Guest Post: Can Probiotics Help Allergies? We Review the Research

By Brenda Kimble, Nutritionist/Wellness Blogger

Studies about the link between gut bacteria and health have been gaining a great deal of attention lately. This field of study has come out with exciting finds that continue to change the way we think about health and medicine.

These studies show that the microbes in our gut have even more of an impact on our bodies than previously thought. We knew they could determine how well we digest food and absorb nutrients, but now we are seeing that gut bacteria can also affect our hormone balance, immune response and more.

Since allergies are an immune response, it is reasonable to think that probiotics could affect allergy sufferers. Some research has come out recently that seems to prove that idea.

What Are Allergies?

To understand how probiotics can help allergy sufferers, it helps to know what allergies are. Allergies are an immune response to various substances in the environment called allergens. These allergens can be dust, pollen or substances in food.

When allergens enter the body, an immune response is triggered. T-cells are dispatched to attack the invading molecule. Extra blood is pushed toward the area to help move T-cells and increase their concentration. Tissues begin to inflame, and other area-specific responses can start. For example, mucus production can ramp up to try and move allergens out of the nose.

In short, it is the body’s overreaction to allergens that lead to the unpleasant, and sometimes dangerous, allergy response.

The Gut Microbiome

The gut, or intestines, has hundreds of species of microbes whose individual numbers are in the billions. These microbes function as an entire organ and have one of the highest metabolic rates for organs in the body.

While there are yeasts in the gut, their numbers are relatively low. The majority of the microbes in the gut are bacteria.

These bacteria are responsible for much of our digestion and nutrient absorption. In addition to the gastric and pancreatic enzymes, the bacteria excrete enzymes which help break food down and release nutrients we would not be able to access on our own. They also can facilitate the movement of nutrients into the bloodstream or keep nutrients from entering the body.

Recent research has also indicated that microbes can do a lot more than affect our nutrition. They can also affect other important regulatory compounds. For instance, research has shown that taking probiotics can increase the production of the neurotransmitter serotonin, which can lead to a more stable mood.

Research like this has sparked interest in looking at other areas where probiotics might affect our health. Some researchers have taken that search in the direction of allergies. What they have found has been fascinating.

Probiotics and Hay Fever Symptoms

A study published in 2017 in The American Journal of Clinical Nutrition received a lot of notice with its findings that a mixture of three probiotic bacteria positively improved the symptoms of allergy sufferers during allergy season. These bacteria include Lactobacillus and two Bifidobacterium species.

This was a double-blind study of 173 patients who self-reported as allergy sufferers. They took the MRQLQ test, which is used to determine the severity of symptoms and quality of life-related to allergies, before and after taking either a placebo or the three bacteria as part of a probiotic for eight weeks.

While improvements were not as high as the team initially predicted based on previous research, there was a distinct improvement in scores in the probiotic group compared to the placebo group. This indicates the probiotic did improve the symptoms and life quality of the patients tested.

An Overview of the Metadata for Probiotics and Rhinitis Research

A metadata analysis is when multiple research studies are gathered and analyzed as a group. This determines trends over many studies and helps validate data. If multiple studies show the same or similar results, the hypothesis gains validity. If results are all different, the hypothesis is considered invalid, or the tests have been inadequate.

So far there has been one metadata analysis for the research concerning probiotics and seasonal allergies or hay fever. The analysis showed that taking probiotics is likely to help allergy sufferers. However, there are some issues with this analysis.

One of the limitations that this meta-analysis showed is that many of the studies were using different bacterial strains in their probiotics. This makes it harder to tell if specific strains work better or if probiotics, in general, are the key.

However, the analysis was positive and strongly encouraged more research into this topic.

Gut Microbiomes and Infant Allergies

Arthur C. Ouwehand published an article in the The Journal of Nutrition in 2007 that became the basis of many research projects involving probiotics’ effect on allergies.

This article looked at the gut bacteria in infants and the rates of certain types of allergies they exhibited. What he found was that infants with more adult-like microbiomes were more likely to have specific allergic reactions.

Infants with a strain of Lactobacillus rhamnosus or Bifidobacterium lactis (a Bifidobacterium more common in children than in adults) were less likely to have certain allergic reactions.

Ouwehand posited that certain microbes would change what type of immunoglobulins the infants created in their bodies. The adult-like microbes created IgE, which created an immune response, while infants with higher levels of the Bifidobacterium species created IgA, which reduces inflammation response and inhibits allergy response. Blood serum tests seem to support this.

A Cure for Allergies?

The evidence is adding up to suggest that taking probiotics and taking care of your body will likely help reduce allergen symptoms. However, they are not a cure. 

The more likely scenario for using probiotics to treat allergies is that they will be used as part of a holistic approach to manage symptoms. If the gut can be kept healthy and the immune response is dampened, then patients will be less likely to have allergy symptoms or will at least be able to reduce the symptoms.

This approach may not work for everyone, and patients should always consult with a doctor before adding anything to their routine or changing any medicines. We also do not know which strains of bacteria are most effective for reducing symptoms yet nor do we know proper dosage. Further research is needed in all areas of this field, but the future looks promising.