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NCCIH Clinical Digest

for health professionals

Asthma and Complementary Health Approaches: What the Science Says

May 2022

Clinical Guidelines, Scientific Literature, Info for Patients: 
Asthma and Complementary Health Approaches

Man using an inhaler

Acupuncture

Several studies have examined the effects of acupuncture and asthma, and there is some evidence that the use of acupuncture may be associated with modest improvement of symptoms but not with improvement in measures of lung function.

What Does the Research Show?


  • A 2019 systematic review and meta-analysis of 9 studies (777 participants) that compared conventional asthma treatment plus acupuncture with conventional treatment alone in adults or adolescents found that the use of acupuncture was associated with improved symptoms but not with improvement in measures of lung function.
  • Although studies have been done on moxibustion and the application of herbal patches to acupuncture points to treat asthma, no conclusions can be reached about whether these techniques are helpful because of the poor quality of the research.

Safety


  • Acupuncture is generally considered safe when performed by an experienced practitioner using sterile needles. Improperly performed acupuncture can cause potentially serious side effects. Moxibustion can cause allergic reactions, burns, and infections. Acupoint herbal patching can cause skin redness and itching at the patch site.

Breathing Techniques

Breathing exercises may have positive effects on quality of life and hyperventilation symptoms, but they are unlikely to have a beneficial effect on asthma symptoms.

What Does the Research Show?


  • A 2020 Cochrane review of 22 studies involving 2,880 adults found that breathing exercises may have positive effects on quality of life and hyperventilation symptoms but probably not on asthma symptoms in adults with asthma.
  • A 2019 review looked at 10 studies (466 participants) that evaluated breathing exercises in children with asthma. The breathing exercises were performed alone, as part of yoga, or as part of composite interventions that also included other treatments. The data were insufficient to allow clear conclusions to be reached.

Safety


  • No harmful effects have been reported in studies of breathing techniques in people with asthma.

Meditation

Only a few studies have been conducted on the effects of meditation in people with asthma, but there is some limited evidence that meditation may help improve quality of life in asthma patients.

What Does the Research Show?


  • Not much research has been done on the effects of meditation in people with asthma. However, a 2018 systematic review and meta-analysis of 4 studies (201 participants) found some evidence that meditation may help to improve quality of life in asthma patients.

Safety


  • In general, meditation is usually considered to have few risks. However, because only a few studies of meditation have systematically looked for harmful effects, it isn't possible to make definite statements about its safety.

Yoga

There is some evidence that yoga may lead to small improvements in quality of life and asthma symptoms in people with asthma. 

What Does the Research Show?


  • A 2016 Cochrane review of 15 studies (1,048 total participants, mostly adults) of yoga for asthma found that yoga probably leads to small improvements in quality of life and asthma symptoms. In most of these studies, yoga was added to usual care for asthma.
  • A 2020 review of 9 studies (1,230 participants) of yoga for children or adolescents with asthma provided preliminary evidence that yoga may help to reduce stress and anxiety and improve quality of life and lung function. However, it is uncertain which components of yoga or how much yoga is needed to provide benefits.

Safety


  • Yoga is generally considered a safe form of physical activity for healthy people when performed properly, under the guidance of a qualified instructor. However, as with other forms of physical activity, injuries can occur. The most common injuries are sprains and strains. Serious injuries are rare. People with health conditions, older adults, and those who are pregnant may need to avoid or modify some yoga poses and practices and should discuss their individual needs with their health care providers and the yoga instructor.

Omega-3 Fatty Acid Supplements

What Does the Research Show?


  • A 2021 systematic review and meta-analysis examined 16 studies (464 participants) of omega-3 fatty acid supplementation in people with asthma. Four of the studies looked at fractional exhaled nitric oxide, a marker of lung inflammation, and found that it was lower in participants who were taking omega-3 supplements than in those taking placebos. Four studies reported that omega-3 fatty acids reduced the decline in lung function after exercise that is seen in people whose asthma symptoms are triggered by exercise-induced bronchoconstriction. However, data on the effects of omega-3s on lung function in general and on asthma symptoms were inconclusive.
  • Researchers have looked at whether higher intakes of omega-3s or fatty fish by those who are pregnant might reduce the risk of asthma in their children. In a 2020 systematic review of 4 studies (1,743 participants), 3 of which tested omega-3 supplements and 1 of which tested fatty fish (salmon), no significant reduction in asthma or wheezing was seen in the children.
  • Studies have also tested whether giving infants or children omega-3 supplements could reduce their risk of later developing asthma. A 2015 systematic review and meta-analysis of 5 such studies (with a total of 2,415 infants and children), showed no effect on asthma development.

Safety


  • Side effects from omega-3 supplements are usually mild and may include an unpleasant taste in the mouth, bad breath, digestive symptoms, headache, and smelly sweat. Omega-3s may interact with anticoagulant medicines such as warfarin (Coumadin).

Probiotics

Environmental changes such as improved hygiene may have led to reduced contact with microorganisms early in life, and this decrease may have contributed to an increase in diseases related to allergies, such as asthma. Studies have been done in which probiotics (live microorganisms that are intended to have health benefits) have been given to those who were pregnant and/or young infants in the hope of preventing the development of allergies. To date, probiotic supplementation has not been associated with a lower risk of asthma in infants or had beneficial effects in children with asthma. The effects of probiotics in people who already have asthma have also been studied. 

What Does the Research Show?


  • A 2020 review of 19 studies (5,157 participants) in which probiotics were administered to those who were pregnant and/or infants to try to prevent asthma did not show a significant effect of the probiotics on the risk of asthma in the children. All probiotics were considered together in the analysis of these studies, so it’s not clear whether some individual strains of probiotics might have had an effect that was not detectable in the data as a whole.
  • A 2018 systematic review and meta-analysis of pooled data from 11 studies (910 participants) in which probiotics were evaluated in children with asthma found that taking probiotics led to fewer episodes of asthma and to improvements in 2 measures of immune responses related to allergic disease. However, no significant improvements were seen in measures of asthma control, asthma symptoms, or lung function, and both the number and quality of the studies were low. The reviewers concluded that the evidence does not confirm or rule out beneficial effects of probiotic supplements in children with asthma.

Safety


  • Probiotics have an extensive history of apparently safe use, particularly in healthy people. However, few studies have looked at the safety of probiotics in detail, so there’s a lack of solid information on the frequency and severity of side effects. The risk of harmful effects from probiotics is greater in people who are seriously ill or have compromised immune systems.

Soy Isoflavones

Data suggest that soy isoflavone supplementation does not improve lung function or clinical outcomes in people with asthma, but it may be associated with a reduction in the number of severe asthma attacks in certain populations.

What Does the Research Show?


  • Because preliminary research had suggested a possible link between dietary intake of the soy isoflavone genistein and asthma severity, several U.S. treatment centers looked at whether a soy isoflavone supplement could improve asthma control. The 2019 study, which included 386 adults and adolescents with poorly controlled asthma, showed that the supplement did not improve lung function or clinical outcomes when data from all the participants were considered together. However, further analysis of the data showed that the use of soy isoflavones was associated with a significant reduction in the number of severe asthma exacerbations (asthma attacks) in participants who had specific genotypes associated with high production of plasminogen activator inhibitor 1 (PAI-1), which is associated with asthma severity.

Safety


  • Soy isoflavones appear to be safe for short-term use.

Vitamin D

There is some evidence that suggests that vitamin D may help reduce the risk of asthma exacerbations in adults, particularly in those with low vitamin D levels. Some research has suggested that women with lower intakes of vitamin D may be more likely to give birth to children who develop asthma; however, two large studies have investigated this and found no difference in the occurrence of asthma between children whose mothers had received high-dose vitamin D and those whose mothers had received lower doses.

What Does the Research Show?


  • A 2019 meta-analysis of 14 studies of vitamin D supplementation for asthma (1,421 participants) found evidence that vitamin D may help reduce the risk of asthma exacerbations, particularly in people with low vitamin D levels. This effect was seen only in adults, but only 2 studies in children, with a total of 70 participants, looked at effects on asthma exacerbations. Additional evidence on children comes from a study published in 2020. This study, which included 192 children, all of whom had low vitamin D levels, did not find a protective effect of vitamin D supplementation against severe asthma exacerbations.
  • Some research has suggested that women with lower intakes of vitamin D may be more likely to give birth to children who develop asthma. Two large studies have been done to find out whether giving high-dose vitamin D supplements to those who are pregnant can reduce the risk of asthma in their children. 
    • One of the studies, conducted in Denmark, involved more than 600 women; the other, in the United States, involved more than 800. In both studies, pregnant women were randomly assigned to receive either high doses of vitamin D or the usual doses included in prenatal vitamin supplements. 
    • When the children were assessed at the age of 3, the findings were inconclusive. In both studies, fewer of the children whose mothers had received high-dose vitamin D had been diagnosed with asthma or recurrent wheezing, but the difference between the two groups did not reach statistical significance. 
    • The children in both studies were assessed again at the age of 6 in a follow-up study published in 2020. At that time, there was no difference in the occurrence of asthma between children whose mothers had received high-dose vitamin D and those whose mothers had received lower doses.

Safety


  • Vitamin D can be harmful if taken in excessive amounts, causing symptoms such as nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, and dehydration.

References


NCCIH Clinical Digest is a service of the National Center for Complementary and Integrative Health, NIH, DHHS. NCCIH Clinical Digest, a monthly e-newsletter, offers evidence-based information on complementary health approaches, including scientific literature searches, summaries of NCCIH-funded research, fact sheets for patients, and more.

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