Vitamin D has proven to be a champion of cognitive health in a recent study assessing healthy adults who possessed a baseline vitamin D of ≤ 100nmol/L, and located in British Columbia, Canada (54˚ North Latitude).
82 adults were randomized and blinded to receive either high dose vitamin D3 (4000 IU/day) or low dose vitamin D3 (400 IU/day) for 18 weeks. The serum levels of 25(OH)D were observed to increase significantly in the high dose vitamin D group, from 67.2 ± 20 to 130.6 ± 26, compared to the low dose group, which increased from 60.5 ± 22 to 85.9 ± 16 nmol/L (p=0.0001). The high dose group also experienced performance improvement on nonverbal (visual) memory, assessed by the Pattern Recognition Memory task (PRM), (84.1 ± 14.9 to 88.3 ± 13.2) (d = 0.3), as well as the Paired Associates Learning Task, (PAL) number of stages completed, from 4.86 ± 0.35 to 4.95 ± 0.22 (p=0.044) (d=0.5). These improvements were not exhibited in the low dose group. It was also noted that the “degree of improvement was comparatively greater in the high dose group for these tasks.” For those possessing insufficient 25(OH)D at baseline (<75nmol/L), a significant improvement (p=0.005, d=0.7) was demonstrated in the high dose group (n=23) (p=0.005, d=0.7).
“Nonverbal (visual) memory seems to benefit from higher doses of vitamin D supplementation, particularly among those who are insufficient at baseline (<75nmol/L).” Thus, they suggested that “higher 25(OH)D is particularly important for higher level cognitive functioning, specifically nonverbal (visual) memory.”
Ref: Petterson JA. Does high dose Vitamin d supplementation enhance coginition? A randomized trial in healthy adults. Exp. Gerontol. 2017 Apr; 90:90-97. Doi: 10.1016/j.exger.2017.01.019. Epub 2017 Feb 4.