British Journal of Nutrition

Full Papers

Inhibition of bone turnover by milk intake in postmenopausal women

Jean-Philippe Bonjoura1 c1, Marion Brandolini-Bunlona2, Yves Boiriea2, Françoise Morel-Laportea2, Véronique Braescoa2, Marie-Claude Bertièrea3 and Jean-Claude Souberbiellea4

a1 Service of Bone Diseases, University Hospital, Rue Micheli-Du-Crest, Geneva 1211, Switzerland

a2 Centre de Recherche en Nutrition Humaine d'Auvergne, 58 rue Montalembert, 63009 Clermont-Ferrand, France

a3 Centre de Recherche et d'Information Nutritionnelles, 45 rue Saint-Lazare, 75314 Paris, France

a4 Laboratoire d'Explorations Fonctionnelles, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75015 Paris, France

Abstract

Increased postmenopausal bone turnover leads to bone loss and fragility fracture risk. In the absence of osteoporosis, risk preventive measures, particularly those modifying nutritional lifestyle, are appropriate. We tested the hypothesis that milk supplementation affects bone turnover related to biochemical markers in a direction that, in the long term, may be expected to reduce postmenopausal bone loss. Thirty healthy postmenopausal women aged 59·3 (sd 3·3) years were enrolled in a prospective crossover trial of 16 weeks. After a 4-week period of adaptation with diet providing 600 mg calcium plus 300 mg ingested as 250 ml semi-skimmed milk, participants were maintained during 6 weeks under the same 600 mg calcium diet and randomized to receive either 500 ml semi-skimmed milk, thus providing a total of 1200 mg calcium, or no milk supplement. In the next 6 weeks they were switched to the alternative regimen. At the end of the each period, i.e. after 4, 10 and 16 weeks, blood and urinary samples were collected. The changes in blood variables between the periods of 6 weeks without and with milk supplementation were: for parathyroid hormone, − 3·2 pg/ml (P = 0·0054); for crosslinked telopeptide of type I collagen, − 624 pg/ml (P < 0·0001); for propeptide of type I procollagen, − 5·5 ng/ml (P = 0·0092); for osteocalcin, − 2·8 ng/ml (P = 0·0014). In conclusion, a 6-week period of milk supplementation induced a decrease in several biochemical variables compatible with diminished bone turnover mediated by reduction in parathyroid hormone secretion. This nutritional approach to postmenopausal alteration in bone metabolism may be a valuable measure in the primary prevention of osteoporosis.

(Received August 22 2007)

(Revised December 19 2007)

(Accepted January 21 2008)

(Online publication February 26 2008)

Correspondence:

c1 Corresponding author: Professor Jean-Philippe Bonjour, fax +41 223829973, email Jean-Philippe.Bonjour@medecine.unige.ch

Footnotes

Abbreviations: aBMD, areal bone mineral density; BAP, bone alkaline phosphatase; BRI, net calcium bone resorption index; CTX, crosslinked telopeptide of type I collagen; IGF, insulin-like growth factor; PINP, propeptide of type I procollagen; PTH, parathyroid hormone; TmPi, tubular inorganic phosphate reabsorption capacity; TRCaI, renal tubular calcium reabsorption index

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