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Probiotic bacteria may help alleviate allergy symptoms

Probiotic bacteria may help alleviate allergy symptomsDuring spring and summer, many people suffer from allergy symptoms and hay fever because their immune system overreacts to airborne pollen. However, according to a new American study, it is possible that different lactic acid bacteria and bifidobacteria can help alleviate the symptoms. The explanation lies in our intestinal microflora and its importance for a properly functioning immune system.

Our intestinal microflora harbors as many as 50 trillion bacteria that keep each other in check in a delicate balance. Lactic acid bacteria and bifidobacteria have many functions that are relevant for our health. However, overconsumption of candy, junk food, alcohol, antibiotic medicine, and pain-reliving medicine, combined with stress may affect negatively or even remove entirely large parts of our microflora, giving ground to more resistant innate microorganisms that multiply and cause problems with our digestion, immune system, and many other biological functions. It is therefore highly important to make sure that the intestinal microflora contain adequate amounts of lactic acid bacteria and bifidobacteria (also known as probiotics, which means “pro life”). Always make sure to choose a supplement with probiotic bacteria that are able to survive their passage through the stomach acid so that they are sure to reach the small intestine and colon. Here, they can colonize the gut and repress harmful bacteria and fungus.

Lactic acid bacteria (Lactobacillus acidophilus)

Lactic acid bacteria are found everywhere in nature. This type of bacteria produces lactic acid through carbohydrate fermentation. Their name is misguiding, as they do not contain milk.

Only certain types of probiotics have an effect on allergies

According to the researchers from University of Florida, USA, many studies have demonstrated that probiotics are able to control the body’s immune response in connection with allergies. However, not all kinds of probiotics are able to do this. The scientists already knew that a combination of particular lactic acid bacteria (Lactobacillus gasseri KS-13) and bifidobacteria (Bifidumbacterium bifidum G9-1 and Bifidumbacterium longum MM2) seems to have a positive effect on the digestion and immune system. They claim that these specific probiotics suppress allergies by increasing the amount of regulatory T cells, a type of white blood cells with an immunosuppressive effect. Therefore, the researchers were interested in investigating whether this combination of probiotics could alleviate allergy symptoms.

Carried out the study when the pollen season peaked

The study was carried out during spring at the peak of the pollen count and included 173 health adults who suffered from seasonal allergies. The scientists divided the participants in two groups. One group received the above-mentioned combination of probiotics, while the other group received matching placebo (dummy pills). Every week during the eight-week long study, the participants were asked to answer an online questionnaire with questions about their hay fever and the severity of their symptoms.
In addition, the researchers studied DNA from fecal samples to see how the study participants’ intestinal microflora changed (probiotics are known to promote the growth of beneficial gut bacteria). The DNA test also revealed who took probiotics and who got placebo.

Probiotics reduced symptoms of hay fever during the peak season

According to the study results, study participants who took probiotics reported having fewer symptoms than the participants who took placebo. They had fewer allergy-related symptoms such as runny nose, and they felt less troubled by their condition in the course of the day.
The researchers made it clear that their study did not include any patients with severe allergies. Still, the combination of probiotics that they used demonstrated a clinical effect on patients with mild seasonal allergy. The study was published in the American Journal of Clinical Nutrition in 2017.

Allergy impairs sleep and quality of life

Earlier research has shown that seasonal allergy disrupts your sleep and causes daytime fatigue, preventing patients from functioning optimally in school or at the job. Also, the red nose that is the result of blowing it all the time may cause stress, irritation, and embarrassment. Conventional allergy medication can cause side effects such as fatigue and mouth dryness, which is why there is an increasing interest in finding natural therapies without side effects.

Only one out of seven other studies with probiotics showed a positive effect

The American scientists used a specific combination of probiotics that is known to be effective and which can even be detected in stool samples. However, Danish researchers from the University of Copenhagen conducted a systematic review of seven studies on an earlier occasion. Here, adults were given different kinds of probiotics in food and as supplements. Using advanced genetic DNA sampling methods, the scientists studies gut bacteria in stool samples from the participants before and after prolonged consumption of probiotics. All but one study showed that probiotics failed to affect the composition and function of gut bacteria in normal healthy adults. The review study is published in the scientific journal Genome Medicine.

Probiotics must be protected until they reach the small intestine

It seems puzzling that only one study out of seven showed an effect, and it is most likely because the probiotic bacteria in the remaining six studies were not alive when they reached the small intestine. This also suggests that there are vast quality differences between different probiotic preparations on the market.
It is important to choose a product that retains the viable bacteria in a gastro-resistant capsule. That way, it is possible to ensure that the probiotic bacteria are not released before they have passed through the stomach acid and reached the small intestine where they can reproduce and colonize the enormous intestinal microflora.

A healthy intestinal microflora helps us by:

  • optimizing and regulating our immune defense
  • lowering the risk of allergies and autoimmune diseases
  • lowering the risk of overweight
  • displacing pathogenic microorganisms
  • producing lactic acid that helps maintain a normal pH value
  • improving our digestion and uptake of vitamins and minerals
  • producing antioxidants, B vitamins, vitamin K, and enzymes
  • helping to regulate our cholesterol balance
  • stimulating intestinal peristalsis
  • producing neurotransmitters that control the immune system, nervous system, and hormone system


University of Florida. “Allergies? Probiotic combination may curb your symptoms, new study finds”. ScienceDaily, 1 March 2017

Jennifer C Dennis-Wall et al. Probiotics (Lactobacillus gasseri KS-13, Bifidumbacterium bifidum G9-1, and Bifidumbacterium longum MM2) improve rhinoconjunctivitis-specific quality of life in individuals with seasonal allergies. The American Journal of Clinical Nutrition, 2017

Nadja B. Kristensen et al. Alterations in fecal microbiota composition by probiotic supplementation in healthy adults: a systematic review of randomized controlled trials. Genome Medicine 2016

Pernille Lund: Immunforsvarets nye ABC. Hovedland

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