• Recurrent attacks of shortness of breath, cough, and coughing up thick mucus
• Prolonged expiration phase with generalized wheezing and abnormal breath sounds
• Laboratory signs of allergy (increased levels of eosinophils in blood, increased serum IgE levels, positive food and/or inhalant allergy tests)
Asthma is a breathing disorder characterized by spasm and swelling of the bronchial airways along with excessive excretion of a viscous mucus that can also make breathing difficult. Asthma affects approximately 7% of the population of the United States and causes 4,210 deaths per year. Although it occurs at all ages, it is most common in children younger than 10. There is a 2:1 male-to-female ratio among affected children, which equalizes by the age of 30.1
The incidence of asthma is rising rapidly in the United States, especially in children. Reasons often given to explain the rise in asthma include the following:
• Increased stress on the immune system due to factors such as greater chemical pollution in the air, water, insect allergens (mostly from dust mites), and food
• Earlier weaning and earlier introduction of solid foods to infants
• Food additives
• Higher incidence of obesity2
• Genetic manipulation of plants, resulting in food components with greater allergenic tendencies
In addition, certain genetic variables may make certain individuals more susceptible to asthma.3–6
Asthma has typically been divided into two categories: extrinsic and intrinsic. Extrinsic or atopic asthma is generally considered an allergic condition with a characteristic increase in IgE—the antibody produced by white blood cells that can bind to specialized white blood cells, known as mast cells, and cause the release of mediators such as histamine. Intrinsic asthma is associated with a bronchial reaction that is due not to an allergy but rather to such factors as chemicals, cold air, exercise, infection, and emotional upset.
Asthma is often clinically classified according to the frequency of symptoms, forced expiratory volume in 1 second (FEV1), and peak flow rate.
WARNING: An acute asthma attack can be a medical emergency. If you are suffering from an acute attack, consult your physician immediately or go to an emergency room.
The U.S. National Asthma Education and Prevention Program (NAEPP) guidelines for the diagnosis and management of asthma state that a diagnosis of asthma begins by determining if any of the following indicators are present:
• Wheezing (high-pitched whistling sounds during breathing out), especially in children. (Lack of wheezing and a normal chest examination do not exclude asthma.)
• History of any of the following:
Cough, worse particularly at night
Recurrent difficulty breathing
Recurrent chest tightness
• Symptoms occur or worsen in the presence of:
Animals with fur or hair
Dust mites (in mattresses, pillows, upholstered furniture, carpets)
Smoke (from tobacco or wood)
Changes in weather
Strong emotional expression (laughing or crying hard)
Airborne chemicals or dusts
Onset of menstruation
• Symptoms occur or worsen at night, awakening the patient
Determining respiratory function with the use of a spirometer plays a central role in the management of asthma and should be performed at the time of initial diagnosis, after treatment is initiated and symptoms are stabilized, whenever control of symptoms deteriorates, and every one or two years on a regular basis.
Asthma is caused by a complex interaction of environmental and genetic factors. The strongest risk factor for developing asthma is a history of allergies such as eczema (atopic dermatitis) and hay fever. The presence of atopic dermatitis increases the risk of asthma three- to fourfold. Allergies and the response of the immune system are obviously involved in asthma. The specific imbalance is an increase in the number or function of specialized white blood cells known as Th2 helper T cells. These cells ultimately lead to an increase in the release of compounds that heighten the allergic response.2–4
Both extrinsic and intrinsic factors trigger the release from mast cells of chemicals that mediate (produce or control) inflammation. The inflammatory mediators are responsible for the signs and symptoms of asthma. They are either preformed in little packets (granules) within mast cells or generated from fatty acids that reside in cell membranes.
The preformed mediators include histamine and compounds known as leukotrienes. These compounds are responsible for producing much of the allergic reaction seen in asthma. Some leukotrienes are 1,000 times more potent than histamine as stimulators of bronchial constriction and allergy. It has been observed that asthmatics have a tendency to form higher levels of leukotrienes.5 This abnormality is further aggravated in patients with aspirin-induced asthma. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs, such as indomethacin and ibuprofen) result in the production of excessive levels of leukotrienes in sensitive individuals.6,7 Tartrazine (yellow dye #5) produces similar effects on leukotriene levels and is often a cause of asthma, particularly in children. Tartrazine is added to most processed foods and can even be found in vitamin preparations and anti-asthma prescription drugs. Tartrazine may also indirectly support the asthmatic process via its role as an antimetabolite of vitamin B6 (see the discussion in “Tryptophan Metabolism and Pyridoxine Supplementation,” later in this chapter).
The Autonomic Nervous System and Adrenal Glands
The autonomic nervous system and adrenal glands are also involved in asthma.8 Some of the inflammatory mediators block the beta-2 receptors for the neurotransmitter epinephrine (adrenaline), secreted by the adrenal gland. This ultimately results in constriction of the smooth muscle of the airway, as well as the release of histamine and other allergic compounds from mast cells and basophils. Also, if the adrenal gland is not producing sufficient levels of cortisol and epinephrine, it can set the stage for bronchial constriction.
An evaluation of 448 children and adolescents in Britain who had received only breast milk for the first six months of life, and in particular on the first day after birth, produced some interesting findings. All of the children were weaned after one year of age and were older than four years at the time the parents responded. The mean age was 7.87 years. In response to the question “Has your child ever been diagnosed as asthmatic?” there were 30 positive answers (6.72%). The surprise came when the researchers classified the respondents according to whether or not they had received the pertussis (whooping cough) vaccine.9
Among the 243 immunized children, 26 were diagnosed as having asthma (10.69%). In contrast, of the 203 children who had not been immunized, only 4 had asthma (1.97%). The relative risk of developing asthma from the pertussis vaccine was 5.43 in this study.
Even though all of the children who received the pertussis vaccine received other vaccinations, the researchers suspected that the statistical evidence focused on pertussis. Among the children who did not receive the pertussis vaccine, most had received some other vaccination. Of the 91 subjects of the study who received no vaccines, only one had asthma, compared with 3 of the 112 who had other vaccinations. Therefore the relative risk of developing asthma is about 1% in children receiving no immunizations, 3% in those receiving vaccinations other than pertussis, and 11% for those receiving the pertussis vaccine. Another finding to weigh is that in the group not immunized against pertussis, 16 developed the disease, compared with only 1 in the immunized group.
One evaluation of more than 9,600 children was employed to determine the safety of intranasal influenza virus vaccine in children. Although this relatively new vaccination was deemed safe for children and adolescents, there was a four times greater risk in children 18 to 35 months old of asthma and associated reactive airway disease.10
Antibiotics, Probiotics, and Mucosal IgA
In a combined analysis of seven studies involving more than 12,000 youngsters, researchers at the University of British Columbia found that those prescribed antibiotics before their first birthday were more than twice as likely as untreated children to develop asthma.11 If they had had multiple courses of antibiotics, that bumped up the risk even higher—16% for every course of the drugs taken before age one. There are a couple of explanations for this association between antibiotic use and asthma. One is that antibiotics contribute to a state of “excess hygiene,” leading to reduced exposure to microbes, which in turn creates an oversensitive immune system that mounts an over-the-top allergic reaction to pollen and dust mites, ultimately leading to asthma. The second explanation is that antibiotics have a negative effect on the normal flora of the gastrointestinal and respiratory passages. Some studies have shown that giving probiotics (active lactobacillus and bifidobacteria cultures) lowers the risk of atopic allergic disease such as asthma and eczema. Some of this protective effect may be mediated by mucosal IgA, an antibody that participates in antigen elimination. In a group of 237 allergy-prone infants given either a combination of four probiotic strains or a placebo, researchers found that the probiotic supplementation increased fecal IgA while reducing inflammatory markers.12 In infants with high fecal IgA concentration at the age of six months, the risk of having any allergic disease or any IgE-associated (atopic) disease before the age of two years was cut by nearly 50%. High intestinal IgA in early life is associated with minimal intestinal inflammation and indicates reduced risk for IgE-associated allergic diseases.
The first step in the natural approach to asthma is to reduce allergic tendencies. Allergens can be viewed as straws on a camel’s back. Adding enough straws to the camel’s back will ultimately cause the camel’s back to break. Similarly, increasing the exposure to allergens will ultimately cause symptoms. By reducing allergic tendencies, as well as the offending allergens in many cases, the allergic process can be prevented. There are two primary ways to increase the allergic threshold: reduce exposure to airborne allergens and reduce intake of food allergens.
Mechanisms of Asthma
Airborne allergens, such as pollen, dander, and dust mites, are often difficult to avoid entirely, but measures can be taken to reduce exposure. Removing dogs and cats as well as surfaces where allergens can collect (carpets, rugs, upholstered furniture) is a great first step. If this can’t be done entirely, make sure that the bedroom is as allergy-proof as possible. Encase the mattress in an allergen-proof plastic; wash sheets, blankets, pillowcases, and mattress pads every week in hot water with additive- and fragrance-free detergent; consider using bedding material made from Ventflex, a special hypoallergenic synthetic material; and install an air purifier. The best mechanical air purifiers are HEPA (high-efficiency particulate air) filters, which can be put into rooms or attached to central heating and air-conditioning systems.
For high-risk children, breastfeeding can produce significant benefits. First, there is substantial evidence that breastfeeding alone has some effect in the prevention of asthma.13,14 But when breastfeeding is combined with allergy avoidance, even better results are seen. For example, the Canadian Asthma Primary Prevention study collected two years of data in which researchers chose 545 infants who were considered at high risk of asthma on the basis of family history.15 These children were broken down into control and intervention groups. The interventions included (1) house dust control measures; (2) recommendations for avoidance of pets, environmental tobacco smoke, and day care during the first year; and (3) only breast-feeding or use of partially hydrolyzed whey formula until at least the age of four months. At one year of age, asthma was significantly reduced by 34% in the intervention group. At two years of age, the intervention group had 60% fewer children with persistent asthma and a 90% reduction in recurrent wheezing. Studies such as this one are quite useful in order to show the effectiveness of a combined approach vs. a single intervention.
Many studies have indicated that food allergies can play an important role in asthma.16–20 Adverse reactions to food may be immediate or delayed. Double-blind food challenges in children have shown that immediate-onset sensitivities are usually due to (in decreasing order of frequency) eggs, fish, shellfish, nuts, and peanuts, while foods most commonly associated with delayed onset include (in decreasing order of frequency) milk, chocolate, wheat, citrus, and food colorings. Elimination diets have been successful in identifying allergens and treating asthma and are a particularly valuable diagnostic and therapeutic tool in infants.17 Elimination of common allergens during a child’s first two years has been shown to reduce allergic tendencies in high-risk children (e.g., those with a strong family history).13
The presence of food allergies greatly lowers the threshold for asthma. In other words, it sets the stage for overreactivity of the airways to airborne allergens. Something as simple as lack of stomach acid production may be responsible for food allergies in asthmatics. Gastric analyses in 200 asthmatic children in 1931 showed that 80% of them had gastric acid secretions below normal levels.21 This high occurrence suggests that decreased gastric acid output may predispose these children to food allergies, have a major impact on the success of rotation or elimination diets, and if not corrected lead to the development of additional food allergies.
Food allergies are thought to be responsible for “leaky gut” syndrome in asthmatics.22 Another important consideration is an overgrowth of the common yeast Candida albicans.23 As a result of increased gut permeability due to either a leaky gut or candida, there is a greater antigen load on the immune system. This subsequently overwhelms the immune system and the ability of the Kupfer cells in the liver to clear immune complexes and incompletely digested proteins from the intestines, increasing the likelihood of developing additional allergies as well as increasing the amount of bronchoconstrictive compounds in circulation. It is essential to identify offending foods as soon as possible to avoid the development of further allergies. For more information, see the chapter “Food Allergy.”
Vitally important in the control of asthma is the elimination of food additives.24 Artificial dyes and preservatives are widely used in foods, beverages, and drugs. In particular, the dye tartrazine and the preservatives benzoate, sulfur dioxide, and sulfite have been reported to cause asthma attacks in susceptible individuals.24,25 It is estimated that 2 to 3 mg sulfites are consumed each day by the average U.S. citizen, while an additional 5 to 10 mg are ingested by wine and beer drinkers.
It has been postulated that a deficiency of the trace mineral molybdenum may be responsible for sulfite sensitivity.26 Sulfite oxidase, the enzyme responsible for neutralizing sulfites, is molybdenum dependent.
Strong evidence indicates that an increased intake of salt raises bronchial reactivity and mortality from asthma.27,28 The degree of bronchial reactivity to histamine is positively correlated with two-hour urinary sodium excretion and rises with increased dietary sodium. Because the severity of asthma correlates with the degree of bronchial reactivity, the severity of asthma can clearly be influenced by alterations in dietary sodium consumption.
A number of research studies corroborate the notion that people who have a diet rich in fruit and vegetables have a lower risk of poor respiratory health.29–31 This effect is most likely due to the increased levels of antioxidants. One study found that among children, consumption of fresh fruit, particularly fruit high in vitamin C, has been related to a lower prevalence of asthma symptoms and higher lung function.32 The effect was observed even at low levels of fruit consumption (one or two servings per week, compared with less than one serving per week); this suggests that even a small increase in fruit intake could be beneficial. This same review discussed consumption of fish as also being related to lower airway hyperreactivity among children and higher lung function in adults.
A study of Scottish adults also found a dose-response relationship between fruit consumption and pulmonary function, whereby increased fruit consumption led to decreases in phlegm and better pulmonary function.33 Another study of 607 asthma patients and 864 controls highlighted apples and moderate amounts of red wine (preferably low in sulfites) as sources of antioxidants that decreased asthma severity.34
Dietary intake of soy foods may be helpful, as the soy isoflavone genistein is associated with reduced severity of asthma and improved lung function.35 While this effect may be due to some antioxidant action, studies have also shown that genistein is able to block the manufacture of allergic mediators, including leukotrienes, in asthma patients.36,37 However, when increasing soy consumption, be sure to check for an allergic reaction.
A long-term trial of a vegan diet (elimination of all animal products) provided significant improvement in 92% of the 25 treated patients who completed the study (nine dropped out).38 Improvement was determined by a number of clinical variables, including lung capacity, FEV1, and physical working capacity. The researchers also found a reduction in susceptibility to infectious disease. Note, however, that although 71% of the patients responded within four months, one year of therapy was required before the 92% level was reached.
The diet excluded all meat, fish, eggs, and dairy products. Drinking water was limited to spring water (chlorinated tap water was specifically prohibited); and coffee, ordinary tea, chocolate, sugar, and salt were excluded. Herbs were allowed for seasoning, and water and herbal teas were allowed up to 1.5 l a day. Vegetables used freely were lettuce, carrots, beets, onions, celery, cabbage, cauliflower, broccoli, nettles, cucumber, radishes, Jerusalem artichokes, and all beans except soybeans and green peas. Potatoes were allowed in restricted amounts. A number of fruits were also used freely: blueberries, cloudberries, raspberries, strawberries, black currants, gooseberries, plums, and pears. Apples and citrus fruits were not allowed, and grains were either restricted or eliminated.
The beneficial effects of this dietary regimen are probably related to three factors:
• Elimination of food allergens
• Altered prostaglandin metabolism
• Increased intake of antioxidant nutrients and magnesium
The importance of avoiding food allergies was discussed earlier. The avoidance of dietary sources of arachidonic acid (derived from animal products) appears to be quite significant, as well, as the prostaglandins and leukotrienes derived from arachidonic acid contribute significantly to the allergic reaction in asthma. The benefits of altering prostaglandin metabolism are further discussed later, as is the role of increased dietary antioxidants in preventing asthma.
Perhaps the most significant effects noted in the trial of the vegan diet, besides the patients’ improvement in health, were the great reduction in health care costs (the patients had been receiving corticosteroids and other drugs and therapies for an average of 12 years) and, according to the authors, patients’ changed attitude toward increased responsibility for their own health.
Omega-3 Fatty Acids
Population-based studies have shown that children who eat fish more than once a week have one-third the asthma risk of children who do not eat fish regularly.39 Several clinical studies have shown that increasing the intake of omega-3 fatty acids through supplementation with fish oils (which contain EPA and DHA) offers significant benefits in asthma, as demonstrated by improvements in airway responsiveness to allergens, as well as improvements in respiratory function.40,41 These benefits are related to increasing the ratio of omega-3 to omega-6 fatty acids in cell membranes, thereby reducing the availability of arachidonic acid, which can lead to the production of inflammatory leukotrienes. Omega-3 fatty acid ingestion leads to a significant shift in leukotriene synthesis, from the extremely inflammatory 4-series to the less inflammatory 5-series leukotrienes. This shift is directly related to improvements in asthma symptoms.42 It may take as long as one year before benefits are apparent, as it appears to take time to produce new cellular membranes that include the omega-3 fatty acids.
Tryptophan Metabolism and Pyridoxine Supplementation
Children with asthma have been shown to have a metabolic defect in tryptophan metabolism and reduced platelet transport for serotonin.43,44 These defects may be related to low vitamin B6 (pyridoxine) levels. In one study, plasma and red blood cell vitamin B6 levels were significantly lower in 15 adult patients with asthma than in 16 controls.45 Oral supplementation with 50 mg pyridoxine twice per day given to seven of the patients failed to produce a substantial elevation of these low levels. However, all patients reported a dramatic decrease in frequency and severity of wheezing and asthmatic attacks while taking the supplements. In a study of 76 asthmatic children, pyridoxine at a dosage of 200 mg per day produced significant reductions in symptoms and in the dosages of bronchodilators and corticosteroids required. However, a double-blind study failed to demonstrate any significant improvement with B6supplementation in patients who depended on steroids for control of symptoms.46
Although vitamin B6 supplementation may not help patients on steroids, it is definitely indicated for asthmatics being treated with the drug theophylline. Theophylline significantly depresses pyridoxal-5-phosphate levels.47 In addition, another study has shown that vitamin B6 supplementation can significantly reduce the typical side effects of theophylline (e.g., headaches, nausea, irritability, sleep disorders).48
The substantial increase in the prevalence of asthma over the past 20 years can be partially explained by the reduced dietary intake of antioxidant nutrients such as beta-carotene and vitamins A, C, and E, as well as the mineral cofactors essential for antioxidant defense mechanisms, such as zinc, selenium, and copper.49 Patients in acute asthmatic distress are known to have lowered serum total antioxidants.50Genetic influences may also play a role in the need for antioxidants.
One study of 158 children with moderate to severe asthma revealed that supplementation with 50 mg per day of vitamin E and 250 mg per day of vitamin C produced significant protection against reduction in pulmonary function caused by an ozone challenge.51 Antioxidants are thought to provide important defense mechanisms against the oxidizing agents that can both stimulate bronchoconstriction and increase hyperreactivity to other agents.52Acetaminophen, which is known to deplete antioxidant levels such as glutathione in animals, should be used with caution in asthmatic patients.
Vitamin C. Vitamin C is very important to the health of the lungs, as it is the major antioxidant substance present in the extracellular fluid lining the airway surfaces. Vitamin C in-take in the general population appears to inversely correlate with asthma: low vitamin C (in the diet and the blood) is an independent risk factor for asthma. In a survey of 771 people with current asthma, 352 people with former asthma, and 15,418 people without asthma, lower vitamin C concentrations were observed among those with current or former asthma than among people who had never had asthma.53 Additional support is offered by the fact that children of smokers have a higher rate of asthma (cigarette smoke is known to deplete respiratory vitamin C and E levels), and symptoms of ongoing asthma in adults appear to be increased by exposure to environmental oxidizing agents and decreased by vitamin C supplementation.57
Both treated and untreated asthmatic patients have been shown to have significantly lower levels of ascorbic acid in serum and leukocytes.53 From a clinical perspective, it appears that asthmatics have a higher need for vitamin C. From 1973 to 1994 there were 11 clinical studies of vitamin C supplementation in asthma.54 Seven of these studies showed significant improvements in respiratory measures and asthma symptoms as a result of supplementing the diet with 1 to 2 g vitamin C per day. This dosage recommendation appears extremely wise based on the increasing exposure to inhaled oxidants today, along with the growing appreciation of the antioxidant function of vitamin C in the respiratory system.
High-dose vitamin C therapy may also help asthma by lowering histamine levels.55 The importance of vitamin C as a natural antihistamine has emerged in the context of concern over the safety of antihistamine medications and the recently recognized immune-suppressing effects of histamine. In the initial stages of an immune response, histamine amplifies the immune response by increasing capillary permeability and smooth muscle contraction, thus enhancing the flow of immune factors to the site of infection. Subsequently, histamine exerts a suppressive effect on the accumulated white blood cells in an attempt to contain the inflammatory response.
Vitamin C acts in a number of ways against histamine. Specifically, it prevents the secretion of histamine by white blood cells and increases the detoxification of histamine. One study examined the antihistamine effect of short- and long-term vitamin C administration and its effect on neutrophil function in healthy men and women. In the long-term part of the study, 10 subjects ingested a placebo during weeks one, two, five, and six and 2 g per day of vitamin C during weeks three and four. Fasting blood samples were collected at the end of weeks two, four, and six. Blood vitamin C levels rose significantly following vitamin C administration, while blood histamine levels fell by 38% during the weeks vitamin C was given. The ability of white blood cells to respond to an infection (chemotaxis) increased by 19% during vitamin C administration and fell 30% after vitamin C withdrawal. Interestingly, these changes were linked to histamine concentrations. Chemotaxis was greatest when histamine levels were the lowest. In the part of the study looking at the short-term effects of vitamin C, blood histamine concentrations and chemotaxis did not change four hours after a single dose of vitamin C. This result suggests that vitamin C will lower blood histamine only if taken over a period of time. Individuals prone to allergy or inflammation are encouraged to increase their consumption of vitamin C through supplementation.55
In a small study, asthmatic subjects with documented exercise-induced bronchoconstriction participated in a randomized, placebo-controlled double-blind crossover trial.56 Subjects entered the study on their usual diet and were placed on either two weeks of vitamin C supplementation (1,500 mg per day) or a placebo, followed by a one-week washout period, before crossing over to the alternative treatment. The vitamin C group significantly reduced the maximum fall in postexercise FEV1 (–6.4 %) compared with the usual diet (–14.3%) and the placebo (–12.9%). Asthma symptom scores significantly improved with vitamin C supplementation compared with the placebo and the usual diet. Postexercise inflammatory mediators were also significantly lower with ascorbic acid supplementation.
Flavonoids. Flavonoids appear to be key antioxidants in the treatment of asthma. Various flavonoids, chief among them being quercetin, have been shown to have beneficial effects in preventing the formation and release of allergic mediators.57–60 In addition, flavonoids have both a vitamin-C-sparing effect and a direct stabilizing effect on membranes, including those of mast cells.
Quercetin or more bioavailable forms of quercetin can be used (e.g., enzymatically modified isoquercitrin, or EMIQ). However, flavonoid-rich extracts such as those from grape seed, pine bark, green tea, or ginkgo biloba may prove even more helpful in the treatment of asthma. In particular, the proanthocyanidins, from grape seed or pine bark extracts, appear to have an affinity for the lungs. In a randomized, placebo-controlled, double-blind study involving 60 subjects between 6 and 18 years old, a proprietary pine bark extract (Pycnogenol) significantly improved pulmonary function and asthma symptoms compared with a placebo. Specifically, the subjects in the Pycnogenol group were able to reduce or discontinue their use of rescue inhalers more often than the placebo group. There was also a significant reduction of urinary leukotrienes in the Pycnogenol group.61
In another study, a flavonoid preparation derived from purple passion fruit peel (PFP) was studied in a four-week randomized, placebo-controlled, double-blind trial in asthma patients. The dosage of the PFP extract was 150 mg per day. The prevalence of wheezing, coughing, and shortness of breath was reduced significantly in the group treated with PFP extract, whereas the placebo caused no significant improvement. Supplementation with PFP extract also resulted in a marked increase in the ability to breathe while the placebo showed no effect.62
Carotenes. Carotenes are powerful antioxidants that may increase the integrity of the epithelial lining of the respiratory tract and decrease inflammatory leukotriene formation.63 Some studies have shown that asthmatics have reduced plasma antioxidant potential due to low whole-blood levels of carotenoids (beta-carotene, alpha-carotene, beta-cryptoxanthin, lutein, and zeaxanthin)64 and in particular low lycopene levels,65 and thus are more susceptible to the damaging effects of oxidative stress. This highlights the potential role for carotenoid supplementation in these subjects. Lycopene may emerge as the most useful supplemental carotenoid. In animal models of asthma, lycopene supplementation suppresses allergic responses in the bronchioles, lung tissue, and blood and also reduces the number of mucus-secreting cells in the airways.66
In a proof-of-concept human study, 32 asthmatic adults consumed a low-antioxidant diet for 10 days, then commenced a randomized crossover trial involving three 7-day treatment arms: placebo, tomato extract (45 mg lycopene a day), and tomato juice (45 mg lycopene a day).67 With consumption of a low-antioxidant diet, plasma carotenoid concentrations decreased, the asthma control score worsened, lung function (as measured by FEV1) decreased, and sputum white blood cells (neutrophils) increased. Treatment with both tomato juice and extract reduced airway neutrophil influx. Treatment with tomato extract also reduced sputum neutrophil elastase activity. This short-term study indicates that antioxidant status, particularly carotenoids, modifies some signs and symptoms of asthma.
There have been two double-blind studies of lycopene supplementation (30 mg per day) in exercise-induced asthma. One study failed to show any benefit,68 while another showed that in some patients it prevents airway constriction and reduced breathing capacity.69
Selenium. Reduced selenium levels have been demonstrated in asthma patients.70–72 Glutathione peroxidase, a selenium-dependent enzyme, is important for reducing leukotriene formation. Reduced levels of glutathione peroxidase have also been reported for asthmatics. Supplemental selenium appears warranted to address any deficiency of glutathione peroxidase.
Noted physician Jonathan Wright believes that “B12 therapy is the mainstay treatment for childhood asthma.”73 In one clinical trial, weekly 1,000 mcg intramuscular injections produced definite improvement in asthmatic patients.74Of 20 patients, 18 showed less shortness of breath on exertion, as well as improved appetite, sleep, and general condition. Vitamin B12 appears to be especially effective in sulfite-sensitive individuals.
In 1912 P. Trendelenburg demonstrated that magnesium relaxed bovine bronchial smooth muscle in test tube studies.75 Later, uncontrolled clinical studies revealed magnesium’s beneficial effect in the treatment of patients with acute attacks of bronchial asthma.78 Now, intravenous magnesium (2 g magnesium sulfate infused every hour, up to a total of 24.6 g) is a well-proved and clinically accepted measure to halt an acute asthma attack as well as acute exacerbations of chronic obstructive pulmonary disease (COPD).77–81
Although these initial studies used injectable magnesium, it has been demonstrated that oral magnesium is just as effective at restoring magnesium status (except in the case of an emergency situation such as an acute heart attack or acute asthma attack), although it will usually take six weeks to achieve significant elevations in tissue magnesium concentrations.82 Oral supplementation appears to be warranted because low levels of plasma magnesium have been found in asthmatic patients83 and dietary magnesium intake is independently related to lung function and asthma severity.84 Several double-blind studies of oral magnesium supplementation in adults and children with asthma have demonstrated an improvement in respiratory function, antioxidant status (i.e., increased glutathione concentrations), reduced reactivity to chemical challenge with methacholine, and measures of asthma control and quality of life.85–87 Dosages ranged from 300 mg a day in children to 340 mg a day in adults, usually in divided dosages.
Nebulized magnesium has also proved useful as an adjunct to standard bronchodilation therapies in severe asthmatics, with a greater response in those with life-threatening asthma.88
Vitamin D deficiency is linked to increased airway reactivity, reduced lung function, and worse asthma control.89 One study of more than 1,000 children with asthma showed that 35% had insufficient levels of vitamin D (30 ng/ml or less 25-hydroxyvitamin D).90 After adjusting for age, sex, body mass index, income, and treatment group, insufficient vitamin D status was associated with higher odds of any hospitalization or emergency department visit. In addition to correcting a vitamin D insufficiency, vitamin D supplementation may improve asthma control by blocking the cascade of inflammation-causing proteins in the lung. Preliminary clinical evidence is encouraging, especially in childhood asthma prevention at a dosage of 1,200 IU per day of vitamin D3.91 This study, done in Japan, looked at the efficacy of supplemental vitamin D for preventing influenza infection. The researchers were surprised to find that the vitamin D not only decreased flu by 42% but also decreased asthma attacks by a remarkable 83%.
Asthma patients commonly employ botanical self-treatments. A cross-sectional analysis of 601 adults with asthma found that 14% of asthma sufferers use either herbal products, coffee, or black tea in order to treat their condition. Unfortunately, this study illustrated that those who used these methods had a higher incidence of hospitalization.92 Because of the possibility of improper use of botanicals and the inability of the users to recognize the need for acute conventional interventions, we recommend that before using natural therapies, patients with asthma consult a naturopathic physician or another qualified practitioner who understands the proper use of botanicals and can assess the asthmatic patient’s risk severity.
The most popular historical herbal treatment of asthma involved the use of Ephedra sinensis (ma huang) in combination with herbal expectorants. This approach appeared to have considerable merit, as ephedra and its alkaloids have proved effective as bronchodilators in treating mild to moderate asthma and hay fever.93 However, ephedra preparation are no longer sold in the United States owing to safety concerns when excessive dosages were used as a weight loss aid.
Ivy (Hedera helix)
In Europe, herbal preparations containing extracts from the leaves of ivy (Hedera helix) enjoy great popularity for the relief of coughing as well as asthma. In 2007, more than 80% of herbal expectorants prescribed in Germany included ivy extract, amounting to nearly 2 million prescriptions nationwide. Ivy leaf contains saponins (alpha-hederin and hederacoside C) that show expectorant, mucolytic, spasmolytic, bronchodilatory, and antibacterial effects.94A 2003 meta-analysis of three double-blind studies in children showed that the ivy preparations used were significantly superior to a placebo.95 One study compared ivy leaf extract cough drops with a placebo, one compared suppositories with drops, and one tested syrup against drops. The reviewers concluded that ivy leaf extract preparations improve a variety of respiratory functions in children with chronic bronchial asthma, but noted the data were meager. In the only placebo-controlled, double-blind study reviewed, 24 children with asthma between the ages of 4 and 12 were given a dry ivy leaf extract (35 mg) in cough drops or a placebo for three days with a washout of three to five days before crossing over to the other treatment. Superiority of the ivy leaf extract over the placebo was noted by small improvements in airway resistance, residual volume, and breathing capacity when the baseline measurements were compared with the third day at three hours after the morning dose.
Licorice (Glycyrrhiza glabra) root has a long history of use as an anti-inflammatory and antiallergic agent, and there is considerable documentation in the scientific literature. The primary active component of licorice root in this application is glycyrrhetinic acid, a compound that has shown cortisol-like activity. In particular, glycyrrhetinic acid has been shown to inhibit phospholipase A2, the enzyme responsible for cleaving arachidonic acid from the phospholipid membrane pool and initiating the formation of inflammatory prostaglandins and leukotrienes.96 Licorice is also an expectorant, which is useful to treat asthma.
Capsaicin from Cayenne Pepper
Experimental evidence has shown that capsaicin, the major active component of cayenne pepper (Capsicum frutescens), desensitizes airway mucosa to various mechanical and chemical irritants.97 This effect is probably due to capsaicin-induced depletion of substance P (which normally increases vascular permeability and flow) in the respiratory tract nerves.98 The respiratory and gastrointestinal tracts have large numbers of neurons that contain substance P. Because of the location of substance P and its physiological action, it is believed to play an important role in atopic conditions such as asthma and atopic dermatitis. Therefore, depletion of substance P may be desirable in these conditions.
The jujube plum (Zizyphi fructus) has been used extensively in Chinese medicine for the treatment of asthma and allergic rhinitis.99 It contains cyclic AMP—a compound that promotes bronchial relaxation—at a level of 100 to 500 nmol/g of dry weight, a concentration 10 times greater than that of any other plant or animal tissue thus far reported in the literature.100 These experimental findings, in conjunction with the jujube plum’s long historical use, strongly support its clinical use.
The leaves of tylophora (Tylophora asthmatica) have been used extensively in ayurvedic medicine for asthma and other respiratory tract disorders. Tylophora’s mode of action is unknown but is thought to be due to its alkaloids, especially tylophorine, which have been reported to possess antihistamine and antispasmodic activity, as well as inhibition of mast cell degranulation.101,102 However, a more central mechanism may be responsible for the clinical effects in asthma.
Several double-blind clinical studies have shown tylophora to produce good results.103,106 In one study of 135 patients, those given 200 mg tylophora leaves twice per day for six days demonstrated improvements in symptoms and respiratory function during the treatment period and for up to two weeks after treatment.103 Side effects such as nausea and vomiting occurred in 9.8% of subjects in the tylophora group and 14% in the placebo group.
In another double-blind study of 103 patients, those receiving 40 mg of the dry alcoholic extract of Tylophora indica per day for only six days demonstrated significant improvement in symptoms of asthma compared with a placebo group.105 At the end of the first week, 56% had complete to moderate improvement, as compared with 31.6% of the 92 patients receiving the placebo. At the end of 4 weeks, the respective figures were 32% and 23.8%; at 8 weeks, 23.8% and 8.4%; and at 12 weeks, 14.8% and 7.2%. The incidence of side effects such as nausea, partial diminution of taste for salt, and slight mouth soreness was 16.3% in the tylophora group and 6.6% in the placebo group. These results, as well as the results from an additional study, indicate that the benefits of tylophora are short-lived.106
Ginkgo Biloba Extract (GBE)
Ginkgo biloba contains several unique terpene molecules, known collectively as ginkgolides, that antagonize platelet-activating factor (PAF), a key chemical mediator in asthma, inflammation, and allergies. Ginkgolides compete with PAF for binding sites and inhibit the various events induced by PAF. The antiasthmatic effects of orally administered or inhaled ginkgolides have been shown to produce improvements in respiratory function and reduce bronchial reactivity in several double-blind studies.107,108 Treatment consisted of 120 mg of the pure ginkgolides per day—a dosage that is currently expensive to achieve using GBE with 24% ginkgo flavonglycosides and 6% total terpenoids.
Administration of aloe vera preparations may be effective for patients who are not dependent on corticosteroids. In one study, the oral administration of an aloe vera extract for six months was shown to produce good results in the treatment of asthma in some individuals of various ages.109 The extract was produced from fresh leaves stored in the dark at 4°C for seven days. Subjecting the leaves to dark and cold results in an increase in the polysaccharide fraction—1 g of crude extract obtained from leaves stored in cold and dark produced 400 mg neutral polysaccharide compared with only 30 mg produced from leaves not subjected to cold or dark. The dosage was 5 ml of a 20% solution of the aloe vera extract in saline twice per day for 24 weeks; 11 of 27 patients (40%) without corticosteroid dependence felt much better at the study’s conclusion. The mechanism of action is thought to be restoration of protective mechanisms, plus augmentation of the immune system.
Coleus forskohlii extract may be particularly useful in asthma, as its active component, forskolin, has been shown to have remarkable effects in relaxing constricted bronchial muscles in asthmatics.110–111However, these studies used inhaled doses of pure forskolin. Whether orally administered forskolin in the form of C. forskohlii extract would produce similar bronchodilator effects has yet to be determined. However, on the basis of the plant’s historical use and additional mechanisms of action, it appears likely.
The Indian ayurvedic botanical Boswellia serrata exerts anti-inflammatory and anti-allergy effects. In one double-blind, placebo-controlled study, bronchial asthma was reduced in 70% of 40 patients treated with boswellia gum resin at 300 mg three times per day for six weeks, whereas only 27% of the control group improved. Improvement was seen in physical symptoms and signs such as shortness of breath, the number of attacks, breathing capacity, and eosinophil counts.112
Acupuncture and Acupressure
In traditional Chinese medicine (TCM), chronic asthmatic symptomology is usually characterized as a lung or spleen deficiency. This model considers that acute symptoms may be caused by invasion from cold wind (environmental factors) or by an internal condition stemming from a lung heat condition (increased inflammation and eosinophilia). Chronic asthma is considered more of a weakness in the lung itself or a weakness of the spleen, which is responsible for nourishing the lung chi. In TCM, the emotion of grief is also known to weaken lung chi.
In one study, 41 patients with chronic obstructive asthma were randomly assigned to receive acupuncture plus standard care, acupressure plus standard care, or standard care alone. For each subject, 20 acupuncture treatments were given, and self-administered acupressure was performed daily for eight weeks. According to a standard respiratory questionnaire, the acupuncture subjects showed an average 18.5-fold improvement, whereas the improvement for the acupressure-only subjects was 6.57-fold. Additionally, for patients who received acupressure, the irritability domain score exhibited an 11.8-fold improvement.113 Another study involved 44 patients receiving bona fide or sham acupressure. Each received five 16-minute treatments per week for four weeks. On the basis of breathing function and shortness of breath scores, 6-minute walking distance measurements, and state anxiety scale scores, the acupressure group had significant improvements in breathing and less anxiety compared with the sham group.114
• Cases of asthma are growing in number and severity.
• The first step in the natural approach to asthma is to reduce the allergic threshold by avoiding airborne and food allergens.
• Elimination diets have been successful in identifying allergens and treating asthma.
• A vegan diet can be very effective in reducing asthma symptoms.
• Omega-3 fatty acids can relieve asthma.
• Food additives can trigger allergic reactions and asthma.
• Vitamin B6 supplementation is recommended for the treatment of asthma, especially if the asthmatic has to take the drug theophylline.
• Antioxidants, especially high doses of vitamin C and flavonoid-rich extracts such as grape seed or pine bark, are highly recommended for the treatment of asthma.
• Magnesium can help open the airways.
• Asthmatics should avoid salt.
• Ivy extract has shown benefits in improving lung function in asthmatics.
The effective treatment of asthma requires the consideration of many environmental, dietary, and supplement factors. We recommend consulting a naturopathic physician or another medical practitioner who can help coordinate all of these different factors.
Airborne allergens such as pollen, dander, and dust mites are often difficult to avoid entirely, but measures described above must be taken to reduce exposure.
All food allergens and food additives should be eliminated. The patient who has many food allergies may need to use a four-day rotation diet. Garlic and onions should be liberally used unless the patient reacts to them. If the patient is willing, or if his or her asthma is unresponsive to recommended therapy, a vegan diet (with the possible inclusion of cold-water fish) should be tried for a minimum of four months to one year. Moderate fruit consumption, especially apples, should also be encouraged, along with the liberal use of green tea. For dietary guidelines, see the chapter “A Health-Promoting Diet.”
• A high-potency multiple vitamin and mineral formula as described in the chapter “Supplementary Measures”
• Key individual nutrients:
Vitamin B6: 25 to 50 mg two times per day
Vitamin B12: 800 to 1,000 mcg per day
Vitamin C: 10 to 30 mg/kg in divided doses
Vitamin E (mixed tocopherols): 100 to 200 IU per day
Magnesium (citrate, malate, aspartate, or glycinate): 200 to 400 mg three times per day
Selenium: 200 mcg per day
Vitamin D3: 2,000 to 4,000 IU per day (ideally, measure blood levels and adjust dosage accordingly)
• Fish oils: 1,000 to 3,000 mg EPA + DHA per day
• One of the following:
Grape seed extract (>95% procyanidolic oligomers): 100 to 300 mg per day
Pine bark extract (>95% procyanidolic oligomers): 100 to 300 mg per day
Some other flavonoid-rich extract with a similar flavonoid content, super greens formula, or another plant-based antioxidant that can provide an oxygen radical absorption capacity (ORAC) of 3,000 to 6,000 units or more per day
• Quercetin: 400 mg 20 minutes before meals, or enzymatically modified isoquercitrin (EMIQ) 100 mg per day.
• Lycopene: 15 to 30 mg per day
• Take one or more of the following:
Ivy leaf (Hedera helix), available as tincture, fluid extract, and dry powdered extract in capsules and tablets; typical dosage for adults and children over 12 years of age for a 4:1 dry powdered extract is 100 mg per day (the equivalent of 420 mg dried herbal substance); for children 1–5 years old, dosage is the equivalent of 150 mg dried herbal substance; for children 6–12 years old, the equivalent of 210 mg dried herbal substance
– Powdered root: 1 to 2 g three times per day
– Fluid extract (1:1): 2 to 4 ml three times per day
– Solid (dry powdered) extract (4:1): 250 to 500 mg three times per day
Tylophora asthmatica: 200 mg tylophora leaves or 40 mg dry alcoholic extract twice per day
Coleus forskohlii: 50 mg of an extract standardized to contain 18% forskolin two to three times per day
For patients who respond to emotional stress with asthmatic attacks, counseling is important. Counseling is also important for children with moderate to severe asthma, who may develop behavioral problems.
Acupuncture and Acupressure
Regular acupuncture and home acupressure treatments should be used.