Histamine intoxication

Biogenic amines such as histamine, tyramine and putrescine play an important role in many critical functions in man and animals. However, consumption of food containing high amounts of these amines may have deleterious effect on human health.

Toxic compound such as histamine, originally classified as ptomaines, result from the microbial decomposition of proteins and in some instances, decarboxylation of amino acids.

Theoretically, some amino acids can give rise to a ptomaine derivative plus carbon dioxide. Histamine intoxication can be distinguished from food allergy on the basis of:
*Lack of previous history of allergic reaction to the food involved
*The high attack rate in outbreaks involving groups of individuals
*The detection of high levels of histamine in the food implicated

Histamine poisoning can results from the ingestion of foods containing high levels of histamine. Histamine is the most toxic amine detected in food.

This poisoning historically been referred to as scombroid poisoning because of the frequent association of the illness with the consumption of spoiled scombroid fish such as mackerel and tuna. The poisoning has also been reported in connection with non-fish fermented foods like cheese and sauerkraut.

Histamine intoxication is a chemical intoxication and self-limited illness. Even without treatment symptoms usually subside within a few hours. However of left untreated, symptoms can persist for as long as 24 to 48 hr.

Some of the symptoms of histamine intoxication, e.g. nausea, vomiting, gastric pain, and headache, may be seen with other foodborne diseases or intoxications. However, the cutaneous symptoms, e.g. rash, urticaria, facial flushing, can be used to distinguish histamine poisoning from other types of foodborne intoxication.

Histamine intoxication can be severe in person with a history of allergic disease, with preexisting cardiac or respiratory conditions, or in people being treated with certain drugs, such as isoniazid or monoamine oxidase inhibitors.
Histamine intoxication

Histamine formation in food

Bacteria used to ferment foods contain enzymes, which decarboxylate amino acids to amines. Histamine in formed in food stuffs by the enzymatic decarboxylation of L-histidine by histidine decarboxylase produced the growth of certain bacteria.

L-histidine occurs in the bound form in proteins, but it is also present as the free amino acid in relatively high concentration in the tissues of certain fish e.g. tuna and mackerel.

Histidine decarboyxlase is found in some bacterial species. These include various species of Enterobacteriaceae, Clostridium, Vibrio, Photobacterium, and Lactobacillus.

The presence of most of the bacteria is often the result of unacceptable food-handling and hygienic practices.

Histamine, tyramine, and other amines such as putrescine, tryptamine, and cadaverine have been found in a variety of fermented foods including cheeses, meats, vegetables, fish products, and Oriental foods.
Histamine formation in food

Histamine in human body

Histamine is a naturally occurring compound synthesized in the body. It is a low molecular weight biogenic amine. It has been identified as a toxic agent which causes allergic reactions.

It is derived from amino acid histidine by the action of histidine decarboxylase. Histamine is found within granules of mast cells. basophils and platelets. It is concentrated especially in skin, gastrointestinal tract and lung.

Indigenous histamine is produced in the human body mainly in mast cells and is released as a result of response to allergens.

Mast cells release histamine in response to a number of stimuli, including mechanical stimulation, anaphylatoxins formed from complement and certain neuropeptides.

The mechanisms of histamine toxicity involves mediators known as histamine receptors such are responsible for the development of the various symptoms.

Histamines, one in the bloodstream has a number of effects. Histamine relaxes the smooth muscle of the arterioles leading to the wounded area, so increasing its blood flow.

It causes the cells of the capillary walls to draw away from one another, so that the capillaries become leaky. More plasma escapes from capillaries and collects in the site of the wound. The fluid causes the site of the wound to swell and become warm.

Allergic reactions to foods contain histamine depend not only how much histamine is, but also on individual threshold and the ability to breakdown histamine.
Histamine in human body