The effect of Lactobacillus helveticus fermented milk on acute changes in calcium metabolism in postmenopausal women.
BACKGROUND
Milk fermented with Lactobacillus helveticus ( L. helveticus) has been shown to lower blood pressure and to increase bone mineral content in spontaneously hypertensive rats. The effect of L.helveticus may be due to better calcium availability.


OBJECTIVE
In the present study the effect of milk fermented with L. helveticus on acute changes in calcium metabolism and bone resorption in postmenopausal women was studied.


METHODS
The study was performed as a randomised double-blind crossover study of 20 postmenopausal women (mean age 65, range 50-78). The study was carried out in two parts. Firstly, L. helveticus fermented milk was compared to a control milk. Secondly, juice containing peptides formed with L. helveticus bacteria was compared to a control juice. The acute effect on calcium metabolism was measured during the study day by serum ionised calcium (iCa), parathyroid hormone (PTH), calcium (Ca), phosphate (P), and urinary calcium. A direct marker of bone turnover, carboxyterminal telopeptide of type I collagen (ICTP), was measured from the serum.


RESULTS
L. helveticus fermented milk reduced serum PTH (405.3 +/- 37 ng/l vs. 454.9 +/- 37, p = 0.012) and increased serum calcium (19.1 +/- 0.2 mmol/l vs. 18.8 +/- 0.2, p = 0.031) compared to the control milk. L. helveticus derived peptides had no significant acute effect on calcium metabolism, in fact, ionised calcium was lower and PTH higher after the juice containing peptides compared to the control juice.


CONCLUSIONS
Fermentation of milk with Lactobacillus helveticus had a positive acute effect on calcium metabolism. This effect was not explained by the small peptides formed by L. helveticus.
Narva
Mirkka
M
Institute of Biomedicine, Pharmacology, Helsinki University, Helsinki, Finland.
Nevala
Riikka
R
Poussa
Tuija
T
Korpela
Riitta
R
D000368:Aged; D000704:Analysis of Variance; D019540:Area Under Curve; D001862:Bone Resorption / Q000178:diet therapy* / Q000378:metabolism; D002118:Calcium / Q000097:blood* / Q000652:urine; D024042:Collagen Type I; D018592:Cross-Over Studies; D043302:Cultured Milk Products / Q000378:metabolism*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007778:Lactobacillus; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides / Q000008:administration & dosage; D010710:Phosphates / Q000097:blood; D017698:Postmenopause / Q000378:metabolism*; D011347:Procollagen / Q000097:blood; D013997:Time Factors
D024042:Collagen Type I; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D010455:Peptides; D010710:Phosphates; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; D002118:Calcium