Maybe Insulin Nasal Spray Can Slow Alzheimer’s

Insulin is known to be critical for normal brain function, and patients with Alzheimer's disease exhibit decreased levels of insulin in the central nervous system.  This raises fhe possibility that raising these levels to normal might help maintain cognitive ability.  The development of a different form of insulin, which is given as a spray into the nose, has allowed a study to be done exploring the possible effects of insulin in mild cognitive impairment (MCI).  (The idea behind intranasal administration is to avoid the risk of hypoglycemia, or too low blood sugar.)  Seattle researchers conducted a small pilot study, and published their findings in the journal Archives of Neurology.

The study enrolled 104 subjects; 64 had MCI with memory problems as the prime symptom, and 40 had mild to moderate Alzheimer’s.  Their average age was 72, and over half of them were women.  They were randomly assigned to take either a placebo spray, a spray containing 20 international unit (IU) of insulin, or one containing 40 IU insulin.  A small group of the subjects underwent a lumbar puncture and a positron emission tomography (PET) scan before and after the 4-month treatment period.  All the participants had standard before-and-after cognitive, recall, and activities-of-daily-living tests, as well as a rating of their dementia level.

Treatment with 20 IU insulin was associated with delayed memory scores, and both dose levels preserved activities-of-daily-living, compared with deterioration in the placebo-treated subjects. Both insulin doses also preserved general cognition in the younger participants, compared with placebo scores.  The spinal fluid exams didn’t show any clear-cut changes with insulin therapy.  However, the PET scans revealed less dementia-related low glucose uptake in multiple areas of the brain for patients receiving insulin.

The researchers conclude that the results of this pilot study show that intranasal insulin can stabilize or improve cognition and function in subjects with MCI or Alzheimer’s disease. But they, and other experts, emphasize that future clinical trials for a longer period are needed to substantiate these findings, and to determine the appropriate place of this route for insulin in the treatment of cognitive impairment.

Exciting findings – but don’t expect to be able to get nasal insulin from your doctor, just yet . . . There’s still a lot to find out, first.