This is a 2021 study that has resurfaced in the news cycle; the findings are not new, but they remain relevant. Researchers analyzed data from 17,294 adults in the 2003 to 2012 cycles of the US National Health and Nutrition Examination Survey, with mortality records linked through 2015. After adjustment, an increase of one ounce-equivalent of seafood per day was not associated with higher all-cause or cardiovascular mortality — the hazard ratios were 0.84 and 0.89, both with confidence intervals crossing 1.0. Blood mercury levels, comparing the highest to the lowest quartile, were likewise not associated with higher mortality (hazard ratios 0.82 and 0.90). The authors' conclusion: at current low-to-moderate mercury exposure, seafood consumption was not associated with mortality risk.
Two limits belong in the reading. The study is observational, so it shows association rather than proof — and it cannot settle the mercury question for people who eat very large amounts of high-mercury fish. The practical message that survives: for typical US consumption, the seafood-and-mercury worry does not match the mortality data.
Seafood is one of the stone diet's best protein groups: fish and shellfish measure zero oxalate, and they provide the animal protein the stone plan counts alongside poultry and eggs. The measured version of the seafood rotation keeps the fish at the protein slot of the plate and watches the two stone-relevant extras: the high-sodium preparations (breaded, battered, and sauce-heavy fish) and the shellfish, which carry the same zero-oxalate column but need the portion eye on their sodium. The mercury worry, per this study's data, does not support skipping seafood at typical consumption levels.
The table below shows the measured values of the common seafood options — the oxalate column is zero across the group, and the measured choices are about preparation and portion.
| Food | Oxalate (mg) | Serving | Rating |
|---|---|---|---|
| Salmon, baked | 0 | 4 oz | Safe |
| Cod, baked | 0 | 4 oz | Safe |
| Tuna, canned in water | 0 | 3 oz | Safe |
| Tilapia, baked | 0 | 4 oz | Safe |
| Shrimp, cooked | 0 | 3 oz | Safe |
| Crab, cooked | 0 | 3 oz | Safe |
| Breaded fish (high-sodium) | 0 | 1 fillet | Safe |
| Oysters, cooked | 0 | 3 oz | Safe |
The stone-safe seafood week is two to three fish servings at the protein slot, prepared plainly — baked, broiled, or grilled — with the lemon and herbs for flavor and the water or milk as the drink. The breaded and fried versions are the sodium items to portion, and the shellfish are fine in the same rotation. The person who has been avoiding fish out of mercury worry has, per this study's data, been avoiding one of the stone plan's cleanest proteins without a mortality-based reason — the measured version brings it back to the plate.
Yes — fish and shellfish measure zero oxalate, which makes them among the cleanest proteins on the stone table. The measured choices are the plain preparations; the breaded, fried, and sauce-heavy versions carry the sodium to portion.
At typical US consumption levels, the 2021 JAMA study of 17,294 adults found no association between seafood intake or blood mercury and mortality risk. The data do not support avoiding seafood at ordinary amounts; people eating very large quantities of high-mercury fish can follow the FDA's guidance on those specific choices.
Salmon, cod, tilapia, and tuna all measure zero oxalate and carry the omega-3s. The measured version is the plain preparation — baked or broiled — with water or milk as the drink, and the breaded or fried versions portioned for their sodium.
The seafood question on the stone table is mostly a preparation question: the fish itself measures zero oxalate, and the measured choices are about what happens to it before it reaches the plate. The breaded and fried versions — fish sticks, fried shrimp, battered fillets — carry the sodium and the oil, and the sauce-heavy preparations (the sweet-and-sour, the teriyaki, the cream sauces) add sugar and sodium to a clean protein. The measured version is the plain preparation — baked, broiled, grilled, or poached — with the lemon, the herbs, and the vegetables on the same plate. The canned options fit the same rule: tuna and salmon canned in water are the clean versions, and the oil-packed or flavored versions are the ones to read the label on. The person who cooks the fish plainly has solved the seafood question without a second thought.
The serving rhythm closes the loop: two to three fish servings a week at the protein slot, with the water or milk as the drink and the urine color check as the day's gauge. The seafood rotation is one of the stone plan's easiest, because the oxalate column is zero across the whole group — the measured work is in the preparation, not the choice.
See how oxalate values are measured and verified on our data methodology page.