A balanced diet is key to maintaining a healthy lifestyle, and this is especially true in people with asthma. While no single vitamin, mineral or supplement can treat or cure asthma, research shows that adequate nutrition may relate to the number of asthma attacks and frequency of symptoms experienced. More specifically, ensuring adequate levels of the vitamins C, D, E and the mineral magnesium may be especially important, since links between low levels of these vitamins and asthma symptoms have been reported.
In people with asthma, constriction of the airways causes wheezing and difficulty breathing. Wheezing and coughing are often prominent symptoms. A January 2000 article from the "Thorax" journal reported an association between vitamin C and asthma attacks. This study found that people with asthma who had a low intake of vitamin C-rich fruits like oranges also had higher risks of wheezing. A February 2006 article from the same journal reported that people with controlled asthma and no wheezing had higher levels of vitamin C in their blood than those who had uncontrolled asthma and wheezing.
Vitamin D is important for the immune system, strong bones and lung health. Unfortunately, it's present naturally in very few commonly consumed foods, and many people are deficient. Vitamin D seems to improve the lungs' response to steroids -- medications used to reduce airway inflammation in asthma. According to an April 2010 article in the "American Journal of Respiratory and Critical Care Medicine," adequate vitamin D levels correlated with less severe asthma and less sensitivity of the airways to asthma triggers. An October 2012 article from the same journal found that asthmatic children who needed more steroid treatments had lower vitamin D levels than children whose asthma was better controlled.
Vitamin E is important for a healthy immune system and function of organs such as the eyes and skin. It naturally occurs in a variety of foods as different forms, or isomers. There is some evidence from animal studies that the alpha isomer, known as α-tocopherol, has anti-inflammatory properties that might help with airway inflammation in the lungs of mice. According to an August 2013 article in the "American Journal of Respiratory and Critical Care Medicine," some studies in humans have reported a small beneficial effect associated with higher alpha-tocopherol, but others have not.
In asthma, it's not just airway inflammation but also smooth muscle contraction that leads to the narrowing of the airways, wheezing and shortness of breath. When given intravenously, magnesium dilates and relaxes the smooth muscles of the bronchi and is sometimes used in this way for severe asthma attacks. Adequate magnesium levels are important, and magnesium intake may also have helpful effects when taken orally. According to a June 2006 article from the "European Journal of Clinical Nutrition," magnesium might work to amplify the effects of inhaled steroids, reduce bronchial sensitivity to allergens and potentially reduce the use of albuterol. Further research is ongoing.
Warning and Precautions
Vitamin and mineral supplements can help maintain adequate nutrition. Although they can be purchased without prescription, vitamins and minerals should be used in accordance with their labels. Some vitamins may lead to dangerous side effects when used in excess. Interactions with medications and adverse effects in those with specific illnesses are also possible, so it's important to inform your doctor about all supplements.