Issues of Aging in Preventive Medicine and the Example of Osteoporosis

Comparison of the effect of medium-chain and long-chain triacylglycerols on calcium absorption in healthy subjects

BACKGROUND

The absorption efficiency of calcium in humans is low. Some studies in infants have shown that calcium absorption can be increased by adding medium-chain triacylglycerols to the formula diet.

OBJECTIVE

The effect of medium- and long-chain triacylglycerols on calcium absorption was studied in 18 healthy, young men. The results were compared with data obtained from calcium ingestion of a protein-carbohydrate formula devoid of triacylglycerols.

DESIGN

Calcium absorption was measured by using a double-isotope technique and the kinetic parameters were obtained by using a deconvolution method.

RESULTS

The total fractional calcium absorption measured in the presence of medium-chain triacylglycerols (0.236 +/- 0.016) or from a protein-carbohydrate formula without triacylglycerols (0.235 +/- 0.012) was not significantly different. The same result was observed with long-chain triacylglycerols (0.309 +/- 0.026) and the protein-carbohydrate formula (0.275 +/- 0.012). No kinetic parameters were significantly different regardless of the diet (protein-carbohydrate, medium-chain triacylglycerol, or long-chain triacylglycerol). This suggests that the same mechanism for calcium absorption was operative.

CONCLUSIONS

Triacylglycerols had no direct effect on calcium absorption from a protein-carbohydrate formula in healthy subjects. These data do not support the use of medium-chain triacylglycerols as adjuvants to increase the absorption of calcium in healthy adults.

Enhancement of calcium transport in the Caco-2 cell monolayer model

The overall objective of this research was to identify enhancers of calcium transport using an in-vitro Caco-2 cell monolayer model. The enhancers studied were medium-chain triglycerides (MCT) and acylcarnitines (AC). The extent of cell damage associated with the use of these enhancers was determined by monitoring the release of cellular lactate dehydrogenase (LDH). The effect of chain-length and concentration dependence of these agents on enhancement were also determined. The effects of ACs were found to be superior to those of MCTs. However, the ACs elicited a greater release of LDH than the MCTs. The possible mechanisms of enhancer-mediated increase in calcium transport and the potential significance of this study with regard to the prevention of osteoporosis are discussed.

Development and evaluation of the Osteoporosis Health Belief Scale

The Osteoporosis Health Belief Scale was developed to measure health beliefs related to osteoporosis. It is a 35-item self-report questionnaire based on the Health Belief Model which is specifically designed to assess beliefs related to exercise behaviors and calcium intake of elderly subjects. The instrument consists of seven subscales: Seriousness, Susceptibility, Health Motivation, Calcium Benefits, Calcium Barriers, Exercise Benefits, and Exercise Barriers. The instrument was tested on a sample of 150 elderly individuals. The psychometric properties of the scales are discussed along with recommendations for its use in research and practice.