By means of isotope ⁴⁷Ca, changes in the rate and intensity of calcium absorption from lactose-free milk and normal milk were investigated as well as ⁴⁷Ca losses in faeces and urine and Ca retention in the organism during a 7-day period in healthy volunteers and in patients with lactose intolerance. The shape of ⁴⁷Ca absorption curves after lactose-free milk in healthy subjects is lower than after milk with a normal lactose content. Conversely, in subjects with lactose intolerance, the shape of the absorption curves of ⁴⁷Ca was lower after ingestion of normal milk and higher after ingestion of lactose-free milk. The total amount of absorbed and retained Ca practically does not differ, regardless whether Ca was administered in milk or lactose-free milk. No significant differences were found in the utilization of Ca in subjects with lactose intolerance. In these patients, the retardation of the peaks of the absorption curves after ingestion of milk most probably suggests a compensatory delay of gastric evacuation. The slower supply of chyme into the gut improves the utilization of Ca in spite of relative lactase insufficiency. Well-tolerated lactose-free milk could be used to ensure a sufficient dietary supply of Ca in subjects with lactose intolerance.

By comparison with controls the investigation of ⁴⁷Ca absorption and excretion kinetics after oral administration to patients with Billroth I gastrectomy (without milk intolerance) showed no differences in excretion of the isotope in urine and stool or in retention in the body. Patients with Billroth II gastrectomy had a higher degree of isotope excretion in stool and a lower retention of ⁴⁷Ca. The higher absorption curves of isotope in Billroth I patients suggest a more rapid rate of ⁴⁷Ca absorption without an actual change in transport capacity.

No abstract

The authors assessed the clavicular corticodiaphyseal indexes in 167 patients after partial gastrectomy and follow-up on a long-term basis. The results are compared with findings in healthy controls. When the gastrectomy group was divided into two subgroups with regard to milk (lactose) tolerance, a significant difference was found between the two groups.The findings suggest that the width of the cortical layer of the clavicle in subjects with lactose intolerance declines significantly more rapidly than in subjects of similar age without intolerance. The values of bone indexes in subjects without lactose intolerance were on an average higher than the values in controls, while the values of the group with lactose intolerance are significantly lower and the difference as compared with controls increases with advancing age. It may thus be assumed that in patients, after partial gastrectomy, lactose intolerance participates to a considerable extent in the development of osteopenia.

1. Administration of a large amount of unlabelled calcium orally 60 min after intravenous injection of 47Ca leads to a temporary rise of serum specific radioactivity in healthy volunteers.2. This short-term rise is followed by a more rapid decline and in some instances by oscillations of specific radioactivity.3. Both these effects could be caused by secretion of thyrocalcitonin resulting from a rise of serum calcium concentration during calcium absorption from the gastrointestinal tract.During an investigation of the kinetics of the disappearance of intravenously administered 47Ca unusual results were observed if there was simultaneous alimentary absorption of a considerable amount of unlabelled calcium.Administration of 47Ca alone in tracer amounts does not interfere with the dynamic equilibrium of calcium in the organism and the disappearance curves of activity from serum can be expressed as the sum of two or three exponentials. The oral administration of inactive calcium affects calcium homeostasis and stimulates regulatory mechanisms which oppose the change in serum calcium. The rise of serum calcium concentration due to absorption should result in secretion of calcitonin, which enhances the disappearance of calcium from the rapidly exchangeable pool (Munson & Hirsch, 1967). Such an effect should be revealed by a more rapid decline in serum radioactivity. We found, however, that in all subjects a temporary short-term rise of serum specific radioactivity occurred closely after the increase in total serum calcium. This observation is compared with the findings of other authors, who produced a similar effect in animals and human subjects by infusion of calcitonin (