The question of whether fish oil is high in histamine is a common concern for individuals with sensitivities, but the answer depends entirely on the product’s quality and processing. Fish oil supplements, popular for their beneficial omega-3 fatty acids like EPA and DHA, are derived from fish that naturally contain the precursor to histamine. Histamine is a chemical compound produced by the body’s immune cells and is also found in many foods, causing intolerance symptoms when consumed in excess. Understanding the difference between histamine formed in spoiled fish versus the oil’s biological effects is key to safely incorporating this supplement.
Histamine in Fish Oil: Spoilage and Scombrotoxin
Histamine is not an inherent component of fresh fish oil but is a marker of degradation that occurs after the fish is caught. Fresh fish are rich in the amino acid histidine, particularly in the muscle of species like tuna, mackerel, and mahi-mahi. When fish are not immediately chilled, bacteria grow and produce the enzyme histidine decarboxylase, which converts histidine into histamine.
Histamine levels rise dramatically with improper handling and storage, especially when temperatures exceed 40°F (4°C). High concentrations of histamine in spoiled fish cause scombroid poisoning (scombrotoxin). This illness mimics a severe allergic reaction, causing flushing, headache, and hives, though it is a chemical reaction to the toxin. The histamine itself is heat-stable and cannot be eliminated by cooking, freezing, or the manufacturing processes used for crude oil. Therefore, the histamine found in fish oil directly measures the freshness of the raw fish used.
Choosing High-Quality Supplements to Limit Risk
Consumers concerned about histamine should select fish oil supplements that emphasize freshness and purity standards. High-quality manufacturers process raw fish quickly, drastically limiting histamine formation. The purification method of molecular distillation is standard for premium oils, refining the oil under a vacuum at low temperatures. This process effectively removes environmental contaminants like heavy metals and dioxins, and it also separates undesirable organic compounds, including biogenic amines like histamine.
To verify quality, look for third-party testing certifications, such as the International Fish Oil Standards (IFOS) or adherence to the Global Organization for EPA/DHA Omega-3 (GOED) monograph. While these tests do not always directly measure histamine, they assess oxidation levels—a measure of rancidity or spoilage. Low oxidation scores indicate a stable and fresh oil, which strongly correlates with a minimal risk of histamine content. Pay attention to the expiration date and avoid any liquid oil with a noticeably strong or rancid smell, as this suggests high oxidation.
Does Fish Oil Trigger Histamine Release in the Body?
While the direct histamine content in high-quality fish oil is negligible, the question remains whether the oil’s components can trigger the body’s internal histamine release. In most individuals, the omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), demonstrate an anti-inflammatory effect. Studies suggest that omega-3s dampen the immune response by stabilizing mast cells, the immune cells responsible for releasing histamine and other pro-inflammatory mediators. This action helps alleviate symptoms associated with allergic inflammation.
A small number of people with highly sensitive conditions, such as Mast Cell Activation Syndrome (MCAS), may still react to the supplement. This reaction is usually not due to the omega-3s themselves but may be triggered by trace amines not fully removed during processing or specific additives and fillers used in the capsule. Fish oil is generally well-tolerated and is not considered a histamine liberator for the majority of the population, with its consumption often associated with a reduced inflammatory state.