There are a lot of reasons to be sceptical of this study.
The main results of the actual study show that the confidence interval for the study includes zero (-0.003, 0.13)], indicating no significant effect. I don’t understand why they are calling that significant.
Also, “ CMV has received research support from Nestlé-Purina Petcare Company, Mars Edge, and American Foundation for Suicide Prevention…
The COcoa Supplement and Multivitamin Outcomes Study (COSMOS) is supported by an investigator-initiated grant from Mars Edge, a segment of Mars dedicated to nutrition research and products“
The only significant results they have come from a meta analysis where its not clear they account for multiple-testing