Vitamin C. Familiar yet powerful, C is a potent antioxidant that supports the immune system and protects cells from free radicals, which increase in production during allergic reactions. Studies suggest taking vitamin C in high doses can relieve airway constriction by accelerating histamine breakdown. Choose a food-based C supplement, such as one made from rosehips, recommends Lise Alschuler, ND, author of Five to Thrive (Active Interest, 2011) and a Delicious Living advisory board member. Reduce the supplement dose if loose stools result.
Dose: 2,000–3,000 mg daily, divided

Stinging nettle. This mineral- and vitamin C–rich green (Urtica dioica) has been used since medieval times as a tonic and diuretic. Although painful to the skin, in supplements nettles’ irritating chemicals can actually inhibit pro-inflammatory COX-1 and COX-2 enzymes and cytokines, which transmit pain signals in the body. In a study of 69 people with allergic rhinitis, more than half reported relief of most symptoms after taking freeze-dried nettle for one week. Nettle may have a diuretic effect and occasionally causes mild stomach upset; do not use during pregnancy. Dose: 400–600 mg freeze-dried leaf in capsules, twice daily

Probiotics. Eating probiotic-rich fermented foods like yogurt or sauerkraut, or taking supplements of live probiotic microorganisms, helps maintain a healthy balance of gut bacteria, supporting the immune system. Researchers believe probiotics may dampen inflammation (which allergic rhinitis can cause) by balancing the generation of pro- and anti-inflammatory cytokines. In two clinical studies, people with allergic rhinitis who took strains of lactobacillus and Bifidobacterium longum for eight weeks or longer reduced nasal symptoms. Dose: 5–20 billion CFU (colony forming units) daily