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Dysbiosis of the Gut Microbiota
An imbalance (dysbiosis) in the gut microbiota – the population of microbes residing in the intestinal tract – is associated with airway diseases such as cystic fibrosis and asthma. In cystic fibrosis, abnormal intestinal mucosa is associated with alterations in gut microbiota.41 Patients with cystic fibrosis have a reduced overall bacterial abundance and lower species diversity compared with healthy people.41 Researchers conducted one study of 43 individuals with cystic fibrosis and 69 controls without the disorder.42 Although the greatest differences in diversity of the intestinal microbiota occurred between cystic fibrosis patients and healthy controls, alterations in the gut microbiota were also observed between individuals with cystic fibrosis when divided into groups based upon different parameters including the percent predicted FEV1 (a measurement of lung dysfunction) and the amount of intravenous antibiotic courses received in the previous year. Patients with cystic fibrosis who had severe lung impairment had markedly lower gut microbiota diversity compared with patients who had mild or moderate impairment. Additionally, greater number of IV antibiotic courses was significantly associated with lower diversity of the gut microbiota.
There is also a relationship between the gut microbiota and asthma. Infants given antibiotics have an altered gut microbiota and immune development and an increased risk of childhood asthma.43 However, in one study similar associations were found for maternal antibiotic use before and after pregnancy. This indicated the correlation is either not directly causal or it's not specific to pregnancy.43 Furthermore, researchers have observed a difference in the microbiota profile of people with asthma compared with healthy controls.44
In mice with a predisposition to develop allergic airway diseases, oral administration of the live probiotic Bifidobacterium adolescentis ATCC 15703 alleviated allergic airway inflammation and decreased levels of eosinophils in the airway, hallmarks of allergic asthma.45 In humans, supplementation with 108 CFU per day of the probiotic L. reuterii was effective in reducing bronchial inflammation in children with well-controlled asthma.46
Another study evaluated the effects of supplementation with the prebiotic Bimuno-galactooligosaccharide (B-GOS) on exercise-induced bronchoconstriction and airway inflammation.47 Ten adults with asthma and bronchoconstriction caused by hyperpnea (increased depth and rate of breathing) and eight healthy controls randomly received either 5.5 grams/day of B-GOS or a placebo for three weeks separated by a two-week washout period. The prebiotic intervention resulted in reduced airway hyper-responsiveness along with reductions in markers of airway inflammation.
Air Pollution and Environmental Exposures
Epidemiological evidence indicates there is a significant association between air pollution and the development and worsening of asthma and COPD. The primary components of pollution responsible are ozone (O3) and nitrogen dioxide (NO2), as well as particulate matter (PM) derived from car exhaust and industry.1,48 Diesel exhaust particulate (DEP) can bind proteins and may act as a carrier of allergens, allowing them to penetrate deep into the respiratory tract.1,48 Furthermore, acute flare ups and worsening of idiopathic pulmonary fibrosis correlate with exposure to O3, NO2, and particulate matter.49 In addition, chronic exposure to air pollution might actually cause the development of IPF.49
Indoor pollution including secondhand cigarette smoke and emissions from wood-burning stoves can also exacerbate asthma symptoms.16 Secondhand smoke up-regulates the Th2 immune response in animal studies.50 Exposure to cigarette smoke is also responsible for most cases of COPD.51 Gas appliances can increase the level of nitrogen dioxide breathed in, impairing lung function.16 Offgasing of volatile organic compounds and formaldehyde emitted from paints, adhesives, furniture, carpet, and building materials are also associated with an increased risk of asthma attacks.16
Environmental exposure is also linked to IPF. A meta-analysis found that smoking at any time throughout life or exposure to agriculture/farming, livestock, wood dust, metal dust, and stone/sand were each considered significant risk factors for IPF.19
Natural Support for Lung Conditions
A number of nutritional and lifestyle options exist for patients with pulmonary concerns. Here are some suggestions based on both clinical practice and research.
Idiopathic Pulmonary Fibrosis. Animal studies have reported on the promising effects of a number of botanicals. In a rat model, rosemary extract, which contains rosmarinic and carnosic acids, reduced and cured pulmonary fibrosis even when it was administered after fibrosis occurred.52 Similar results were achieved with rosemary extract in other animal studies.53,54 Green tea is another botanical that has demonstrated anti-fibrotic activity in animal studies. In one of those studies, a rat model of pulmonary fibrosis, green tea extract reduced oxidative stress and suppressed endothelin-1 expression, a mediator of pulmonary fibrosis.55 In another rodent model of pulmonary fibrosis, a combination of green tea extract and curcumin exhibited powerful, synergistic anti-inflammatory effects.56
Gingko biloba and carnitine were also studied in rats exposed to a substance that causes pulmonary fibrosis.57 Researchers induced pulmonary fibrosis in the animals then administered ginkgo or carnitine. Ginkgo decreased the collagen content in the lungs of the rats and reduced inflammation and oxidative stress. Carnitine did not reduce the collagen content but did lower oxidative stress and inflammation.
Additionally, promising results were achieved using Rhodiola rosea L. in a rat model of pulmonary fibrosis.58 Rhodiola protected against fibrotic lung damage through its anti-inflammatory, antioxidant, and anti-fibrotic actions.
Furthermore, a combination of the botanicals Astragali Radix, Angelicae Sinensis Radix, Paeoniae Radix Alba, Pheretima, Chuanxiong Rhizoma, Carthami Flos, and Persicae Semen (known as a Buyang Huanwu decoction) alleviated pulmonary fibrosis of rats by improving lung tissue morphology and reducing levels of serum collagen types I and III.59
Human studies of dietary supplements and IPF have focused on the use of N-acetylcysteine (NAC). A meta-analysis found that although NAC did not have a beneficial effect on changes in forced vital capacity, changes in predicted carbon monoxide diffusing capacity, rates of adverse events, or death rates, it did significantly improve decreases in percentage of predicted vital capacity and 6 minutes walking test distance.60 Inhalation of NAC is a promising route of administration as noted in a study where patients with early stage IPF experienced enhanced forced vital capacity after exposed to NAC in an aerosol form.61
Cystic Fibrosis. In addition to supplementation with probiotics, as noted earlier in this article, there is also justification for support with other nutraceuticals in patients with cystic fibrosis. An imbalance in omega-6/omega-3 polyunsaturated fatty acids is common in cystic fibrosis (CF) patients.62 Consequently, researchers have explored the effects of omega-3 fatty acid supplementation in these individuals. One randomized, placebo-controlled study found that compared to the previous year, cystic fibrosis patients given omega-3 fatty acids experienced a decline in pulmonary exacerbations at 12 months.63 In addition, the subjects receiving the omega-3 fatty acids took antibiotics for a shorter period of time (26.5 days compared with 60 days in participants not receiving the fatty acids.)
NAC is another nutraceutical studied in patients with cystic fibrosis. When combined in an inhaled form together with an aerosol form of an antibiotic drug, it has synergistic effects against P. aeruginosa infections in this group of patients.9 NAC is known for its ability to break down mucus. Therefore, combining it with the drug enhanced the ability of the antibiotic to diffuse into the mucus, compared to when the drug was used alone.
There's also indication that vitamin A may play a role in the health of cystic fibrosis patients. After excluding subjects with acute pulmonary exacerbations, researchers found that cystic fibrosis patients with a moderately high retinol level (up to 110 μg/dL) had the best respiratory function without any signs of toxicity.64
Asthma. Since oxygen radicals play a prominent role in the development of asthma, antioxidant supplementation is important. In one study, levels of the antioxidant vitamins C and E were low in the lung lining fluid of individuals with asthma, despite normal or increased plasma concentrations of the vitamins.65 Furthermore, vitamins E and C may be able to prevent air pollution damage in patients with asthma. Four randomized, controlled trials found that vitamin E combined with vitamin C protected against bronchoconstriction caused by ozone in people with and without asthma.66-69 Furthermore, the gamma tocopherol isoform of vitamin E suppressed markers of inflammation in subjects with asthma and reduced acute airway response.70
Vitamin D is another nutrient of interest to asthmatics. Although not all studies have found an association between vitamin D and asthma, enough evidence exists to warrant its use. Three population-based studies demonstrated a correlation between lower serum vitamin D concentrations and severe asthma exacerbations or core measures of exacerbations such as hospitalizations.71-73 For example, one of these studies observed that vitamin D insufficiency or deficiency in Puerto Rican children is linked to increased likelihood of having had one or more severe asthma exacerbation in the previous year.71
Other nutrients that may be important for individuals with asthma include pyridoxine (vitamin B6), magnesium, and omega-3 fatty acids.74-76
One botanical showing promise in supporting asthma patients is Boswellia serrata, which suppresses the formation of leukotrienes, inflammatory metabolites of arachidonic acid. One double-blind, placebo-controlled trial investigated the effects of 300 mg Boswellia extract three times daily for six weeks in 40 subjects with asthma.77 Symptoms such as difficulty breathing, number of attacks, and wheezing improved in 70% of the participants given Boswellia compared to only 27% of the placebo group. Measurements of lung function also improved in the patients given Boswellia and eosinophilia was reduced.
Due to the connection between GERD and asthma and the finding that stomach acid is low in asthmatics, some clinicians have successfully used hydrochloric acid in asthma patients, indicating there may be justification for its use.16 Moreover, in some people with asthma, aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) can trigger an attack, so avoiding this class of drugs is important.16 By blocking the cyclooxygenase enzyme, NSAIDs lead to production of leukotrienes, which in turn promote inflammation and bronchial constriction.16 Dehydration may also play a role in asthma symptoms.78 Cautioning asthma patients to stay well-hydrated is therefore important. Acupuncture, biofeedback, yoga breathing, and chiropractic care may offer other solutions.16
Chronic Obstructive Pulmonary Disease. Dietary supplements can offer support to COPD patients. Carotenoids and vitamins D and E help suppress lung injury after pollution exposure.79 Furthermore, nitric oxide (NO) modulates lung function and low serum NO concentrations are associated with COPD severity.80 This indicates that NO-balancing supplements such as L-citrulline and beetroot juice may be beneficial.
Additionally, NAC may be beneficial in COPD. In patients with COPD who were at high risk for exacerbations, a randomized, placebo-controlled trial showed that 600 mg twice per day of NAC was associated with a reduction in exacerbations and increased the time to the first exacerbation.81 In another trial, Chinese patients with moderate-to-severe COPD given 600 mg of NAC twice daily for a year experienced a reduced number of exacerbations, especially in the patients with moderate disease severity.82
Our lungs are vulnerable to an onslaught of toxins including cigarette smoke and indoor and outdoor pollution. Lung disorders can seriously affect quality of life and in the case of idiopathic pulmonary fibrosis significantly increase mortality. Incorporating specific nutraceuticals into the regimens of patients with pulmonary concerns and in some cases implementing lifestyle solutions can have a beneficial impact on lung health.
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Dr. Chris D. Meletis is an educator, international author, and lecturer. His personal mission is "Changing America's Health One Person at a Time." He believes that when people become educated about their bodies, that is the moment when true change and wellness begins. Dr. Meletis served as dean of naturopathic medicine and chief medical officer for 7 years at National College of Natural Medicine (NCNM) and was awarded the 2003 Physician of the Year award by the American Association of Naturopathic Physicians. www.DrMeletis.com
Kimberly Wilkes is a freelance writer specializing in health, science, nutrition, and complementary medicine. She has written more than 300 articles covering a variety of topics from the dangers of homocysteine to sugar's damaging effects on the heart. She is the editor of ProThera ® Inc.'s practitioner newsletter and enjoys scouring the medical literature to find the latest health-related science .