If you have been on the Internet this week, you may have come across a study reportedly showing that vitamin C can be as good for your heart as exercise. Several outlets breathlessly reported the finding under giddy headlines suggesting it was time to cancel that gym membership and stock up on orange juice:
It’s a tempting angle — many of us view exercise as a chore and will jump at any opportunity to avoid this supposedly critical aspect of heart health. Share the post on social media, pop some multivitamins and wait for your heart muscles to spontaneously strengthen and your arteries to unclog themselves.
Sadly, that is not at all what the study showed. The findings, presented at the American Physiological Society Conference, involve a very specific physiologic pathway in a very specific subset of people. You can garner as much just from the title: “Vitamin C Supplementation Reduces ET-1 System Activity in Overweight and Obese Adults.”
For this small study, 35 sedentary overweight and obese (OW/OB) adults were assigned three months of either a daily vitamin C supplementation or a moderate aerobic exercise program. Researchers were specifically looking at the effects on the activity of endothelin-1, a protein that is a regulator of vascular health and is often elevated in OW/OB adults. ET-1 overactivity is associated with high blood pressure, heart attacks, strokes and heart failure. causing constriction of blood vessels.
Lead author Caitlin Dow and her colleagues were investigating whether vitamin C supplementation would be as effective at reducing ET-1 system activity as aerobic exercise — one of the accepted, proven treatments. They found that ET-1 was reduced to a similar extent in both the vitamin C and exercise groups. The research did not look at the benefits of exercise beyond lowering blood pressure, such as strengthening the heart and reducing cholesterol, but they did find that the participants in the exercise group had increased fitness and stamina.
It is an intriguing finding, but this small, early stage, non-peer reviewed study did not show (or claim to show) the results currently being touted in many media outlets. Vitamin C did not affect obesity — there was no evidence of weight loss in either group over the three month period. The results are not generalizable to the overall population, as implied by many of the outlets reporting on the abstract — the small study group was limited to sedentary OW/OB. The study, focused on the ET-1 protein, did not demonstrate a change in any clinically significant measures of cardiovascular disease like cholesterol or blood pressure. Future research is needed before we know if healthcare professionals should consider vitamin C as part of a treatment plan for heart disease. In other words, this study is not a good excuse for anyone to spend more time on the couch.
Speaking to the science reporting on her unexpectedly viral study, Dow explained:
“I’ve actually only seen one or two articles that mention ET-1 as the system we were evaluating. Nearly all of the titles misrepresent the results from the study. I’ve seen articles with titles making claims about vitamin C replacing exercise or calling it the ‘exercise pill,’ which is not what we demonstrate. What’s strange is that in some cases that title will be followed with a statement in the body of the article about how I and the other authors want to point out that vitamin C is, in fact, not an exercise replacement, but a good option for adults with overweight and obesity who can’t exercise. I would prefer it if the title would match the article content better.”
Unfortunately, all that makes for a much less clickable headline.
Caroline Weinberg is a freelance science and health writer covering issues at the intersection of culture and health. She can be found on Twitter @ckw583.