The effects of energy restriction and exercise on body composition and bone mineral density in overweight lactating women

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Heather L. Colleran (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Advisor
Cheryl Lovelady

Abstract: Lactation is a time of rapid bone loss due to hyperprolactinemia, amenorrhea, and increased bone turnover, especially in the lumbar spine and hip. Childbearing may be one of the causes for the high prevalence (59%) of overweight and obesity among women. Exercise, combined with a modest restriction in energy intake, has been shown in non-lactating women to improve body composition and protect bone during periods of weight loss. However, there is a paucity of research on exercise and dietary interventions in lactating women aimed at promotion of bone health and weight loss. Therefore, the primary objectives of the two studies in this dissertation were: 1) to describe the changes in dietary intake, bone turnover markers, and hormones related to lactation and exercise, as well as predict changes in bone mineral density (BMD) during lactation in women whom had undertaken resistance exercise, and 2) to promote lifestyle changes through a home-based nutrition and exercise intervention targeting overweight lactating postpartum women. The first study concluded exercise and a higher dietary calcium intake were inversely related to bone loss during lactation, when controlling for parity. Additionally, an increase in bone formation markers predicted an increase of lumbar spine BMD, whereas increased levels of estradiol and IGF-1 were positively related to total body BMD. The second study results suggest moderate energy restriction and resistance training are safe methods for weight loss in overweight fully breastfeeding women with no adverse affects on BMD and infant growth. Additionally, the use of MyPyramid Menu Planner appeared to be a novel tool to aid in weekly individual dietary counseling and weight loss. This dissertation research was the first to examine the effects of an exercise and weight loss intervention on attenuation of lactation-induced bone loss in overweight women. The results suggest moderate energy restriction, walking, and resistance training are safe methods for weight loss in overweight fully breastfeeding women with no adverse affects on BMD and infant growth.

Additional Information

Publication
Dissertation
Language: English
Date: 2010
Keywords
Bone density, Exercise, Lactation, Weight loss
Subjects
Lactation $x Physiological aspects.
Exercise for women $x Physiological aspects.
Bone densitometry.
Overweight women.
Reducing diets.
Body composition.