Extra Insulin in Brain Boosts Performance

Raising insulin levels in the brain may improve the symptoms of Alzheimer’s Disease. Researchers have known for some time that people with Alzheimer’s have lower levels of insulin in the central nervous system. Not only are insulin levels lower, but the insulin that is there may not be as efficient.
Administering extra insulin through injections has too many drawbacks. For one thing, people might experience sudden and calamitous drops in blood sugar. For another, insulin injections can cause other side effects including insulin resistance. Veterans Affairs scientists used a special nasal drug delivery device to get insulin into the brain.
More than 100 people with Alzheimer’s disease or memory loss were randomized to get insulin or placebo. Over the four months of the study, those getting insulin were better able to remember a story they’d heard 20 minutes earlier. Patients getting insulin maintained their initial scores on cognitive tests, while those on placebo declined. There were no serious side effects reported. As promising as this preliminary study appears, it is still too early to recommend intranasal insulin for treating Alzheimer’s disease. Larger, longer-term studies are needed to confirm these potential benefits.
[Archives of Neurology, online Sept. 12, 2011]