Acute Calcium Assimilation from Fresh or Pasteurized Yoghurt Depending on the Lactose Digestibility Status

Abstract

Objective: The major aim of this trial was to evaluate the potential interaction of fresh or pasteurized yoghurt intake with lactose intolerance on calcium assimilation by means of the stable isotope ⁴³Ca as a tracer.

Methods: Forty volunteers (age: 32 ± 7 years) participated in this parallel simple blind study (20 of them with moderate lactose intolerance). The protocol included the intake of a test meal consisting on ⁴³Ca-labelled fresh or pasteurized yoghurt. Volunteers, in whom the calcium status was assessed, collected the 24-h urine before and after the test meal to measure the stable isotope output. The intake-related ⁴³Ca enrichment in urine was measured by isotopic rate mass spectrometry.

Results: In lactose tolerant and intolerant volunteers taken together, the fresh yoghurt consumption resulted in a statistically higher circulating calcium levels (p = 0.028) and urinary ⁴³Ca output (p = 0.017) than after the pasteurized yoghurt intake. The lactose maldigestion status resulted in higher urinary ⁴³Ca excretion (p = 0.013) after the fermented milk consumption, regardless of the nature of ingested product (p = 0.887).

Conclusions: This novel and non-aggressive protocol allowed the in vivo comparison of calcium utilization from two different dairy sources, revealing a higher acute calcium assimilation from fresh as compared to the pasteurized yoghurt, in both lactose digesting and maldigesting subjects.

• calcium assimilation
• stable isotopes
• yoghurt
• lactose maldigestion

The authors wish to thank Iñigo Navarro from the Department of Chemistry (University of Navarra, Spain) for the help in preparing urine samples, as well as Paul Field from the Institute of Marine and Coastal Sciences (Rudgers University, USA) for the analysis of ⁴³Ca content in urine samples and Danone for the supplied products. We also thank our nurse Salomé Pérez, and our technicians Ana Lorente and Verónica Ciaurriz for excellent technical assistance.