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Five Key Lessons from NST 160


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Nutritional Sciences and Toxicology professor Andreas Stahl's class "Metabolic Bases of Human Diseases" focuses on recent developments in basic science to illuminate the causes and treatment options of metabolic disorders. The recently revamped class is now roughly divided between disorders caused by overnutrition (excessive food intake), such as heart disease, diabetes, and cancer, and those caused by undernutrition, such as rickets.

Breakthroughs asked Stahl to share five key lessons that he hopes will resonate with students—and with you.

1. The body senses nutrients. It detects which nutrients are present—and which are not—and then compensates to try to maintain homeostasis, i.e., relatively steady levels. This happens on the level of the body as a whole organism as well as within individual organs and cells.

2. Nutrient sensing gone wrong can cause disease. Disruptions in the nutrient sensing pathways—due to genetic mutations, overloading the sensing mechanism with too many nutrients, or other factors—can cause severe diseases.

3. There are different kinds of diabetes: inherited and acquired. Type 2, the most common, is tightly linked to overnutrition. Too many nutrients coming in causes cellular stress that interferes with the normal response to insulin. Inappropriate storage of fat in organs like the pancreas and liver also interferes with insulin release and sensing, as do other stresses, such as inflammation, environmental factors, and genetic predisposition.

4. The brain regulates your urges to eat and expend energy. Your brain receives nutrient-related signals from different organs telling it whether your stomach is full, if the food you are eating is tasty, what you are digesting at the moment, how full your fat stores are, etc. The brain's hypothalamus region integrates all these signals and generates the feelings of hungry versus full.

5. Your cells remember. Changes in diet can affect the disease susceptibility of following generations. These environmental effects change which parts of your DNA can be activated (though not the DNA sequence itself). So, a mother's diet during gestation can impact the development of obesity and diseases in her children. A more surprising transgenerational effect: Your chances of developing diabetes may hinge on whether your grandfather was starving during his boyhood.