缺乏维生素D影响大脑功能（在线收听）

Low Levels of Vitamin D Might Hurt Your Brain 缺乏维生素D影响大脑功能

From VOA Learning English, this is the Health & Lifestyle report.

Health experts have long known that vitamin D is important for healthy bones and teeth. It may also help to protect the body against diseases such as diabetes and cancer. And now, researchers say vitamin D might help fight brain diseases called dementias.

Dementias are brain diseases that damage thinking and memory processes, what scientists call “cognitive abilities.” Dementias are difficult to treat. Taking care of someone who has dementia is extremely demanding. And the disease is very frightening to sufferers.

Chris Roberts suffers from dementia. He says the worst part of living with this disease was getting lost while driving.

"The worst thing that I found was getting lost in the car, not just forgetting where I was going - I wouldn't know where I was."

More than 47 million people around the world suffer from dementia. The World Health Organization reports that 60 percent of them live in low- and middle-income countries.

Now a new study in the United States shows a possible link between dementia and low levels of vitamin D.

From where do we get vitamin D?

We get vitamin D from some foods like nuts, lentils and fatty fish like salmon and mackerel.

We also get vitamin D from the sun. But that is not dependable. In some parts of the world, there is not enough sunlight to provide enough vitamin D.

Also, sunblock substances prevent the vitamin from entering the body. To add to the problem, the skin’s ability to process vitamin D weakens as a person ages. As a result, low levels of vitamin D are common among older people.

Researchers at Rutgers University in New Jersey are exploring the relationship between vitamin D and dementia. The team recently measured vitamin D levels and cognitive ability in older people.

Nutritional sciences professor Joshua Miller led the team. He said cognitive abilities differed among the study subjects. He said tests showed that about 60 percent of the group was low in vitamin D.

"Some of the subjects had outright dementia, some had mild cognitive impairment and some had what we would call normal cognitive functioning."

Those subjects who had low vitamin D levels showed more short-term memory loss. They were also less able to organize thoughts, order tasks by importance and make decisions.

"Those who had dementia also had lower vitamin D status than those who had mild cognitive impairment or who had normal cognitive functioning.”

The findings suggest that vitamin D might play a part in slowing dementia. But, more studies are needed to see if vitamin D supplements could help.

The research was published in the Journal of the American Medical Association (JAMA) Neurology.

And that’s the Health & Lifestyle report.

Words in This Story

dementia – n. a brain disease that causes thinking problems

cognitive – adj. of, relating to, or involving conscious mental activities (such as thinking, understanding, learning, and remembering)

status – n. the position or rank of someone or something when compared to others in a society, organization, group, etc.

mild – adj. not strong in action or effect

impairment – n. a condition in which a part of your body or mind is damaged and does not work well

functioning – n. work or operation

decline – v. to become lower in amount or less in number : to become worse in condition or quality

adequate – adj. enough for some need or requirement : of a quality that is good or acceptable

supplement – n. dietary :  a product taken orally that contains one or more ingredients (as vitamins or amino acids) that are intended to supplement one's diet and are not considered food