Diabetes and other diseases related to the obesity epidemic depend on how the body stores excess energy according to evolutionary biologist Mary Jane West-Eberhard, emeritus researcher at the Smithsonian Tropical Research Institute. In Proceedings of the National Academy of Sciences she describes her theory of fat in the peritoneal visceral fat tissue or the VAT "VAT priority hypothesis".
More than 300 million people are affected by obesity-associated diabetes. Heart disease is a great killer. Both involve chronic inflammation.
"Pathogenic obesity is a beneficial process gone wrong," said West-Eberhard. "Very early in life, the body makes decisions about where to store fat. It makes sense for poorly nursed fetuses to invest in VAT instead of fat under the skin because moms evolved to protect us from infections, but this choice puts us up for disaster if we have access to too many calories later in life. "
Scientists are studying obesity from various perspectives, but West-Eberhard took a broader look to ask how the body makes decisions about where to deposit fat and why .
Trying to understand obesity-related diseases without understanding the abdominal structures becoming obese is like trying to understand circulatory diseases without knowing heart functions, "said West-Eberhard.
Visceral fat is nature's super-band support. Called "abdominal policeman", an abundant structure called omentum, a loosely hanging fold of the membrane, covering the abdominal cavity, sticking to wounds, foreign bodies such as shrapnel and infection sites like a bandage filled with antibiotics. In fact, surgeons sometimes use pieces of omentum to control Severe postoperative infections Moms surround the small intestine, defend the body from ingested pathogens and toxins. "The fact that visceral adipose tissue evolved to combat visceral infections provides a causal hypothesis for how high fructose sweeteners and saturated fats contribute to chronic diseases. as type 2 diabetes, "West-Eberhard said." seems which bacteria grow in the intestines [called the microbiome] makes the intestinal walls more permeable and releases more toxins into the bloodstream, stimulates the visceral immune system and potentially leads to chronic inflammatory disease. "
Previously, the role of visceral fat as part of the immune system may have been more important than it is today because hunger and infections were more common. West-Eberhard suggests that in nutritionally stressed fetuses, more energy can be stored as fat around the abdominal muscles than as fat under the skin (subcutaneous fat or SAT). She notes that childhood collection growth, a better prediction for obesity-associated disease than low birth weight, can be a sign of the error the body has made as it distributes energy to moms that produce the apple formation of abdominal obesity rather than the body fat body shape in hips, hams or thighs or more evenly under the skin.
In obese individuals, a dangerous feedback loop can be developed: increased VAT leads to increased chronic inflammation, which in turn leads to increased insulin resistance, leading to additional VAT retention and increased susceptibility to disease. Eventually, the ability to produce insulin is reduced and these people may inject insulin to control diabetes type 2 diabetes.
"I believe that the combination of premature malnutrition combined with modern diets of saturated and trans fats and high fructose foods available globally leads to a situation that is toxic to people in many different cultures West Eberhard said. "People's body shape ̵
In the future, she hopes to see more research revealing fetal cues that activate VAT storage, the development of the visceral immune system, the role of the omentum, disease resistance in obese persons and the ability of humans of different geographical and ethnic origin to distribute fat differently.
The stomach is the most dangerous, but losing it from anywhere helps
Mary Jane West-Eberhard, Nutrition, the Visceral Immune System and the Evolutionary Origin of Pathogenic Obesity Proceedings of the National Academy of Sciences (2019). DOI: 10.1073 / pnas.1809046116
The Smithsonian Tropical Research Institute
VAT fat can cause pathogenic obesity (2019, January 11)
January 11, 2019
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