Almost every week there is news about leptin. This small peptide hormone discovered about 12 years ago is still looking for a disease it can cure or prevent. In the past, leptin has been promoted as a cure for aging, help with weight loss, improving depression, increasing libido and cognition. Now there is news that fat hormone may help prevent Alzheimer’s dementia (AD).
"Hopefully, in 10 or 15 years this may be one of many agents that we use to reduce the risk of Alzheimer's disease. Or it may be one of many markers that we measure in combination to predict risk,” said Dr Sudha Seshadri, an associate professor of neurology at the Boston University School of medicine.
Dr Seshadri added, “But many more studies of different population groups are needed to determine whether leptin can play such a pivotal role in predicting the risk of Alzheimer's. There has been some data relating body weight to the risk of Alzheimer's disease. When we looked at animal studies, we found some data to indicate that leptin not only produces a feeling of satiety but also has a beneficial effect on the hippocampus. It was important to see if that was true in humans."
In the present study, 198 patients had MRI scans that calculated brain volume an average of 7.7 years after leptin was measured. The researchers also kept a lookout for all new patients diagnosed with AD among the study participants.
The scientists observed that higher leptin levels were associated with a lower incidence of Alzheimer's and all other forms of dementia. At least one quarter in the study who had the lowest leptin levels had a 25 percent risk of developing AD over a 12-year period. On the other hand, those with high levels of leptin had a much lower incidence of developing AD. Moreover, lower leptin levels were also linked to a decrease in brain size.
Dr Seshadri went on to say that at present the role of leptin in the brain is a mystery and, “we're not recommending that anyone get leptin or increase leptin levels."
As a final note, all consumers should know that there is no correlation between levels of leptin and AD. Even though low levels of leptin have been found in patients with AD, this is by no means a universal or reproducible finding.
Over the past decade, Leptin supplements have been widely sold in many health food stores and experts believe that these are just fake pills. Even though leptin is heavily marketed as a weight loss agent, there is no proof in humans that it does what the vendors of the products claim. At least for now, the only thing leptin can reduce is the weight of your hard earned money.
Study is reported in the Dec. 16 issue of Journal of the American Medical Association.