A new study published in the Journal of the American Medical Association concludes Omega-3 pills have no effect on the health of your brain; however, eating whole seafood increases your risk mercury poisoning. The Food and Drug Administration recommends eating more low-mercury seafood.
“The hypothesis was that [the supplements] would have an effect,” study author Emily Chew tells The Salt. But “we found there was absolutely no effect on the cognitive decline in this group over time,” says Chew, who is the deputy clinical director at the National Eye Institute, part of the National Institutes of Health.
“Omega-3s [found in fish] are important, we think, because they reduce inflammation and help neurons function well,” says researcher Joseph Hibbeln of the National Institutes of Health.
Table is sorted from lowest mercury concentrations to highest:
| CLAM * | 0.009 | 0.002 | 0.011 | ND | 0.028 | 15 | FDA 1991-2010 |
| SCALLOP | 0.003 | ND | 0.007 | ND | 0.033 | 39 | FDA 1991-2009 |
| ANCHOVIES | 0.017 | 0.014 | 0.015 | ND | 0.049 | 14 | FDA 2007-2010 |
| SHRIMP * | 0.009 | 0.001 | 0.013 | ND | 0.05 | 40 | FDA 1991-2009 |
| CRAWFISH | 0.033 | 0.035 | 0.012 | ND | 0.051 | 46 | FDA 1991 -2007 |
| SQUID | 0.023 | 0.016 | 0.022 | ND | 0.07 | 42 | FDA 2005-2010 |
| SARDINE | 0.013 | 0.01 | 0.015 | ND | 0.083 | 90 | FDA 2002-2010 |
| TILAPIA * | 0.013 | 0.004 | 0.023 | ND | 0.084 | 32 | FDA 1991-2008 |
| SALMON (CANNED) * | 0.008 | ND | 0.017 | ND | 0.086 | 34 | FDA 1992-2009 |
| WHITING | 0.051 | 0.052 | 0.03 | ND | 0.096 | 13 | FDA 1991-2008 |
| MACKEREL ATLANTIC (N.Atlantic) | 0.05 | N/A | N/A | 0.02 | 0.16 | 80 | NMFS REPORT 1978 |
| SHEEPSHEAD | 0.093 | 0.088 | 0.059 | ND | 0.17 | 6 | FDA 2007 – 2009 |
| SHAD AMERICAN | 0.045 | 0.039 | 0.045 | 0.013 | 0.186 | 13 | FDA 2007-2010 |
| MACKEREL CHUB (Pacific) | 0.088 | N/A | N/A | 0.03 | 0.19 | 30 | NMFS REPORT 1978 |
| SALMON (FRESH/FROZEN) * | 0.022 | 0.015 | 0.034 | ND | 0.19 | 94 | FDA 1991-2009 |
| CROAKER ATLANTIC (Atlantic) | 0.065 | 0.061 | 0.05 | ND | 0.193 | 57 | FDA 2002 – 2009 |
| HADDOCK (Atlantic) | 0.055 | 0.049 | 0.033 | ND | 0.197 | 50 | FDA 1991-2009 |
| FLATFISH [2*] | 0.056 | 0.05 | 0.045 | ND | 0.218 | 71 | FDA 1991-2009 |
| LOBSTER (NORTHERN / AMERICAN) | 0.107 | 0.086 | 0.076 | ND | 0.23 | 9 | FDA 2005-2007 |
| OYSTER | 0.012 | ND | 0.035 | ND | 0.25 | 61 | FDA 1991-2009 |
| TUNA (FRESH/FROZEN, SKIPJACK) | 0.144 | 0.15 | 0.119 | 0.022 | 0.26 | 3 | FDA 1993 – 2007 |
| LOBSTER (Spiny) | 0.093 | 0.062 | 0.097 | ND | 0.27 | 13 | FDA 1991-2005 |
| MULLET | 0.05 | 0.014 | 0.078 | ND | 0.27 | 20 | FDA 1991-2008 |
| CARP | 0.11 | 0.134 | 0.099 | ND | 0.271 | 14 | FDA 1992 – 2007 |
| MONKFISH | 0.181 | 0.139 | 0.075 | 0.106 | 0.289 | 9 | FDA 2006-2008 |
| CATFISH | 0.025 | 0.005 | 0.057 | ND | 0.314 | 57 | FDA 1991-2010 |
| WHITEFISH | 0.089 | 0.067 | 0.084 | ND | 0.317 | 37 | FDA 1991-2008 |
| PERCH (Freshwater) | 0.15 | 0.146 | 0.112 | ND | 0.325 | 19 | FDA 1991-2007 |
| BUTTERFISH | 0.058 | N/A | N/A | ND | 0.36 | 89 | NMFS REPORT 1978 |
| SKATE | 0.137 | N/A | N/A | 0.04 | 0.36 | 56 | NMFS REPORT 1978 |
| HAKE | 0.079 | 0.067 | 0.064 | ND | 0.378 | 49 | FDA 1994-2009 |
| CROAKER WHITE (Pacific) | 0.287 | 0.28 | 0.069 | 0.18 | 0.41 | 15 | FDA 1997 |
| BUFFALOFISH | 0.137 | 0.12 | 0.094 | 0.032 | 0.43 | 17 | FDA 1992-2008 |
| LOBSTER (Species Unknown) | 0.166 | 0.143 | 0.099 | ND | 0.451 | 71 | FDA 1991-2008 |
| SCORPIONFISH | 0.233 | 0.181 | 0.139 | 0.098 | 0.456 | 6 | FDA 2007 – 2008 |
| JACKSMELT | 0.081 | 0.05 | 0.103 | 0.011 | 0.5 | 23 | FDA 1997-2007 |
| TILEFISH (Atlantic) | 0.144 | 0.099 | 0.122 | 0.042 | 0.533 | 32 | FDA 2002-04 |
| HERRING | 0.084 | 0.048 | 0.128 | ND | 0.56 | 26 | FDA 2006-2009 |
| PERCH OCEAN * | 0.121 | 0.102 | 0.125 | ND | 0.578 | 31 | FDA 1991-2010 |
| CRAB [1] | 0.065 | 0.05 | 0.096 | ND | 0.61 | 93 | FDA 1991-2009 |
| TROUT (FRESHWATER) | 0.071 | 0.025 | 0.141 | ND | 0.678 | 35 | FDA 1991 -2008 |
| MACKEREL SPANISH (S. Atlantic) | 0.182 | N/A | N/A | 0.05 | 0.73 | 43 | NMFS REPORT 1978 |
| WEAKFISH (SEA TROUT) | 0.235 | 0.157 | 0.216 | 0 | 0.744 | 46 | FDA 1991-2005 |
| POLLOCK | 0.031 | 0.003 | 0.089 | ND | 0.78 | 95 | FDA 1991-2008 |
| TUNA (FRESH/FROZEN, ALBACORE) | 0.358 | 0.36 | 0.138 | ND | 0.82 | 43 | FDA 1992-2008 |
| TUNA (CANNED, ALBACORE) | 0.35 | 0.338 | 0.128 | ND | 0.853 | 451 | FDA 1991-2010 |
| TUNA (CANNED, LIGHT) | 0.128 | 0.078 | 0.135 | ND | 0.889 | 551 | FDA 1991-2010 |
| MARLIN * | 0.485 | 0.39 | 0.237 | 0.1 | 0.92 | 16 | FDA 1992-1996 |
| BASS (SALTWATER, BLACK, STRIPED) [3] | 0.152 | 0.084 | 0.201 | ND | 0.96 | 82 | FDA 1991-2010 |
| COD | 0.111 | 0.066 | 0.152 | ND | 0.989 | 115 | FDA 1991-2010 |
| SABLEFISH | 0.361 | 0.265 | 0.241 | 0.09 | 1.052 | 26 | FDA 2004 – 2009 |
| ORANGE ROUGHY | 0.571 | 0.562 | 0.183 | 0.265 | 1.12 | 81 | FDA 1991-2009 |
| GROUPER (ALL SPECIES) | 0.448 | 0.399 | 0.278 | 0.006 | 1.205 | 53 | FDA 1991-2005 |
| TUNA (FRESH/FROZEN, Species Unknown) | 0.415 | 0.339 | 0.308 | 0 | 1.3 | 120 | FDA 1991-2010 |
| SNAPPER | 0.166 | 0.113 | 0.244 | ND | 1.366 | 67 | FDA 1991-2007 |
| BLUEFISH | 0.368 | 0.305 | 0.221 | 0.089 | 1.452 | 94 | FDA 1991-2009 |
| TUNA (FRESH/FROZEN, YELLOWFIN) | 0.354 | 0.311 | 0.231 | 0 | 1.478 | 231 | FDA 1991-2010 |
| HALIBUT | 0.241 | 0.188 | 0.225 | ND | 1.52 | 101 | FDA 1992-2009 |
| MACKEREL SPANISH (Gulf of Mexico) | 0.454 | N/A | N/A | 0.07 | 1.56 | 66 | NMFS REPORT 1978 |
| MACKEREL KING | 0.73 | N/A | N/A | 0.23 | 1.67 | 213 | GULF OF MEXICO REPORT 2000 |
| TUNA (FRESH/FROZEN, ALL) | 0.391 | 0.34 | 0.266 | 0 | 1.816 | 420 | FDA 1991 – 2010 |
| TUNA (FRESH/FROZEN, BIGEYE) | 0.689 | 0.56 | 0.341 | 0.128 | 1.816 | 21 | FDA 1991 – 2005 |
| BASS CHILEAN | 0.354 | 0.303 | 0.299 | ND | 2.18 | 74 | FDA 1994-2010 |
| SWORDFISH | 0.995 | 0.87 | 0.539 | ND | 3.22 | 636 | FDA 1990-2010 |
| TILEFISH (Gulf of Mexico) | 1.45 | N/A | N/A | 0.65 | 3.73 | 60 | NMFS REPORT 1978 |
| SHARK | 0.979 | 0.811 | 0.626 | ND | 4.54 | 356 | FDA 1990-2007 |