Effect of calcium sources in the diets of adult cats on urinary parameters and acid-base balance / Efeitos das fontes de cálcio na dieta de gatos adultos sobre parâmetros urinários e equilíbrio ácido-básico

Calcium is a macroelement that is part of the mineral composition of the diet of companion animals, and is considered a cation of strong alkalizing power, increasing urinary pH. Calcium salts have different solubilities and depending on the anion to which calcium is associated with, it can be more or less absorbed, modifying the pH of the urine. The aim of this study was to evaluate the efficiency of calcium sources on alkalinization of urinary pH, as well as excretion of urinary electrolytes and acid-base balance of adult cats. An extruded diet for cats was selected, and had 160mEq/kg of calcium from the sources of either calcium carbonate (CaCO3) or calcium gluconate (C12H22CaO14) added. In the control treatment there was no addition of calcium sources, resulting in three treatments. Nine adult cats were used, mixed breed, in two experimental periods, with six replicates per treatment. Animal average age was 4±1.3 years old and average weight was 3.96±0.71kg. The cats remained in metabolic cages for an adaptation period of seven days, followed by six days of urine total collection, with volume, density, pH and calcium concentration (g/d) measurements. The acid-base balance was studied by blood gas analysis of venous blood. The two sources of calcium alkalinized the urine (P<0.001). However, calcium gluconate had less alkalinization power compared to the calcium carbonate (P<0.05). Urinary calcium was not affected by treatments, and represented less than 0.5% of calcium intake. The experiment showed that calcium, although an alkaline cation and considered strong influencer of the EB of the diet, cannot be evaluated individually, because depending on its associated anion it may have greater or lesser influence on cats urine pH.(AU)

O cálcio (Ca) é um macroelemento que faz parte da composição mineral da dieta de animais de companhia. Este macroelemento é considerado um cátion de forte capacidade alcalinizante e, de acordo com a fonte e quantidade inclusa, pode aumentar o pH urinário. Os sais de cálcio têm diferentes solubilidades e dependendo do ânion ao qual o cálcio está associado, pode ser mais ou menos absorvido e assim, alterar o pH da urina. O objetivo deste estudo foi avaliar os efeitos de duas fontes de cálcio na alcalinização do pH urinário, bem como a excreção de eletrólitos urinários e o equilíbrio ácido-básico de felinos. Foi selecionada uma dieta extrusada para gatos e adicionados 160mEq/kg de cálcio das fontes carbonato de cálcio (CaCO3) ou gluconato de cálcio (C12H22CaO14). No tratamento controle, não houve adição de fontes de cálcio. Foram utilizados nove gatos adultos, de raças mistas, em dois períodos experimentais, com seis repetições por tratamento. Os animais apresentavam idade média de 4,0±1,3 anos e peso corporal médio de 3,96±0,71kg. Estes permaneceram em gaiolas metabólicas em período de adaptação durante sete dias, seguido de coleta total de urina durante seis dias. Nestas amostras foram aferidos o volume, densidade, pH e concentração de cálcio (g/d). O equilíbrio ácido-básico foi avaliado por hemogasometria em amostras de sangue venoso. As duas fontes de cálcio alcalinizaram a urina (P<0,001). No entanto, o gluconato de cálcio apresentou menor potencial de alcalinização em comparação ao carbonato de cálcio (P<0,05). O cálcio urinário não foi afetado pelos tratamentos e representou menos de 0,5% da ingestão de Ca. O experimento demonstrou que o cálcio, apesar de ser um cátion alcalinizante e influenciador do EB da dieta, não pode ser avaliado individualmente, porque dependendo do ânion associado, pode apresentar maior ou menor influência no pH da urina de gatos.(AU)

Respuesta de la calciuria a suplementos de vitamina D / Calcium response to vitamin D supplementation

Múltiples estudios muestran la importancia de mantener niveles suficientes de vitamina D para prevenir varias enfermedades crónicas. Sin embargo, la suplementación de vitamina D sobre la calciuria es controvertida. El objetivo de este trabajo prospectivo, intervencionista, fue evaluar la respuesta de la calciuria en mujeres con hipercalciuria y normocalciuria, luego de conseguir niveles adecuados de 25 OH D. Se estudiaron 63 mujeres con hipercalciuria idiopática (9 con litiasis renal) y 50 mujeres normocalciúricas. Ambos grupos presentaron déficit/insuficiencia de 25 OH D y fueron suplementadas con vitamina D2 o D3 semanales o vitamina D3 en dosis de 100 000 UI mensuales. A todas se les midió la calciuria basal y final al alcanzar el valor de 25 OH D deseado (> 30 ng/dl). No observamos cambios significativos en los valores de la calciuria inicial y final en las que recibieron vitamina D2 o D3 semanal ni en las que recibieron dosis mensuales. Sin embargo, un subgrupo de mujeres: 19% (n = 12) de las hipercalciúricas y 12% (n = 6) de las normocalciúricas (con vitamina D semanal) aumentaron la calciuria en forma significativa. Mientras que, con dosis mensuales, un 40% (n = 4/10) de las hipercalciúricas y 44% (n = 4/9) de las hipercalciúricas con litiasis renal aumentaron la calciuria. En conclusión, niveles adecuados de 25 OH D son seguros en la mayoría de las pacientes. En aquellas que requieren dosis de carga mensuales podrían observarse aumentos de la calciuria en forma significativa con riesgo de formar cálculos renales o perder masa ósea, cuando están genéticamente predispuestas.

Several studies show the importance of serum vitamin D sufficient levels to prevent multiple chronic diseases. However, vitamin D supplementation and its effects on urine calcium excretion remain controversial. The objective of this prospective and interventional study was to evaluate urine calcium excretion in women with normal calciuria or hypercalciuria, once serum vitamin D sufficiency was achieved. We studied 63 women with idiopathic hypercalciuria, (9 with renal lithiasis) and 50 normocalciuric women. Both groups had serum vitamin D levels low (deficiency or insufficiency). Baseline urine calcium excretion was measured before being supplemented with vitamin D2 or D3 weekly or vitamin D3 100.000 IU monthly. Once serum vitamin D levels were corrected achieving at least 30 ng/ml, a second urine calcium excretion was obtained. Although in the whole sample we did not observe significant changes in urine calcium excretion according to the way of supplementation, some of those with weekly supplementation had significant higher urine calcium excretion, 19% (n = 12) of hypercalciuric women and 12% (n = 6) of the normocalciuric group. Monthly doses, also showed higher urine calcium excretion in 40% of hypercalciuric women (n = 4/10) and in 44% (n = 4/9) of the renal lithiasis hypercalciuric patients. In conclusion, different ways of vitamin D supplementation and adequate serum levels are safe in most patients, although it should be taken into account a subgroup, mainly with monthly loading doses, that could increase the calciuria significantly eventually rising renal lithiasis risk or bone mass loss, if genetically predisposed.

Calcium intake: good for the bones but bad for the heart? An analysis of clinical studies

ABSTRACT The proper dietary calcium intake and calcium supplementation, when indicated, are important factors in the acquisition of peak bone mass during youth and in the prevention of fractures in old age. In addition to its deposition in bone, calcium confers an increase in its resistance and exhibits important activities in different enzymatic pathways in the body (e.g., neural, hormonal, muscle-related and blood clotting pathways). Thus, calcium supplementation can directly or indirectly affect important functions in the body, such as the control of blood pressure, plasma glucose, body weight, lipid profile and endothelial function. Since one publication reported increased cardiovascular risk due to calcium supplementation, many researchers have studied whether this risk actually exists; the results are conflicting, and the involved mechanisms are uncertain. However, studies that have evaluated the influence of the consumption of foods rich in calcium have reported no increase in the cardiovascular risk, which suggests that nutritional intake should be prioritized as a method for supplementation and that the use of calcium supplements should be reserved for patients who truly need supplementation and are unable to achieve the recommended daily nutritional intake of calcium.

Does calcium intake affect cardiovascular risk factors and/or events?

Dietary intervention is an important approach in the prevention of cardiovascular disease. Over the last decade, some studies have suggested that a calcium-rich diet could help to control body weight, with anti-obesity effects. The potential mechanism underlying the impact of calcium on body fat has been investigated, but it is not fully understood. Recent evidence has also suggested that a calcium-rich diet could have beneficial effects on other cardiovascular risk factors, such as insulin resistance, dyslipidemia, hypertension and inflammatory states. In a series of studies, it was observed that a high intake of milk and/or dairy products (the main sources of dietary calcium) is associated with a reduction in the relative risk of cardiovascular disease. However, a few studies suggest that supplemental calcium (mainly calcium carbonate or citrate) may be associated with an increased risk of cardiovascular events. This review will discuss the available evidence regarding the relationship between calcium intake (dietary and supplemental) and different cardiovascular risk factors and/or events.

Calcium intake and its relationship with risk of overweight and obesity in adolescents / Ingesta de calcio y su relación con la prevalencia deriesgo de sobrepeso y obesidad en adolescentes

Adolescents’ eating habits are determined by social, psychological, economic, political, and educational influences. They tend to prefer foods with inadequate nutritional value and high fat and carbohydrate content which leads to excessive weight gain and for many, calcium intake is restricted. According to some authors, low calcium intake is linked to increased adiposity. The objective was to evaluate adolescent calcium intake and investigate a possible relationship between calcium intake and nutritional state. As part of their first consultation at Botucatu Adolescent Outpatient Clinic -UNESP, 107 adolescents were nutritionally classified by BMI, according to age, gender, and bands proposed by CDC and AAP. Diet was evaluated by a 3 day 24h food recall, adopting 1300mg/day calcium intake as recommended by Dietary Reference Intakes. Median calcium intake for the whole sample was 546.6mg/day, with 91.30 percent female and 86.84 percent male presenting lower than adequate daily recommended ingestion levels (DRI). There was significant difference between calcium densities (Ca mg/1000kcal) in eutrophic and overweight/obesity in males. Male adolescents showed an inverse relationship between calcium intake and adiposity (r= -0.488 and p=0.0173), which corroborates the hypothesis that low calcium intake is linked to fatty tissue gain. Only 8.70 percent of female and 13.16 percent of male adolescents reached their daily recommended calcium intake levels. It must therefore be stressed that nutritional education is an important protection factor for children and adolescents in later life.

Los hábitos alimentarios se desarrollan dependiendo de los determinantes sociales, psicológicos, económicos, políticos y educacionales y sus preferencias recaen sobre alimentos con inadecuado valor nutricional, elevado contenido de grasa y carbohidratos que conducen a un aumento excesivo de peso. De acuerdo con algunos autores la baja ingestión de calcio se asocia al incremento de la adiposidad. Los objetivos fueron evaluar la ingestión de calcio por adolescentes e investigar una posible relación con el estado nutricional. En su primera consulta en el Ambulatorio de Medicina del Adolescente-Botucatu-UNESP, 107 adolescentes se clasificaron nutricionalmente por el IMC, de acuerdo con la edad y sexo y puntos de corte propuestos por el CDC y AAP. La evaluación dietética fue realizada por el método de recordatorio de 24 hrs. en 3 días diferentes y se adoptó la recomendación de Dietary Reference Intakes (DRI), de 1.300 mg de Ca/día. La ingestión mediana de calcio para la muestra total fue de 546,6 mg/día. Un 91,3 por ciento de las adolescentes y un 86,8 por ciento de los jóvenes presentaron un consumo inferior a los valores de DRI. Al comparar la densidad de calcio (Ca mg/1.000 kcal) entre los grupos eutróficos y sobrepeso/obeso del sexo masculino, se constató una diferencia significativa. En los adolescentes masculinos se evidenció una relación inversa enttre consumo de calcio y adiposidad (r = -0,488 y p = 0,0173), lo cual confirma la hipótesis de que la baja ingestión de calcio se asocia al aumento de tejido graso. Solamente el 8,7 por ciento de las adolescentes mujeres alcanzaron las recomendaciones diarias de DRI y de los adolescente masculinos, el 13,16 por ciento.

Principais causas de diminuição da massa óssea em mulheres na pré-menopausa encaminhadas ao ambulatório de doenças ósteo-metabólicas de um Hospital Terciário de Curitiba / Main causes of low bone mass in premenopausal women referred to a Metabolic Bone Clinic of Curitiba / Main causes of low bone mass in premenopausal women referred to a Metabolic Bone Clinic of Curitiba

Selecionamos mulheres pré-menopausadas com redução da DMO encaminhadas ao ambulatório de Metabolismo Osseo do Hospital de Clínicas da UFPR, com o objetivo de definirmos o perfil destas pacientes em relação aos fatores de risco e prováveis causas secundárias de osteoporose. Trinta e quatro mulheres foram estudadas (19­48 anos). Em 29 pacientes (85,3 por cento) a coluna lombar estava acometida, 8 (23,5 por cento) apresentaram Z-score < -2,5 e 21 (61,8 por cento) Z-score entre -1,0 e -2,5. Vinte pacientes (58,8 por cento) apresentaram redução da DMO em fêmur, 2 (6,2 por cento) com Z-score < -2,5 e 18 (56,2 por cento) com Z-score entre -1,0 e -2,5. Causa secundária foi identificada em 26 pacientes (76,5 por cento). Este estudo demonstra que a realização de densitometria óssea é importante em mulheres na pré-menopausa com fatores de risco para redução da massa óssea, uma vez que permite o início precoce do tratamento e a prevenção das complicações relacionadas.

We conducted a chart review of premenopausal women with low bone mineral density referred to the Metabolic Bone Clinic of Federal University of Paraná, to determine the outline of these patients regarding their risk factors and secondary causes of osteoporosis. Thirty-four women (19­48 years old) were evaluated. Twenty nine (85.3 percent) patients presented a low bone mineral density (BMD) in lumbar spine, 8 (23.5 percent) had Z-score < -2.5 and 21 (61.8 percent) had Z-score between -1.0 and -2.5. Twenty patients (58.8 percent) had a low bone mass in total femur, 2 (6.2 percent) with Z-score < -2.5 and 18 (56.2 percent) with Z-score between -1.0 and -2.5. A secondary cause could be identified in 26 patients (76.5 percent). This study shows that DMO is important in premenopausal women with risk factors of low BMD because it leads to the best treatment option and follow-up.

Consumo de leite de vaca e anemia ferropriva na infância / Cow's milk consumption and iron deficiency anemia in children

OBJETIVO: Revisar aspectos do consumo de leite de vaca associados à anemia na infância. FONTES DOS DADOS: As informações foram coletadas a partir de artigos publicados nas 2 últimas décadas, pesquisados nas bases de dados Lilacs e MEDLINE, livros técnicos e publicações de organizações internacionais. SíNTESE DOS DADOS: A anemia ferropriva é um grave problema de saúde pública nos países em desenvolvimento. Até os 6 meses de idade, o leite materno supre as necessidades de ferro das crianças nascidas a termo. A partir daí, torna-se necessária a ingestão de uma alimentação complementar rica em ferro. Considerando a importância da dieta na determinação da anemia e o alto consumo de leite de vaca na infância, discute-se neste artigo a relação desse alimento com a deficiência de ferro. A introdução precoce ou a substituição do leite materno por leite de vaca pode ocasionar problemas gastrintestinais e alérgicos. Além disso, esse alimento apresenta baixa biodisponibilidade e densidade de ferro, excesso de proteínas e minerais, especialmente cálcio, interferindo na absorção do ferro de outros alimentos, e associa-se às micro-hemorragias intestinais, principalmente nas crianças menores. CONCLUSÕES: A utilização do leite de vaca em detrimento de outros alimentos ricos em ferro biodisponível constitui um risco para o desenvolvimento da anemia. O estímulo ao aleitamento materno exclusivo até os 6 meses de vida e sua continuidade até pelo menos 24 meses, juntamente com uma dieta complementar rica em ferro são medidas de grande importância para a prevenção da anemia e de suas conseqüências na infância.

Dietary habits of calcium stone formers

1. Since dietary factors are known to be related to nephrolithiasis, calcium stone-forming (CSF) patients were evaluated in terms of calcium, total protein of both animal and plant origin, carbohydrate and energy intakes, on the basis of 72-h dietary records during the week plus 24-h dietary records during the week-end. 2. The data for 77 calcium stone formers (57 with absorptive hypercalciuria and 20 with renal hypercalciuria) were compared to those for 29 age-matched healthy subjects. The body mass index of the CSF group was higher than that of healthy subjects (P < 0.05). Consumption of all nutrients was similar for both groups during the week but week-end dietary records for CSF showed higher calcium intake (586 +/- 38 vs 438 +/- 82 mg/day, P < 0.05), protein to body weight ratio (1.2 +/- 0.1 vs 1.0 +/- 0.5 g kg-1 day-1, P < 0.05) and animal protein (56 +/- 3 vs 40 +/- 3 g/day, P < 0.05) when compared with healthy subjects. 3. Comparison of hypercalciuria subtypes (renal hypercalciuria and absorptive hypercalciuria) did not indicate any difference in calcium or energy intake between groups, either during the week or during the week-end. However, the absorptive hypercalciuric group presented higher protein and animal protein consumption during the week-end. 4. These data suggest a low calcium intake in this population, even by stone formers. The higher animal protein consumption by our calcium stone formers observed during week-ends seems to be more important than calcium intake for stone formation