I've had many people write to me saying they've heard fermentation "always" raises histamine, and that fermented foods are not good for dogs with allergies or sensitive skin.
I understand the worry — but there is a huge difference between what fermentation process was used.
Some fermentation produces histamine and the other kind in fact reduces it and helps dogs with allergies.
Histamine: Messenger, Not Monster
Before we go further, let's reframe histamine itself. Histamine is not a toxin your dog's body is trying to avoid. It is a signalling molecule involved in digestion, immune responses, and even sleep-wake regulation. Our dog’s body actually produces histamine all the time! The problems only arise when there's too much histamine relative to what the body can break down.
Basically, when histamine load exceeds the body’s histamine clearance capacity.
Think of it like a sink with the tap running. A little water flowing in is fine as long as the drain (your dog's enzymes) can keep up. Trouble starts only when the tap is running faster than the drain can handle — that's histamine intolerance, not a histamine allergy in the classic sense.
Histamine-Producing vs. Histamine-Degrading Microbes
This is the most important part.
Not all fermenting microbes behave the same way, and the difference comes down to which enzymes they carry.
Histamine producers carry an enzyme called histidine decarboxylase, which converts the amino acid histidine into histamine. Certain bacterial strains common in long, bacteria-driven fermentations (some Lactobacillus species among them) are known histamine producers when conditions favor their growth.[1]
This is why aged cheeses, long‑fermented vegetables, and certain fermented meats are often cited as high‑histamine foods. The issue is not “fermentation” as a broad concept; it’s which microbes, under what conditions, and for how long.
Histamine degraders work the opposite direction. They carry amine oxidase enzymes that break histamine (and its cousin, tyramine) down into inactive byproducts.
A 2005 study identified two specific Saccharomyces cerevisiae strains — designated HL10 and HL17 — with strong abilities to actively degrade histamine and tyramine, eliminating substantial concentrations of both compounds from a fermenting medium within 24 hours through measurable amine oxidase activity.[1]
Yes, you read that right, Saccharomyces cerevisiae actively removed histamine from the fermenting medium!
This is the part that surprises most guardians: the beneficial yeast, such as Saccharomyces cerevisiae works against histamine buildup, not contributing to it.
This is why I think it's a mistake to lump "fermentation" into one big, feared category. A jar of long-aged, bacteria-heavy sauerkraut and a carefully controlled Saccharomyces cerevisiae fermentation are entirely different.
One increases and the other one REDUCES histamine.
What This Means for Sensitive, Itchy Dogs
For a guardian with an itchy or sensitive dog, this distinction matters enormously. Avoiding all fermentation out of caution may mean missing out on genuinely helpful, histamine-reducing support — like carefully fermented vitamins such as SoulFood and SoulFood H+.
How SoulFood Uses This Science
SoulFood is formulated using Saccharomyces cerevisiae on certified‑organic, whole‑food nutrients plus vitamins.
It's one of the reasons I feel comfortable recommending and encourage dog parents of allergic dogs to add SoulFood to the health and longevity plan.
Fermentation, approached thoughtfully, is not something to fear — it's one of the oldest and most well-documented tools for improving what your dog's body can actually absorb and use from food. The key, as with most things in health, is not blanket avoidance or blanket enthusiasm, but careful, individualized attention.
Try SoulFood and SoulFood H+ with free lifetime money back guarantee.
FAQ
Does fermentation always increase histamine?
No. Histamine increases mainly when specific bacteria carrying histidine decarboxylase are active. Yeast-driven fermentation, particularly with certain S. cerevisiae strains, can actually reduce histamine and tyramine levels rather than raise them.[1]
Does Saccharomyces cerevisiae produce histamine?
Most studied strains do not carry the enzyme needed to produce histamine, and specific strains have been documented to degrade histamine and tyramine directly.[1]
Can Saccharomyces actually reduce histamine?
Yes — strains HL10 and HL17 demonstrated measurable, enzyme-driven histamine and tyramine degradation in controlled fermentation studies.[1]
Is yeast always bad for histamine-sensitive dogs?
Not based on current evidence. The concern applies more accurately to histamine-producing bacterial fermentation, not yeast fermentation broadly.
What's the difference between histamine intolerance and allergy?
An allergy involves the immune system reacting to a specific allergen. Histamine intolerance is a mismatch between histamine intake/production and the body's ability to break it down — a "sink overflow" problem, not an immune attack.
Is "yeast-free" always better for histamine-sensitive dogs?
Not necessarily. A yeast-free product may still rely on histamine-producing bacterial fermentation, while a yeast-based product may be actively histamine-reducing.
References:
1. Arome Science. Short-chain fatty acids in the human gut: from microbial fermentation to systemic health. 2026.
2. Gupta RK, Gangoliya SS, Singh NK. Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. J Food Sci Technol. 2015;52(2):676-684. Available from: PMC4325021.
3. Lesaffre Institute. Effects of sourdough fermentation on phytic acid and mineral bioaccessibility. 2026.
4. Frontiers in Nutrition. Enhancing iron and zinc bioavailability in maize (Zea mays) through fermentation, soaking, and germination. Front Nutr. 2024.
5. Frontiers in Nutrition. Effects of sourdough- or regular-bread fermentation, and phytate reduction, on iron bioavailability and status in humans: a systematic review of human intervention studies (1970–2024). Front Nutr. 2026.
6. Ekpa O, et al. B-vitamins and heat-processed fermented starchy and vegetable foods: a review. J Food Sci. 2023;88(8).
7. Ashagrie D, et al. Cereal-based fermented foods as a source of folate and cobalamin. Food Res Int. 2025.
8. Wastyk HC, Fragiadakis GK, Perelman D, et al. Gut-microbiota-targeted diets modulate human immune status. Cell. 2021;184(16):4137-4153.
9. Cronin P, Joyce SA, O’Toole PW, O’Connor EM. Dietary fibre modulates the gut microbiota. Cell Metab. 2021.
10. Maastricht University. Short chain fatty acids in human gut and metabolic health. Nutr Res Rev. 2013.
11. Effect of fermentation on the nutritional quality of selected vegetables. Foods. 2023;12(5). Available from: PMC10051273.
12. American Society of Animal Science. Interpretive summary: effects of a Saccharomyces cerevisiae fermentation product on fecal characteristics and oxidative stress in dogs undergoing transport stress. J Anim Sci. 2023.
13. Frontiers in Veterinary Science. Potential benefits of yeast Saccharomyces and their derivatives in dogs and cats. Front Vet Sci. 2023;10:1279506.
14. Zhao Y, et al. The characteristics of histamine and tyramine degradation of Saccharomyces cerevisiae strains HL10 and HL17. Food Chem. 2025. PubMed ID: 40484525.
