Memory seems to be a weird thing to study in isolation from such a study. Is this an example of p-hacking where 100 different variables were tested and 1 had to come out as statistically significant but pure luck?
Not to mention how problematic it is that the variable tested is either cocoa or a multivitamin which can contain hundreds of different chemicals.
They did not study memory in isolation. All the details are available at the link to the journal article. It doesn't seen fair to accuse them of p-hacking without first understanding what was studied.
The Centrum brand is mentioned explicitly in some of the articles on this story as well as a guidance from a scientist to use established brands of multivitamin. Hmmm.
I often think that the supplements industry has experienced too much of a backlash against the snake oil salespitches that it was known for not only in past decades, but still continues today.
Vitamins, minerals, monoamine precursors, peptides, fish oil, and various other supplements can have profoundly strong effects. They often need to be tailored for an individual's particular situation to show profound benefits (or just "get lucky" as an individual sometimes stumbles into something that works for them). But they can have powerful effects, even if they're not needed by that individual.
- Blood pressure: Large amounts of fish oil dramatically reduces my blood pressure. I normally have hypertension but can easily induce hypotension (and even tachycardia) by eating large amounts of fish oil every day (or 0.5-1lb of salmon).
- Dopamine: Even basic amino acids like L-Tyrosine or Phenylalanine can be used to get high, or provide much of the effects of ADHD drugs (beneficially or for abuse). This is much more pronounced with Phenethylamine (an OTC supplement), which can create surprisingly MDMA-like experience. Mucuna extract contains clinically relevant amounts of L-DOPA which is an FDA-approved Parkinson's drug (due to its ability to greatly boost dopamine levels). Even aspartame can significantly (not trivially) raise dopamine levels because it's metabolized to phenylalanine.
- HPV: Trametes versicolor and Ganoderma lucidum (Turkey tail mushroom, Reishi mushrooms, respectively) taken orally daily for 2 months has been shown to clear HPV in 88% of subjects whereas the control group cleared just 5% of cases.
It seems very foolish to categorically write off all vitamins, minerals, and other supplements and say "these are all universally a waste of money" or "these have no effect" or "these don't help anyone" or "these only help people with very specific conditions". There are so, so, so many "very specific conditions" out there - it's basic combinatorics that most people will have at least something that they're desperately trying to address, which isn't cured just by exercise and weight loss.
Doctors do not have the time or knowledge to address most people's "edge cases". They rarely have the time and resources even to test which antibiotics will actually fight a particular infection, and have to default to "try this first, it seems to be working for my other patients who recently came in with similar symptoms. If it doesn't work, come back after completing this round of antibiotics and we'll try guessing another antibiotic". Doctors do great work for many common conditions or things they truly specialize in, but I would bet that the majority of preventable/curable conditions are beyond what our medical industry has the capacity to even identify, let alone find a fix for.
I assume they controlled for that though :P