Alzheimer’s-Linked Brain Proteins Tied to Poor Sleep

Poor sleep in old age may be linked to the brain-clogging plaques thought to contribute to Alzheimer’s disease, new research suggests.

“Sleep appears to be a missing piece in the Alzheimer’s puzzle, and enhancing sleep may lessen the cognitive burden that Alzheimer’s disease imparts,” said study author Bryce Mander, a postdoctoral fellow at the University of California, Berkeley.

It’s not clear how sleep and memory affect – or are affected by – the accumulation of beta amyloid plaques, believed to interfere with mental functioning. Still, the study findings hint at a major message regarding Alzheimer’s, said Mander, who works at the university’s Sleep and Neuroimaging Laboratory.

For the new study, Mander and colleagues recruited 26 mentally healthy adults ages 70 to 79. They underwent brain imaging to assess plaque buildup, and were asked to remember pairs of words before and after a night’s sleep. Overnight, researchers measured their brain waves, and the next day they conducted MRI scans during the memory testing.

Those patients with the highest levels of amyloid plaques in one part of the brain – the medial prefrontal cortex – had lighter sleep and higher levels of memory problems, the researchers found.

“It is not so much that memory after sleep is important, but that sleep after initial learning is important to help us retain memory for a longer period of time,” Mander said.

The study suggests – but does not prove – that insufficient deep sleep contributes to “a reduced ability to cement memories in the brain over the long-term, resulting in greater memory loss,” he noted.

B Vitamins May Not Boost Memory or Thinking

Taking vitamin B12 or folic acid supplements may not reduce seniors’ risk of memory loss, according to a new study.

Past research hinted that taking vitamin B12 and folic acid might help protect memory and thinking skills, according to background information from the study. But follow-up trials have yielded less convincing findings.

The current study included nearly 3,000 people with an average age of 74. Half took a tablet daily with 500mcg of vitamin B12 and 400mcg of folic acid daily for two years. The rest took a placebo. All participants had high levels of homocysteine, which has been linked to memory loss and Alzheimer’s disease.

Memory and thinking skills tests were given at the start and end of the study. Results of the study were published in the November 12 issue of Neurology.

“Since homocysteine levels can be lowered with folic acid and vitamin B12 supplements, the hope has been that taking these vitamins could also reduce the risk of memory loss and Alzheimer’s disease,” Rosalie Dhonukshe-Rutten, of Wageningen University in the Netherlands, said in a journal news release.

Dhonukshe-Rutten and her colleagues found that people taking the vitamin B12-folic acid supplements had larger decreases in homocysteine levels than those taking the placebo. Despite the decrease, there was no difference between the two groups on the thinking and memory tests.