VOA标准英语2011--Study: Vitamin B12 Deficits in Older Adults Linked to Brain Decline

（单词翻译）

Study: Vitamin B12 Deficits¹ in Older Adults Linked to Brain Decline

A new study says deficiencies of Vitamin B12 might be responsible for declining brain function in older adults. Although people normally get plenty of B12 from fish, meat and dairy products, as well as fortified² cereals and supplements, their ability to absorb the essential nutrient³ can be blocked by a number of factors.

Those include excessive alcohol consumption, anemia⁴ and various digestive-system disorders⁵. Health experts say regular screening and heightened public awareness⁶.can help avoid those potentially brain-wasting deficits.

Just as muscles in the body shrink from malnutrition⁷, a new study done on people age 65 and older says the human brain starts shrinking when there is not enough vitamin B12 in the body.

It’s a key component⁸ of the neurotransmitters in the brain, and part of the nutritional⁹ substance essentially¹⁰ of the brain cells, of the nerves or neurons in the brain," said Dr. Michael Yochelson, a neurologist and the chief medical officer at National Rehabilitation¹¹ Hospital in Washington.

He says the link between vitamin B12 deficiencies and loss of brain volume is important to know about, because the vitamin plays such a critical role in cognition.

“We found that evidence of B12 deficiency was associated with a smaller brain volume and with increased white-matter hyper intensities¹² on the brain images. We also found that the markers of vitamin B12 deficiency were associated with lower cognitive¹³ scores in this sample," said Dr. Martha Claire Morris, one of the authors of the study.

Fish, meat, dairy products, and foods rich in protein are good sources of vitamin B12. Yochelson notes that plant-based diets, as well as diets high in carbohydrates¹⁴, are generally lacking in B12.

He believes people worldwide should be taking vitamin B12 supplements, in the form of pills, injections, or nasal sprays, to prevent the kind of brain function loss described in the study.

“The key [lesson] from this is that we probably need to be testing for this very early on because if there is any hope of successful treatment, it's most likely early treatment before somebody develops cognitive impairment,” Yochelson said.

Dr. Yochelson says the new study should serve as a foundation for more research on younger populations, especially those in Africa, South Asia, and South and Central America, regions with the highest rates of B12 deficiency.