Friday, November 27, 2020

New Satiety Hormone Described

I've often felt that people who have always had problems with weight have something wrong with their appetite control, so after a meal that would make most people feel full, they're still hungry. And if food is available, it's difficult not to eat it when you're hungy.

I gave an example of this in my book The First Year: Type 2 Diabetes. Someone described a time when a coworker brought some pastries into work and offered them to everyone. A thin person said, "Oh my those look good. I wish I were hungry so I could eat one." The overweight man said he was flabbergasted. He was hungry all the time and just assumed everyone else was too.

Now a new satiety hormone that decreases appetite after eating has been described. The interesting thing about this hormone, called lipocalin-2, is that it seems to work in people who are obese but not in those who are normal weight.

In mice, giving lipocalin-2 long term reduces their food intake and prevents weight gain, without leading to the slowdown in metabolism that is often seen when people try to lose weight by eating less. Studies to see if the mouse results could be replicated in humans showed that normal weight subjects showed an increase in lipocalin-2 after eating, and this coincided with how satisfied they felt after eating.

But in people who were obese, lipocalin-2 levels did not increase after a meal and in fact decreased. It's not clear if they became obese because of a defect in producing lipocalin-2, if they had lipocalin resistance, or if they became obese for other reasons and the obesity caused the defect in lipocalin-2 production. But those who lost weight after gastric bypass surgery (and presumably those who lost weight in other ways) had their lipocalin-2 levels restored to the levels seen in normal weight people, suggesting that the obesity came first.

This sounds like a miracle hormone, but we don't yet know a lot about it. The authors say "the hormone can curb appetite with negligible toxicity," but like most hormones, it does have other effects. For example, it sequesters iron and increases inflammation. and it also plays a role in the central nervous system.

This is not the only hormone that affects appetite; the incretin GLP-1 does the same about the same amount. The GLP-1 agonists like  Byetta and Victoza act in part by reducing appetite.

Time will tell if lipocalin-2 drugs, not yet available, have more benefits than drawbacks. You can read a little more about lipocalin here



Sunday, November 1, 2020

EMFs and Diabetes

 "Remote control of blood sugar: Electromagnetic fields (EMFs) treat diabetes in animal models" When I saw that headline, I thought, "Oh wow! Remote control of blood sugar. My doctor could sit in her office and dial up a good blood sugar level and send it, and I'd be cured."

Unfortunately, that's not what the story is about.

Rather, exposing diabetic mice to a combination of static electric and magnetic fields for a few hours per day normalizes blood sugar and insulin resistance. The fields used were approximately 100 times that of the Earth, and the researchers said they reversed the diabetes within three days of treatment.

Note that the study was done in mice, and human studies often don't replicate rodent studies. However, the researchers also treated human liver cells with EMFs for six hours and showed that a surrogate marker for insulin sensitivity improved significantly. So the EMFs might also work in humans.

Here is a link to the full article, which notes that "attempts to investigate the potential effects of EMFs on glucose metabolism have yielded conflicting findings with some studies demonstrating that EMFs raise fasting blood glucose and others suggesting that EMFs have no effect." But the authors criticize the methods of the earlier studies.

One researcher, Magda Havas, thinks that EMFs from electrical wiring (dirty electricity) may may elevate blood glucose and contribute to "brittle" diabetes.

Clearly, we have a lot to learn about EMFs and diabetes, but the current study is certainly interesting. Stay tuned for more developments.