Across 3 studies, 1 reported a small beneficial effect of vitamin C on cognitive function, while 2 reported neutral effects. The evidence is inconsistent and the small beneficial signal is tempered by the lack of significance in the majority of studies. No consistent dose or population was identified across the limited evidence base.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The one beneficial study (a systematic review) itself noted insufficient evidence to support use.
Ascorbic acid and a high dose of vitamin E, when given separately, also showed positive effects on cognitive performance, but there is not sufficient evidence to support their use.
Mixed results were seen for omega (ω)-3, tea, and plant extracts
Antioxidants, including vitamins C, B2, and D, along with polyphenols such as xanthohumol, fermented papaya, peanuts, and berry extracts, demonstrate the potential to support cognitive function and promote gut health through mechanisms that modulate microbiome diversity and reduce inflammation.