Can supplementing Vit D help memory?
Vitamin D deficiency is widespread and several studies have found associations between vitamin D, memory impairment and dementia. 
Researchers found a link between vitamin D and the way the brain works. Receptors for vitamin D are found in many parts of the brain and the brain relies on these receptors for protection against damage. Development of plaques and tangles that form Alzheimer’s Disease (AD) are examples of such damage (1).It has been found that people with AD have fewer vitamin D receptors in the part of the brain involved in forming memories (2).
A 2015 study involving 383 participants found that “vitamin D insufficiency was associated with significantly faster decline in both episodic memory (past personal experiences) and executive function performance (the set of mental skills that help get things done), which may correspond to elevated risk for incident AD” The participants ranged from those with dementia, mild cognitive decline and the others were healthy. At the time, the researchers commented on the need to determine if vitamin D supplementation could slow cognitive decline (3).
A 2017 study (4) investigated this question. To help clarify whether or not vitamin D supplementation could improve memory, a group of healthy adults were supplemented with a high (4000IU/daily) or low dose (400IU/daily) of vitamin D3 for 18 weeks. Over the study duration, blood vitamin D levels increased to a mean level up to 130nmol/L in the high dose group and 85.9nmol/L in the low dose group.
The higher dose group resulted in improvement in aspects of visuospatial memory (perception of objects and their spatial relationships eg; retracing ourselves across the city with our visual map) and this benefit seemed to be most prominent in those who were vitamin D deficient at the start of the study.
The optimal level for bone health has been suggested as 75nmol/L or higher. The optimal level for cognition is currently unknown but these findings suggest a potentially higher level may be required to support learning and memory tasks. Vitamin D levels can be increased via diet, supplements and/or sun exposure)
Further research on the benefits of vitamin D supplementation and brain health is required. However, getting your vitamin D levels tested is the first crucial step, whatever your age.
Research:
- Soni M, kos K, Lang IA, et al. Vitamin D and cognitive function. Scand J Clin Lab Invest Suppl.2012;243:79-82
- Qudshoorn C, Mattace-Raso FUS, van der Velde N, et al. Higher serum vitamin D3 levels are associated with better cognitive test performance in patients with Alzheimer’s disease. Dement Geriatr Cogn Disord. 2008;25:539-543.
- Miller JW, Harvey DJ, Beckett LA, et al. Vitamin D Status and Rates of Cognitive Decline in a Multiethnic Cohort of Older Adults. JAMA Neurology. 2015; 72 (1) 1295-1303.
- Pettersen JA. Does high dose vitamin D supplementation enhance cognition? A randomized trial in healthy adults. Exp Gerontol. 2017 Apr;90:90-97
