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Pollen from flowers causes allergy symptoms that can be lowered

Reduce Allergy Symptoms by Balancing Immune Function

A targeted probiotic and yeast compound lowers the allergic response to pollen and other allergens, thus reducing irritating seasonal symptoms. Clinical studies reveal how this non-drug approach rebalances immune function and slashes common allergy miseries.

Scientifically reviewed by: Dr. Gary Gonzalez, MD, in August 2023. Written by: Steven Rosen.

Seasonal allergies affect over 50 million adults.1,2

Allergies are the sixth leading cause of chronic illness in America, costing society in excess of $18 billion annually.1

During allergy season, people use an assortment of over-the-counter medications for runny noses and itchy eyes.

Certain allergy medications have now been shown to increase the risk of Alzheimer’s, among other side effects.3

Most allergy drugs treat symptoms, but do nothing to stop the underlying causean out-of-balance immune response.

This immune imbalance is what causes the body to overreact to harmless substances, and results in annoying allergy symptoms.

A probiotic and yeast compound have demonstrated robust effects in balancing the immune response and suppressing allergy attacks.

When allergy sufferers were given a unique probiotic or novel yeast compound, results from three different studies revealed:

  • 43% fewer days with nasal congestion,
  • 24% reduction in swollen nasal passages, and
  • 31% reduction in eye symptoms.4-6

For many sufferers of seasonal allergies, this probiotic or yeast restrained immune overreaction starting in the digestive track.

What you need to know

  • Seasonal allergies affect millions of people, yet there is no medication that can provide complete symptom relief.
  • All available products work near the end of the complex series of steps that lead our immune systems to overreact to something as innocuous as a pollen grain.
  • A new approach works to “retrain” the immune system to respond in a more measured way.
  • Yeast fermentate and Lactobacillus acidophilus L-92 have been shown to restore the normal balance between excitable immune cells and cells with a capacity to calm and modulate the hyperactive response.
  • This modulation of the immune response significantly reduces symptoms such as runny nose and itchy, watery eyes without resorting to steroids, antihistamines, or decongestants.
  • Studies have shown that these supplements reduce medication-symptom scores, indicating that many people could cut back on their reliance on standard allergy medications.

Getting to the Root of Seasonal Allergies

Seasonal Allergies  

An allergic reaction occurs when the immune system overreacts to something in the environment that is harmless to most people.

When the body perceives a threat from an allergen such as dust or pollen, it swings into defensive action. The result is watering eyes and a runny nose designed to flush out the allergen from the body.

These allergy symptoms are the last in a long domino effect of reactions involving the body’s immune-system cells.

Once an allergy attack occurs, most people reach for over-the-counter medications for relief. The problem is that antihistamines, steroids (like Flonase®), and decongestants only provide temporary relief.

A better solution is to stop the body from overreacting to harmless threats like pollen or dust.

For that to happen we need to restore normal immune balance—and that involves retraining immune system cells in the Th2 family.

Th2 cells are also known as T helper type 2 cells. Th2 cells play a role in organizing a protective immune response to outside invaders such as allergens.

Balancing the Immune System

When there is an overreaction of Th2 cells to an irritant such as dust or pollen, it forces the immune system into high alert. The result is an allergic reaction, and the body works to protect itself from the perceived threat.

Scientists in Japan and the U.S. have uncovered two compounds that help restore normal Th2 balance and reduce the immune system’s allergic responses.

These two ingredients, yeast fermentate and Lactobacillus acidophilus L-92 reduce symptoms by lowering the allergic response to pollen and other allergens.

As a result, this probiotic and yeast compound can quell allergy symptoms without resorting to anti-inflammatory, antihistamine, or decongestant drugs.

Let’s look at the evidence from human clinical studies.

Baker’s Yeast Modulates the Immune System

Baker’s yeast (Saccharomyces cerevisiae) provides the leavening for dough to rise, and the fermentation to brew beer. But it also has the ability to help modulate the immune system.

A special fermented form of baker’s yeast called dried yeast fermentate has favorable effects on the immune balance (specifically preventing overactive Th2) that is essential for retraining an overactive immune response associated with seasonal allergies.

Because dried yeast fermentate has these immune-balancing benefits, scientists wanted to find out if it would have an impact on allergies. They tested its effects on hay fever and grass pollen—and it proved capable of reducing both the severity and duration of symptoms.

How an Allergic Reaction Occurs

An imbalance in the immune system is the root cause of an allergic reaction.

In the innate immune system, specialized white blood cells called antigen-presenting cells first identify the harmful substance and mount an initial attack. They then inform the adaptive immune system of the specific threat so it can send in the appropriate troops for the job.

When the threat occurs outside of the cells, a type of T helper cell called Th2 is called into action to neutralize the invaders. But when Th2 becomes overactive, it causes the overreaction that is responsible for allergic conditions.

Activated Th2 cells stimulate two kinds of immune cells: eosinophils and B cells.

Eosinophils are white blood cells that release a variety of toxic chemicals aimed at destroying invading organisms. In the case of allergies, these potent “bullets” are fired off in error, and exert their destructive forces on host tissues, where they induce leaky capillaries and promote inflammation.

B cells release specialized antibodies called IgE, which then bind to mast cells and basophils, which are packed with granules containing signaling molecules such as histamine, leukotrienes, and other mediators of inflammation. These chemicals circulate freely in the body, triggering allergy symptoms.

Exaggerated Th2 dominance is ultimately to blame for allergy symptoms. Targeting Th2 and bringing the immune system back into balance should be the target of any good allergy treatment. Yet most of the available treatments only act after Th2 dominance has become established.16,17 For example:

  • Antihistamines block histamine activity – but only after the toxic histamine molecules have been released from mast cells.
  • Steroids (including topical sprays like Flonase®) can suppress inflammation induced by activated eosinophils—but only after they have been stimulated by Th2 activity, and the chemical mediators of inflammation are on the loose.
  • And decongestants act still further down the line, tightening loose capillaries that trigger nasal drainage and watery eyes—but only after histamines have taken effect.

The reason yeast fermentate and Lactobacillus acidophilus L-92 can be so beneficial against allergies is because they help calm overactive Th2, bringing the immune system back into a more balanced state.

Hay-Fever Allergies

Hay fever, or allergic rhinitis, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. The result is a runny or stuffy nose, sneezing, and red, itchy, watery eyes—symptoms that are similar to a common cold.

In a pilot study, 25 healthy subjects were treated with dried yeast fermentate (500 mg/day) or placebo for five weeks during the beginning of the allergy season.7

Half of those taking the yeast supplement reported complete absence of seasonal allergies. Once they stopped taking the supplement, the allergy symptoms returned. The placebo group had no change or relief from their symptoms.

One of the causes of hay fever symptoms are antibodies called IgE. Based on this study, researchers surmised that yeast fermentate helps reduce IgE.

IgE causes the body to release chemicals (like histamines) that cause an allergic reaction and produce symptoms that can affect the eyes, nose, throat, lungs, or skin.

Over the course of this five-week study, as the allergy season went into full swing, blood levels of IgE steadily increased among placebo recipients indicating heightened allergic responses.

In those subjects taking the yeast fermentate, IgE levels barely changed, indicating a reduced allergic reaction. The conclusion from this study is that yeast fermentate calms allergic responses by stabilizing IgE levels.

Grass-Pollen Allergies

A larger study included 96 people who all had seasonal grass-pollen allergies.4 Subjects took 500 mg of yeast fermentate or placebo daily for 12 weeks during the highest pollen-count portion of the year.

Compared to those taking the placebo, the supplemented subjects experienced two significant benefits:

  • A decrease in the severity of runny nose and nasal congestion,
  • A 43% reduction in total days with nasal congestion.4

They also experienced a decrease in the number of inflammatory white blood cells in their nasal mucus. This objective indicator shows a reduction in the activation of allergy-causing cells.

Reducing the severity of symptoms as well as the number of days with symptoms offers real quality-of-life improvements for those who suffer from seasonal allergies.

What is the Connection Between Benadryl and Dementia?

Many people reach for anticholinergic drugs like Benadryl® to decrease allergy symptoms. But anyone taking these drugs for long periods of time is risking increasing something far worse.

A recent report published in JAMA Internal Medicine shows that taking anticholinergic drugs for long periods is associated with an increased risk of dementia.3

The study tracked almost 3,500 people over age 65 for seven years. The researchers also had access to pharmacy records for both prescription and over-the-counter drugs the participants took for 10 years prior to the start of the study.

The researchers found that the people who used anticholinergic drugs long-term had a much higher risk of developing dementia. Specifically, those who used the drugs for at least three years had a 54% higher dementia risk than nonusers.

The link should not come as a surprise to doctors and scientists. Anticholinergic drugs are already well-known for side effects that affect short-term memory, reasoning, and confusion.

These drugs work by blocking the action of acetylcholine, an important neurotransmitter that plays a role in learning and memory. Individuals already make less acetylcholine as they age, so taking a drug that further reduces it can have disastrous consequences on the brain.

In the end, drugs like Benadryl® don’t address the underlying problem. A better alternative is to take ingredients that target the root cause of allergies.

Yeast fermentate and Lactobacillus acidophilus L-92 bring the immune system back into a more balanced state, which reduces allergy symptoms naturally.

Probiotic Improves Seasonal Allergies

Besides yeast fermentate, probiotics have also been found to have beneficial effects against allergies. This makes sense, since probiotics are essential for maintaining a healthy gut, where more than 70% of the immune system resides.

Some probiotics are more effective than others against seasonal allergy symptoms. After comparing 12 strains of probiotics in a laboratory study, one strain in particular stood out for its impact on seasonal allergies: heat-treated Lactobacillus acidophilus L-92 (HT L-92).8,9

Animal studies have shown that this specialized probiotic strain reduces the inflammatory IgE antibodies as does the yeast fermentate. They also demonstrated significant reductions in substances associated with Th2, and increases in cells that bring about better immune balance.8,10

This preliminary data paved the way for three important clinical studies that support the use of heat-treated Lactobacillus acidophilus L-92 for the treatment and prevention of seasonal allergies.

Preventing Seasonal Allergies

The first clinical study was conducted in Japan among people with seasonal allergies to Japanese cedar pollen, a potent allergen. The study was conducted over the course of two annual allergy seasons. Subjects received a heat-treated probiotic Lactobacillus acidophilus L-92 or a placebo.5

In the first allergy season, supplemented subjects experienced a 31% reduction in their eye symptom/medication score—a score representing the combination of symptoms experienced and medications used. A lower score is an improvement because it means reduced itchy and watery eyes and fewer medications.

In the second allergy season, there was also a significant reduction in the total eye symptom/medication score.

This study showed a trend toward lower scores for swelling and color of the membranes lining the nostrils.5 Color is an important objective indicator because allergic mucous membranes appear pale, while healthy, non-inflamed ones are pink.

Tackling Year-Round Allergies

Tackling Year-Round Allergies  

The same research group conducted a second study that involved 49 people with year-round hay fever.6 This condition can be even harder to manage than seasonal allergies.

For this study, subjects received either a placebo or a heat-treated probiotic Lactobacillus acidophilus L-92 every day for eight weeks.6

The physician examinations found an approximate 28% improvement in the color of nasal mucous membranes at week six, and an approximate 24% reduction in swelling of the nasal membranes at week eight.6

In addition, patient-reported symptom/medication scores fell by an approximate 19% compared with placebo recipients at week eight. There was also a trend for improvement in eye symptoms (like itchiness and redness).

Seasonal Allergy Treatment

The third study was a bit different because it showed the ability of the heat-treated probiotic Lactobacillus acidophilus L-92 to alleviate allergy symptoms even if people didn’t start taking the supplement until after they were exposed to the allergen.

For this study, 80 people with an allergy to cedar pollen were exposed to cedar pollen for three hours before receiving the probiotic.9 The study lasted for eight weeks.

Compared with placebo recipients, supplemented patients had a 2.5-fold improvement in nasal symptoms and a 4.7-fold improvement in eye symptoms. These findings were considered to be statistically significant.9

Taken together, these findings demonstrate important reductions in symptoms of seasonal and year-round allergies, both in runny nose and in itchy eyes.

Current Approaches to Quelling Allergy Symptoms

Although the core problem that triggers seasonal allergy symptoms is the over-dominance of Th2 cells under the surface of our mucous membranes, mainstream treatment strategies all focus on the end results, aiming to block histamine effects, to suppress inflammation, and to tighten the leaky blood vessels that produce runny nose and watery eyes. A more basic approach would be to “retrain” T helper cells to rein in the Th2 dominance, downregulating the entire cascade. This approach produces far fewer side effects.

Eczema Relief

Lactobacillus acidophilus L-92 has also been shown to have favorable effects in another related allergic condition: eczema (also called atopic dermatitis). Eczema is an allergic response that is characterized by itchy, scaly, weeping lesions on the skin, and it can happen on parts of the body that don’t come into direct contact with the allergen.

This skin condition was once primarily a childhood illness, but is becoming more common in adults.11,12

Research has now demonstrated that taking Lactobacillus acidophilus L-92 results in a more than 50% reduction in symptom scores for eczema.13,14 One study showed that it helped reduce the spread of the condition from one part of the body to another.15

Clearly, this supplement’s capacity to restore equilibrium to an imbalanced immune system is driving improvements in various allergy-related symptoms throughout the body.



Current tools used against seasonal allergies all focus on the end result of the complex domino effect that produces the symptoms.

A novel approach that is gaining traction among clinicians and scientists is to intervene much earlier in that process, to restore the normal balance between immune system cells that promote reactions to allergens and those that suppress such reactions.

Yeast fermentate and Lactobacillus acidophilus L-92 show promise at restoring the disrupted immune balance.

Studies in humans and animals have shown that this “retraining” of the immune system reduces the effects that produce the allergic symptoms. The result is a reduction in symptoms and duration of seasonal allergies—and, ultimately, an improvement in quality of life.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.


  1. Available at: Accessed November 8, 2016.
  2. Available at: Accessed November 8, 2016.
  3. Gray SL, Anderson ML, Dublin S, et al. Cumulative use of strong anticholinergics and incident dementia: a prospective cohort study. JAMA Intern Med. 2015;175(3):401-7.
  4. Moyad MA, Robinson LE, Kittelsrud JM, et al. Immunogenic yeast-based fermentation product reduces allergic rhinitis-induced nasal congestion: a randomized, double-blind, placebo-controlled trial. Adv Ther. 2009;26(8):795-804.
  5. Ishida Y, Nakamura F, Kanzato H, et al. Effect of milk fermented with Lactobacillus acidophilus strain L-92 on symptoms of Japanese cedar pollen allergy: a randomized placebo-controlled trial. Biosci Biotechnol Biochem. 2005;69(9):1652-60.
  6. Ishida Y, Nakamura F, Kanzato H, et al. Clinical effects of Lactobacillus acidophilus strain L-92 on perennial allergic rhinitis: a double-blind, placebo-controlled study. J Dairy Sci. 2005;88(2):527-33.
  7. Jensen GS, Patterson, K.M., Barnes, J., Schauss, A.G., Beaman, R., Reeves, S.G. and Robinson, L.E.,. A double-blind placebo-controlled, randomized pilot study: consumption of a high-metabolite immunogen from yeast culture has beneficial effects on erythrocyte health and mucosal immune protection in healthy subjects. The Open Nutrition Journal. 2008;2:pp.68-75.
  8. Ishida Y, Bandou I, Kanzato H, et al. Decrease in ovalbumin specific IgE of mice serum after oral uptake of lactic acid bacteria. Biosci Biotechnol Biochem. 2003;67(5):951-7.
  9. Enomoto MI, T; Take, CR; et. al. . Effects of oral ingestion of L. acidophilus GRAS L. acidophilus L-92 strain on the cedar pollen allergy - Verification of preventive action in artificial exposure facility. The 56th Annual Meeting of the Japanese Society of Allergology, Tokyo, Japan. 2006.
  10. Torii A, Torii S, Fujiwara S, et al. Lactobacillus Acidophilus strain L-92 regulates the production of Th1 cytokine as well as Th2 cytokines. Allergol Int. 2007;56(3):293-301.
  11. Koch C, Dolle S, Metzger M, et al. Docosahexaenoic acid (DHA) supplementation in atopic eczema: a randomized, double-blind, controlled trial. Br J Dermatol. 2008;158(4):786-92.
  12. Weidinger S, Novak N. Atopic dermatitis. The Lancet. 387(10023):1109-22.
  13. Torii S, Torii A, Itoh K, et al. Effects of oral administration of Lactobacillus acidophilus L-92 on the symptoms and serum markers of atopic dermatitis in children. Int Arch Allergy Immunol. 2011;154(3):236-45.
  14. Yamamoto K, Yokoyama K, Matsukawa T, et al. Efficacy of prolonged ingestion of Lactobacillus acidophilus L-92 in adult patients with atopic dermatitis. J Dairy Sci. 2016;99(7):5039-46.
  15. Inoue Y, Kambara T, Murata N, et al. Effects of oral administration of Lactobacillus acidophilus L-92 on the symptoms and serum cytokines of atopic dermatitis in Japanese adults: a double-blind, randomized, clinical trial. Int Arch Allergy Immunol. 2014;165(4):247-54.
  16. Kidd P. Th1/Th2 balance: the hypothesis, its limitations, and implications for health and disease. Altern Med Rev. 2003;8(3):223-46.
  17. Maggi E. The TH1/TH2 paradigm in allergy. Immunotechnology. 1998;3(4):233-44.