beta-carotene

^[1]^[2]^[3]^[4]^[5]^[6]

Introduction

beta-Carotene is a precursor for vitamin A.

excess consumption associated with carotenodermia
beta-carotene may increase the risk for lung cancer (RR=1.20) & stomach cancer (RR=1.54)^[4]
beta carotene 20-30 mg/day associated with increased cardiovascular mortality & increased risk of lung cancer in those who smoke or had workplace asbestos exposure^[6]

beta-Carotene supplements have been touted for health benefits;
meta-analysis of 8 randomized trials involving 138,000 subjects followed for as long as 6 years, overall mortality & cardiovascular mortality was higher in the beta-carotene group (7.4% vs 7.0% & 3.4% vs. 3.1%, respectively)
subjects taking beta-carotene 50 mg QOD for a mean of 18 years had modest but significantly lower risk for cognitive decline than placebo group
- no baseline cognitive measures obtained,
- no benefits were seen after 1 year^[3]

↑ Journal Watch 24(1):7, 2004
↑ Journal Watch 23(16):125, 2004 Vivekananthan DP et al, Lancet 361:2017, 2003 PMID: https://www.ncbi.nlm.nih.gov/pubmed/12814711
↑ ^3.0 ^3.1 Grodstein F et al, A randomized trial of beta-carotene supplementation and cognitive function in men: The physicians' health study II. Arch Intern Med 2007, 167:2184 PMID: https://www.ncbi.nlm.nih.gov/pubmed/17998490
Yaffe K Antioxidants and prevention of memory decline: Does duration of use matter? Arch Intern Med 2007, 167:2167 PMID: https://www.ncbi.nlm.nih.gov/pubmed/17998489
↑ ^4.0 ^4.1 Druesne-Pecollo N, Latino-Martel P, Norat T, et al. Beta-carotene supplementation and cancer risk: a systematic review and meta-analysis of randomized controlled trials. Int J Cancer. 2010;127:172-184 PMID: https://www.ncbi.nlm.nih.gov/pubmed/19876916
↑ ^5.0 ^5.1 Medical Knowledge Self Assessment Program (MKSAP) 19 American College of Physicians, Philadelphia 2022
↑ ^6.0 ^6.1 US Preventive Services Task Force Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer. US Preventive Services Task Force Recommendation Statement. JAMA. 2022;327(23):2326-2333. June 21 PMID: https://www.ncbi.nlm.nih.gov/pubmed/35727271