No cardiovascular or mortality effects were seen with multivitamins, vitamin D, calcium, or vitamin C in a meta-analysis incorporating 156 randomised controlled trials and meta-analyses, according to a group led by Dr David Jenkins, of the University of Toronto in Ontario. Only moderate-quality evidence was available associating folic acid (vitamin B9; RR 0.79, 95% CI 0.69-0.92) and B vitamins (RR 0.90, 95% CI 0.81-1.00) with reduced stroke risk, Jenkins and colleagues reported.
"In the last 2 years, there have been no trials of sufficient size and consistency to alter the advice previously given by the US Preventive Services Task Force 7 years ago that identified a general lack of effect of vitamins and minerals in altering the risk of cardiovascular disease (CVD) or total mortality, with the exception of folic acid and the B vitamins that reduce stroke," the authors noted.
Niacin (vitamin B3) was tied to increased all-cause mortality (RR 1.10, 95% CI 1.00-1.20) when taken with background statins, the researchers warned.
They noted the addition of 35 papers to the dataset since their last literature review of diet supplements in 2018.
With newer data, the verdict is in for vitamin D: these supplements "do not benefit cardiovascular health in the general population and therefore should not be taken for this purpose," said another group, led by Dr Erin Michos, of Johns Hopkins School of Medicine in Baltimore.
"The pendulum has shifted, and the hype for vitamin D supplements as a panacea for multiple diseases, including CVD, is over. Even the benefits of supplemental vitamin D on bone health appear overstated for the general population," Michos and co-authors wrote.
They undertook a separate literature review of dietary supplementation data, finding calcium to be potentially harmful while also arriving at the conclusion that vitamin D does not benefit cardiovascular health.
These two supplements, often taken together for bone health, had no heart benefits when looking at the totality of observational and randomised studies such as ViDA and the more definitive VITAL trial, the team said.
Yet whether vitamin D supplementation helps in cancer, COVID-19, or people who are vitamin D deficient remains unknown, Michos' team acknowledged.
No trial of calcium supplementation has been a designated cardiovascular outcome trial. Nevertheless, since some data suggested cardiovascular harm with calcium supplements, the group suggested they "be used cautiously, striving for recommended intake of calcium predominantly from food sources."
Jenkins and colleagues also stressed that people get their essential nutrients from diet, stating: "In the absence of very clear micronutrient health benefits and with concerns that excess consumption of certain micronutrients may have undesirable consequences, it appears that more certain CVD gains can be achieved by dietary change that follows the move to more plant-based diets, as advised now internationally."
Study details
Supplemental Vitamins and Minerals for Cardiovascular Disease Prevention and Treatment: JACC Focus Seminar
David JA Jenkins, J David Spence, Edward L Giovannucci, Young-in Kim, Robert G Josse, Reinhold Vieth, Sandhya Sahye-Pudaruth, Melanie Paquette, Darshna Patel, Sonia Blanco Mejia, Effie Viguiliouk, Stephanie K Nishi, Meaghan Kavanagh, Tom Tsirakis, Cyril WC Kendall, Sathish C Pichika, John L Sievenpiper
Published in the American Journal of Cardiology in February, 2021
Abstract
This is an update of the previous 2018 systematic review and meta-analysis of vitamin and mineral supplementation on cardiovascular disease outcomes and all-cause mortality. New randomized controlled trials and meta-analyses were identified by searching the Cochrane library, Medline, and Embase, and data were analyzed using random effects models and classified by the Grading of Recommendations Assessment Development and Evaluation approach. This updated review shows similar findings to the previous report for preventive benefits from both folic acid and B vitamins for stroke and has been graded with moderate quality. No effect was seen for the commonly used multivitamins, vitamin D, calcium, and vitamin C, and an increased risk was seen with niacin (with statin) for all-cause mortality. Conclusive evidence for the benefit of supplements across different dietary backgrounds, when the nutrient is sufficient, has not been demonstrated.
[link url="https://www.medpagetoday.com/primarycare/dietnutrition/90876"]Full MedPageToday report[/link]
[link url="https://www.jacc.org/doi/abs/10.1016/j.jacc.2020.09.619"]Journal of the American College of Cardiology (Open access)[/link]
[link url="https://www.jacc.org/doi/10.1016/j.jacc.2020.09.617"]JACC literature review[/link]
See also MedicalBrief archives:
[link url="https://www.medicalbrief.co.za/archives/vitamin-d-supplements-not-reduce-cardiovascular-risk/"]Vitamin D supplements do not reduce cardiovascular risk[/link]
[link url="https://www.medicalbrief.co.za/archives/omega-3-fish-oil-supplements-linked-with-lower-cvd-risk/"]Omega-3 fish oil supplements linked with lower CVD risk[/link]
[link url="https://www.medicalbrief.co.za/archives/studies-show-little-or-no-benefit-from-omega-3-supplements-and-slight-risk/#:~:text=Omega%203%20supplements%20have%20little,will%20protect%20against%20heart%20disease."]Studies show little or no benefit from omega-3 supplements and slight risk[/link]
[link url="https://www.medicalbrief.co.za/archives/supplements-no-magic-bullet-analysis-277-clinical-trials/"]Supplements no ‘magic bullet’ — analysis of 277 clinical trials[/link]