Asthma is a lung disorder in which spasms of the bronchial passages restrict the flow of air in and out of the lungs. The number of people with asthma and the death rate from this condition have been increasing since the late 1980s. Environmental pollution may be one of the causes of this growing epidemic. Work exposure to flour or cotton dust, animal fur, smoke, and a wide variety of chemicals has been linked to increased risk of asthma.¹

Studies suggest that high salt intake may have an adverse effect on asthma, particularly in men. In a small, open study, doubling salt intake for one month led to a small increase in airway reactivity in men with asthma (indicating a worsening of asthma), and in non-asthmatics.³ A larger, double-blind trial showed that increased sodium intake produced an increase in airway reactivity in men, but not in women.⁴ In another double-blind trial, switching from a low-sodium diet (1.8 g per day) to a high sodium diet (4.6 g per day) for five weeks resulted in increased use of asthma medications, increased asthma symptoms, and reductions in lung function in men with asthma.⁵ When the diets were reversed, the airway reactivity, use of medications, and symptoms were reduced, with accompanying improvements in lung function.

Although most people with asthma do not suffer from food allergies,⁶ unrecognized food allergy can be an exacerbating factor.⁷ A medically supervised "allergy elimination diet," followed by reintroduction of the eliminated foods, often helps identify problematic foods. A healthcare professional must supervise this allergy test because of the possibility of triggering a severe asthma attack during the reintroduction.⁸

Some asthmatics react to food additives, such as natural salicylates—sulfites, tartrazine (yellow dye #5), aspirin, and aspirin-like substances.^{9 10} A doctor or an allergist can help determine whether chemical sensitivities are present.

Nutritional supplements that may be helpful: Vitamin B6 deficiency is common in asthmatics.¹¹ This deficiency may relate to the asthma itself or to certain asthma drugs (such as theophylline and aminophylline) that deplete vitamin B6.¹² In a double-blind study of asthmatic children, 200 mg per day of vitamin B6 for two months reduced the severity of their illness and reduced the amount of asthma medication needed.¹³ In another study, asthmatic adults experienced a dramatic decrease in the frequency and severity of asthma attacks while taking 50 mg of vitamin B6 twice a day.¹⁴ Nonetheless, the research remains somewhat inconsistent and at least one double-blind study did not find high levels of B6 helping asthmatics who require the use of steroid drugs.¹⁵

Magnesium levels are frequently low in asthmatics.¹⁶ Magnesium supplements might help prevent asthma attacks because magnesium can prevent spasms of the bronchial passages. Intravenous injection of magnesium has been reported to stop acute asthma attacks within minutes in double-blind research.¹⁷ Although the effect of oral magnesium has not been appropriately studied, many doctors recommend magnesium supplements for their asthma patients. The usual amount of magnesium taken by an adult is 200–400 mg per day (children take proportionately less based on their body weight).

Supplementation with 1 gram of vitamin C per day reduces the tendency of the bronchial passages to go into spasm,¹⁸ an action that has been confirmed in double-blind research.¹⁹ Some individuals with asthma have shown improvement after taking 1–2 grams of vitamin C per day. A buffered form of vitamin C (such as sodium ascorbate or calcium ascorbate) may work better for some asthmatics than regular vitamin C (ascorbic acid).²⁰

Very high amounts of vitamin B12 supplements (1,500 mcg per day) have been found to reduce the tendency for asthmatics to react to sulfites.²¹ The trace mineral molybdenum also helps the body detoxify sulfite,²² though the ability of supplemental molybdenum to help asthma patients remains mostly unexplored. It is not known how much supplemental molybdenum might be needed to help individuals with asthma. A typical American diet contains about 200 to 500 mcg per day,²³ and short-term studies have used supplemental amounts of 500 mcg per day.²⁴ A physician should be involved in any evaluation and treatment of sulfite sensitivity.

People with low levels of selenium have a high risk of asthma.^{25 26} Asthma involves free radical damage²⁷ that selenium might protect against. A double-blind trial gave 45 mcg of selenium to twelve people with asthma.²⁸ Half showed clear clinical improvement even though lung function tests did not change. Most doctors recommend 200 mcg per day for adults (and proportionately less for children)—a much higher, though still safe, level.

A study conducted many years ago showed that eighty percent of children with asthma had hypochlorhydria (low stomach acid). Supplementation with hydrochloric acid (HCl) in combination with avoidance of known food allergens led to clinical improvement.³⁴ In more recent times, HCl has usually been supplemented in the form of betaine HCl. The amount needed depends on the severity of hypochlorhydria and on the size of a meal. Because it is a fairly strong acid, betaine HCl should be used only with medical supervision.

Quercetin, a flavonoid found in most plants, has an inhibiting action on lipoxygenase, an enzyme that contributes to problems with asthma.³⁵ No human studies have confirmed whether quercetin decreases asthma symptoms. Some doctors are currently experimenting with 400–1,000 mg of quercetin three times per day.

Bromelain reduces the thickness of mucus, which may be beneficial for those with asthma,³⁶ though clinical actions in asthmatics remain unproven.

Some researchers have suggested that asthma attacks triggered by exercise might be affected by free radical damage caused by the exercise. Beta-carotene is an antioxidant that could protect against such free radical damage. Israeli researchers have given 64 mg per day of natural beta-carotene for one week to asthmatics who experienced attacks as a result of exercise.³⁷ In that report, 20 of 38 patients receiving natural beta-carotene were protected against exercise-induced asthma.

The oral administration of a thymus extract known as thymomodulin has been shown in preliminary and double-blind clinical studies to improve the symptoms and course of asthma.^{38 39 40 41} Presumably this clinical improvement is the result of restoration of proper control over immune function.

Are there any side effects or interactions? Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful: Ephedrine, an alkaloid extracted from ephedra, is an approved over-the-counter treatment for bronchial tightness associated with asthma.⁴² Over-the-counter drugs containing ephedrine can be safely used by adults in the amount of 12.5–25 mg every four hours. Adults should take a total of no more than 150 mg every twenty-four hours. They should refer to labels for children’s dosages. Ephedrine has largely been replaced by other broncho-dilating drugs, such as alupent and albuterol. Ephedra sinica, also known as ma huang, continues to be a component of traditional herbal preparations for asthma, often in amounts of 1–2 grams of the herb per day.

Two open-label, non-placebo controlled human studies have shown picrorhiza to be of benefit in asthma.^{43 44} However, a follow-up double-blind study did not confirm these earlier studies.⁴⁵ Because a range of 400 to 1,500 mg of powdered, encapsulated picrorhiza per day has been used in a variety of studies, it is currently unclear how effective picrorhiza is for people with asthma.

A small double-blind study found that a constituent of coleus, called forskolin, when inhaled, could decrease lung spasms in asthmatics compared to placebo.⁴⁶ Coleus extracts standardized to 18% forskolin are available and 50–100 mg can be taken two to three times per day. Fluid extract can be taken in the amount of 2–4 ml three times per day. Most studies have used injected forskolin, so it is unclear if oral ingestion of coleus extracts will provide similar benefits in the amounts recommended above.

Different preparations of tylophora, including crude leaf, tincture and capsule, have been tested in human clinical trials. One such study randomly assigned 110 bronchial asthma patients to receive one tylophora leaf (150 mg of the leaf by weight) or comparable placebo to be chewed and swallowed daily in the early morning. After six days, 62% of the patients consuming tylophora reported experiencing moderate to complete relief of their asthma symptoms compared to 28% in the placebo group. Moreover, when patients were switched from the placebo to the active group and vice versa, similar positive trends could be seen, with 50% of the tylophora group and 11% of the placebo group reporting symptomatic relief.⁴⁷

In a follow-up study, the alcoholic extract of crude tylophora leaves in 1 gram of glucose had comparable effects to that of chewing the crude leaf, with 56% of the patients reporting moderate to complete improvement in asthmatic symptoms compared to 32% in the placebo group.⁴⁸ In another clinical trial, 30 patients diagnosed with bronchial asthma for at least two years were assigned at random to one of two treatment groups consisting of 15 individuals each.⁴⁹ One group received either 350 mg of tylophora leaf powder or placebo daily in the first week. A second group of asthmatics were given a similar amount of the leaf for seven days followed by an anti-asthmatic drug combination. Overall, results of the study showed the amount of oxygen in the lungs (e.g., vital capacity) increased in those using the leaf, but decreased in those using the placebo. In addition, those taking the herb had a notable nighttime reduction in their symptoms of shortness of breath. Unfortunately, tylophora did not fare as well in improving asthmatic symptoms when compared to the anti-asthmatic drug combination. In addition, another controlled clinical trial found no significant changes in lung volume measurements or asthmatic symptoms after treatment with either tylophora or placebo.⁵⁰

A controlled study in 28 children with bronchial asthma suggested that 25 drops of ivy leaf extract given twice daily was effective in increasing the amount of oxygen in the lung after only three days of use. For example, airway resistance in the ivy leaf group decreased by 24% on day three of the study, compared to only 5% in the placebo group. However, the incidence of cough and shortness of breath symptoms did not change during the short trial period.⁵¹

Traditionally, herbs that have a soothing action on bronchioles are also used for asthma. These include marshmallow, mullein, hyssop, and licorice. Elecampane has been used traditionally to treat coughs associated with asthma.⁵² Refer to the individual herb articles for information about how much to take of each of these herbs.

Ginkgo biloba extracts have been considered a potential therapy for asthma for some time. This is because the extracts block the action of platelet-activating factor (PAF), a compound the body produces that in part causes asthma symptoms. A study using isolated ginkgolides from ginkgo (not the whole extract) found they reduced asthma symptoms.⁵³ A controlled study used a highly concentrated tincture of ginkgo leaf and found this helped decrease asthma symptoms.⁵⁴ For asthma, 120–240 mg of standardized extract or 3–4 ml of regular tincture three times daily can be used.

Eclectic physicians—doctors at the turn of the century in North America who used herbs as their main medicine—considered lobelia to be one of the most important plant medicines.⁵⁵ Traditionally, it was used by Eclectics to treat coughs and spasms in the lungs from all sorts of causes.⁵⁶

Are there any side effects or interactions? Refer to the individual herb for information about any side effects or interactions.

Other integrative approaches that may be helpful: Ionized air may also play a role in allergies. Research suggests that some allergy-provoking substances, such as dust and pollen, have a positive electrical charge. Meanwhile, negative ions appear to counteract the allergenic actions of these positively charged ions on respiratory tissues. Negative ions generally lead to favorable actions, and many individuals experience relief from their respiratory allergies.⁵⁷ Other allergy sufferers report considerable relief, with a few allergy reactions resolving completely, after negative ion therapy. The majority of allergy sufferers appear to be able to reduce reliance on other treatments (nutritional, biochemical, or prescription) during negative ion therapy.

A set of breathing exercises called Buteyko breathing techniques has been reported to significantly reduce the need for prescription drugs for people with asthma.⁵⁸ Although the people in this blinded randomized trial had improved quality of life while doing these exercises, objective measures of breathing capacity did not improve despite the decreased need for drugs.

Antibiotic use during the first year or two of life has been associated with an increased risk of asthma in preliminary studies.^{59 60} Whether this association might result from allergic versus non-allergic effects remains unknown. However, the association does suggest that until more is known, gratuitous use of antibiotics in early childhood (e.g. to inappropriately treat viral diseases) should be carefully considered before being automatically accepted. Current evidence in no way suggests against appropriate use of antibiotics in the treatment of infections. Concerns should be discussed with the prescribing physician.

Acupuncture might be useful for some asthmatics. Case reports^{61 62} and uncontrolled studies^{63 64 65} have suggested acupuncture may be helpful for people with asthma, either as a treatment for an acute attack or as a longer-term therapy for reducing the number or severity of attacks, decreasing the need for medications, and so on. Placebo-controlled studies using fake acupuncture, however, have been quite contradictory, many of them showing a strong placebo effect that is not significantly improved upon by real acupuncture.^{66 67 68 69} It is possible that needle insertion in non-acupuncture points has a stimulating effect that benefits asthma. The success of acupuncture may also depend on other factors, such as the type of asthma being treated and certain characteristics of the patient. Nonetheless, since some controlled research has demonstrated positive effects of real acupuncture, people with asthma may want to consider a trial of acupuncture treatment to see if it helps their individual case.

Information about the effects of a particular supplement or herb on a particular condition has been qualified in terms of the methodology or source of supporting data (for example: clinical, double blind, meta-analysis, or traditional use). For the convenience of the reader, the information in the table listing the supplements for particular conditions is also categorized. The criteria for the categorizations are: "Primary" indicates there are reliable and relatively consistent scientific data showing a health benefit. "Secondary" indicates there are conflicting, insufficient, or only preliminary studies suggesting a health benefit or that the health benefit is minimal. "Other" indicates that an herb is primarily supported by traditional use or that the herb or supplement has little scientific support and/or minimal proven health benefit.

1. Blanc PD, Eisner MD, Israel L, Yelin EH. The association between occupation and asthma in general medical practice. Chest 1999;115:1259–64.

2. Lindahl O, Lindwall L, Spangberg A, et al. Vegan regimen with reduced medication in the treatment of bronchial asthma. J Asthma 1985;22:45–55.

3. Javaid A, Cushley MJ, Bone MF. Effect of dietary salt on bronchial reactivity to histamine in asthma. BMJ 1988;297:454.

4. Burney PG, Neild JE, Twort CH, et al. Effect of changing dietary sodium on the airway response to histamine. Thorax 1989;44:36–41.

5. Carey OJ, Locke C, Cookson JB. Effect of alterations of dietary sodium on the severity of asthma in men. Thorax 1993;48:714–8.

6. Chiaramonte LT, Altman D. Food sensitivity in asthma: perception and reality. J Asthma 1991;28:5–9.

7. Rowe AH, Young EJ. Bronchial asthma due to food allergy alone in ninety-five patients. JAMA 1959;169:1158.

8. Sampson HA, Mendelson L, Rosen JP. Fatal and near-fatal anaphylactic reactions to food in children and adolescents. N Engl J Med 1992;327:380.

9. Genton C, Frie PC, Pecoud A. Value of oral provocation tests to aspirin and food additives in the routine investigation of asthma and chronic urticaria. J Asthma 1985;76:40–5.

10. Townes SJ, Mellis CM. Role of acetyl salicylic acid and sodium metabisulfite in chronic childhood asthma. Pediatrics 1984;73:631–7.

11. Collipp PJ, Chen SY, Sharma RK, et al. Tryptophane metabolism in bronchial asthma. Ann Allergy 1975;35:153–8.

12. Weir MR, Keniston RC, Enriquez JI, McNamee GA. Depression of vitamin B6 levels due to theophylline. Ann Allergy 1990;65:59–62.

13. Collipp PJ, Goldzier S III, Weiss N, et al. Pyridoxine treatment of childhood bronchial asthma. Ann Allergy 1975;35:93–7.

14. Reynolds RD, Natta CL. Depressed plasma pyridoxal phosphate concentrations in adult asthmatics. Am J Clin Nutr 1985;41:684–8.

15. Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:141–52.

16. Haury VG. Blood serum magnesium in bronchial asthma and its treatment by the administration of magnesium sulfate. J Lab Clin Med 1940;26:340–4.

17. Skobeloff EM et al. Intravenous magnesium sulfate for the treatment of acute asthma in the emergency department. JAMA 1989;262:1210–3.

18. Zuskin E et al. Byssinosis and airway responses due to exposure to textile dust. Lung 1976;154:17–24.

19. Bucca C, Rolla G, Oliva A, Farina J-C. Effect of vitamin C on histamine bronchial responsiveness of patients with allergic rhinitis. Ann Allergy 1990;65:311–4.

20. Ruskin SL. Sodium ascorbate in the treatment of allergic disturbances. The role of adrenal cortical hormone-sodium-vitamin C. Am J Dig Dis 1947;14:302–6.

21. Anibarro B, Caballero T, Garcia-Ara C, et al. Asthma with sulfite intolerance in children: A blocking study with cyanocobalamin. J Allergy Clin Immunol 1992;90:103–9.

22. Johnson JL, Wuebbens MM, Mandell R, Shih VE. Molybdenum cofactor deficiency in a patient previously characterized as deficient in sulfite oxidase. Biochem Med Metabol Biol 1988;40:86–93.

23. Sardesai VM. Molybdenum: an essential trace element. Nutr Clin Pract 1993;8:277–81.

24. Moss M. Effects of molybdenum on pain and general health: a pilot study. J Nutr Environ Med 1995;5:55–61.

25. Stone J, Hinks LJ, Beasley R, et al. Reduced selenium status of patients with asthma. Clin Sci 1989;77:495–500.

26. Flatt A, Pearce N, Thomson CD, et al. Reduced selenium in asthmatic subjects in New Zealand. Thorax 1990;45:95–9.

27. Owen S, Pearson D, Suarez-Mendez V, et al. Evidence of free-radical activity in asthma. N Engl J Med 1991;325:586–7 [letter].

28. Hasselmark L, Malmgren R, Zetterstrom O, Unge G. Selenium supplementation in intrinsic asthma. Allergy 1993;48:30–6.

30. Broughton KS, Johnson CS, Pace BK, et al. Reduced asthma symptoms with n-3 fatty acid ingestion are related to 5-series leukotriene production. Am J Clin Nutr 1997;65:1011–7.

32. Thien FCK, Woods RK, Waters EH. Oily fish and asthma— a fishy story? Med J Aust 1996;164:135–6 [editorial].

33. Hodge L, Salome CM, Peat JK, et al. Consumption of oily fish and childhood asthma risk. Med J Austral 1996;164:137–40.

34. Bray GW. The hypochlorhydria of asthma in childhood. Q J Med 1931;24:181–97.

35. Welton AF, Tobias LD, Fiedler-Nagy C, et al. Effect of flavonoids on arachidonic acid metabolism. Prog Clin Biol Res 1986;213:231–42.

36. Schafer A, Adelman B. Plasma inhibition of platelet function and of arachidonic acid metabolism. J Clin Invest 1985;75:456–61.

37. Neuman I, Nahum H, Ben-Amotz A. Prevention of exercise-induced asthma by a natural isomer mixture of beta-carotene. Ann Allerg Asthma Immunol 1999;82:549–53.

38. Cazzola P, Mazzanti P, Bossi G. In vivo modulating effect of a calf thymus acid lysate on human T lymphocyte subsets and CD4+/CD8+ ratio in the course of different diseases. Curr Ther Res 1987;42:1011–7.

39. Kouttab NM, Prada M, Cazzola P. Thymomodulin: Biological properties and clinical applications. Med Oncol Tumor Pharmacother 1989;6:5–9. [review]

40. Genova R, Guerra A. A thymus extract (thymomodulin) in the prevention of childhood asthma. Pediatr Med Chir 1983;5:395–402.

41. Bagnato A, Brovedani P, Comina P, et al. Long-term treatment with thymomodulin reduces airway hyperresponsiveness to methacholine. Ann Allergy 1989;62:425–8.

42. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Foods, Drugs, and Cosmetics, 2d ed. New York: John Wiley and Sons, 1996, 227–9.

43. Rajaram D. A preliminary clinical trial of Picrorrhiza kurroa in bronchial asthma. Indian J Pharmacol 1975;7:95–6.

44. Shan BK, Kamat SR, Sheth UK. Preliminary report of use of Picrorrhiza kurroa root in bronchial asthma. J Postgrad Med 1977;23:118–20.

45. Doshi VB, Shetye VM, Mahashur AA, Kamat SR. Picrorrhiza kurroa in bronchial asthma. J Postgrad Med 1983;29:89–95.

46. Bauer K, Dietersdorfer F, Sertl K, et al. Pharmacodynamic effects of inhaled dry powder formulations of fenoterol and colforsin in asthma. Clin Pharmacol Ther 1993;43:76–83.

47. Shivpuri DN, Menon MPS, Prakash D. A crossover double-blind study on Tylophora indica in the treatment of asthma and allergic rhinitis. J Allergy 1969;43:145–50.

48. Shivpuri DN, Singhal SC, Parkash D. Treatment of asthma with an alcoholic extract of Tylophora indica: a cross-over, double-blind study. Ann Allergy 1972;30:407–12.

49. Thiruvengadam KV, Haranatii K, Sudarsan S, et al. Tylophora indica in bronchial asthma: a controlled comparison with a standard anti-asthmatic drug. J Indian Med Assoc 1978;71:172–6.

50. Gupta S, George P, Gupta V, et al. Tylophora indica in bronchial asthma—a double blind study. Ind J Med Res 1979;69:981–9.

51. Mansfeld HJ, Höhre H, Repges R, Dethlefsen U. Therapy of bronchial asthma with dried ivy leaf extract. Münch Med Wschr 1998;140:32–6.

52. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. New York: John Wiley & Sons, 1996, 222–4.

53. Guinot P, Brambilla Dunchier J, et al. Effect of BN 52063, a specific PAF-ascether antagonist, on bronchial provocation test to allergens in asthmatic patients—a preliminary study. Prostaglandins 1987;34:723–31.

54. Li M, Yang B, Yu H, Zhang H. Clinical observation of the therapeutic effect of ginkgo leaf concentrated oral liquor on bronchial asthma. Chinese J Integrative & Western Med 1997;3:264–7.

55. Felter HW, Lloyd JU. King’s American Dispensatory, 18th ed. Sandy, OR: Eclectic Medical Publications, 1898, 1983, 1199–205.

56. Ellingwood F. American Materia Medica, Therapeutics and Pharmacognosy, 11th ed. Sandy, OR: Eclectic Medical Publications, 1919, 1998, 235–42.

57. Soyka F, Edmonds A. The Ion Effect. New York:Bantam, 1977.

58. Bowler SD, Green A,Mitchell CA. Buteyko breathing techniques in asthma: a blinded randomised controlled trial. Med J Aust 1998;169:575–8.

59. Wickens K, Pearce N, Crane J, Beasley R. Antibiotic use in early childhood and the development of asthma. Clin Exp Allergy 1999;29:766–71.

60. Farooqi IS, Hopkin JM. Early childhood infection and atopic disorder. Thorax 1998;53:927–32.

61. Youguang J. Clinical applications of point Futu. J Tradit Chin Med 1986;6:6–8.

62. Minji W, Yancen Z. Clinical experience of Dr. Shao Jingming in treatment of diseases by puncturing back-shu points. J Tradit Chin Med 1996;16:23–6.

63. Zang J. Immediate antiasthmatic effect of acupuncture in 192 cases of bronchial asthma. J Tradit Chin Med 1990;10:89–93.

64. Sternfeld M, Fink A, Bentwich Z, Eliraz A. The role of acupuncture in asthma: changes in airways dynamics and LTC4 induced LAI. Am J Chin Med 1989;17:129–34.

65. Zwolfer W, Keznickl-Hillebrand W, Spacek A, et al. Beneficial effect of acupuncture on adult patients with asthma bronchiale. Am J Chin Med 1993;2:113–7.

66. Kleijnen J, ter Riet G, Knipschild P. Acupuncture and asthma: a review of controlled trials. Thorax 1991;46:799–802 [review].

67. Jobst KA. Acupuncture in asthma and pulmonary disease: an analysis of efficacy and safety.J Altern Complement Med 1996;2:179–206 [review].

68. Biernacki W, Peake MD. Acupuncture in treatment of stable asthma. Respir Med 1998;92:1143–5.

69. Medici TC. Acupuncture and bronchial asthma. Forsch Komplementarmed 1999;6 Suppl 1:26–8 [in German].