Betty Greer

Regulation of adiposity by dietary calcium

Recent data from this laboratory demonstrate that increasing adipocyte intracellular Ca2+ results in a coordinated stimulation of lipogenesis and inhibition of lipolysis. We have also noted that increasing dietary calcium of obese patients for 1 year resulted in a 4.9 kg loss of body fat (P<0.01). Accordingly, we tested the possibility that calcitro‐phic hormones may act on adipocytes to increase Ca2+ and lipid metabolism by measuring the effects of 1,25‐(OH)2‐D in primary cultures of human adipocytes, and found significant, sustained increases in intracellular Ca2+ and a corresponding marked inhibition of lipolysis (EC50 ~50 pM; P<0.001), suggesting that dietary calcium could reduce adipocyte mass by suppressing 1,25‐(OH)2‐D. To test this hypothesis, we placed transgenic mice expressing the agouti gene specifically in adipocytes on a low (0.4%) Ca/high fat/high sucrose diet either unsupplemented or with 25 or 50% of the protein replaced by non‐fat dry milk or supplemented to 1.2% Ca with CaCO3 for 6 wk. Weight gain and fat pad mass were reduced by 26–39% by the three high calcium diets (P<0.001). The high calcium diets exerted a corresponding 51% inhibition of adipocyte fatty acid synthase expression and activity (P< 0.002) and stimulation of lipolysis by 3.4‐ to 5.2‐fold (P< 0.015). This concept of calcium modulation of adiposity was further evaluated epi‐demiologically in the NHANES III data set. After controlling for energy intake, relative risk of being in the highest quartile of body fat was set to 1.00 for the lowest quartile of Ca intake and was reduced to 0.75, 0.40, and 0.16 for the second, third, and fourth quartiles, respectively, of calcium intake for women (n=380;P≪ 0.0009); a similar inverse relationship was also noted in men (n=7114; P<0.0006). Thus, increasing dietary calcium suppresses adipocyte in‐tracellular Ca2+ and thereby modulates energy metabolism and attenuates obesity risk.—Zemel, M. B., Shi, H., Greer, B., DiRienzo, D., Zemel, P. C. Regulation of adiposity by dietary calcium. FASEB J. 14, 1132–1138 (2000)

Predictors of body mass index in female parents whose children participate in a competitive, creative, problem-solving program

Background Recent findings from our research indicate that children participating in a creative afterschool program exhibit overall healthier lifestyle practices compared to the average US pediatric population. This observation led us to investigate the prevalence of overweight/obesity and lifestyle practices of their parents. Objective To determine the strongest predictors of weight status for female parents whose children were participating in such creative afterschool program. Design Surveyed subjects were parents of children who competed in the 2008 and 2009 Destination ImagiNation® Global Finals in Knoxville, Tennessee. A total of 4,608 children participated in data collection, with parental consent. For the combined 2 years, 1,118 parents, 87% of whom were females (n=1,032) completed online questionnaires, which were based on the Behavioral Risk Factor Surveillance System and included self-reported height, weight, dietary intake, physical activity, and socioeconomic status. The majority of this population was white, and less than 5% were African American or Hispanic. Results We report here results obtained for the female parents. Only 45.2% of these female parents were overweight/obese, compared to a national average of 64.1% reported by the National Health Nutrition Examination Surveys for 2007—2008. Furthermore, this population was significantly more physically active compared to national average. Most parents (76%) had completed a college degree and reported high incomes. Parents with the lowest income were the most obese in this population. Finally, we found a significant association between parent and child weight status. Conclusions These studies demonstrate that female parents of children who have healthy lifestyles were physically active, which likely accounts for the parents’ lower overweight/obesity rates. In addition to physical activity, income and percentage of calories from fat were all predictors of weight status.

Observations and Conversations: Home Preparation of Infant Formula Among a Sample of Low-Income Mothers in the Southeastern US

Objective: Explore infant formula preparation attitudes and beliefs among low‐income, formula‐feeding, Southeastern US mothers. Design: Cross‐sectional study using in‐home observations and in‐depth interviews. Setting: Participant homes. Participants: Thirteen low‐income mothers of normal birth weight, healthy, term infants aged ≤3 months, who were predominantly feeding powdered or from‐concentrate formula. Variables Measured: Reading formula preparation instructions; order of added ingredients; leveling powdered formula scoop(s); adding cereal or other ingredients to bottles. Phenomenon of Interest: Perceptions of formula preparation or manipulation. Analysis: Descriptive statistics described sample characteristics and home observation variables. Thematic analysis of in‐depth interviews revealed the following major themes: formula preparation can be intimidating; expressions of complex heuristic perceptions about formula preparation; cost and convenience motivate maternal behaviors; and infant cues override recommendations. Data from qualitative and quantitative activities were triangulated. Results: Behaviors, including improper reconstitution and modifications/additions to prepared formula (eg, infant cereal) were observed during home observations and/or described during in‐depth interviews. Inconsistencies were detected between observed behaviors (eg, adding too much water to the bottle) and those reported during in‐depth interviews (eg, stating over‐dilution could be detrimental to the infants health). Conclusions and Implications: Targeting knowledge or skills gaps and behavioral motivators in the formula‐feeding population could positively affect infant‐feeding practices that occur outside of recommendations.