The purpose of this study is to determine the effects of galactooligosaccharide (GOS) supplementation on calcium absorption and and gut microbe profiles.
Galactooligosaccharides (GOS) have been shown to have positive effects on calcium absorption in animals and postmenopausal women. This study aims to see whether the addition of fiber in the form of GOS to a calcium-containing yogurt drink will increase calcium absorption compared to placebo in a group of girls near menarche. Secondary outcomes are to assess physical fitness and determine the relationship between physical fitness and calcium absorption in adolescent girls as well as assess changes in gut microbiota. During this three phase, randomized, controlled crossover study, participants will consume yogurt drinks supplemented with 0, 2.5 or 5 grams of GOS twice daily for three weeks. Following each three week period, participants will complete a weekend clinical visit to measure calcium absorption. Height, weight, bone density and geometry, calcium absorption, gut microbiota and physical fitness will be measured. Effects of this GOS fiber intervention may help elucidate a mechanism of action for improving bone health with fiber supplementation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
31
Zero, 5 or 10 g/day of galactooligosaccharide will be administered in two yogurt drinks containing about 300 mg total calcium each per day for three weeks. During a clinical visit following three weeks of consumption, zero, 2.5 or 5 g of galactooligosaccharide will be administered in the same yogurt with the addition of 15 mg Ca-44 (calcium chloride). Participants will be given one of the above yogurts at breakfast in addition to intravenously receiving 3.5 mg Ca-43 (calcium chloride) in 4 ml saline one hour after breakfast consumption.
Purdue University
West Lafayette, Indiana, United States
Calcium Absorption
Calcium absorption will be measured using dual isotope methods. Calcium-44(Ca-44) as calcium chloride will be administered in a yogurt drink provided at breakfast along with a roll, butter, jam and juice. A second isotope, Calcium-43 (Ca-43) as calcium chloride will be administered intravenously, one hour after consumption of breakfast. Urine and blood samples will be collected over a period of 48 hours and levels of Ca-44 and Ca-43 will be measured in urine and blood. Levels of Ca-44 and Ca-43 will be expressed as a ratio (Ca-44/Ca-43).
Time frame: baseline and 48 h urine and blood
Change in fecal microbiota
Time frame: after 3 weeks of product consumption
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