Fifteen of sixteen trials never measured the thing people take it for
The sixteen trials pooled 6,276 people who were not deficient and found nothing on memory, attention or depression. Fatigue was meant to be the third outcome, and there was nothing to pool.
What the study found
Fatigue was the outcome fifteen of sixteen trials never measured
Those sixteen trials pooled 6,276 people who were not deficient, and found nothing on memory, attention or depression scores. Fatigue was to have been the third outcome, and there was nothing to pool. Untested is not the same as tested and found useless.
The caveat · Often given with folate, not alone
Everyone studied already had normal B12, so this says nothing about people who are actually short of it. Several of the pooled trials gave B12 inside a B complex alongside folate, so the B12-only signal rests on fewer studies. The fatigue gap is an absence of trials, not a pooled null.
What we don't know
Everyone studied already had normal B12, so this says nothing about people who are actually short of it. Several of the pooled trials gave B12 inside a B complex alongside folate, so the B12-only signal rests on fewer studies. The fatigue gap is an absence of trials, not a pooled null.