A recent study out of Rutgers University has some interesting finding regarding vitamin D supplementation and some cognitive functions.
Essentially, researchers found that overweight and obese older women who took three times the recommended daily dose of vitamin D showed improvements in memory and learning.
There was also a morbidity however, and the researchers also found that subjects had slower reaction times.
Researchers looked at three groups of ladies between the ages of 50 and 70 in a randomized controlled trial. The groups followed the following protocols:
- One group took 600 international units per day for a year
- The next group took 2,000 IU
- The final group took 4,000 IU
Researchers found that memory and learning improved at 2,000 IU per day, but did not improve in the 4,000 IU group. They also found reaction time to be slower at 2,000 IU and significantly slower at 4,000.
It is unclear from the literature just what type of vitamin D was taken, and if it was ingested alongside complimentary compounds such as vitamin K2.
Another issue of course is the population chosen. This is not what anyone would call a healthy population. Results here have little to do with how a healthy, performance minded individual would perform under the same circumstances.
Lastly, we know very little about the lifestyle choices of the subjects, other than we do know that they are overweight or obese.
What we do know from other studies is the role vitamin D plays in the improvement of cognitive function. While this study is certainly flawed, it still points to some improvement in cognitive functions that other studies point to, which in a way is replication.
I look forward to more work on the reaction time question, and hope that work will be a bit more rigorous in the future.