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You may've never heard of scombroid poisoning a.k.a. histamine fish poisoning but it’s one of the most common types of seafood poisoning. In this article we'll discover what scombroid poisoning exactly is, what causes it, and what probiotics can help afterwards.
Scombroid poisoning occurs after someone ingests spoiled fish that has been incorrectly cooked or stored. Histidine is an amino acid that naturally occurs in fish and at certain temperatures, bacteria on the fish can break down this histidine and turn it into histamine. Histamine toxicity is responsible for the poisoning1 and results in mild to moderate symptoms. It’s very rare, but should be noted that in some cases, victims have ended up in coronary care experiencing symptoms of a heart attack 2. However, these serious issues were seen in those with a history of coronary artery disease or anaphylaxis. Mostly, the condition is temporary and doesn’t last for a long time.
Fish from the Scombridae family such as tuna and mackerel along with other fish, such as sardines, herring, mahi-mahi and anchovies can all cause this type of foodborne poisoning. It can occur in fresh, canned, or smoked fish and it’s all down to the way it has been processed, stored or cooked. Outbreaks are more common in the summer, and it can be hard to tell if a fish has been spoiled as histamine will not affect the smell, which is normally a tell-tell sign that something is ‘off’. As histamine is heat stable, cooking the fish is ineffective in stopping the poisoning3. As with regular food poisoning, public health authorities should be notified if scombroid poisoning was contracted from a restaurant so the source can be investigated and removed from distribution.
The symptoms of scombroid poisoning are similar to an allergic reaction and will begin almost immediately up until after an hour or so. The most common symptoms are facial tingling, facial flushing, sweating, nausea, tongue or face swelling, rashes, headaches and dizziness. Gastrointestinal symptoms can include abdominal cramps, nausea, vomiting and diarrhea3.
Usually taking OTC (over the counter) anti-histamines is enough to resolve the symptoms, however, in some cases, epinephrine may be used if the symptoms are more severe. Following the initial symptoms, fatigue will usually follow and could last a few days, especially if epinephrine has been administered.
As the symptoms are very similar to an allergic reaction, it’s strongly recommended to rule out an allergy to the fish ingested – do not assume it’s scombroid poisoning! If this was indeed an allergic reaction, then precautions need to be taken by the patient in future such as carrying an epinephrine injector pen. It’s always best to suggest that individuals seek the advice of their doctor after this type of reaction to arrange allergy testing for the type of fish ingested.
For digestive symptoms, such as loose stools and cramps, the probiotic Saccharomyces boulardii has been clinically trialled to help4. Therefore, this probiotic strain could form part of a scombroid poisoning protocol to support afterwards to calm these GI symptoms. Saccharomyces boulardii is different from usual probiotics, in that it is a probiotic yeast. It has been studied for over 50 years and originates from the skins of lychee fruit. It should be noted that this strain is transient, meaning that it doesn’t colonise within the gut, so it may be prudent to take a supplement containing colonising probiotic strains at the same time to help repopulate the gut with good bacteria following the food poisoning.
As histamine toxicity is the cause of scombroid poisoning, it would be advisable to choose strains to repopulate the gut that have been shown to not exacerbate histamine production within the body. In fact, some species including Lactobacillus rhamnosus, Bifidobacterium infantis, Bifidobacterium longum, Lactobacillus plantarum, and possibly Lactobacillus reuteri5 may even downgrade biogenic amines such as histamine so could be worth selecting to take.
We often get asked by practitioners about the best probiotic after food poisoning and scombroid poisoning. As I alluded to in the previous section, the answer lies in a combination of probiotic stains and as always, it comes down to individual symptoms too.
Alongside Saccharomyces boulardii for GI symptoms such as loose stools, probiotic strains can be taken to globally improve the composition of the microbiome and potentially reduce the histamine response, so for this purpose, you could advise taking a supplement with great-quality strains from the species listed above.
There are very few specific strains which have been shown to be beneficial in terms of lowering histamine, however, one strain from the above-mentioned species is the Lactobacillus rhamnosus GG® strain. This strain has been shown in vitro to have beneficial effects on histamine intolerance symptoms6. However, as the research is still very limited in this area you could instead look at recommending very high-quality strains to support all round gut and immune health such as Lactobacillus acidophilus NCFM®, Bifidobacterium lactis BI-04 and B. lactis HN019. These strains are not in the above list which help to downgrade histamine, but they do not produce histamine so will not exacerbate symptoms.