Two Studies - Common Conclusion
One study shows that consuming a diet rich in the antioxidant powerhouse vitamin E may help reduce the risk for dementia, including Alzheimer's disease. Another study suggests that low blood levels of vitamin D may increase risk for cognitive decline.
In the vitamin D study of 858 adults aged 65 and older, those with the lowest blood levels of vitamin D -- less than 25 nanomoles per liter of blood -- were 60% more likely to show signs of general cognitive decline during the six-year study and 31% more likely to show declines in their ability to plan, organize, and prioritize (so-called executive function), than their counterparts who had sufficient blood levels of vitamin D.
But experts, including the study researchers, caution that it is still too early to make any blanket recommendations about what individuals should eat and what supplements they should take to reduce their risks for age-related cognitive decline and dementia.
A decline in memory and cognitive (thinking) function is considered by many authorities to be a normal consequence of aging. While age-related cognitive decline (ARCD) is therefore not considered a disease, authorities differ on whether ARCD is in part related to Alzheimer’s disease and other forms of dementia or whether it is a distinct entity. People with ARCD experience deterioration in memory and learning, attention and concentration, thinking, use of language, and other mental functions. ARCD usually occurs gradually. Sudden cognitive decline is not a part of normal aging. When people develop an illness such as Alzheimer’s disease, mental deterioration usually happens quickly. In contrast, cognitive performance in elderly adults normally remains stable over many years, with only slight declines in short-term memory and reaction times.
Vitamin E and Alzheimer's Risk
A second study in the July issue of the Archives of Neurology shows that eating foods rich in vitamin E may help lower risks of developing dementia and Alzheimer's disease.
In the study of 5,395 people aged 55 and older, those who got the most vitamin E in their diet -- 18.5 milligrams per day, on average -- were 25% less likely to develop dementia, than their counterparts who got the least vitamin E on their diet, about 9 milligrams per day.
Vitamin E can be found in whole grains, wheat germ, leafy green vegetables, sardines, egg yolks, nuts and seeds, but most participants in the new study got their vitamin E from margarine, sunflower oil, butter, cooking fat, soybean oil, and mayonnaise. Antioxidants like vitamin E protect the body from damage caused by harmful molecules called free radicals.
Elizabeth R. Devore ScD, of Erasmus Medical Center in Rotterdam, Netherlands, and colleagues followed the study participants for 9.6 years. During this time, 465 developed dementia, including365 cases of Alzheimer's disease. The researchers also looked at how much vitamin C, beta-carotene and flavonoids participants consumed, but only dietary vitamin E seemed to be related to dementia risk.
Vitamin D is often called the sunshine vitamin because our bodies produce it in response to sunlight. Vitamin D has become the "it" vitamin in recent years, as growing research links its deficiency to a host of health problems including heart disease, certain cancers, osteoporosis, diabetes, schizophrenia, and some autoimmune disorders.
Anywhere from 40% to 100% of older adults in the U.S. and Europe may be vitamin D-deficient, according to information cited in the new study.
Vitamin D and Dementia Risk
"Our study demonstrates that low levels of vitamin D are associated with an increased risk of new cognitive problems," study researcher David J. Llewellyn, PhD, of the University of Exeter, England, says in an email. "This raises the possibility that vitamin D supplements may have therapeutic potential for the prevention of dementia and clinical trials are now urgently needed."
"We do not yet know the optimal intake of vitamin D to protect the brain as we need the results of clinical trials to confirm this," says Llewellyn.
Andrew Grey, MD, of the University of Auckland in New Zealand, co-authored an editorial accompanying the new study that calls for rigorously designed trials. The new study "should serve as a springboard to conduct a randomized placebo-controlled trial to investigate whether vitamin D supplements prevent dementia."
"Similarly, other observational studies have reported associations between lower levels of vitamin D and many other diseases [and] randomized controlled trials of vitamin D supplementation are required to determine whether these associations are causal," says Grey.
As of right now, "vitamin D should only be measured if clinically indicated -- [such as in] the frail elderly, dark-skinned people -- and those who avoid the sun for religious, cultural, or medical reasons are at risk of clinically important vitamin D deficiency," he says.
"At present, there is not rigorous evidence for health benefits of vitamin D supplementation in community-dwelling individuals, beyond avoiding the very low levels," he says. The bottom line? "Routine supplementation of vitamin D is not, at present, justified."
Currently, the dietary reference intake (DRI) for vitamin D is 200 IU per day for adults aged 14 to 50, 400 IU per day for adults 50 to 71, and 600 IU per day for those older than 71. The Institute of Medicine is considering new recommendations for vitamin D intake.
While the jury is still our regarding vitamin D and dementia risk, there are many people in the medical community that believe there are numerous health dangers associated with vitamin D deficiency.
For proponents of vitamin D supplementation, they believe the time to supplement is before you develop signs of dementia or other diseases.
The role of vitamin D is to prevent and reduce risk of certain diseases, so there is no need to treat people for these diseases.
More Study Needed
Right there are conflicting study’s regarding the potential benefits of vitamin D or vitamin E supplementation for reducing the risks to cognitive decline, dementia and Alzheimer’s disease.
While the studies are interesting and may prove beneficial for future approaches for the prevention cognitive decline, dementia and Alzheimer’s disease, there is no assurance that raising the levels of vitamin D or vitamin E would reduce the association with these conditions.
However, if one's levels of vitamin D or vitamin E are severely low then of vitamin D or vitamin E supplementation may be warranted for many health reasons, including but not limited to cognitive decline, dementia, and Alzheimer’s disease.
As far as eating more vitamin E-rich foods to reduce risk of Alzheimer's disease, other factors may be at play; meaning that it may not be the E per se as much as the fact that people who eat diets that are rich in vitamin E and other antioxidants may eat less fat and sugar. It is also important to note that the study benefits were seen from whole foods, not supplements. Several studies indicate that anti aging and disease prevention benefits associated with antioxidants are only associated with antioxidants derived from foods and not from supplementation. Until studies prove otherwise, people looking to improve their health and reduce their risk to several chronic diseases and conditions associated with aging, should consider improving their diet to ensure that they are not deficient in vitamin D, vitamin E and antioxidants.
Devore, E.E. Archives of Neurology, July 12, 2010; vol 67: pp 819-825.
Llewellyn, D.J. Archives of Internal Medicine 2010; vol 170: pp 1135-1141.
Grey A. Archives of Internal Medicine, 2010; vol 170: pp 1099-1100.