Shrimp can contain histamine, though it is not inherently considered a histamine-rich food compared to some other fish. The actual histamine content in shrimp can vary significantly based on its freshness, how it is stored, and preparation methods. Understanding histamine and how it develops in seafood is helpful for individuals who may be sensitive to this compound.
Understanding Histamine and Intolerance
Histamine is a naturally occurring chemical compound involved in various bodily processes, including immune responses, digestion, and neurotransmission. When the immune system detects an allergen, it releases histamine, which can cause symptoms often associated with allergies, like congestion or swelling.
Histamine intolerance occurs when the body struggles to break down histamine effectively, leading to an accumulation of the compound. This imbalance can result from insufficient activity of the enzyme diamine oxidase (DAO), which primarily metabolizes ingested histamine. Symptoms can be diverse, including headaches, skin rashes, nasal congestion, fatigue, or digestive issues. These symptoms can mimic allergic reactions.
Shrimp’s Histamine Content
Shrimp, like other seafood, can become a source of histamine due to bacterial action after harvest. Freshly caught or immediately frozen seafood has very low histamine levels. Histamine forms when certain bacteria convert the amino acid histidine, present in seafood, into histamine through an enzyme called histidine decarboxylase.
Histamine accumulation in shrimp develops over time, particularly under improper storage conditions. Factors such as temperature and duration of storage significantly influence histamine levels. For instance, if harvested seafood is stored at temperatures above 15°C for several hours, histamine concentrations can increase due to bacterial activity. Even at refrigeration temperatures, some histamine-producing bacteria can slowly continue to form histamine.
Reducing Histamine in Seafood
To minimize histamine exposure from shrimp and other seafood, consumers can take several steps. Purchasing the freshest possible seafood is a primary consideration, such as shrimp flash-frozen immediately after catch. When buying fresh shrimp, store it on ice or under refrigeration below 5°C.
Proper storage is also important; refrigerate or freeze shrimp as soon as possible after purchase. Freezing slows histamine buildup, though it does not completely halt the process. Consume frozen seafood within a few months. When thawing frozen shrimp, do so in the refrigerator or using a cold water bath or microwave to ensure a rapid transition, rather than at room temperature, which encourages bacterial growth. Cooking, canning, or freezing seafood cannot destroy histamine once it has formed because the compound is heat-stable.
Other foods that can be higher in histamine or trigger its release include:
- Fermented products
- Aged cheeses
- Alcohol
- Certain vegetables like tomatoes and spinach