Paul E Marik1, Mark Flemmer. 1. Department of Medicine and the Nutrition Study Group, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA. marikpe@evms.edu
Abstract
BACKGROUND: Dietary supplements are regularly used by at least half of the American population, yet the health benefits of these agents are unclear. OBJECTIVE: A systematic review to determine the benefits and risks of dietary supplements in Westernized societies. DATA SOURCES: MEDLINE, Embase, Cochrane Register of Controlled Trials and citation review of relevant articles. STUDY SELECTION: Randomized, placebo-controlled clinical trials in non-pregnant Westernized adults that evaluated clinical outcomes of nutritional supplements. DATA EXTRACTION: Data were abstracted on study design, study size, study setting, patient population, dietary intervention and clinical outcomes. The outcome of each study was classified as non-beneficial, beneficial or harmful according to whether the end-point(s) of interest reached statistical significance. DATA SYNTHESIS: Sixty-three studies met the criteria for our systematic review. No benefit was recorded in 45 studies, with 10 of these showing a trend towards harm and with two showing a trend towards benefit. Four studies reported harm with increased cancer deaths (n=2) and increased fractures (n=2). Two studies reported both a harmful as well as a beneficial outcome. A beneficial outcome was reported in 12 studies; 6 which studied vitamin D and three which investigated omega-3 fatty acids. While a benefit was reported in one study each which investigated Vitamin E, folic acid and Ginkgo biloba this benefit was not confirmed by larger and more adequately powered studies. CONCLUSIONS: With the possible exceptions of Vitamin D and omega-3 fatty acids there is no data to support the widespread use of dietary supplements in Westernized populations; indeed, many of these supplements may be harmful.
BACKGROUND: Dietary supplements are regularly used by at least half of the American population, yet the health benefits of these agents are unclear. OBJECTIVE: A systematic review to determine the benefits and risks of dietary supplements in Westernized societies. DATA SOURCES: MEDLINE, Embase, Cochrane Register of Controlled Trials and citation review of relevant articles. STUDY SELECTION: Randomized, placebo-controlled clinical trials in non-pregnant Westernized adults that evaluated clinical outcomes of nutritional supplements. DATA EXTRACTION: Data were abstracted on study design, study size, study setting, patient population, dietary intervention and clinical outcomes. The outcome of each study was classified as non-beneficial, beneficial or harmful according to whether the end-point(s) of interest reached statistical significance. DATA SYNTHESIS: Sixty-three studies met the criteria for our systematic review. No benefit was recorded in 45 studies, with 10 of these showing a trend towards harm and with two showing a trend towards benefit. Four studies reported harm with increased cancer deaths (n=2) and increased fractures (n=2). Two studies reported both a harmful as well as a beneficial outcome. A beneficial outcome was reported in 12 studies; 6 which studied vitamin D and three which investigated omega-3 fatty acids. While a benefit was reported in one study each which investigated Vitamin E, folic acid and Ginkgo biloba this benefit was not confirmed by larger and more adequately powered studies. CONCLUSIONS: With the possible exceptions of Vitamin D and omega-3 fatty acids there is no data to support the widespread use of dietary supplements in Westernized populations; indeed, many of these supplements may be harmful.
Authors: Marco Vinceti; Gabriele Dennert; Catherine M Crespi; Marcel Zwahlen; Maree Brinkman; Maurice P A Zeegers; Markus Horneber; Roberto D'Amico; Cinzia Del Giovane Journal: Cochrane Database Syst Rev Date: 2014-03-30
Authors: Aly Bernard Khalil; Salem A Beshyah; Nabila Abdella; Bachar Afandi; Mounira M Al-Arouj; Fatheya Al-Awadi; Mahmoud Benbarka; Abdallah Ben Nakhi; Tarek M Fiad; Abdullah Al Futaisi; Ahmed Ak Hassoun; Wiam Hussein; Ghaida Kaddaha; Iyad Ksseiry; Mohamed Al Lamki; Abdulrazzak A Madani; Feryal A Saber; Zeyad Abdel Aal; Bassem Morcos; Hussein Saadi Journal: Oman Med J Date: 2018-07
Authors: Luigi Barrea; Barbara Altieri; Barbara Polese; Barbara De Conno; Giovanna Muscogiuri; Annamaria Colao; Silvia Savastano Journal: Int J Obes Suppl Date: 2019-04-12
Authors: Marco Vinceti; Catherine M Crespi; Carlotta Malagoli; Cinzia Del Giovane; Vittorio Krogh Journal: J Environ Sci Health C Environ Carcinog Ecotoxicol Rev Date: 2013 Impact factor: 3.781