By Tirhas Mekonnen, PharmD Student, Cedarville University
Dietary supplements have been used for various reasons. Dietary supplements such as ascorbate, vitamin E, and ß-carotene, are reducing agents and thereby, detoxify reactive oxygen intermediates in the laboratory.1 Researchers are studying to find out if consumption of food rich in these antioxidant compounds could potentially reduce the risk for certain types of cancers as well as other chronic health problems like cardiovascular disease. However, clinical trials with antioxidants as dietary supplements have failed to show clear beneficial effects.1
This article on Medpage Today by Todd Neale discussed a systematic review that investigated the use of mineral and dietary supplementation for primary prevention of cardiovascular disease or cancer.2 The review evaluates 24 randomized, controlled trials and 2 cohort studies that examined the benefits and harms of using vitamin and mineral supplements for primary prevention of CVD, cancer, or all-cause mortality in healthy individuals without known nutritional deficiencies.3 The study found that except for two clinical trials, there was only “a small borderline-significant benefit” from multivitamin supplements on cancer (but only in men), limited evidence supports any benefit from vitamin and mineral supplementation for the prevention of cancer or cardiovascular disease”.3 Although the review looked at many studies there are some limitations.
One of the limitations is that the review included short term studies that analyze the use of dietary supplements.3 However, those short-term studies may not confirm or indicate the outcomes of chronic use of dietary supplements. For example, the median follow up time of the study titled, “Randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals” was only for seven and half years.4 The review also consists of studies done in various countries. However, poor eating habits, tobacco use, consumption of alcohol, and many other variables may differ from one country to the other country. These variables are risk factors for chronic heart disease or cancer.
Other sources have also not found consistent evidence to recommend minerals and dietary supplements for the primary prevention of cardiovascular disease and cancer. An article titled “Nutrient supplements and cardiovascular disease” discussed associations between carotenoids, folic acid, and vitamin E with CVD risk.5 As the article illustrated, previous researchers thought that vitamin E, due to its antioxidant effect, may reduce CVD. However, the article also noted more recent randomized placebo-controlled interventional trials do not support the original assumption regarding vitamin E.5 The article also pointed out that “With few exceptions, a large series of primary and secondary prevention trials have reported no significant benefit of moderate-to high-dose vitamin E supplementation of cardiovascular outcomes”.5
In addition, the use of dietary supplement folate and its association with cardiovascular health benefit was discussed in another review article by Ulrich and Potter et al. This article also is consistent with the previous reviews and studies mentioned above. “The prevention of cardiovascular disease was assumed to be another health benefit of increased folate intake; unfortunately, the results from randomized controlled trials with actual disease outcomes provide no evidence for such an effect.”6 Therefore, there is currently a lack of evidence to suggest that folate prevents cardiovascular disease or cancer.
In conclusion, after reading these reviews and studies, I agree with Mr. Todd Neale, that there is no clear answer for the following question: Is there clear evidence to recommend minerals and dietary supplements for the primary prevention of cardiovascular disease? I would like to get your professional opinion on this matter. Please participate if you have found studies that do have a better explanation as to whether to recommend or to not recommend dietary supplements for the primary prevention of cardiovascular disease or cancer.
- Harvey R, Ferrier D. Lippincott’s illustrated Reviews. 6th ed. Wolters Kluwer Health, Philadelphia, PA/Lipincott Williams & Wilkins; 2011.
- Neale T. USPSTF: Evidence for Supplement Use Lacking. Medpage Today. Published: Nov 11, 2013 Retrieved from http://www.medpagetoday.com/Cardiology/Prevention/42842?xid=nl_mpt_DHE_2013firstname.lastname@example.org&mu_id=5381424
- Fortmann S, Burda B, Senger C, Lin J, Whitlock E. Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force. Annals of Internal Medicine. 2013; published on-line doi:10.7326/0003-4819-159-12-201312170-00729.
- Hercberg S, Galan P, Preziosi P, Bertrais S, Mennen L, Malvy D, et al. The SU.VI.MAX Study: a randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals. Arch Intern Med. 2004;164(21):2335-42. [PMID: 15557412]
- Lichtenstein A. Nutrient supplements and cardiovascular disease: a heartbreaking story. J. Lipid Res. 200; 50:(S429-S433).Available from: http://www.jlr.org/content/50/Supplement/S429.full
- Ulrich M, Potter J. Folate Supplementation: Too Much of a Good Thing? Cancer Epidemiology Biomakers & Prevention Feb 2006;15:189. Retrieved from http://cebp.aacrjournals.org/content/15/2/189.full