Lack of insulin-like growth factor-1 seems to correlate with not developing cancer, diabetes, Alzheimer's, and other diseases of aging:

Loja is a remote place, a province located in the mountains in the south of Ecuador. To the east lies a forest that quickly becomes the Amazon. The border with Peru is not much further south, though journeys in this region tend to be slow.

In this hard-to-reach zone live a number of people — about 100 — with a special trait: They seem to be protected from certain diseases that devastate the rest of the world.

No matter how old they get, almost none die of cancer. No matter what they eat, they don't seem to develop diabetes.

This group represents approximately one-third of the global population of people who have what's known as Laron syndrome, a genetic disorder that makes the body unable to use growth hormone.

The primary symptom of the disorder is dwarfism, but as many years of study have shown, the syndrome also seems to protect against cancer, diabetes, and other diseases that are some of the most common causes of death in the world.

What's more, scientists think that if we can understand this unusual constellation of symptoms, there's a chance we could replicate them. It might be possible to take the biological pathway that causes these effects in people with Laron syndrome and recreate it in otherwise healthy adults, according to Valter Longo, a professor of gerontology and biological science and the director of the USC Longevity Institute.

Doing so, we might be able to drastically reduce the number of people who suffer from diabetes and cancer, and potentially also from autoimmune diseases, Alzheimer's, and other illnesses, according to Longo. This wouldn't just increase people's life spans — they'd stay healthier for those years, too.

"Treating aging used to be just an idea that was confronted with skepticism. [People would say] 'You're going make them live longer sick,'" Longo told Business Insider.

But he says that what they've seen with people with Laron syndrome is that lives don't have to be crippled by chronic disease. In animals that researchers have activated these same biological pathways, the animals have lived longer, disease-free lives.

People with Laron syndrome differ from others with dwarfism in an important way: Their bodies still produce growth hormone. But their livers can't process it to generate what's really needed — something called insulin-like growth factor-1, or IGF-1.

The lack of IGF-1 prevents growth and makes people with Laron syndrome much more sensitive to insulin, which helps regulate blood sugar. That better regulation of blood sugar is what researchers think prevents diabetes.

Cancer protection comes from the same thing that prevents growth. Cancer itself is a disease of growth, where the process of cell division goes out of control. People with acromegaly — that's an excess of growth hormone (like André the Giant) — have an increased risk of cancer. Interestingly, they also have a higher risk of developing diabetes.