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Vitamin C and Lung Disease

A study carried out in China pointing out the importance of having a diet rich in vitamin C appears to support findings done elsewhere. A recent report in the American Journal of Epidemiology concludes that dietary vitamin C can help prevent chronic obstructive pulmonary disease (COPD).


COPD is a major cause of death and disability in many countries, both east and west. Patients with (COPD) become hypoxemic (lack of oxygen) especially during sleep, particularly during the rapid eye movement (REM) part of sleep. Those who are most hypoxemic when awake experience the most severe hypoxemia during sleep. A continuous supply of supplemental oxygen is one way to treat people with COPD.

The researchers used a combination of a lung function test together with blood analyses and a diet / health questionnaire to establish factors which may be beneficial against the onset of COPD. As in any study of this nature it is often difficult to link cause and effect. But the data did show that those people who reported diets that were rich in vitamin C, and those who had high levels of vitamin C in their blood, had the best lung function. Other dietary factors, including other anti-oxidants in the diet, did not appear to be related to good lung function which strengthened the conclusion that it was dietary vitamin C that was the important contributor to good lung function.

The immediate question that comes to mind is ’what is the level of vitamin C in the diet that provides protection against COPD?‚ The data in this Chinese study can’t be used to answer that question, but it is clear that once again anti-oxidants in the diet have a major impact on our long term health.

Sources of Vitamin C in the Diet
100g Food mg Vitamin C % of RDA
raw orange:4575
raw grapefruit:3762
raw apple:5.710
raw plum:9.816
potato, baked:12.821
carrot, raw:9.316
peas, boiled:47.980
tomato, raw:19.132
squash, acorn, baked:10.818


American Journal of Epidemiology, vol. 148, pages 594-599, 1998

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