In a 2012 study, researchers from Australia revealed that people who ate a meat-based diet – versus one higher in fruits and vegetables – were at greater risk of hay fever and asthma. It’s thought a diet that’s low in antioxidants (from plant foods), high in saturated fat and calories contributes to allergy symptoms by triggering inflammation.
Despite limited evidence to establish such a connection, some allergy sufferers are adamant that consuming dairy worsens upper respiratory tract congestion. Turns out, there may be a scientific explanation. According to a report published in the journal Medical Hypothesis, milk that contains a higher amount of a protein called A1 can trigger mucus production in people who have what’s called a leaky gut (when the tight junctions that control what passes through the lining of the small intestine into the bloodstream don’t work properly). Scientists speculate that a byproduct from the digestion of A1 milk can enter the bloodstream and stimulate phlegm in the respiratory tract. But there’s no way to know if the milk you buy is high in the A1 protein. To determine if dairy exacerbates your symptoms, eliminate it from your diet for two weeks. If you find you benefit from a dairy-free diet, include other calcium-rich foods in your diet such as fortified plant beverages (e.g. almond, rice, soy), canned salmon (with bones), cooked leafy green vegetables, legumes and almonds.
Rotate more plant-based protein into your weekly menu to reduce saturated fat and increase beneficial phytochemicals. Try spinach salad with chickpeas, hearty lentil soup, black-bean tacos, tofu stir-fry or a vegetable and hummus sandwich.
Increase fruit and vegetables
Include antioxidant-rich fruit and vegetables at all meals. Aim to eat at least seven servings each day. One serving is equivalent to one medium-sized fruit, 1/4 cup of dried fruit, 1/2 cup of cooked or raw vegetables and 1 cup of salad greens.
Cook with onions
There’s some evidence that quercetin, a phytochemical in onions, helps control the release of histamine and other chemicals that trigger allergic reactions. In so doing, quercetin may help relieve congestion, runny nose and watery eyes. Other good sources of quercetin include citrus fruits, apples, parsley, sage and tea.
Boost vitamin C
This nutrient has been shown to reduce histamine levels and congestion. It may also reduce exercise-induced airway constriction in people with asthma. Vitamin-C-rich foods include citrus fruit, kiwifruit, strawberries, cantaloupe, papaya, pineapple, red and green pepper, cauliflower, broccoli and tomato juice. To supplement your diet, take 500 milligrams once or twice daily.
Increase vitamin E
It’s an antioxidant and it helps immune compounds called mast cells work properly. When mast cells react in an uncontrolled manner, inflammatory compounds are released, which can contribute to allergies and asthma. The best food sources include wheat-germ oil, sunflower oil, safflower oil, grapeseed oil, sunflower seeds, almonds, hazelnuts, peanuts, soybeans and whole grains.
Consider a probiotic
In addition to promoting a healthy digestive system, research suggests that Lactobacillus casei, a so-called “friendly” bacteria, can prevent the body’s immune system from overreacting to pollen.
Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto.