Probiotics for histamine intolerance

The question of whether probiotics can help with histamine intolerance is a topic of interest for many of our users. There are supplements to be found on the market that are marketed as very effective for histamine intolerance, while others are supposedly less suitable since they contain lactic acid bacteria with the genetic ability to produce histamine. Here we take a closer look at what we know about the relationship between histamine and our intestine and consider what is still to be learned.


Does the intestinal flora produce histamine?

Up until now it has generally been accepted that histamine intolerance is caused by a low diamine oxidase (DAO) capacity in the intestine. The intestinal wall contains too few histamine-metabolizing enzymes to adequately break down the histamine that is found naturally in many common foods. Another factor, one that is much less studied, could be bacteria in the gut that, through their metabolic activity, can produce histamine.

Histamine production through lactic acid bacteria

Of the lactic acid bacteria that are useful to us, many strains carry a gene that enables them to synthesize histamine, and many of these bacteria can be found naturally in our intestinal flora. A good body of research exists on them, since they are used in the production of many foods, such as yoghurt, cheese, and salami. They are also widely found in probiotics.

Known sources of lactic acid bacteria that can form histamine are:
  • Lactobacillus casei (found in fermented milk products)
  • Lactobacillus delbrueckii subsp. bulgaricus (used in the production of yoghurt)
  • Limosilactobacillus reuteri (found in sourdough)

In theory the presence of these bacteria can also contribute to increased histamine levels in the gut. However, whether they do this on a relevant scale is a very contested question. The internet is rife with hasty conclusions offered by self-proclaimed experts who consider probiotics with these bacteria to be completely unsuitable for people with histamine intolerance. It is therefore worth taking a closer look at what we know to be true about our intestinal flora and histamine intolerance.

Is there a difference in intestinal health between people with and without histamine intolerance?

We can detect clear changes in microbiome in people with histamine intolerance. For example, there is an increased number of putrefying bacteria (Proteobacteria), whereas the amount of lactic acid bacteria and bifidobacteria is significantly reduced. A heightened amount of Proteobacteria is usually an indicator of dysbiosis, which is an imbalance in the intestinal flora. Too much putrefying bacteria causes minor intestinal inflammation, impairing the function of the intestinal wall and damaging its capacity to protect against unwanted compounds like histamine.

Lactobacilli as a harmful influence?

What we have established above contradicts the assertion that lactobacilli are associated with an unhealthy increase in histamine levels in the intestine. In none of the participants with histamine intolerance have any studies revealed an increased number of histamine-producing lactobacilli, but there were abnormalities in the amounts of putrefactive bacteria, which we know to be proven to produce histamine. Moreover, a connection between asthma and an intestinal flora that produces reliable amounts of histamine has already been demonstrated in asthmatic research.

The gene for synthesizing histamine is also specific to a strain of bacteria, not a species. Over 370 different strains have been identified for L. casei alone, and even though one of them contains the histamine gene, it does not follow that the others do. As an example, let us consider the strain L. reuteri DSM 17938, which is widely used in commercial food production. No histamine gene has been detected in this strain, although it can be found in the alternative strains listed above. Thus, one would have to examine each single strain of bacteria separately to determine which contain the gene for synthesizing histamine and which do not.

Are some probiotic strains best avoided?

A bacterium’s suitability for a probiotic should not just be determined by the presence of the gene for synthesizing histamine. Even with histamine-producing lactobacilli, studies have revealed an anti-inflammatory effect, such as reduced chronic intestinal inflammation. Lactic acid bacteria regulate the immune system and keep inflammation in check, but they also secrete lots of useful metabolic products and can even break down histamine. In short, lactobacilli are good for the body and their benefits are more than likely to outweigh the possible drawbacks.

How do I choose the right probiotic?

Our immune system’s activity is controlled via a combination of symbiotic and pathogenic factors. With many diseases, this balance is out of kilter and unhealthy changes will develop in the intestinal flora. The dysbiosis leads to inflammation in the intestinal mucosa, which can ultimately disrupt DAO synthesis.

By contrast, healthy people have significantly more lactobacilli and bifidobacteria that help keep their intestines healthy via the metabolic products they contain. Probiotics give us access to an external supply of various strains of specially selected bacteria, which allows us to stabilize the intestinal flora. A growing body of evidence also shows that certain bacteria have disease-preventing effects.

A stimulating effect on the intestinal barrier function has been demonstrated for individual probiotic strains. This effect has been particularly well researched for bifidobacteria (e.g. Bifidobacterium bifidum), which can improve intestinal problems such as diarrhea or constipation. Also of note, incidentally: bifidobacteria cannot produce histamine. Nevertheless, there is currently nothing to suggest that probiotic strains that carry the gene for histamine synthesis have a negative effect on histamine intolerance.

It has become almost impossible to keep track of the sheer number of probiotics available today, but do not be discouraged; even cheaper products from a drugstore will often contain effective probiotic strains. You do not necessarily need to purchase expensive remedies, not least because probiotics develop their effectiveness over a sustained period, so costs can be prohibitive. A specialist doctor or pharmacist can often help when it comes to choosing the right supplement.

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