Seafood and Headaches

If you get a headache after eating fish, it might not just be a coincidence. The preservatives or other additives in seafood can trigger a painful migraine. The reasons for an after-dinner headache may also include an illness caused by contaminated fish or — although unlikely — a seafood allergy.

Did you know that some foods are thought to trigger migraines or headaches in some people? According to the American Migraine Foundation, these triggers are based on self-report and aren't backed by scientific studies. Even so, certain foods seem to trigger headaches more often than others. While alcohol and chocolate are at the top of the list, seafood is a recurrent offender as well.

Read more: 5 Types of Headaches and How To Ease The Pain

For those who report getting a headache after eating salmon, specifically smoked or dried salmon, tyramine could be the culprit. This naturally occurring compound is often found in pickled, smoked or dried fish and forms during the fermentation or preservation process. The American Migraine Foundation states that more studies need to be done on the connection between tyramine and headaches. They suggest eating fresh fish instead of smoked or dried fish.

The Cleveland Clinic recommends checking the nutritional labels of pre-packaged fish for chemicals and preservatives like nitrates and nitrites, phenylethylamine, salicylates, aspartate and gluten. Any of them can be a headache trigger.

The food additive MSG (monosodium glutamate) is often the culprit. While seafood itself doesn't contain this compound, some sauces or marinades could. An October 2016 review published in Current Neurology and Neuroscience Reports has found no association between MSG and headaches. Researchers did conclude, however, that more studies should be conducted to assess the connection between diet and headaches, and that eliminating possible triggers may help.

The American Migraine Foundation suggests keeping a food diary. If food is the trigger, it will cause a headache within 12 to 24 hours after consuming it. Thus, you can go back and trace the potential source of pain.

If you get a headache after eating salmon or another type of fish, you might have consumed contaminated fish. According to the U.S. National Library of Medicine, a headache after eating fish is a common sign of food poisoning, along with nausea, vomiting, cramping, numbness, tingling and difficulty breathing. You may also experience a metallic taste in the mouth, diarrhea and low blood pressure. See a doctor immediately if you notice these symptoms.

The three most common types of food poisoning come from the ciguatera species (sea bass, grouper, red snapper), scombroid species (tuna, mackerel, mahi-mahi) and shellfish (clams, oysters, mussels). Remember, it doesn't matter how thoroughly the fish or seafood is cooked as heat doesn't kill the poison.

So, how can you protect yourself? The U.S. National Library of Medicine recommends avoiding seafood (including shellfish and fish) during algae blooms, which occur in the summer. When eating out or buying fish, you should always ask where it came from.

An October 2018 study in the Journal of Asthma and Allergy confirmed that fish and shellfish, including shrimp, crab, lobster, squid and oysters, are some of the most common food allergens. In the United States, about 0.4 percent of people are allergic to fish and 0.2 percent are allergic to both fish and shellfish.

Still, the Australasian Society of Clinical Immunology and Allergy doesn't list headaches among the most common symptoms of a seafood allergy. Instead, seafood allergies often trigger hives, tingling of the throat and mouth, swelling, vomiting and diarrhea. Suffers may also develop anaphylaxis, a life-threatening reaction that requires emergency care.

Read more: 10 Facts You Need to Know About Food Allergies

It's worth noting, though, that fish allergies are potentially life-threatening. Headache or not, if you experience one or more of these symptoms after eating seafood, contact a doctor immediately. Don't take unnecessary risks. A healthcare provider can determine the cause of your symptoms and recommend the best course of action.