Ok, so first, I think Frontiers is trash. I am very biased against them. Disclosure : )

Where the heck is this 70K coming from? The consort shows 42k, and only 11k included, and 860 with depression.

So the REAL important sample size is 860 with depression. Compared to 10k without... but the focus on odds ratio may alleviate the sample size difference problems.

Also t he depressed and non depressed groups differ on almost EVERYTHING. So why the focus on this diet effect. They have different BMI, blood pressure, age, gender. You can't necessary jsut 'covary' those out. They could have run a sensitivity analysis limiting that 10k non depressed people to a sample matched across other variables. There are challenges here too but... would have strengthen the results.

Lastly, the measure of depression is weak at best, and not at all diagnostic. But that's very typically a challenge of cohort studies.

Some interesting findings maybe, but if I had to rate it (I don't but I'm gonna), C+.

EDIT PS: Seriously, where the hell does that 70k in the abstract come from? Seems so deceptive to me!