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Large doses of vitamin C improve lung function in patients with COPD

Large doses of vitamin C improve lung function in patients with COPDVitamin C is of vital importance to our immune defense, and it serves as a powerful antioxidant to protect cells and tissues. Large quantities of vitamin C are able to improve lung function in patients with chronic obstructive pulmonary disease (COPD) and other chronic lung disorders. This was demonstrated in a large meta-analysis published in International Journal of Chronic Obstructive Pulmonary Disease.

In recent years, there has been a growing interest in mapping out different antioxidants and their ability to protect against various diseases. One of the vitamins that has attracted the most attention with regard to COPD and other chronic lung disorders is vitamin C. In a new meta-analysis, scientists have collected randomized controlled studies (RCT) from different databases to look closer at vitamin C and its effect on lung function, antioxidant status, and nutritional status in 487 patients with COPD (chronic obstructive pulmonary disease). They found that supplementation with large doses (400 mg per day or more) of vitamin C significantly improved breathing and lung function in these patients. Using a so-called spirometer to measure the expiratory flow, the patients showed clear signs of improvement. This was the case with FEV1 (Forced Expiratory Volume in one second) and FVC (Forced Vital Capacity) that measures the total volume of air that can be exhaled during a maximal forced expiration effort.
The meta-analysis also showed that supplementation with vitamin C increased vitamin C levels in blood serum. Also, there was an increase in levels of glutathione (GSH), which is another powerful antioxidant. Glutathione is produced naturally by the body’s cells. Like vitamin C, GSH has a protective and detoxifying effect.

Facts on COPD

  • COPD is short for Chronic Obstructive Pulmonary Disease
  • The lung tissue is damaged and there is a narrowing of the airways
  • Around 430,000 Danes have COPD, but only half of them know that they have the disease
  • Normally, the treatment consists of smoking cessation, medicine, and physical activation/training
  • COPD is considered the 3rd most common cause of death worldwide

COPD, oxidative stress, and vitamin C

COPD is primarily caused by smoking. Tobacco smoke contains thousands of different chemicals that attack lung tissue and enter the bloodstream. The body generates free radicals as a natural byproduct of its energy turnover and other metabolic processes, but this is normally something the body is able to protect itself against. What is worse is oxidative stress where the harmful free radicals outnumber the protective antioxidants, thereby overwhelming the body’s natural defense mechanism. Oxidative stress is known to cause respiratory infections and chronic inflammation, which can lead to additional damage to cells and tissues
Smoking is known to increase oxidative stress and an increased need for antioxidants. With regard to vitamin C, the meta-analysis showed that patients who took 400 mg of the vitamin daily had a significant positive effect on their lung function. However, this was not the case with those who took lower doses.
Apparently, the high doses of vitamin C reduce local damage caused by oxidative stress. Vitamin C is also important for the immune defense, including its ability to support macrophages in the respiratory tract that protect against infections.
There is also a synergistical effect between vitamin C and vitamin E. Vitamin C recycles oxidized vitamin E, thereby helping to reinforce the total antioxidant capacity (TAC).
Vitamin C is also important for supporting different enzyme functions and for synthesizing collagen in lungs and in other tissues.
Taking large amounts of vitamin C therefore support the body in many different ways by reducing oxidative stress and improving lung function.

How to get enough vitamin C

Vegetables, herbs, fruit, and berries are some of the good sources of vitamin C. The recommended daily intake for vitamin C is 80-100 mg and can easily be achieved by eating a varied diet. But the 400 mg that were found to have a positive effect in the meta-analysis may require supplementation. People who smoke or suffer from COPD or other respiratory diseases may therefore consider taking a supplement. A non-acidic form of vitamin C (e.g., calcium ascorbate) may be a good idea because it is gentle on the stomach.


Ling Lei et al. Efficacy of Vitamin C Supplementation on Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis. International Journal of Chronic Obstructive Pulmonary Disease. 2022

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