Regular Consumption of a Functional Symbiotic Yogurt Increases Calcium Absorption in Young Adult Women

Abstract

We investigated the effect of daily consumption of a yogurt containing prebiotic fiber and probiotics (functional yogurt) compared to a common yogurt (control), on calcium absorption in adult women (21–33 years; n=30) using a cross‐over design. Each yogurt was consumed during 3 weeks separated by a 3 week wash‐out period. Calcium absorption was measured at the end of each yogurt‐consumption period, using an oral isotope tracer (42Ca) administered along with a standard breakfast meal. Recovery of 42‐‐‐‐‐‐‐Ca in urine was measured in complete collections at 4h, 24h, and 36h post‐dosing using magnetic sector thermal ionization mass spectrometry. Bone mass, PTH and vitamin D status were evaluated at baseline. Bone mineral content (BMC) and density (BMD) at total body (TB), lumbar spine (LS), femoral neck (FN) and trochanter (TR) were measured by dual energy X‐ray absorptiometry. Serum 25(OH)D and intact PTH were determined by chemiluminescent assays. Temporal changes in urinary 42‐‐‐‐‐‐‐Ca recovery were analyzed by repeated‐measures ANOVA. Comparison between treatments at each time point was evaluated by paired t test. Relationships between variables were examined by correlation analysis. Average Z scores of bone measurements were adequate, 0.59 (TBBMC), 0.49 (TBBMD), 0.05 (LSBMD), 0.99 (FNBMD), −0.54 (TRBMD) although TRBMD and LSBMD Z scores were lower than −1 in 30% and 7% of the women, respectively. Serum 25(OH)D was 37.9 ± 9.9 ng/mL indicating vitamin D sufficiency. As expected, urinary 42‐‐‐‐‐‐‐Ca recovery increased over time for each type of yogurt (P<0.01). There were no significant differences by yogurt type at 4h or 24h but at 36h, 42‐‐‐‐‐‐‐Ca recovery in urine was 37% higher after consumption of the functional yogurt compared to the control yogurt (P=0.05). Urinary recovery of 42‐‐‐‐‐‐‐Ca was not related to vitamin D, PTH or bone mass measurements. These results suggest that the functional yogurt tested increased calcium absorption possibly by passive processes in the distal small intestine or in the colon.Support or Funding InformationCooperativa Nacional de Productores de Leche (CONAPROLE), Uruguay