Vitamin E deficiency leads to neuro damage, embryonic death in lab animals

Researchers have found that a dietary deficiency of vitamin E in laboratory animals can cause neurological impairment in developing embryos as well as physical abnormalities and embryonic death.

The researchers, with the Linus Pauling Institute at Oregon State University (OSU) in the United States, have reported their findings in Redox Biology.

While the study was done with zebrafish, a vertebrate that has neurologic development very similar to humans, its results suggest that the one mechanism leading to the damage may be loss of the role vitamin E plays in protecting levels of docosahexaenoic acid (DHA).

DHA, known to be one of the most important of the omega-3 fatty acids, plays a crucial role in brain and cellular development.

In the zebrafish, vitamin E-deficient embryos did not respond correctly to visual cues, had severe physical abnormalities as early as two days after fertilization, and many died before the end of five days.

"DHA in a developing embryo is very important for cell signaling and membrane development," said Melissa McDougall, an OSU graduate research assistant in the Linus Pauling Institute and the College of Public Health and Human Sciences.

"Our research," the lead author of the study noted, "showed that adequate levels of vitamin E are important in preventing depletion of DHA in the embryo."

"Without enough DHA, there was also evidence for disruption of the structural integrity of cell membranes as a whole. It appears that vitamin E protects these critical lipids, such as DHA, from excessive depletion that can cause physical and behavioral damage."

The study showed loss of locomotor activity in vitamin E-deficient embryos. Such embryos were 82 percent less responsive to a light/dark stimulus.

Past research done elsewhere with rodents has correlated low DHA levels with less memory and intelligence, and one study in Bangladesh with vitamin E-deficient pregnant women showed a higher level of miscarriage.

The new findings take on special significance, the researchers say, because more than 90 percent of the adults in the United States who do not take supplements have diets deficient in vitamin E.

The recommended daily allowance of vitamin E for human adults is 15 milligrams a day, and the typical American diet rarely provides that. Vitamin E is most common in nuts, seeds, some leafy greens like spinach, and a few varieties of vegetable oils like sunflower and canola.

In addition, low-fat diets present a special challenge in getting enough vitamin E. Endit