The limited effectiveness of conventional allergy treatment is one reason for the growing interest in alternative and complementary therapies. In the case of asthma, fewer than one in three people enjoy what is considered to be an adequate level of symptom control.
Several alternative treatment modalities have been studied using the most exacting methodology of clinical research, the double-blind placebo-controlled trial. In this technique, neither the person being studied nor the scientist knows whether the subject is receiving the treatment being tested or a placebo until the code is broken.
Those found to be valid treatments for seasonal allergies in some studies using this double-blind controlled method include:
Probiotics are cultures of live bacteria. Their benefits have been established with allergic rhinitis. Most preparations contain species of Lactobacillus or Bifidobacterium. Several have been shown to help people with nasal allergies by relieving symptoms and improving immune balance. The species with the best track record for allergic rhinitis is Lactobacillus paracasei. Administration of Lactobacillus paracasei can improve symptoms and quality of life. Probiotics may also stimulate the immune system in ways that counteract Type 1 hypersensitivity. For people with grass pollen allergy, L. paracasei was shown to decrease the allergic response to grass pollen, reduce nasal itching during the pollen season and enhance the treatment response to antihistamines.
Other probiotics shown to relieve symptoms of seasonal allergies in controlled clinical trials include: Bifidobacterium lactis, which reduced nasal allergies and diminished the inflammatory response to grass pollen and, when combined with Lactobacillus acidophilus, to birch pollen; and Bifidobacterium longum, which reduced symptoms associated with allergy to Japanese cedar pollen and significantly reduced the use of medication.
The benefits of probiotics for nasal allergies take between three and eight weeks to become evident and may last for many weeks after the probiotics are stopped.
Fish oil is a rich source of anti-inflammatory omega-3 fats. In addition to decreasing production of inflammatory mediators like leukotrienes, omega-3s from fish oil inhibit the activity of a dangerous enzyme called NOX (NADH oxidase), which is found in mast cells and contributes to respiratory damage.
Anti-allergic benefits of omega-3 supplements have primarily been demonstrated in asthmatics. At doses of 690 to 6,000 milligrams per day, omega-3 supplements have been shown to improve lung function and bronchial symptoms in people with seasonal allergic asthma and decrease the inflammatory response to inhaled allergens. Benefits take three to eight weeks to be seen and may disappear after supplementation is stopped.
Supplements of magnesium at doses of 200 to 340 milligrams per day have been shown to reduce the need for medication in children and adults with allergic asthma and to diminish allergen-induced skin test responses.
Allergic reactions produce considerable biochemical stress in inflamed tissues. This may be counteracted by antioxidants. Antioxidant supplements are often taken to treat symptoms of allergy. The most common are vitamins C and E, quercetin (a bioflavonoid) and NAC (N-acetylcysteine, an amino acid). Controlled studies have shown inconsistent results.
Caution is needed in choosing vitamin E supplements. Vitamin E is not one substance but eight, two of which (alpha- and gamma-tocopherol) predominate in human tissues. Researchers at Northwestern University have demonstrated that alpha-tocopherol has protective effects in asthma, but that gamma-tocopherol may actually increase respiratory inflammation in asthmatics and interfere with the benefits of alpha-tocopherol.
A number of herbs have anti-inflammatory effects that may relieve symptoms of seasonal allergies. Individual herbs showing benefits in clinical trials include butterbur (Petasites hybridus), which was as effective as the antihistamine drug fexofenadine, black cumin seed (Nigella sativa) and milk thistle (Silybum marianum). Herbal mixtures, in particular those derived from traditional Chinese medicine, have also produced significant symptomatic relief.
Several clinical trials have shown benefits from acupuncture in the treatment of seasonal allergic rhinitis.
Homeopathy uses extreme dilutions of various substances to relieve symptoms. Results of clinical trials are variable and may depend on the nature of the homeopathic treatment used.