Leptin Levels Associated with Dementia Risk

New research from the Boston University School of Medicine has found a positive correlation between high plasma leptin levels and reduced risk of dementia and Alzheimer's Disease. High leptin levels reduced the risk of Alzheimer's Disease by 19%.

Leptin is a hormone produced by adipocytes (fat cells) that regulates body fat storage by modulating satiety, glycemic control and metabolism. Leptin triggers the sensation of satiety, giving the feeling of having eaten enough. Generally speaking when a person is properly nourished, serum leptin levels increase, and hunger levels decrease. Additionally, leptin plays a role in metabolic regulation and helps the body utilize stored fat.

However, diet and stress can lead to chronic inflammation and leptin resistance. Chronic inflammation increases levels of C-Reactive protein. C-Reactive protein binds to leptin, preventing it from doing its job. When leptin resistance occurs, the body does not get the signal to stop eating, leaving one feeling hungry, even after having consumed enough calories.

However, as this new research attests, weight management is not the sole function of leptin.

For this study, researchers used data collected from 785 participants in the Framingham Heart Study. All participants were free of dementia and Alzheimer's Disease at the onset of the study. The researchers performed volumetric brain MRIs on a subset of 198 dementia-free patients to assess two measures of brain aging, total cerebral brain volume and temporal horn volume (which is inversely related to hippocampal volume).

After a median follow up period of 8.3 years, 111 participants (of the full 785) developed dementia, 89 developed Alzheimer's Disease. Upon analyzing the data, the researchers found that those with the highest leptin levels had a significantly lower incidence of dementia and Alzheimer's Disease. Those with the lowest leptin levels had a 25% absolute risk of developing Alzheimer's Disease, while those with the highest levels had a 6% absolute risk -- only one-fourth the risk of developing this debilitating disease.

Even more strikingly, those with higher leptin levels had higher total cerebral brain volume and lower temporal horn volume, which translates to greater hippocampal volume, the area of the brain that deals with long term memory.

The researchers concluded that "circulating leptin was associated with a reduced incidence of dementia and Alzheimer's Disease and with cerebral brain volume in asymptomatic older adults." They went on to state that "leptin levels in older adults may serve as one of several possible biomarkers for healthy brain aging and, more importantly, may open new pathways for possible preventive and therapeutic intervention."

This is not the first time that leptin has been linked to brain health. In fact, there is a growing body of research indicating that leptin may have a beneficial effect on brain development and function. A 2006 study found that low leptin levels compromised learning and memory. Those researchers speculated that low leptin may be the cause of cognitive deficits in individuals with Type II Diabetes. Additionally leptin has been shown to reduce extracellular beta-amyloid, the primary material that forms plaques in the brain that are the hallmark of Alzheimer's Disease.

LeptiFit™ works by reducing leptin resistance, which increases the amount of free leptin in the blood, allowing leptin to reach the brain and perform multitude of tasks, not the least of which is to help curb appetite. Learn more about LeptiFit™ here.

1. Lieb, W., A. S. Beiser, et al. (2009). "Association of plasma leptin levels with incident Alzheimer disease and MRI measures of brain aging." Jama 302(23): 2565-72.