HEALING SLEEP: Just one night of poor sleep can significantly increase levels of a toxic brain substance linked to Alzheimer’s disease, a study has found. Researchers used a radioactive tracer to measure the buildup of amyloid-beta peptide in the brains of 20 volunteers aged 22 to 72 over the course of two nights. For one of the nights, participants were allowed a restful period of sleep. For the other, they were sleep deprived. Positron Emission Tomography (Pet) scans were used to track the tracer. They showed that restricting sleep to as little as five hours led to a “significant increase” in amyloid-beta burden in two brain regions vulnerable to damage in Alzheimer’s patients.
The hippocampus plays a key role in memory while the thalamus acts as a relay centre for motor and sensory nerve signals. Amyloid-beta is a protein building block that accumulates in sticky plaques in the brains of people with Alzheimer’s, leading to destruction of neurons. Sleep may play an important role in a natural “waste disposal” system that clears potentially harmful material including amyloid-beta out of the brain, scientists believe. The new findings are published in the journal Proceedings of the National Academy of Sciences.
SKINNY GENES: A gene that makes humans eat more sugar can also lower body fat, new research suggests. Scientists have known since 2013 that a version of the gene FGF21 makes people consume more carbohydrates. Now a group of researchers is showing that despite the effect it has on diet this gene variant decreases fat in the body. Scientists at the University of Exeter said the findings went against the perception that eating sugar was bad for health. The FGF21 hormone, which is made mostly in the liver, has multiple functions. It acts on the hypothalamus in the brain to suppress sugar and alcohol intake, stimulates glucose uptake by fat cells, and acts as an insulin sensitiser. Analysis showed that, although the ‘A’ version of the FGF21 gene leads to greater sugar and alcohol consumption, it is associated with a lower percentage of total body fat. It was also associated with higher blood pressure and a higher waist-to-hip ratio. The findings are published in the journal