Impact of multivitamin-mineral and cocoa extract on incidence of mild cognitive impairment and dementia: Results from the COcoa Supplement and Multivitamin Outcomes Study for the Mind (COSMOS-Mind)

Alzheimers Dement. 2023 Nov;19(11):4863-4871. doi: 10.1002/alz.13078. Epub 2023 Apr 10.


Introduction: We assessed the effects of multivitamin-mineral and cocoa extract supplementation on incident mild cognitive impairment (MCI) and all-cause probable dementia.

Methods: COSMOS-Mind (N = 2262), a 2 × 2 factorial, randomized-controlled clinical trial administered a telephone-based cognitive battery at baseline and annually for 3 years. Incidence rates of MCI, and separately dementia, were compared among treatment arms with proportional hazards regression.

Results: Over 3 years, 110 incident MCI and 14 incident dementia cases were adjudicated. Incidence rates did not vary by assignment to multivitamin-mineral or cocoa extract (all p's ≥ 0.05); however, statistical power was low. When participants assigned to multivitamin-mineral versus placebo converted to MCI, their scores for global cognition (p = 0.03) and executive function (p < 0.001) were higher and had declined less relative to the previous year (p = 0.03 for global cognition; p = 0.004 for executive function).

Discussion: Multivitamin-mineral therapy may provide cognitive resilience, countering conversion to MCI, but not significantly reduce its incidence over 3 years.

Highlights: Multivitamin-mineral supplementation did not reduce risks for cognitive impairment. Cocoa extract supplementation did not reduce risks for cognitive impairment. Multivitamin-mineral supplementation slowed cognitive declines for incident mild cognitive impairment.

Keywords: cognitive impairment; dietary supplements; pragmatic clinical trial.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Cognition
  • Cognitive Dysfunction* / drug therapy
  • Cognitive Dysfunction* / epidemiology
  • Cognitive Dysfunction* / prevention & control
  • Dementia* / drug therapy
  • Dementia* / epidemiology
  • Dementia* / prevention & control
  • Dietary Supplements
  • Humans
  • Incidence
  • Minerals / pharmacology
  • Vitamins / therapeutic use


  • Vitamins
  • Minerals