Leptin Sensitivity

In obesity, a decreased sensitivity to leptin can occur. The consequences of this result in the person’s inability to detect satiety, even though there may be high energy stores. No surprise, any decline in the level of circulating leptin impacts brain activity in areas that involve the cognitive and/or emotional control of appetite. In 1996 a study published in the New England Journal of Medicine [334 (5): 292–5] reported that while leptin typically reduces appetite as a circulating signal, obese individuals generally exhibit a higher circulating concentration of leptin than normal weight individuals This is likely due to their higher percentage of body fat. In addition, they also ten to show leptin resistance similar to the insulin resistance seen in people with type 2 diabetes. However, the elevated levels of leptin fail to control hunger or modulate their weight.

Leptin vs Lectin

I know it can be confusing since there is only a one-letter difference between these two words. It’s worth paying attention to what they mean or represent, however. Leptin is an extremely vital and valuable hormone. When you hear the word Leptin, think “thin.” Really. Because it comes from a Greek word meaning thin. Made by fat cells, this substance—known as the “satiety hormone” is designed to put on the hunger brakes. Leptin is opposite—no surprise—from grehlin, its opposing hormone known as the “hunger hormone.” Both hormones can bind to receptors in the hypothalamus to regulate appetite: Grehlin pushes you to eat; leptin says that you have enough energy and need no more food. More tomorrow.

Brain and Hugs, 2

Sheldon Cohen, who led the study on hugging at Carnegie Mellon University, said that the research” suggests that being hugged by a trusted person may act as an effective means of conveying support and that increasing the frequency of hugs might be an effective means of reducing the deleterious effects of stress. The apparent protective effect of hugs may be attributable to the physical contact itself or to hugging being a behavioral indicator of support and intimacy. Either way, those who receive more hugs are somewhat more protected from infection." “But I live alone and there’s no one to hug,” some say. That may be a challenge although just because you live with someone doesn’t guarantee a good hug. There are families that live together but fail to hug each other. Fortunately, I have a few relatives and a couple close friends who are skilled huggers—it’s both an art and a science and may be the ultimate “being rather than doing” affirmation. 

Brain and Hugs

Research at Carnegie Mellon University studying the impact of conflict and social support—including hugging by trusted persons. Lead researcher Sheldon Cohen and associates assessed 404 healthy individuals including the frequencies of interpersonal conflicts and receiving hugs. The 404 participants were then exposed to a cold virus and quarantined to assess for infection and symptoms of illness. They found?

• Perceived social support reduced the risk of infection associated with experiencing conflicts. Hugs were responsible for one-third of the protective effect of social support

• Among participants who became infected, greater perceived social support and more frequent hugs both resulted in less severe illness symptoms whether or not they experienced conflicts 

Are You A ‘Hugger?’

"Are you a “hugger?” Did you come from a family of “huggers?” Growing up I hugged my pets (the ones that were huggable – it’s a tad difficult to hug a snail or a box turtle or even a parakeet!) I sometimes hugged close friends (but not always as hugging was never a measure of how much I cared about and valued a specific individual). It’s commonly understood that ongoing stressors such as conflict with others can reduce immune system function and increase the risk of infection. And the brain and immune system have their hands in each other's pockets, so to speak. Recently research by scientists at Carnegie Mellon University looked at conflict and social support—including hugging by trusted persons—and its association with risk of infection and with severity of illness symptoms. 

Tell Your Brain to Sleep

“Don’t Sleep Well!” I hear this from people all over the world! My first response is “Stop telling your brain anything that you do not wish to be true.” When you say ‘I don’t sleep well,’ a representation of what they means goes into working memory, located directly behind your forehead. Your brain perceives that ‘if you put it into working memory it must be information to you,’ and the brain does everything it can to help you achieve that goal. In this case, not sleeping well. Therefore, knowing that sleep is independently linked with longevity and that your brain appears to be cleared of toxins during sleep, change what you tell your brain. It can only do what it thinks it can do and you tell it what it can do through your thoughts, self-talk, and directions to your brain. I perceive of my brain as a connected although separate entity so I talk to my brain using the pronoun you. Most nights I tell my brain: “Arlene, you are falling asleep quickly and easily and waking up at ____________ am.” And in most cases that’s exactly what happens.

Sleep and Brain Work

Results of the new study, funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the NIH, suggests that during sleep the brain is cleared of damaging molecules associated with neurodegeneration. Sleep changes the cellular structure of the brain. It appears to be a completely different state,” said Maiken Nedergaard, M.D., leader of the study. Not only is sleep important for storing memories, it may be also be the period when the brain cleanses itself of toxic molecules. It appears that during sleep a plumbing system called the glymphatic system opens, letting fluid flow rapidly through the brain. Glial cells help control the flow of cerebrospinal fluid (CSF), a clear liquid surrounding the brain and spinal cord, through the glymphatic system by shrinking or swelling. Since this appears to happen only during sleep, it highlights the critical importance of sleep in clearing the brain of toxins.

Xie et al “Sleep initiated fluid flux drives metabolite clearance from the adult brain.” Science, October 18, 2013. DOI: 10.1126/science.1241224