Vitamin C Lengthens Lifespan
 
   

Vitamin C Lengthens Lifespan

This section is compiled by Frank M. Painter, D.C.
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   Frankp@chiro.org
 
   

Thanks to Nutrition Science News for this article!


Although vitamin C has long been considered the premier antioxidant, studies linking the vitamin to increased survival rates have been inconclusive. However, a major study conducted by researchers at Cambridge University School of Clinical Medicine in the U.K. and published in Lancet offers evidence that vitamin C saves lives.

This analysis, part of the nine–country European Prospective Investigation into Cancer and Nutrition, was conducted on 19,496 men and women, ages 45 to 79, in Norfolk, U.K., between 1994 and 1997. The participants described their supplements intake, had their plasma tested for ascorbic acid, and kept a detailed five–day diet diary. They were placed in five groups according to their serum ascorbic acid levels. Because women naturally have higher serum ascorbic acid levels, men and women were tracked separately.

Prior to December 1999, the researchers observed how many people died of cardiovascular disease, ischemic heart disease, cancer, and all causes in each of the serum ascorbic acid quintiles. In every case (except for women at risk of cancer), death rates were significantly lower among those with higher serum ascorbic acid levels. People with the highest ascorbic acid levels had half the risk of dying from all causes combined. The chances of dying from cardiovascular disease were reduced by 71 percent in men and 59 percent in women in the group with the highest ascorbic acid levels compared with the lowest. The results were virtually the same when smokers and supplements users were eliminated from the analysis (one–third of the men and half the women took nutritional supplements).

The researchers suggest that the true protective power of vitamin C is stronger than they reported because of individual variables. There was a consistent dose–response relationship across the distribution of ascorbic acid intake. A change from the 30th to the 70th percentile in intake was associated with a 30 percent reduction in mortality. Thus, a practical shift within the normal population could substantially reduce death rates


Read the abstract:

Relation Between Plasma Ascorbic Acid and Mortality in Men and Women in EPIC–Norfolk Prospective Study:   A Prospective Population Study

FROM:   Lancet 2001 (Mar 3);   357:   657–663

Summary:  Background Ascorbic acid (vitamin C) might be protective for several chronic diseases. However, findings from prospective studies that relate ascorbic acid to cardiovascular disease or cancer are not consistent. We aimed to assess the relation between plasma ascorbic acid and subsequent mortality due to all causes, cardiovascular disease, ischaemic heart disease, and cancer.

Methods:  We prospectively examined for 4 years the relation between plasma ascorbic acid concentrations and mortality due to all causes, and to cardiovascular disease, ischaemic heart disease, and cancer in 19496 men and women aged 45–79 years. We recruited individuals by post using age–sex registers of general practices. Participants completed a health and lifestyle questionnaire and were examined at a clinic visit. They were followed–up for causes of death for about 4 years. Individuals were divided into sex–specific quintiles of plasma ascorbic acid. We used the Cox proportional hazard model to determine the effect of ascorbic acid and other risk factors on mortality.

Findings:  Plasma ascorbic acid concentration was inversely related to mortality from all–causes, and from cardiovascular disease, and ischaemic heart disease in men and women. Risk of mortality in the top ascorbic acid quintile was about half the risk in the lowest quintile (p<0·0001). The relation with mortality was continuous through the whole distribution of ascorbic acid concentrations. 20 µmol/L rise in plasma ascorbic acid concentration, equivalent to about 50 g per day increase in fruit and vegetable intake, was associated with about a 20% reduction in risk of all–cause mortality (p<0·0001), independent of age, systolic blood pressure, blood cholesterol, cigarette smoking habit, diabetes, and supplement use. Ascorbic acid was inversely related to cancer mortality in men but not women.

Interpretation:  Small increases in fruit and vegetable intake of about one serving daily has encouraging prospects for possible prevention of disease.

AUTHORS:  Kay–Tee Khaw, Sheila Bingham, Ailsa Welch, Robert Luben, Nicholas Wareham, Suzy Oakes, Nicholas Day

Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge School of Clinical Medicine, Cambridge, UK (Prof K–T Khaw FRCP, A Welch BSc, R Luben BSc, N Wareham MRCP, S Oakes, N Day PhD); and MRC Dunn Human Nutrition Unit, Cambridge (S Bingham PhD)

Correspondence to: Prof Kay–Tee Khaw, Clinical Gerontology Unit, Box 251, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK
(e–mail:kk101@medschl.cam.ac.uk)


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