercooked oysters because they can carry Vibrio bacteria. People with liver disease, diabetes, a weakened immune system or other risk factors face the greatest danger.
Are oysters good for you?
Cooked oysters are low in calories and rich in protein, zinc, B12, copper and selenium. People with shellfish allergy, gout or a high-risk health condition should get personal advice first.
Are oysters high in mercury?
No. FDA and EPA place oyster in their lowest-mercury group of fish and shellfish.
Is oyster a major food allergen on labels?
No. Under FDA rules only crustacean shellfish are major allergens. Oysters and other mollusks still appear in ingredient lists, so read them in full.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Mussels: USDA Nutrition, Protein, Safety and Mussels vs Oysters, Foods High in Zinc: USDA List for Meat Eaters, Vegetarians and Vegans, B12 Foods: Animal, Fortified and Vegan Sources Ranked.