High Hopes

Researchers at Ohio State University say that they have found evidence suggesting that compounds found in marijuana may benefit the aging brain by reducing inflammation and possibly stimulating the growth of new brain cells. Professor Gary Wenk and colleagues have already proven that a drug containing synthetic tetrahydrocannabinol, a.k.a. THC, the main psychoactive substance in marijuana, can improve memory in animals. They are now working to uncover the mechanism behind THC’s apparent memory-boosting properties.

Their latest findings suggest that at least three receptors in the brain are activated by the THC-like drug. All three receptors are part of the endocannabinoid system, which plays a role in a variety of physiological processes, including memory, appetite, mood and pain response. Research suggests that when the THC-like drug binds to those receptors, it helps the brain curb inflammation while also stimulating the production of new brain cells, or neurons. 

Tests have also shown, however, that the drug is not effective once memory impairment is already evident, meaning that the drug can be used only to guard against future memory impairment.

“Could people smoke marijuana to prevent Alzheimer’s disease if the disease is in their family? We’re not saying that, but it might actually work,” Professor Wenk said. “What we are saying is it appears that a safe, legal substance that mimics those important properties of marijuana can work on receptors in the brain to prevent memory impairments in aging. So that’s really hopeful.”

Up Your Vitamin D?

Scientists are calling on the government to increase the recommended daily intake of vitamin D to 2,000 international units.

The current RDIs of vitamin D are 200 I.U. for adults up to 50 years of age, 400 I.U. for people between 51 and 70 and 600 I.U. for those aged 70 and over. The scientists say that the current RDI needs to be increased because research conducted in recent years has linked vitamin D deficiency to myriad diseases, including tuberculosis, psoriasis, multiple sclerosis, inflammatory bowel disease, type 1 diabetes, high blood pressure, heart failure, muscle myopathy and cancer. They believe that the incidence of many of those diseases could be reduced by 20 to 50 percent or more if vitamin D deficiency—currently found in 40 to 60 percent of the U.S. population—and insufficiency were eradicated. That could be done by increasing vitamin D intake to ensure serum levels of 40 to 60 ng/m.

The “call to D action” is led by eminent scientist Anthony Norman, professor emeritus of biochemistry and biomedical sciences at the University of California, Riverside. “Two thousand I.U. per day of vitamin D3, a form of vitamin D, is the appropriate intake for most adult Americans,” said Norman. “This intake is the National Academy of Sciences/Institute of Medicine’s upper limit for daily intake and is 400 I.U. less than the National Academy of Sciences/Institute of Medicine’s ‘no adverse health effect’ level.”

In October 2008 the American Academy of Pediatrics announced its decision to double the daily amount of vitamin D it recommends for children to 400 I.U. per day. IM

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