THE SUPER-ALLERGY-FIGHTING ANTIOXIDANT
Rebecca works as a respiratory therapist at a hospital in New York City and ironically developed asthma about a year after starting work. At first glance this seems strange, because the job of a respiratory therapist is to help people with acute or chronic lung diseases breathe better. In fact, the science shows that Rebecca’s case is not unusual. Respiratory therapists are three to five times more likely to develop asthma after they begin to work in respiratory care as before, an article in the prestigious journal Annals of Internal Medicine explains.1
In another study, an international team led by a University of Texas physician sought to uncover the reasons for the elevated level of asthma risk in health-care workers. Knowing environmental exposures to be a prime suspect, they looked into hospitals and found cleaning and disinfecting chemicals, building cleaning solutions, and various adhesives. They determined that “occupational exposures are important contributors to asthma in health care providers.” In addition, they cite earlier research linking administration of aerosolized medications to higher asthma risk for health-care workers.2
I explained to Rebecca that all sorts of chemical aerosols, even household cleaning sprays, increase the risk of developing or aggravating asthma, as we saw in Chapter 5.
Rebecca was being treated daily with a combination of drugs—a steroid and a bronchodilator—that kept her asthma under control. As a respiratory therapist she knew the potential side effects of the medications and did not want to rely on them for the rest of her life. In order to help her overcome dependence on medication, I had to understand all the factors contributing to her chronic asthma.
Rebecca had lifelong allergies to dust and dust mites, those microscopic, spiderlike insects that feed on the debris from human skin. Exposure to these gave her a stuffed nose, which she still experienced most mornings. She also had chronically dry skin, which is common among people with allergies. She kept her apartment very clean and dust-free, used household cleansers labeled “all natural” and “nontoxic,” and ran a humidifier all winter hoping that her skin would stay moist. I saw a problem there, and also a solution.
Indoor humidity encourages the growth of dust mites, as we saw in Chapter 5. So my first recommendation to Rebecca was that she measure the relative humidity in her apartment with an inexpensive device sold in most hardware stores. Technically it’s called a hygrometer, but asking for a humidity meter is more likely to get you to the right place in the store. Mites thrive when the relative humidity is greater than 50 percent.
I recommended that Rebecca keep her home’s humidity between 30 and 40 percent and that we find other ways to keep her skin moist—nutritional ways. For example, supplementation with fish oils and evening primrose oil, described in Chapter 12, not only can help asthmatic symptoms but may also help to keep skin moist, working from the inside. I also recommended mite control measures, as discussed in Chapter 5.
Although Rebecca had less control over her environment at work, there were important protective measures she could take: cleaning her equipment only in a well-ventilated space, avoiding spray cleaners as much as possible, and being careful to minimize the spread of nebulized medication into the air when administering aerosol treatments.
Next, I needed to understand Rebecca’s diet and lifestyle. She lived with her boyfriend, enjoyed her work, went running three or four times a week, and ate a relatively healthy diet, low in sugar and better than the average North American diet, but with considerable room for improvement.
Because Rebecca was a runner, I thought she might be hyperventilating. About a third of all people hyperventilate—that is, they overbreathe from time to time—and hyperventilation due to exercise or psychological stress can trigger asthma attacks.3 I told Rebecca about a simple, effective method of breath control that has been shown to help asthmatics reduce their reliance on medication.4 It was developed by a Russian physician, Konstantin Buteyko, and is described in a book to which I wrote the foreword, Breathing Free, by Teresa Hale, founder of London’s Hale Clinic. Instructional videos are available through Buteyko Centers in several countries.
As a professional respiratory therapist, Rebecca grasped Buteyko’s method quickly and wondered why she’d never learned about it in her training.
Before thinking about next steps, I wanted to suggest some dietary changes. Once we determined that there wasn’t a problem food for Rebecca I turned my attention to enriching her diet for enhanced respiratory health.
I asked her to increase consumption of cruciferous vegetables like broccoli, cauliflower, brussels sprouts, and kale, eating six to eight ounces of food from that family every day. I asked her to eat saltwater fish three times a week and to use nuts, like almonds and walnuts, as her main snack food. I asked her to avoid products containing soybean oil, telling her about the research at Northwestern University that I described in the last chapter.
The final step involved the powerful antioxidant glutathione. To enhance glutathione, Rebecca began using undenatured whey protein every day and 600 milligrams of the amino acid NAC three times a day. When her chronically stuffed nose began to clear, I decided it was okay to wean her slowly and cautiously off her asthma inhalers, first eliminating the bronchodilator, then the inhaled steroid, according to a closely monitored schedule. She’s been off the inhalers for three years now.
Which component of Rebecca’s treatment had the greatest impact: environmental changes, breathing control, diet, or glutathione enhancement? My view is that they were all important and worked together in synergy. And glutathione’s contribution was crucial.
Your Body’s Best Friend
Glutathione is your body’s best antioxidant friend. You’ve already made its acquaintance in some of the earlier chapters of this book. Unseen and unsung, this friend has been working tirelessly behind the scenes to help you detoxify, balance your immune system, and much more. It’s a key weapon in your arsenal for fighting allergic reactions, and now research from around the world is unlocking the potential for glutathione to help improve the condition of asthma as well.
Glutathione is the rock star of antioxidants. It is also a team player, supporting the functioning of vitamin C, vitamin E, and selenium in the body. Glutathione plays an especially important role in helping to maintain the health of your lungs, nose, and sinuses. In fact, it is the major antioxidant in the respiratory tract.
The research suggests that glutathione could be as important for people with nasal allergies and sinus problems as for asthmatics. Levels of glutathione in the nasal lining of people with chronic sinusitis are only half the levels found in people without sinusitis, observed a study from University Hospital Vrije Universiteit in Amsterdam. The greater the degree of inflammation, the lower the level of glutathione.5
Scientific studies usually examine only one variable at a time. In real life there are multiple variables that impact a condition like asthma all the time. I use multiple approaches to enhance glutathione levels because the combination can yield better results than any single approach.
Enhancing Glutathione with Food or Supplements
Foods and supplements that increase the body’s stores of glutathione have been shown in research studies to help provide various potential benefits, which I highlight below. Decisions about whether and how to use them must be individualized. Just as health status and nutritional requirements vary from person to person, the most appropriate methods of enhancing glutathione will vary as well. Always consult your doctor before changing your nutrition routine or taking nutritional supplements.
Whey Protein
Whey supplies the amino acid cysteine, one of the building blocks your body uses to make glutathione. Availability of cysteine is a well-documented limiting factor for glutathione production. Consumption of whey protein at a dose of 30 to 45 grams a day (about two to three level tablespoons) by healthy young adults significantly raised the glutathione levels of their white blood cells in a study done at McGill University in Montreal.6
In adults with exercise-induced asthma, 30 grams of undenatured whey protein a day for four weeks improved postexercise airflow in a randomized, double-blind, placebo-controlled study.7
These research studies suggest that whey protein is potentially a beneficial source of antioxidants for people with asthma and can improve bronchial airflow. However, I do not recommend the use of whey protein by people with cow’s milk allergy, because whey is derived from cow’s milk. Milk allergy may occur in 10 percent of asthmatics.
NAC, a Building Block of Glutathione
N-acetylcysteine (NAC) is a rapidly absorbed form of the amino acid cysteine and is available as a dietary supplement. Its main antioxidant benefit derives from its conversion to glutathione.8 Because NAC administration rapidly increases the synthesis of glutathione, it is used in hospitals to raise glutathione levels of people with liver failure from an overdose of the painkiller acetaminophen, which is best known by the brand name Tylenol. Acetaminophen has been shown to increase the risk of asthma, probably by depleting glutathione (see “Painkillers May Aggravate Asthma” on the next page).
Research on NAC vs. Air Pollution
Research is being done around the world on the potential of NAC to help alleviate asthma, especially when air pollution is involved. One of the major respiratory irritants in provoking asthma is diesel fumes from trucks, buses, and automobiles: asthmatics respond to these fumes with increased asthma symptoms, airway hyperirritability, and inflammation. Recent research has demonstrated the ability of NAC in pill form to help reverse the aggravation of asthma produced by exposure to diesel fumes. This effect is probably caused by increasing glutathione levels in the respiratory tract.
Scientists at the University of British Columbia studied the protective effect of NAC for asthmatics who were exposed to diesel exhaust. They also measured the restriction in airflow produced by exposure to the chemical methacholine, which causes bronchial narrowing.9 They found that taking 600 milligrams of NAC three times a day for six days reduced baseline bronchial reactivity to methacholine by 20 percent and prevented the increase in hyperreactivity provoked by diesel fumes for the participants in the study. These protective effects of NAC were associated with a decrease in measures of oxidative stress.10 Of course you should always avoid diesel fumes and other sources of air pollution.
NAC, taken for three months, has also been shown to be helpful in promoting healing of laryngopharyngeal reflux, a disturbance in upper gastrointestinal function that is closely linked to asthma (see Chapter 9).11
Laboratory studies from the University of Valencia in Spain suggest that NAC inhibits activation of eosinophils and could be a useful treatment of allergic inflammation.12 And NAC may prevent some aspects of the scarring and airway remodeling that occur in chronic asthma, according to laboratory research done in Japan.13 All these effects are likely to be due to the ability of NAC to serve as a precursor of glutathione.
The timing of supplementing with NAC is important. It has a short life span in the blood. A single dose disappears rapidly, and more effective levels are achieved if NAC is given at a moderate dose three times a day rather than at a high dose once a day. At 600 milligrams of NAC three times a day for five days, glutathione levels in red blood cells increase by 50 percent.14
Warning: NAC may interfere with the action of some drugs used to treat cancer. If you are undergoing treatment for cancer, discuss all use of dietary supplements with your doctor.
Painkillers May Aggravate Asthma
Painkillers of different types may aggravate asthma. Aspirin and drugs like ibuprofen (Advil and Motrin) and naproxen (Aleve and Naprosyn) have long been known to precipitate asthma attacks in susceptible people, especially those with nasal polyps. Acetaminophen (Tylenol) has a subtler long-range influence on asthma. Your liver converts it to a highly toxic chemical that requires glutathione for its removal. Taking acetaminophen increases your need for glutathione, and if that need is not met, glutathione deficiency readily results, with disastrous consequences. By depleting glutathione, daily use of acetaminophen reduces total antioxidant capacity in your blood in as little as two weeks.15
Exposure to acetaminophen during the first year of life is associated with an increased risk of developing childhood asthma, according to research from the University of Coimbra in Portugal. Use of acetaminophen by children with a family history of asthma is also associated with an increased risk of developing asthma, as is regular use of the drug by adults. A recent scientific review stated: “There is substantial epidemiological evidence in adults and children that acetaminophen use is associated with asthma symptoms.”16
Helping Glutathione Do Its Job
Your friend glutathione needs co-factors—vitamins and minerals that help it work properly. You can think of them as a friend of a friend. They help glutathione to perform its antioxidant functions in your body.
Selenium from Food Sources
Selenium is an essential mineral, with a recommended daily allowance (RDA) for healthy adults of 55 micrograms per day. The foods richest in selenium are Brazil nuts (two a day can supply the RDA), saltwater fish, and whole grains grown in selenium-rich soil.
Selenium is not itself an antioxidant, but it plays a critical role in allowing glutathione to do its job. When glutathione works as an antioxidant, it essentially sacrifices itself. It helps to restore the oxidant/antioxidant balance in cells by allowing itself to become oxidized. In doing so, it goes from its active antioxidant form, called GSH, to its oxidized and less active state, called GSSG. The enzyme that permits this is glutathione peroxidase (GPx). GPx depends on selenium for its activity.
Selenium and Asthma
Several studies have found reduced dietary intake or blood levels of selenium in asthmatics when compared with controls.17 A few clinical trials have found beneficial effects of selenium supplementation at a level of 200 micrograms per day in adults with asthma. The benefits, according to the research, may include improvement in airflow, decreased need for inhaled steroids, and decreased inflammation as measured by the levels of chemical mediators called soluble adhesion molecules, which are part of the late-phase asthmatic reaction.18
After Brazil nuts, which may contain as much as 544 micrograms of selenium per ounce (almost ten times the recommended daily allowance in 20 nuts), the richest food sources of selenium are seafood and organ meats. Other sources include muscle meats, cereals and other grains, and dairy products.
The amount of selenium in plants depends on the amount of selenium in the soil and several other factors, such as soil pH, amount of organic matter in the soil, and whether the selenium is in a form that is amenable to plant uptake. As a result, selenium concentrations in plant-derived foods vary widely by geographic location. Because the selenium content of soil affects the amount of selenium in the plants that animals eat, the quantity of selenium in animal products can also vary widely.
Magnesium from Food Sources
Magnesium is an essential mineral that affects the activity of hundreds of enzymes in your body. Its major dietary sources are green vegetables, nuts, seeds, beans, and seafood. People can maintain good magnesium levels by eating foods rich in magnesium.
The top food sources of magnesium are:
Magnesium and Asthma
Higher dietary magnesium in the general population is associated with a decreased risk of inflammation and a decreased risk of wheezing and bronchial hyperreactivity. In people with chronic lung disease, reduced magnesium in the blood is linked to impairment of antioxidant defenses.19
When children with allergic asthma were given 12 weeks of magnesium supplementation (200 to 300 milligrams per day, depending upon age), the level of GSH in their red blood cells increased and their need for asthma inhalers decreased.20
Studies done in several countries have demonstrated similar benefits for magnesium supplementation in adolescents and adults. For teenagers with allergic asthma who needed steroid inhalers, 300 milligrams of magnesium per day for eight weeks reduced asthmatic symptoms and bronchial reactivity to methacholine, permitting decreased steroid doses, and also diminished allergen-induced skin test responses.21 Improvement in symptoms and lung function has been seen in adults with mild to moderate asthma who received 340 milligrams of magnesium per day.22 This level of magnesium intake is readily achieved through a healthy, plant-based diet. The Immune Balance Smoothie, consumed just once a day, meets half the magnesium needs of a healthy adult.
Stress can deplete your body’s stores of magnesium by increasing its excretion through your kidneys. This appears to be the result of stress hormones like adrenaline, which blocks the uptake of magnesium into cells. High stress and low magnesium create a vicious cycle. People with low magnesium levels are more susceptible to the jarring effects of stress and produce more adrenaline when stressed, which aggravates the magnesium deficit in their cells. Improved stress management is a key part of the Allergy Solution, as described in Chapter 10.
Adrenaline: A Two-Edged Sword
Adrenaline is a powerful bronchodilator, and injections of adrenaline are given to treat acute asthma attacks. Adrenaline has some powerful side effects, however, which include rapid heartbeat, high blood pressure, and anxiety.
Bronchodilators are drugs with adrenaline-like effects taken as inhaled aerosols for treating asthma. They have the same side effects as injected adrenaline. The most common bronchodilator is albuterol.
A study done in the emergency department of Denver General Hospital found that frequent use of albuterol by nebulizer resulted in a significant decline in serum magnesium levels over 90 minutes.23 When inhaled or oral bronchodilators are used as the only treatment for asthma, there is an increased risk of serious side effects.24 A Canadian study found that people who relied on inhaled bronchodilators as the primary treatment of asthma had a higher rate of hospitalization and emergency room visits.25 Magnesium depletion might be one mechanism for the side effects of bronchodilators.
To improve your magnesium status, increase your consumption of magnesium-rich foods: green vegetables like broccoli and leafy greens, beans, and nuts, picking those to which you have no allergy.
Vitamin C, Enzymes, and GSH
The effects of vitamin C in asthma appear to be quite variable and may depend upon its close relationship with glutathione, the level of air pollution, and the enzymes that utilize glutathione for detoxification and antioxidation, rather than any direct antioxidant effect of vitamin C in the lung.
Supplementation with vitamin C raises glutathione levels but has no effect on levels of vitamin C itself in respiratory secretions.26 Vitamin C’s antioxidant effect may be due to its ability to enhance GSH. A little-known effect of vitamin C supplementation is to increase the activity of GPx and also to increase activity of the enzyme that recycles GSSG back to GSH, an enzyme called glutathione reductase (GR).27 This effect increases the ability of glutathione to function as an antioxidant.
Research on the health benefits of vitamin C in asthma has shown inconsistent results. These inconsistencies may be related to genetics and environment. People are most likely to need supplemental vitamin C if they have genetic deficiencies of detoxifying enzymes called glutathione-S-transferase enzymes (GSTs) and are also exposed to higher levels of air pollution.
GSTs use glutathione to enhance detoxification. They attach glutathione to a toxic substance so that it can be eliminated from the body. People with genetic defects of GSTs develop reduced levels of vitamin C in blood, probably because their level of oxidative stress is greater.28 In some populations they are more susceptible to developing asthma.29 Asthmatic children with defective GST genes are more susceptible to the irritant effects of ozone than are asthmatic children with normal GST genes. They are also more strongly harmed by reduced dietary vitamin C than are asthmatics with normal GST genes.30
The first step in improving vitamin C status is to increase intake of foods, like tomatoes and citrus fruit, that are rich in vitamin C. If you are exposed to higher levels of air pollution and have defects in the enzymes of detoxification, you may also benefit from vitamin C supplements.
Conclusion
This section focused on the globe-spanning research into glutathione, the superstar of antioxidants. Glutathione plays a key role in detoxification and is the major antioxidant in the respiratory tract. It works together with vitamin C and other antioxidants to protect against inflammatory damage to your body’s cells and tissues.
I reviewed the research on enhancing glutathione levels and effects through nutrition. I introduced the nutrients that assist glutathione in its important functions, magnesium and selenium, and pointed out delicious food sources of them. We saw that inflammation is linked to lower glutathione levels and that common painkillers can deplete the body of glutathione.
I encourage you to bring the advances in nutrition and lifestyle presented here with you when you see your doctor. Always consult your doctor before changing your nutrition routine or taking nutritional supplements.