Vitamin C intake and multiple health outcomes: an umbrella review of systematic reviews and meta-analyses

Int J Food Sci Nutr. 2022 Aug;73(5):588-599. doi: 10.1080/09637486.2022.2048359. Epub 2022 Mar 15.

Abstract

The purpose of this article was to assess the existing systematic reviews and meta-analyses for the association between vitamin C intake and multiple health outcomes. A total of 76 meta-analyses (51 papers) of randomised controlled trials and observational studies with 63 unique health outcomes were identified. Dose-response analysis showed that vitamin C intake was associated with reduced risk of all-cause mortality, cardiovascular disease (CVD), oesophageal cancer, gastric cancer, cervical cancer and lung cancer with an increment of 50-100 mg per day. Beneficial associations were also identified for respiratory, neurological, ophthalmologic, musculoskeletal, renal and dental outcomes. Harmful associations were found for breast cancer and kidney stones for vitamin C supplement intake. The benefits of vitamin C intake outweigh the disadvantages for a range of health outcomes. However, the recommendation of vitamin C supplements needs to be cautious. More prospective studies and well-designed randomised controlled trials (RCTs) are needed.

Keywords: Vitamin C; health; meta-analysis; systematic review; umbrella review.

Publication types

  • Review

MeSH terms

  • Ascorbic Acid*
  • Cardiovascular Diseases* / prevention & control
  • Dietary Supplements
  • Humans
  • Meta-Analysis as Topic
  • Nutritional Status
  • Systematic Reviews as Topic

Substances

  • Ascorbic Acid