Week 6: Developmental Origins of Health and Disease: The Adaptive Response of Diabetes?
An important concept that has unified my research is the idea that one’s early environment can affect adulthood outcomes. The Barbados Nutrition Study elegantly revealed that malnourished children had higher rates of attention deficits and metabolic syndrome as adults. Other famine studies have shown how children born during a famine also had greater
risk for obesity, diabetes, hypertension, and other chronic diseases. As I mentioned in earlier posts, my summer project was working on the actual mechanisms behind such mental outcomes via epigenetics. I am seeking to answer why stress and malnutrition at early developmental stages have such long-lasting, adverse effects. Can there possibly be an adaptive reason for it?
The Developmental Origins of Health and Disease is a recent, exploding field in Darwinian biology that gives an evolutionarily sound explanation for the rising rates of obesity and chronic diseases. It stems from the Barker Hypothesis (or “thrifty phenotype hypothesis”). Basically, an unfavorable intrauterine environment causes adaptive changes in metabolism and physiology that theoretically “prepare” the individual for a similar post-natal environment. However, if the fetal setting does not match the adult setting, chronic diseases (like those we see today) can arise.
Let’s suppose there is a very short famine that results in malnutrition among pregnant women. The fetus is not getting enough nutrients, which triggers changes (possibly through epigenetic regulation) that can allow it to adapt in a poor nutrient environment after birth. So, its physiology changes so that the body can hang on to more fat, will be smaller, and will have a lower metabolic rate. However, that famine ends and the child is born into present-day America—where refined, high fat, calorie dense, and accessible food abound. That child may now have an increased risk for obesity and metabolic disorders.
Developmental Origins Theory is definitely fascinating, and was the main theory that got me interested in the type of work I’m doing now. But after working with Dr. Galler, I do have my critiques. First, it seems the field only focuses on pre-natal environment when in fact our Barbadian cohort was only malnourished after they were born. Also, there seems to be a larger focus on the metabolic effects, and not so much on effects to mental health. What might the adaptive response of schizophrenia be? I myself have to do more reading, but I hope you find this topic as interesting as I did!
About the Blogger
Riana Balahadia is studying Human Evolutionary Biology with a secondary in Global Health & Health Policy and pre-med in Kirkland House at Harvard (class of 2014). During the semester she enjoys singing with the Veritones, a premier co-ed a capella group, and planning activities for Harvard Philippine Forum and the Undergraduate Global Health Forum. This summer she will be living in Winthrop as part of the SURF (Summer Undergraduate Research Fellowship) Program hosted by the Global Health Institute. Her mentor is Dr. Janina R. Galler, who has been working on the Barbados Nutrition Study (BNS) for the past 40 years. Riana's primary research will be on linking malnutrition and epigenetics to mental health, and then comparing that information with the BNS cohort in Barbados.