Absorbability and cost effectiveness in calcium supplementation

BACKGROUND

Cost-effectiveness of calcium supplementation depends not only on the cost of the product but on the efficiency of its absorption. Published cost-benefit analyses assume equal bioavailability for all calcium sources. Some published studies have suggested that there are differences in both the bioavailability and cost of the major calcium supplements.

DESIGN

Randomized four period, three-way cross-over comparing single doses of off-the-shelf commercial calcium supplements containing either calcium carbonate or calcium citrate compared with a no-load blank and with encapsulated calcium carbonate devoid of other ingredients; subjects rendered fully vitamin D-replete with 10 microg/day 25(OH)D by mouth, starting one week prior to the first test.

SUBJECTS

24 postmenopausal women

METHODS

Pharmacokinetic analysis of the increment in serum total and ionized calcium and the decrement in serum iPTH induced by an oral calcium load, based upon multiple blood samples over a 24-hour period; measurement of the rise in urine calcium excretion. Data analyzed by repeated measures ANOVA. Cost calculations based on average retail prices of marketed products used in this study from April through October, 2000.

RESULTS

All three calcium sources (marketed calcium carbonate, encapsulated calcium carbonate and marketed calcium citrate) produced identical 24-hour time courses for the increment in total serum calcium. Thus, these were equally absorbed and had equivalent bioavailability. Urine calcium rose slightly more with the citrate than with the carbonate preparations. but the difference was not significant. Serum iPTH showed the expected depression accompanying the rise in serum calcium, and there were no significant differences between products.

CONCLUSION

Given the equivalent bioavailability of the two marketed products, the cost benefit analysis favors the less expensive carbonate product.

Bioavailability of the calcium in fortified soy imitation milk, with some observations on method

BACKGROUND

Calcium-fortified soy milk is growing in popularity, particularly among vegetarians, but the bioavailability of its calcium was not previously known. Additionally, the validity of isotopic labeling methods for fortified liquid products had not been established.

OBJECTIVES

The objectives of this study were to compare the bioavailability of the calcium in fortified soy milk with that of calcium in cow milk and to evaluate the method of labeling soy milk for bioavailability testing.

DESIGN

A within-subject comparison of extrinsically labeled cow milk with intrinsically and extrinsically labeled soy milks was undertaken in 16 healthy men. In all tests, 300-mg Ca loads were given as a part of a light breakfast after an overnight fast. The milks were physically partitioned into liquid and solid phases to enable evaluation of tracer distribution.

RESULTS

Calcium from intrinsically labeled soy milk was absorbed at only 75% the efficiency of calcium from cow milk. Extrinsic labeling of soy milk did not produce uniform tracer distribution throughout the liquid and solid phases and resulted in a 50% overestimate of true absorbability.

CONCLUSION

Calcium-fortified soy milk does not constitute a calcium source comparable to cow milk, and extrinsic labeling of such calcium particulate suspensions does not produce the uniform tracer distribution needed for bioavailability testing. Hence, intrinsic labeling of the fortificant is required for such liquid suspensions.

Effects of movies on children's emotional health

Parents are in a dilemma when it comes to deciding what films they should allow their children to see. They know intuitively that some viewing experiences are entertaining while others are potentially harmful. The authors have been viewing films and talking with parents, educators, and mental health professionals for several years to try to answer questions posed by these conscientious but frustrated parents. This article, the first published regarding our findings, describes the history of today's movie rating system, which represents an early but inadequate attempt to offer parents guidance. A recent film, The Lion King, will demonstrate a developmental approach to thinking about movies for children. This method uses current research on the effects of movies on children and knowledge of child development to predict reactions of children in particular age groups to elements in a movie.

The views of primary health care practitioners regarding legal limitations influencing the practice of primary health care nurses in South Africa

An exploratory descriptive study was performed within the South African context to determine the legal limitations which influence the practice of the registered primary health care nurse. Primary health care medical practitioners and nurses were interviewed to ascertain their views on these limitations. The results confirmed various limitations that need to be rectified by means of the amendment/deregulation of selected legislation. It is also recommended that a model for professional accountability, suitable for the South African health care delivery system, be developed.

Legal limitations in the practice of the primary health care nurse

In this article the legal limitations in the practice of the primary health care nurse in the Republic of South Africa, having direct implications for the achievement of the goal: "Health for all by the year 2000", are explored and described. The questions which had to be answered by means of the research are in relation to the nature and scope of the limitations obstructing the practice of the primary health care nurse. A legislative (document) analysis was performed and limitations in the legislation confirmed. It is recommended that an empirical investigation be done to verify the results after which amendments and clarification of the legislation may be requested.

Legal limitations in primary health care nursing practice in South Africa (Part 2)

This is the second of two articles on the limitations in the practice of the nurse functioning in the primary health care field. An exploratory descriptive study was done within the context of the Republic of South Africa. Medical practitioners and nurses were asked by means of interviews of their experiences of the role of the nurse in primary health care services. The findings were verified by means of a content analysis of health legislation. Arising from this recommendations were made to address legal and other limitations in the practice of the nurse working in a primary health care setting. It was further recommended that a model for accountability for health professions be developed.

Legal limitations in primary health care nursing practice in South Africa (Part 1)

In this, the first of two articles, legal limitations in the practice of the primary health care nurse in the Republic of South Africa, having direct implications for the achievement of the goal 'health for all by the year 2000', are discussed. The questions which had to be answered by means of research relate to the nature and scope of the limitations as well as to how these limitations should be addressed in order to facilitate the practice of the primary health care nurse. A content analysis was done and recommendations formulated to amend and/or clarify certain health legislation. It is recommended that an empirical investigation be done to verify the results.

The roles of self-esteem and self-consciousness in the Wortman-Brehm model of reactance and learned helplessness

The present experiments were designed to study the conditions under which failure would enhance or inhibit subsequent task performance. Based on the theory of Wortman and Brehm (1975), it was expected that small amounts of failure would produce reactance (manifested by improved performance at a subsequent task), whereas large amounts would lead to learned helplessness (i.e., impaired later performance). It was further expected that individual differences in self-esteem and private self-consciousness would serve as moderator variables for the above effects. In Experiment 1, subjects were exposed to either a small amount of failure or no failure before working on an anagrams task. As predicted, subjects high in self-consciousness, who have shown greater reactance arousal in attitude change studies, performed better on the anagrams task than subjects low in self-consciousness in the small-failure condition, but not in the no-failure condition. Further analyses revealed that this Self-Consciousness X Small Failure interaction was attributable to the performance data of the low, but not the high self-esteem subjects. Experiment 2 was designed to replicate and extend these results. Subjects were pretreated with either a small amount of failure, an extended amount of failure, or no failure before working on the anagrams task. A significant Self-Esteem X Helplessness Training interaction emerged. Relative to the no-failure condition, in which the two self-esteem groups did not differ, low self-esteem participants (low SEs) performed marginally better than did high self-esteem individuals (high SEs) in the small-failure condition but significantly worse than high SEs in the extended-failure condition. The effect of private self-consciousness was considerably weaker in this study, possibly because the sample included few low SEs (who are especially influenced by self-focused attention) who were also relatively low in self-consciousness. Questionnaire data from Experiment 2 were consistent with the notion that enhanced performance reflected reactance, whereas impaired performance signified helplessness.

Effects of lysozyme on Trypanosoma lewisi

Daily lysozyme (hen egg) injections, beginning on day 6 of Trypanosoma lewisi infections in rats, significantly reduced the number of circulating trypanosomes. The effect was dose dependent. Maximum reduction (50%) occurred 24 hours after one treatment of 80 mg was given intraperitoneally (I.P.). The same dose of lysozyme was more effective when divided equally into two injections per day. Controls consisting of appropriate buffers as well as human serum albumin had no effect on trypanosome populations. Animals receiving lysozyme exhibited a weight loss of 5% 24 hours following the first injection, but not other ill effects of the treatment were observed. In vitro experiments indicated that lysozyme did not cause lysis or immobilization alone or in combination with fibrinogen or rat antitrypanosomal serum. These results suggest that the cellular immune response of the host and lysozyme's cationic properties may be important in mediating the anti-trypanosomal response. Lysozyme may thus be an effective trypanocide against trypanosomes whose membranes resemble T. lewisi, such as T. cruzi, or as an adjunct to chemotherapy.