Veggie Blog

If you or your child has asthma, you may have read that certain vitamins or herbs can ease it. The old version of this post said that large doses of vitamin C are “very effective” against asthma and that vitamins A, E and B can reduce attacks. That is not what the research shows. This updated article explains the evidence, and the main point is that supplements are not a substitute for asthma medicine.

What is asthma?

According to MedlinePlus, asthma is a chronic lung disease that affects your airways, the tubes that carry air in and out of your lungs. The airways can become inflamed and narrowed, which causes wheezing, coughing and tightness in the chest. When these symptoms get worse than usual, it is called an asthma attack or flare-up. The National Center for Complementary and Integrative Health reports that more than 25 million people in the United States have asthma and that severe attacks can be life-threatening. The NHLBI says there is no cure for asthma, but treatment and an asthma action plan can help you manage it.

What triggers an attack?

Triggers differ from person to person. MedlinePlus lists allergens such as dust mites, mold, pets, pollen and pests, and non-allergen triggers such as cold air, certain medicines, household chemicals, infections like colds and flu, outdoor air pollution and tobacco smoke. Exercise can also trigger asthma, especially when the air is dry. The old post said foods like peanuts and chocolate can trigger attacks. Food allergy can be a trigger for some people, so discuss it with your doctor, but do not cut out foods without advice. The best protection is to learn your own triggers and to use the medicines your doctor prescribes. Read the MedlinePlus page on asthma.

Do vitamins help asthma?

NCCIH has reviewed the evidence on supplements. On vitamin C, a 2013 evaluation of 11 studies with 419 people concluded that there were not enough high-quality studies to show whether it helps asthma, and too much can cause diarrhea, nausea and stomach cramps. On vitamin D, a 2023 comprehensive review of 20 studies (15 in children, 5 in adults) found that supplementation did not reduce the proportion of people who had one or more asthma attacks, although few participants had severe asthma or low vitamin D levels. Selenium did not help in a 2007 trial of 197 adults. NCCIH says evidence does not support using complementary health approaches instead of proven medical management for asthma.

What about herbs such as ginkgo and garlic?

The old post recommended ginkgo biloba and odorless garlic. NCCIH says many herbal products have been studied for asthma, but there has been only a small amount of research on each one. A 2010 evaluation of 26 studies of various herbal preparations found that there was not enough evidence to recommend any of them for asthma. I could not find reliable evidence for ginkgo or garlic specifically. Herbs and supplements can also interact with medicines, so NCCIH advises anyone who takes asthma medicine to talk with their provider before starting a dietary supplement.

What does help?

MedlinePlus says treatment includes strategies to avoid triggers, quick-relief medicines that help relieve symptoms during an attack (including an inhaler that you carry all the time), and control medicines that you take every day to prevent symptoms. A balanced diet with fruit and vegetables is good for everyone, but it is not an asthma treatment. NCCIH says approaches that help people manage stress, anxiety or depression might help them feel better and improve their asthma control when used in addition to medical care. See our article on yoga breathing and asthma for the research on breathing exercises, and vitamins and your health for supplement basics.

When should you get help?

See a doctor if you think you may have asthma, and ask what to do if symptoms get worse. If you have trouble breathing that does not ease with your quick-relief medicine, get emergency medical help. The NHLBI page on asthma explains treatment and action plans in more detail.