Studies about vitamin D and cognitive performance:

Effect of Vitamin D Replacement on Cognition in Multiple Sclerosis Patients (2017)

Conclusion: Three months of high-dose vitamin D3 supplementation (10,000 IU / day) was found to be effective in improving memory in multiple sclerosis patients.

 

Does High Dose Vitamin D Supplementation Enhance Cognition? A Randomized Trial in Healthy Adults (2017)

Conclusion: Supplementing with 4,000 IU of vitamin D3 a day was found to be effective for improving non-verbal memory in adults – especially in deficient subjects.

 

Association of Metabolic Syndrome and 25-Hydroxyvitamin D with Cognitive Impairment Among Elderly Koreans (2016)

Conclusion: In a study of 2,940 elderly Koreans, those suffering from cognitive impairment had lower vitamin D levels compared to those with higher vitamin D levels.

 

Vitamin D Insufficiency and Cognitive Impairment in Asians: A Multi-Ethnic Population-Based Study and Meta-Analysis (2016)

Conclusion: In a study of 2,273 elderly Singaporean Asians, those with higher vitamin D levels achieved better scores on cognitive tests compared to those with lower vitamin D levels.

 

A Study of Cognitive Functions in Female Elderly Patients with Osteoporosis: A Multi-Center Cross-Sectional Study (2016)

Conclusion: In a study of 277 postmenopausal women, those with osteoporosis were found to have worse cognitive function. Osteoporosis is a symptom of long-term vitamin D deficiency.

 

Serum 25-Hydroxyvitamin D Predicts Cognitive Performance in Adults (2015)

Conclusion: In a study of 254 Lebanese adults in the Beirut area, those with higher vitamin D levels performed better on cognitive performance tests compared to those with lower vitamin D levels.

 

Higher Serum 25-Hydroxyvitamin D and Lower Plasma Glucose Are Associated with Larger Gray Matter Volume but Not with White Matter or Total Brain Volume in Dutch Community-Dwelling Older Adults (2015)

Conclusion: A study of 217 elderly Dutch people found that those with higher vitamin D levels also had higher grey matter volume in their brains.

 

Vitamin D and Cognitive Function: The Tromsø Study (2015)

Conclusion: In a Norwegian cross-sectional study of thousands of people, those with higher vitamin D levels were found to have better cognitive function compared to those with lower vitamin D levels.

 

Vitamin D Deficiency Disrupts Neuronal Integrity in Cognitively Impaired Patients (2015)

Conclusion: In a study of 109 memory-impaired patients, those with higher vitamin D levels were found to have better neuronal integrity.

 

Vitamin D Prevents Cognitive Decline and Enhances Hippocampal Synaptic Function in Aging Rats (2014)

Conclusion: Rats given higher doses of vitamin D performed better in cognitive tests compared to rats given lower doses of vitamin D.

 

Serum 25-Hydroxyvitamin D and Cognitive Decline: A Longitudinal Study Among Non-Demented Older Adults (2014)

Conclusion: A multi-year study of 527 non-demented elderly people found that those with lower vitamin D levels also demonstrated worse cognitive function compared to those with higher vitamin D levels.

 

Relationship Between 25-Hydroxyvitamin D and Cognitive Function in Older Adults: The Health, Aging and Body Composition Study (2014)

Conclusion: In a 4-year study of 2,777 elderly people found that those with lower vitamin D levels had worse cognitive function and experienced a greater decline in cognitive function over the 4 years compared to those with higher vitamin D levels.

 

Vitamin D and the Risk of Dementia and Alzheimer Disease (2014)

Conclusion: In an 8-year study of 1,658 elderly people, there was an increased rate of alzheimer’s disease and dementia among those with lower vitamin D levels compared to those with higher vitamin D levels.

 

Vitamin D Deficiency, Cognitive Impairment and Dementia: A Systematic Review and Meta-Analysis (2012)

Conclusion: “Meta-analysis of 5 cross-sectional and 2 longitudinal studies comprising 7,688 participants showed an increased risk of cognitive impairment in those with low vitamin D compared with normal vitamin D”

 

Vitamin D and Cognitive Impairment in the Elderly U.S. Population (2011)

Conclusion: A study of 3,325 elderly Americans found that those with lower vitamin D levels performed worse on cognitive tests compared to those with higher vitamin D levels.

 

Is Vitamin D Important for Preserving Cognition? A Positive Correlation of Serum 25-Hydroxyvitamin D Concentration with Cognitive Function. (2007)

Conclusion: This study of 32 elderly people found that those with higher vitamin D levels performed better on a cognitive test than those with lower levels.

 

Vitamin D Deficiency is Associated with Low Mood and Worse Cognitive Performance in Older Adults (2006)

Conclusion: A study of 80 older adults found that 58% had inadequate vitamin D levels and those with lower levels had worse scores on depression and cognitive function tests.

 

Vitamin D Supplementation Improves Neuromuscular Function in Older People who Fall (2004)

Conclusion: In this randomized, placebo-controlled experiment, 139 elderly patients with a history of falls were given either a 600,000 IU megadose of vitamin D2 or a placebo. At baseline and 6 months later they were evaluated for postural sway, reaction time, physical performance, and leg strength. At 6 months, the supplemented group had higher vitamin D levels and demonstrated superior reaction time and functional performance compared to the placebo group – who actually exhibited deteriorating physical performance. It’s important to note that almost all studies comparing vitamin D2 and D3 have found D2 to be only about 25% as potent as D3 and a dose of 600,000 IU per 6 months averages out to only about 3,500 IU per day, which is unlikely enough for elderly people to get their levels into an optimal range. “Vitamin D supplementation, in fallers with vitamin D insufficiency, has a significant beneficial effect on functional performance, reaction time and balance, but not muscle strength. This suggests that vitamin D supplementation improves neuromuscular or neuroprotective function, which may in part explain the mechanism whereby vitamin D reduces falls and fractures.”

 

Suppression of Melatonin Secretion in Some Blind Patients by Exposure to Bright Light (1995)

Conclusion: Blind people need bright light exposure (or sunlight exposure) too, but they’re less likely than other people to go and get it and this can cause problems with their sleep/wake cycle. In this study bright light exposure was found to be helpful for suppressing melatonin in blind people, which is important for waking up your brain up, getting yourself on a good sleep/wake cycle, and reducing insomnia.

 

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