“This study shows that vitamin C intake is positively correlated with human telomere length, which is of guiding significance for our clinical guidance on people’s health care,” researchers from Guangzhou Medical University wrote in the journal Frontiers in Nutrition.
The cross-sectional study used data from the National Health and Nutrition Examination Surveys (NHANES) database from 1999–2000 and 2001–2002.
Telomeres are like ‘shoelace ends’
The aging and lifespan of normal, healthy cells are linked to the so-called telomerase shortening mechanism, which limits cells to a fixed number of divisions.
During cell replication, the telomeres function by ensuring the cell's chromosomes do not fuse with each other or rearrange, which can lead to cancer.
Elizabeth Blackburn, a telomere pioneer at the University of California San Francisco, likened telomeres to the ends of shoelaces, without which the lace would unravel.
With each replication, the telomeres shorten, and when the telomeres are totally consumed, the cells are destroyed (apoptosis).
Previous studies have also reported that telomeres are highly susceptible to oxidative stress and inflammation. Some experts have noted that telomere length may be a marker of biological aging.
Consumption of foods with antioxidant and anti-inflammatory properties have previously been linked with longer telomere length, from selenium to omega-3 fatty acids.
The study analyzed 7,094 subjects (males 48.2%, females 51.8%) from all races in the United States selected from the NHANES database.
Data on leukocyte telomere length (LTL) was previously analyzed using quantitative polymerase chain reaction (PCR) in Dr. Blackburn’s laboratory, and dietary intake was obtained from the What We Eat in America (WWEIA) 24-hour recall interview to evaluate food intake for energy, nutrients and other components.
The Chinese researchers assessed the correlation between vitamin C and telomere length using a multiple linear regression analysis and three adjustment models. Model 1 adjusted for gender, age and race, while Model 2 further adjusted for physical activity, body mass index (BMI) and poverty income ratio (PIR) and Model 3 for diabetes, hypertension, smoking habits, alcohol intake, stroke and cardiovascular disease.
“In this study, after adjusting for multiple linear regression and confounding factors, dietary vitamin C intake was positively correlated with leukocyte telomere length (LTL),” the study concluded. “We found that when Model 2 adjusted for covariates including BMI and diabetes prevalence, the correlation significance decreased, while when Model 3 added other covariates, the correlation significance increased.”
In considering the mechanisms of action, the study suggests that vitamin C may influence telomere length through several potential pathways, including vitamin C’s activation of telomerase activity to repair the shortened DNA sequence. This may be achieved by antagonizing the expression of telomere sequence deletion after DNA replication, preventing telomere sequence from being too short, the researchers explained. Another study indicated that the potential of vitamin C to increase human telomerase activity may be related to the increased expression of enzyme modified proteins.
The researchers call for more in-depth and comprehensive studies to confirm these results.
Source: Frontiers in Nutrition
“Association between dietary vitamin C and telomere length: A cross-sectional study”
Authors: Yuan Cai et al.