The Facts on Leptin: FAQ
The truth about the hormone leptin and obesity.
Q. What about leptin supplements, such as those sold on the Internet? continued...
“Insulin resistance generates leptin resistance. The practical advice is:
Get your insulin down,” Lustig says. “How do you get insulin down? The best way
is don’t let it go up. Sugar makes insulin go up. We are overdosed on sugar in
this country. I think that if we got the sugar down, our insulin resistance
would improve and that would help with the weight loss.”
Reducing high triglyceride levels helps, too, Lustig says. Too much
triglyceride interferes with leptin’s journey from the blood to the brain via a
leptin transporter that allows the hormone into the brain.
“When you’re insulin-resistant, you have high triglyceride [levels]. That’s
one of the hallmarks,” Lustig says. “Triglyceride seems to block leptin
transport into the brain. In order to make your leptin work, you have to let
the signaling occur. The only way to let the signaling occur is to get your
Q. Does leptin affect other parts of the body?
Leptin appears to have many functions that scientists are still exploring.
"It didn't work as a weight loss agent, but there's now starting to be some
other things that are really interesting about it," Atkinson says.
The hormone plays a role in heart and bone health, Lustig says. "We know
that leptin is very important in keeping the immune system happy and that
chronic inflammation occurs in the face of inadequate leptin signaling, and
that's part of cardiovascular disease."
"We also know that leptin has direct effects on bone to increase bone health
and bone mineral density, so when your leptin's working right, your bones are
healthier and they accrue more calcium," he says.
Scientists are also finding some associations between leptin and certain
cancers, Atkinson says. For example, some recent research suggests that leptin
can promote the growth of melanoma, a type of skin cancer.
According to Atkinson, leptin may even affect women's fertility. "If the
brain doesn't sense leptin, you won't be fertile. If you think back to our
caveman days, when there were lots of famines, if you didn't have enough fat to
survive a pregnancy, then you're better off not getting pregnant in the first
place. Some people have thought that the leptin feeds back on the hypothalamus
to keep the reproductive hormones working well, too."