Balancing the gut microbiome
In humans, the gastrointestinal tract is inhabited by a large, complex group of microbes that play a distinguished role in maintaining health. Collectively, this group includes trillions of bacteria, fungi, parasites, and viruses that are known as the microbiome. A person is first exposed to microorganisms as an infant, during delivery in the birth canal and through the mother’s breast milk.10 As time goes on, the microbiome evolves with the individual and exposures to various environmental factors as well as variations in diet can impact the microbiome leading to improved health benefits or increased risk of disease. The microbiome has numerous important functions including producing various nutrients such as vitamin K, prevention of colonization by intestinal pathogens, and modulation of the immune response to name a few.11 The diverse role of the micro biome has led to the idea that its modification may be a target used to restore and maintain balance of the overall individual. Introducing pre and probiotics are a means to accomplish this. Prebiotics and probiotics may be consumed in the form of raw vegetables and fruit, fermented pickles, or fermented dairy products. Another source may be supplemental formulas and functional food. Studies examining the use of probiotics in patients with allergic rhinitis (hay fever) found that adjuvant use of probiotics resulted in improvement in quality of life.12 Probiotic use has also resulted in increased symptom control as evidenced by decreasing scores on questionnaires designed to assess control of allergic rhinitis and asthma symptoms.12 Additionally, a meta study examining the use of probiotics in the treatment of allergic rhinitis examined 22 double-blind, placebo-controlled studies. Seventeen trials showed significant benefit of probiotics clinically. Eight trials showed significant improvement in immunologic parameters, and all five studies with Lactobacillus paracasei strains revealed clinically significant improvements compared with placebo.13 It is interesting to note that many cultures have historically incorporated fermented foods as part of their daily diet.
Nutritional supplements can provide targeted therapeutic options for the treatment and prevention of allergies. Supplements can address many different factors involved in the expression of allergies and asthma including immune system dysregulation, inflammation, and oxidative stress among many others. Some examples of supplements commonly used in treatment of allergies and asthma include:
Stinging nettles (Urtica dioica) is also commonly called “nettle.” Nettle has a significant research profile as a treatment for allergies and allergic rhinitis.14 National College of Naturopathic Medicine (now National University of Naturopathic Medicine) examined the use of freeze dried nettle leaf for treatment of hay fever, asthma, and seasonal allergies found that the freeze-dried preparation was rated higher than placebo in relieving symptoms after one week.15 Further studies on the use of nettle in preventing lung inflammation associated with asthma have also been promising. Studies using an experimental model of allergic asthma have shown positive benefit in both immune modulation as well as reduction in inflammatory markers with administration of an aqueous extract of stinging nettle.16
Omega 3 fatty acids
The omega 3 fatty acids docosohexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are found in fish oil and are known for their anti-inflammatory properties and protective effects in inflammatory diseases including asthma and allergies. A six month study conducted by Johns Hopkins University examined the role of omega 3 fatty acids in the prevention of environmentally triggered asthma symptoms. They found that having more omega-3 fatty acids in the diet results in fewer asthma symptoms caused by contaminated inside air.17
Quercetin is among the most abundant polyphenols representing the flavonoid subgroup. It is naturally occurring in plant foods such as onions, broccoli, capers, apples, berries, and grapes, herbs like dill, and is also found in tea and wine.18 Quercetin has been utilized in a number of studies examining factors underlying the development of allergies. Quercetin is known for many different properties including its anti-allergic properties such as inhibition of histamine release, decrease in pro-inflammatory compounds, immune system modulation, and inhibition of antigen-specific IgE antibody formation.18 All of these mechanisms can contribute to addressing the underlying cause of allergy symptoms and asthma. In an experimental model of allergic rhinitis, quercetin has been shown to reduce antigen specific IgE levels and well as mitigate the expression of allergic rhinitis symptoms.19
In years past, allergy sufferers were often subjected to extensive series of allergy shots. These were injections designed to aid in reducing the expression of allergy symptoms. Sublingual immunotherapy is a method of allergy treatment that does not involve injections, rather small tablets or liquid drops containing small amounts of specific allergens to build up tolerance and reduce symptoms. Studies have shown that sublingual application of allergen specific immunotherapy is a safe and efficient substitution to injection in the treatment of IgE-mediated respiratory tract allergies.20Meta analysis studies have shown that sublingual immunotherapy reduces allergic diseases symptoms and the need for other medications, improving the quality of life for children with the diseases.20
The diet constitutes an important source of nutrients and non-nutrient components with multiple properties that present a potential opportunity to modulate the risk of asthma and allergies. Elimination diets wherein the offending food is completely avoided can be difficult to follow long term. Contemporary studies have shown that nutrition trends during the early childhood years may produce changes that have a lasting impact on human health at later ages particularly on the respiratory, GI, and immune systems.21 Western diets are characterized by the consumption of highly refined, overly processed, energy-rich foods and beverages. These foods are typically high in fat, sugar, and salt but low in dietary fiber and other nutrients. A decrease in the intake of fresh fruit and vegetables and increase intake of processed foods has previously been linked to an increasing prevalence of asthma and allergies.22 Multiple studies have highlighted evidence of positive effects of fresh fruits, and antioxidant vitamins on asthma.23 Additional studies have specifically looked at the quality and quantity of dietary fats as a source of allergenic response. Research has shown that a high fat diet enables food-induced allergic responses associated with series of negative health effects.24 The quality of fat has also been shown to play a role in increased risk of allergenic response. In a pediatric asthma study, researchers found that for each additional gram of omega 6 fats consumed, children had a whopping 29% increased risk of being in a more severe asthma category.17 Fiber is another nutrient that is consistently lacking in the standard American diet as well as many dietary patterns of many other developed/“Westernized” countries.25 Dietary fiber (especially polysaccharides and oligosaccharides) and its metabolites (SCFAs) have been shown to regulate mast cell function and activation. Mast cell activation can be downregulated by pretreatment with these substances.25 Mast cells are key players in initiating and maintaining inflammation, particularly in allergies and asthma.26
Some parts of our environment are out of our control, particularly outside the home. We cannot control the amount of mold, pollen, or other allergenic inhalants that are in outdoor air. But there are steps we can take inside the home to manage our exposure indoors.
- Rugs, drapes, wall-to-wall carpet, and even overstuffed, upholstered furniture are tremendous collectors of dust and pollen. Removing them, changing them often, or changing styles can help reduce exposure.
- Using specialized air filters like HEPA filters particularly in the bedroom can be helpful. In some cases, whole house filtration systems may also be recommended.
- Avoiding toxic inhalants like perfumes, body sprays, scented candles, room sprays, air fresheners, dryer sheets, and other scented products, especially those with synthetic ingredients.
- Testing home tested for the presence of mold and remediating the source if mold is detected and found.
- Using zippered, allergen resistant covers on mattresses and pillows. According to the Asthma and Allergy Foundation of America, enclosing mattresses works better than air cleaners to reduce allergy symptoms.28
To learn about natural approaches to combating allergies and asthma, contact your local naturopathic doctor. Click here to find an ND in the US and Canada.