Inclusion Criteria:  diagnosis of primary hyperparathyroidism clinically established willing and able to give written informed consent age range 30-80 years commitment not to use any products that may influence the study outcome ability to understand and comply with the requirements of the study.  Exclusion Criteria:  impossibility to carry out DXA type 1 and 2 diabetes mellitus malabsorption alcohol abuse renal or hepatic insufficiency history of any malignancies use of probiotic supplement within four weeks prior to baseline use within the past 8 weeks of medication with known influences on the immune or skeletal system use of antibiotics during the previous two months or frequent user of antibiotics secondary hyperparathyroidism use of glucocorticoids or cinacalcet history of immunological or bone-related disorders