Amid conflicting reports about the need for vitamin E and how much is
enough, a new analysis published today suggests that adequate levels of this essential
micronutrient are especially critical for the very young, the elderly, and
women who are or may become pregnant.
A lifelong proper intake of vitamin E is also important, researchers
said, but often complicated by the fact that this nutrient is one of the most
difficult to obtain through diet alone. It has been estimated that only a tiny
fraction of Americans consume enough dietary vitamin E to meet the estimated
average requirement.
Meanwhile, some critics have raised unnecessary alarms about excessive
vitamin E intake while in fact the diet of most people is insufficient, said
Maret Traber, a professor in the College of Public Health and Human Sciences at
Oregon State University, principal investigator with the Linus Pauling
Institute and national expert on vitamin E.
"Many people believe that vitamin E deficiency never
happens," Traber said. "That isn't true. It happens with an alarming
frequency both in the United States and around the world. But some of the
results of inadequate intake are less obvious, such as its impact on things
like nervous system and brain development, or general resistance to
infection."
Some of the best dietary sources of vitamin E – nuts, seeds, spinach,
wheat germ and sunflower oil - don't generally make the highlight list of an
average American diet. One study found that people who are highly motivated to
eat a proper diet consume almost enough vitamin E, but broader surveys show
that 90 percent of men and 96 percent of women don't consume the amount
currently recommended, 15 milligrams per day for adults.
In a review of multiple studies, published in Advances in Nutrition,
Traber outlined some of the recent findings about vitamin E. Among the most
important are the significance of vitamin E during fetal development and in the
first years of life; the correlation between adequate intake and dementia later
in life; and the difficulty of evaluating vitamin E adequacy through
measurement of blood levels alone.
Findings include:
•
• Inadequate vitamin E
is associated with increased infection, anemia, stunting of growth and poor
outcomes during pregnancy for both the infant and mother.
• Overt deficiency,
especially in children, can cause neurological disorders, muscle deterioration,
and even cardiomyopathy.
• Studies with experimental
animals indicate that vitamin E is critically important to the early
development of the nervous system in embryos, in part because it protects the
function of omega-3 fatty acids, especially DHA, which is important for brain
health. The most sensitive organs include the head, eye and brain.
• One study showed that
higher vitamin E concentrations at birth were associated with improved
cognitive function in two-year-old children.
• Findings about
diseases that are increasing in the developed world, such as non-alcoholic
fatty liver disease and diabetes, suggest that obesity does not necessarily
reflect adequate micronutrient intake.
• Measures of
circulating vitamin E levels in the blood often rise with age as lipid levels
also increase, but do not prove an adequate delivery of vitamin E to tissues
and organs.
• Vitamin E supplements
do not seem to prevent Alzheimer's disease occurrence, but have shown benefit
in slowing its progression.
• A report in elderly
humans showed that a lifelong dietary pattern that resulted in higher levels of
vitamins B,C, D and E were associated with a larger brain size and higher
cognitive function.
• Vitamin E protects
critical fatty acids such as DHA throughout life, and one study showed that
people in the top quartile of DHA concentrations had a 47 percent reduction in
the risk of developing all-cause dementia.
"It's important all of your life, but the most compelling
evidence about vitamin E is about a 1000-day window that begins at
conception," Traber said. "Vitamin E is critical to neurologic and
brain development that can only happen during that period. It's not something
you can make up for later."
Traber said she recommends a supplement for all people with at least
the estimated average requirement of vitamin E, but that it's particularly
important for all children through about age two; for women who are pregnant,
nursing or may become pregnant; and for the elderly.
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