Q: Can a whole food, plant-based diet help with allergies?

A: Allergies have been increasing in prevalence in the general population over the past 20 years, and it has been a subject of great debate as to the cause of this conundrum.

My answer is not going to be terrifically satisfying, but may offer some hope. I am not aware of any compelling research to suggest that changing to a plant-based diet can effectively treat or improve environmental allergies. However, I wouldn’t rule out a role for food altogether. Let me explain:

Allergies go hand in hand with congestion of the sinuses and nasal passages. For those with chronic congestion and recurrent upper airway problems, some of their symptoms may be exacerbated by seasonal allergies. The removal of dairy from the diets of some patients has led to improvements in recurrent congestion and bronchitis, as described in a paper in the Journal of The American Medical Association in 1966^[1]. Researchers write:

We have recently encountered four children whose predisposition to recurrent respiratory tract infections was relieved by the simple expedient of excluding cow’s milk and dairy products from their diets; each child had one parent with analogous if not identical symptoms, who likewise was completely cured when cow’s milk and dairy products were excluded from his or her diet. We think that this syndrome represents a relatively common problem which is not usually recognized as such.

And while it is clearly true that not all patients with congestion will respond to a dairy free diet^[2], it seems like a reasonable trial for a number of reasons.

Other studies more directly address the question of diet and allergies. A recent study on mice^[3] shows that a high-fiber diet created significant differences among gut bacteria, immune system cells, and allergic reactions to food compared to a low-fiber diet. Consuming lots of fiber keeps healthy bacteria in the gut happy, which in turn helps keep the lining of the gut happy and healthy, which in turn may lower the risk of allergic reactions to food. In pregnant women and their infants, taking a probiotic supplement containing potentially helpful gut bacteria (bifidobacterium) reduced the risk of eczema (a skin condition correlated with allergies)^[4]. And in kids with peanut allergies, combining oral immunotherapy with a probiotic resulted in a more long-lasting control of allergies than otherwise would be expected^[5].

So evidence seems to be emerging that, particularly for food allergies, diet may play a role by changing the health of the gut bacterial community and certain related immune system activity. But there is no good evidence that I’m aware of that diet can alter allergies after they’ve developed. The studies simply haven’t been done. We can’t say there is no effect of nutrition, just that it hasn’t been fully investigated.

The Center of Nutrition Studies is fortunate to have Michael Hollie, MD on our board. He is passionate about good nutrition and is a practicing physician board-certified in asthma, allergy, and immunology and a Fellow of the American Academy of Allergy, Asthma and Immunology and the American College of Allergy, Asthma and Immunology. I asked him about his experience and what he thought of the issue, and this is what he said:

My observations would concur with the 1966 JAMA article that many patients experience significant improvement in their respiratory symptoms when removing dairy from their diet regardless if their symptoms are from allergic or nonallergic factors. I encourage patients to remove dairy from their diets and replace with a plant-based milk.

When I see patients who complain of themselves or their children being “sick a lot” I start with assessing their allergic sensitivity but quickly move to their nutritional status. A whole foods, plant-based approach, removing the standard sugar, oil and salt laden processed foods, results in a stronger immune system and increases the patient’s ability to fight off the common viruses that we are exposed to daily.

A 2001 study^[6] showed that asthma, allergic rhinoconjunctivitis (nasal and eye symptoms) rhinitis and eczema improved with more starches, grains and vegetables. Subsequent studies show that increasing the antioxidants in the diet with more fruits and vegetables(7 or more servings a day) significantly improved asthma. A 2017 study^[7] (meta analysis) reinforced this concept concluding “fruit and vegetable consumption appears to be protective against asthma.”

Allergic diseases are characterized by inflammation. Antioxidants combat inflammation. While the volume of studies may be small, the growing evidence points to a diet high in antioxidants (fruits, nuts, beans and vegetables) as being helpful in reducing symptoms of the allergic diseases of rhinitis, asthma and eczema.

I encourage my patients to consume more fruits, vegetables, beans nuts and seeds and reduce or eliminate animal products, especially dairy, in order to improve their allergic symptoms, strengthen their immune system and improve their overall health.

Michael C. Hollie, MD

References

1. Gerrard JW. Familial recurrent rhinorrhea and bronchitis due to cow’s milk. JAMA 1966;198:605-18.
2. Wuthrich B, Schmid A, Walther B, Sieber R. Milk consumption does not lead to mucus production or occurrence of asthma. Journal of the American College of Nutrition 2005;24:547S-55S.
3. Tan J, McKenzie C, Vuillermin PJ, et al. Dietary Fiber and Bacterial SCFA Enhance Oral Tolerance and Protect against Food Allergy through Diverse Cellular Pathways. Cell Rep 2016;15:2809-24.
4. Enomoto T, Sowa M, Nishimori K, et al. Effects of bifidobacterial supplementation to pregnant women and infants in the prevention of allergy development in infants and on fecal microbiota. Allergol Int 2014;63:575-85.
5. Tang ML, Ponsonby AL, Orsini F, et al. Administration of a probiotic with peanut oral immunotherapy: A randomized trial. J Allergy Clin Immunol 2015;135:737-44 e8.
6. Ellwood P, Asher MI, Björkstén B, et al. Diet and asthma, allergic rhinoconjunctivitis and atopic eczema symptom prevalence: an ecological analysis of the International Study of Asthma and Allergies in Childhood (ISAAC) data. ISAAC Phase One Study Group. 2001 Mar;17(3):436-43.
7. Hosseini B, Berthon BS, Wark P, et al. Effects of Fruit and Vegetable Consumption on Risk of Asthma, Wheezing and Immune Responses: A Systematic Review and Meta-Analysis. 2017 Mar 29;9(4). pii: E341.