Date: October 16th, 2008

Speaker's Name and Affiliation:

Beverly Tepper
Rutgers University

Seminar Title: "Pregnancy Changes in Sweet Taste and Endocrine Factors in Healthy Women and Women Who Develop Gestational Diabetes"

Presiding Chair: Harry R. Kissileff, Ph.D.

Rapporteur: Kathleen L. Keller, Ph.D.

Attendees and their Affiliation:

Kathleen Keller	Columbia/Obesity Research Center
Harry Kissileff	Obesity Research Center
Tony Sclafani	Brooklyn College
Allan Geleibter	NY ORC
Karen Ackroff	Brooklyn College
Joelle Grinker	University of Michigan
Jennifer Nasser	ORC
Gerry Smith	Weill Medical College
Susan Carnell	ORC/CU
Jarrett Schanzer	CU/IHN
Katherine Halmi	Cornell
Sally Ann Lederman	CU/IHN

Summary: (Prepared by the Rapporteur)

Dr. Beverly Tepper presented data collected by Dr. Lisa Belzer in partial fulfillment of her doctoral degree on sweet taste and endocrine factors in women who develop gestational diabetes (GDM) during pregnancy. Gestational diabetes (GDM) is glucose intolerance that is first recognized during pregnancy. It affects 3-8% of all pregnancies, and 50% of women with GDM will go on to develop Type II diabetes at some time in their lives. Risk factors for GDM include obesity prior to conception, family history of Type II diabetes, and minority status. There are serious risks associated with GDM, including infant macrosomia and a variety of other fetal complications. Previous studies also find changes in sweet taste with diabetes. There is impaired perception of simple sugars in Type II diabetes and first degree relatives (Perros, 1996; Settle, 1991). Further, in 1996, the speaker found evidence of increased intake of sweet foods that correlated with peak preferences for sweet beverages in type II diabetes. In 1999, Tepper and Seldner found that women with GDM had higher preferences for sweetened strawberry milk, and the degree of hyperglycemia in these women was positively correlated to their preference for glucose solutions and sweetened fruit juices. Therefore, the hypothesis of the present study was that women with GDM will have higher preferences and cravings for sweet foods than women w/o GDM and this might compromise dietary compliance in these women. Objectives of the study were to document the temporal profile of sweet taste and endocrine changes across pregnancy in women with GDM compared to those with normal glucose tolerance (NGT) and to relate changes in sweet taste cravings, intake and preference to changes in endocrine profiles.

Of the 4 time points in which measures were taken (16-20 wks, 24-28 wks, 34-38 wks, and 6-10 wks post-partum), differences in liking of sweetened milks occurred at 34-38 weeks only. Women with GDM had higher liking of the flavor, creaminess, and sweetness of 5% sweetened milks (and the creaminess of 10% sweetened milks), compared to NGTs and non-pregnant controls. In women with GDM (but not NGT), there was a positive association between plasma leptin concentrations (at 24-28 wks) and reported liking of the 10% sweetened milk. At that same time point, plasma insulin correlated positively with reported liking of glucose solutions in GDM but not NGT women. It is possible that leptin and insulin may modulate feelings of motivation and reward from food, but due to a small sample of GDM women, results should be interpreted with caution.

With respect to reported intake and cravings of sweet foods, women with GDM did not report higher values for either. There was, however, a higher reported frequency of sweet food cravings reported by GDM women at 34-38 weeks. The fact that no differences in intake were found (suggesting that these women were not acting on their cravings) speaks to the fact that these women were managing their diets and their diabetes were well controlled. These findings raise the possibility that women with GDM are more susceptible to sweet cravings and future studies are warranted to confirm this as well as determine the clinical significance. Future studies should determine the role of oral stimulation on the control of glucose homeostasis in GDM.

References:

• Tepper, B.J. and Seldner, A.C. Sweet taste and intake of sweet foods in normal pregnancy and pregnancy complicated by gestational diabetes mellitus. American Journal of Clinical Nutrition, 70:277-284, 1999.

Discussion:

Q. How do you know that these women (of the 50% of women with GDM that go on to develop Type II) would not develop Type II anyway?
A. This is looking at an increase in risk above and beyond what their risk would be if they didn't have GDM. The studies are done by comparing women who haven't had a previous GDM pregnancy to those who have. GDM places a metabolic stress on the pancreas that is reduced after delivery (although some women do not completely return to normal glucose tolerance). A history of GDM probably accelerates the progression of Type II diabetes.

Q. In mice, there are data to suggest that leptin modulates sweet taste. Have you looked at that?
A. Hold that question because we will talk about that later.

Q. Do you think this increase in sweet food craving (experienced by pregnant women) is manifested because women are trying to normalize changes in sweet taste perception that occur?:
A. Yes, that is one hypothesis that we are exploring.

Q. Haven't there been studies to suggest that people with type II diabetes are also not quite as satisfied with sweet taste (compared to controls)?
A. That is what our study would suggest. We didn't find any differences in intensity of sweet taste perception.

Q. Would you see the same thing if you looked at the relationship between plasma glucose levels and liking of sweet taste solutions?
A. There have not been any studies looking at type II diabetes.

Q. You said you only got a difference in preference, not intensity. Is that correct?
A. Yes.

Q. If you remove the end points (the individuals with high plasma glucose), is the relationship still significant?
A. Yes, but not as strong.

Q. Were women excluded if they had a previous pregnancy?
A. No, but they were excluded if they had a previous pregnancy with GDM.

Q. Were any of the women breastfeeding post-partum?
A. Up to 65% were breastfeeding (both controls and GDM).

Q. Where did you get the strawberry flavor for your test food?
A. International Flavors & Fragrances (IFF)

Q. What was the fat that you used in your sweetened milks?
A. Corn oil. It was blended well and palatable.

Q. Why didn't you use cream?
A. We wanted to control the dairy flavor of the test food.

Q. Would you have predicted that maternal weight gain would be less than it was?
A. Since they were well controlled in their disease (the women with GDM), they gained less weight and also did not have a problem with macrosomia. I credit this to the doctors and medical staff at St. Peter's hospital in New Jersey that were very proactive with the women's care.

Q. How did their weight gain compare to what is recommended?
A. It was all in the recommended range.

Q. Your controls had BMIs < 25. Why was their fasting insulin so high?
A. I'm not sure. We looked at diet and other possible factors, but couldn't figure it out.

Q. Can you rationalize all those data points (with respect to leptin and insulin) by saying that they parallel with body fat?
A. These measures are all controlled for body weight.
Comment: But, body weight does not capture differences in body fat.

Q. What were the anchors you used on your line scales?
A. Some were "0" to "very strong" (for measuring perception of sweet taste intensity). For the liking scales, we used "dislike extremely" to "like extremely."

Q. How closely did the leptin correlate with BMI in these groups?
A. I'm not sure we looked at this, but we should.

Q. When do you measure leptin?
A. At all time points.

Q. The data are similar to data out of NIH-Phoenix, the project with the Pima Indians that Adam Drewnowski was involved with.
A. Right, I forgot about that study.

Q. Would you expect a correlation between body fatness and liking?
A. We controlled for body weight.

Q. Yes, but I would suggest you look at the relationship between sweetness liking / perception and % body fat (not body weight).
A. Yes, we should do that.

Q. Is there any effect of ethnicity?
A. We looked at Hispanic vs. other, but we had a small group (so we were probably not powered to look at these effects).

Q. Why don't you think you found differences in sweet taste perception between groups?
A. I'm not sure, but we might need to measure taste thresholds to pick this up.

Q. Have other studies looked at preferences for high-fat foods in GDM women and those without?
A. We didn't look at that, and I'm not aware if other groups have.

Q. Is there any possibility that changes are occurring in maternal sweet cravings because the fetus is increasing or changing in weight and the mother is sensing this?
A. Not sure.

Q. Do you think some aspect of treatment might have affected the results you saw in this study?
A. The treatment was the diet the women were on, and because it was so tightly controlled, I do think it affected the results.

Q. Did the women act on any cravings?
A. We had so little data that we could not assess this.