By: Mark Lange, PhD
Over the years, a number of studies have indicated that there may be a protective factor to vitamin c when it comes to cardiovascular health. These results, however, have been considered inconclusive due to their inconsistency and the possibility of fiber as a confounding factor. To more accurately address the connection between vitamin c and cardiovascular mortality, a longitudinal study was conducted with participants in the Seguimiento Universidad de Navarra (University of Navarra follow-up) (SUN).
The SUN project is an ongoing, prospective, and multipurpose cohort of Spanish university graduates. The SUN participants completed a questionnaire every 2 years that allowed researchers to monitor vitamin C intake, fiber, calories, and how often on average they had consumed 136 foods and beverages during the past year. Vitamin C intake was highly correlated with fiber intake because fruits and vegetables are a source of both. However, the researchers were able to adjust the numbers to nullify the fiber effect.
To track the participants’ health, they were asked to fill out questionnaires and report any incident that occurred. Medical records and the death registry were monitored over the course of the study to ensure accuracy.
The results showed that those participants with the highest vitamin C intake had a lower risk of cardiovascular mortality by 70%. Aortic aneurysm, heart failure, and hypertriglyceridemia at baseline were less prevalent among participants with higher vitamin C intake as well. This remained true in the age and sex-adjusted model, the model for demographic, metabolic, and lifestyle risk factors, as well as in models further adjusted for fiber intake.
What it means:
The protective factors of vitamin c stem from its antioxidant capabilities. These protective factors may help prevent oxidative changes which are key in reducing the risk of atherosclerosis. While an inverse association between vitamin c and cardiovascular events was found, the sample size was large, and the study was consistently run over a mean of 11 years, further studies will need to look into a more representative sample to eliminate residual confounding factors.
Vitamin C Intake is Inversely Associated with Cardiovascular Mortality in a Cohort of Spanish Graduates: The SUN Project: doi: 10.3390/nu9090954