Last Updated: December 10, 2018
Vitamin D is essential for good health in aging adults and may play a role in the prevention of diabetes, hypertension and multiple sclerosis.
A recent study has found that a vitamin D deficiency may also play a role in the development of dementia. Learn more about the link found between the deficiency and the disease.
Vitamin D primarily acts as a hormone, synthesized in one place while affecting another.
An estimated 40-75% of all adults are vitamin D deficient. This may be because vitamin D is only naturally present in a few foods. It can be absorbed through sunlight, but because of concerns about skin cancer, doctors recommend getting vitamin D through certain food and supplements.
An international research team conducted a study that observed over 1,600 seniors for six years. They found that those who were severely deficient in vitamin D were more than twice as likely to develop Alzheimer’s and dementia than those who had adequate levels.
Participants who were only mildly deficient had an increased risk of 53%, while those who were severely deficient had a 125% increased risk of developing dementia.
Lead author David Llewellyn, of the University of Exeter Medical School, said:
“We expected to find an association between low vitamin D levels and the risk of dementia and Alzheimer’s disease, but the results were surprising — we actually found that the association was twice as strong as we anticipated.”
The study showed a strong link between dementia and vitamin D deficiency, but researchers are not yet ready to say that a vitamin D deficiency causes dementia. Clinical trials and further research are needed to establish whether adequate levels of the vitamin can prevent or treat the disease.
A more recent study published in JAMA Neurology adds to the growing body of evidence linking low vitamin D levels to cognitive decline. The most recent study to demonstrate the importance of vitamin D to brain health involved 382 participants with an average age of 75.5 years. Some participants had dementia, others had mild cognitive decline and others were healthy.
Researchers took blood tests every year for five years to evaluate the vitamin D levels in each participant and found that participants who had been diagnosed with dementia had a lower vitamin D average than the other groups. Researchers also conducted cognitive tests that evaluated episodic memory, semantic memory, visual perception and executive function. Those tests showed that participants with lower levels of vitamin D demonstrated a greater decline in both cognitive ability and episodic memory.
Authors of the study say that their findings demonstrate a link between vitamin D and cognitive decline:
“Vitamin D insufficiency was associated with significantly faster declines in both episodic memory and executive function performance, which may correspond to elevated risk for incident AD [Alzheimer’s disease] dementia.”
Researchers also note that the study does not prove how the two are related and that “it remains to be determined whether vitamin D supplementation slows cognitive decline.”
It is recommended that adults under the age of 69 consume 600 IU/day and that adults over 70 increase their consumption to 800 IU/day.
Older adults require more vitamin D because they typically spend less time outside getting vitamin D from the sun and their skin does not produce vitamin D as efficiently as younger adults.
While the sun is one of the best sources of vitamin D, some doctors worry about skin cancer risks and recommend getting vitamin D from these sources:
Do you have a vitamin D deficiency? How do you consume enough vitamin D? Do you have any tips that you’d like to share with us? Let us know in the comments below.