Study links brain health to presence of vitamin D
People with moderate-to-severe vitamin D deficiencies are significantly more likely to develop Alzheimer's disease or other forms of dementia than those who have an adequate supply of the vitamin in their body, a study has found.
Researchers led by David Llewellyn at the University of Exeter Medical School found that adults who suffered from a moderate deficiency of vitamin D had a 53 percent higher risk of some form of dementia, while the risk increased 125 percent in those with severe deficiencies. People moderately deficient in vitamin D were 69 percent more likely to develop Alzheimer's-caused dementia, while those severely deficient raised the risk to 122 percent.
The team discovered what appear to be clear threshold levels for brain health using standard medical measurements of concentration in the blood. The risk of dementia appears to rise for people with vitamin D blood levels below 25 nanomoles per liter, while vitamin D levels above 50 nanomoles appear to be good levels for brain health.
The researchers acknowledged the possibility of reverse causation — that is, that having dementia might alter a person's behavior or diet in such a way as to contribute to vitamin D deficiency — but suggested that the makeup of the study made that unlikely.
Llewellyn said that although the international team of researchers expected to find a link between vitamin D deficiency and dementia, the strong correlation between the two was surprising. He said further study was necessary to determine whether consuming oily fish or vitamin D supplements might prevent Alzheimer's disease.
“We thought it was important for bone health. But there's this recent revelation that it might be playing an important role throughout the body,” Llewellyn said. He said more recent research suggests that vitamin D may act as a buffer that regulates calcium levels in brain cells.
Alzheimer's disease is the leading cause of dementia, affecting more than 5 million people in the United States. That number is expected to reach 16 million by 2050 as the population ages.
Vitamin D, which helps the body use calcium, is created when skin is exposed to sunshine. Milk is often fortified with the vitamin, and it is also found in fatty fish and other foods.
Researchers in the Exeter study noted that laboratory experiments have shown that vitamin D may play a role in ridding cells of beta-amyloid plaques, an abnormality that distinguishes Alzheimer's.
“It seems to be that vitamin D was actually helping to break down and take away those protein abnormalities,” Llewellyn said Wednesday in an interview.
Knowing that previous studies have also linked vitamin D deficiency to heightened risk of cognitive decline in older people, the multinational team of researchers studied vitamin D blood levels in 1,658 people age 65 and older who were able to walk, free of dementia, and without a history of cardiovascular disease or stroke. Medical personnel tracked the subjects over six years, using brain scans, cognitive tests, medical records and other diagnostic tools, to see how many developed Alzheimer's disease or other forms of dementia.
The study, funded in part by the Alzheimer's Association, appeared in Neurology, the medical journal of the American Academy of Neurology.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Boy, 13, arrested in fatal stabbing at David Wark Griffith Middle School in East Los Angeles
- National Weather Service to evaluate work after missed call on storm
- Pentagon puts ‘fork’ in news about ex-captive Bergdahl
- Pittsburgh travelers feel effects of Northeast blizzard
- Ramping up e-cigarette voltage may be more hazardous to health
- Systemic flaws found in safety oversight of gas pipelines
- 3 million gallons of brine leak from N.D. pipeline
- Medicare payments to tie doctor, hospital payments to quality rather than volume of care
- Blizzard howls its way into Boston but largely spares NYC
- Evidence doesn’t support charges in Ferguson shooting death, sources say
- House GOP cancels vote on abortion bill