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Wei Perng
, PhD


Last week, I met with a prospective Master’s student wrapping up her B.S. in Nutritional Sciences. She told me about her background in nutrition, her laboratory training, and her desire to conduct nutrition-related research in human populations. I asked her whether there was a particular focus area that piqued her interest and she said, “I feel as though there isn’t a lot known regarding what a healthy diet is supposed to look like for normal people. I’d like to look into that.”

This caught me off guard, especially because the overarching goal of nutrition research is to characterize healthy diets in order to promote health, both for individuals and the broader population. As I thought more about our conversation, it occurred to me that perhaps the issue isn’t a lack of research on what constitutes a healthy diet, but rather that our views on this topic are constantly changing due to new research, and that translating and disseminating those findings to a lay audience is challenging.


 
 
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Marie-France Hivert
, MD, MMSc


Diabetes that appears for the first time in pregnancy is called gestational diabetes, and affects 5 to 20% of pregnant women. High blood sugar – also known as hyperglycemia – in pregnancy is associated with adverse outcomes for both mother and child, including higher rates of pre-eclampsia, caesarian section, babies born large for their gestational age and shoulder dystocia, and hypoglycemia in newborns. We also know that treatment of gestational diabetes decreases the risk of these complications.
Gestational diabetes is caused by an imbalance between the capacity of the pancreas to secrete insulin and the sensitivity of different tissues such as fat, liver and muscles to insulin. During pregnancy, these tissues become less sensitive to insulin because of hormonal changes that occur.

We can refine our definition of gestational diabetes by whether the imbalance is caused more by inadequate insulin secretion or low insulin sensitivity. In a large prospective cohort of about 800 pregnant women called Gen3G, we found that about half of the women with gestational diabetes had predominantly an insulin sensitivity defect, meaning that while their pancreas may make enough insulin, their tissues fail to respond to it.  About 30% have mainly an insulin secretion defect, meaning that their pancreas makes too little insulin for the demands that pregnancy hormones induce on the body.  Less than 20% have a mix of both defects. We showed that women with gestational diabetes due to an insulin sensitivity defect are the ones at higher risk of complications at delivery, with a higher rate of newborns classified as large-for-gestational age and that experience hypoglycemia soon after birth. These women are also more likely to need a caesarian section to deliver the baby. Pregnant women with gestational diabetes due to low insulin sensitivity had a higher BMI prior to pregnancy, but the risk of higher complications remained significant even after accounting for mother’s weight status. These higher rates of complications in pregnant women with gestational diabetes due to low insulin sensitivity were observed despite all women with gestational diabetes receiving similar clinical care and tight control of maternal glucose. This suggests factors other than maternal hyperglycemia might contribute to the rate of complications, such as inflammatory cytokines, adipokines, or some lipid fractions that increase with lower insulin sensitivity. Future studies will need to identify factors that might be contributing to these complications, and to assess whether we can target or treat these metabolic anomalies in addition to controlling maternal glucose.
 
 
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Harvard Medical School has removed nutrition education from its curriculum.

Last summer, I taught a section of the week-long HMS nutrition course for second year medical students, and there were rumblings of this possibility then. But at least to me, it still seemed likely that with nutrition-related diseases being of such overwhelming concern to the general public, HMS leadership would change its mind.



 
 
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Jason Block, MD, MPH


Several months ago, I got into a twitter spat. In response to a blog post that decried how inadequately doctors were treating patients with obesity, I wrote in a series of tweets: “When will we stop blaming doctors for what they fail to do about obesity and accept that they cannot reverse the epidemic? Primary care docs have a role but not enough support or time to spend on obesity while treating myriad other issues. Reversing obesity is more of a policy and societal challenge than a health care matter. Surgery and drugs can only do so much.”  In response, the author of the original blog post wrote another piece, quoting me anonymously, lamenting that I thought there was nothing that doctors could do to treat obesity.

 
 
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Jen Thompson, MPH


Full disclosure: all of my colleagues refused to write a blog post on this topic.  “Ewww,” one said.  “I don’t feel comfortable writing about that,” said another.  Even when I pointed out that our department has written papers on very similar topics, they all declined.  So I decided to tackle it myself, because a) it’s a topic that applies to everyone who was ever born, b) is biologically very important and interesting, and c), I think it’s an excellent example of how the implications of a small but interesting scientific study can be misinterpreted, exaggerated, or distorted.

 
 
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Kristina Lewis, MD

Whatever your take on the Affordable Care Act (ACA), the Syrian refugee crisis, or the bailout of Wall Street, there is probably at least one area where we can (mostly) agree that the Obama Administration has earned high marks over the past 8 years – Obesity. Michelle Obama, with her “Let’s Move” campaign, has been a champion for healthful dietary choices and physical activity, with a strong focus on obesity prevention in children. As great as this has been for those of us who research, treat, or are generally passionate about obesity, the era is now coming to an end. Entering the heart of the 2016 presidential campaign, I often find myself wondering – how will Obama’s successor deal with this important issue? Will the nation’s current laser focus on health and wellness fade into the background as a new family, with new issues to promote, moves into the White House?

 
 
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Wei Perng
, PhD


Advancements in high-throughput technologies have enabled us to assess health from a more holistic point of view by considering our genetic code (“genomics”), actual expression of our genes (“epigenomics” and “transcriptomics”), the structure of proteins that carry out the biological processes (“proteomics”), and the unique chemical fingerprints that reflect our physiological response to external and internal conditions (“metabolomics”). Of particular interest to an obesity-prevention researcher is the possibility of “omics” to influence nutrition counseling, a one-on-one process between a patient and a nutritionist that aims to help the patient make and maintain dietary changes necessary for good health. These recommendations have historically been based on dietary recommendations derived from nutrient needs of heterogeneous populations. Enter the concept of personalized nutrition - a diet plan designed at the level of the individual, tailored to meet their specific health needs.

 
 
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My friends and teammates frequently ask me how I avoid added sugar – sugar added to processed or pre-packaged food during the production process – in what I eat.  Here are some ways to reduce sugar without sacrificing taste or switching to artificial sweeteners.

In general, pick food items with short ingredient lists, and know one teaspoon of sugar = 4 grams to help visualize just how much sugar you are consuming when you buy processed or pre-packaged goods.  The average soda can has over 10 teaspoons of added sugar -- would you put 10 teaspoons of sugar in your cup of coffee?


 
 
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Karen Switkowski, MPH, MS

My 1-year-old is an impressive eater. During recent holiday family gatherings, he provided regular entertainment as he sat at the table devouring near-adult-size portions of a variety of foods. Commentary ranged from “Wow, where does it all go?” “But he has such a tiny stomach!” And inevitably, the (well-intentioned, I’m sure) “so… you just let him eat as much as he wants?”

 
 
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Lauren Fiechtner,
MD
, MPH

In previous studies, we investigated if distance to a supermarket was associated with a child’s BMI or weight status. However, these studies only measured one point in time, and we wanted to know if children participating in an obesity intervention who lived closer to a supermarket would do better than those living farther away. Our findings from this study were recently published in the American Journal of Public Health.