Effects of ovariectomy, caffeine intake and aerobic exercise associated or not with the adequate intake of calcium on body composition, on bone tissue and on balance of calcium in rats / Efeitos da ovariectomia, ingestão de cafeína e exercício aeróbico associados à adequação ou não de cálcio alimentar na composição corporal, no tecido ósseo e no balanço de cálcio em ratas

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Wistar adult female rats were allocated into 16 groups in a factorial 2 x 2 x 2 x 2 design: Ovariectomy (OVX or SHAM), Caffeine (Placebo or 6 mg caffeine/day), Exercise (sedentary or treadmill running at 16 m/min) and Calcium (100 or 50% of the recommended intake). The objectives of the current study were: 1) To evaluate the effects of ovariectomy, caffeine intake and aerobic exercise on body composition of female rats fed the recommended dose of dietary calcium (Chapter III); 2) To verify whether the intake of 50% of the recommended dose of dietary calcium alters the effects of ovariectomy, caffeine and exercise on body composition (Chapter IV); 3) To evaluate the effects of the ovariectomy, caffeine and exercise on bone tissue of female rats fed the recommended dose of dietary calcium (Chapter V); 4) To verify whether the intake of 50% of the recommended dose of dietary calcium alters the effects of ovariectomy, caffeine and exercise on bone tissue (Chapter VI); and 5) To evaluate the effects of calcium and caffeine intake and ovariectomy on calcium balance in sedentary and exercised female rats (Chapter VII). In Chapter III, it was observed that the ovariectomy promoted higher body weight gain and raised body fat; the exercise raised body water and protein and reduced fat and ash; however, the intake of caffeine did not affect body composition. In Chapter IV, the low intake of calcium did not alter the effects of ovariectomy, exercise and caffeine on body composition; however, the exercise and caffeine abstinence minimized the lean mass losses promoted by the ovariectomy. In Chapter V, it was verified that the estrogen deficiency reduced bone mineral content and resistance, increased bone resorption and reduced bone formation. The exercise attenuated the effects of ovariectomy, but, it reduced bone zinc. Although caffeine intake have not affected bone resistance, it raised urinary and bone calcium losses and bone resorption. In Chapter VI, it was observed that the low calcium intake strengthened the interaction between ovariectomy and caffeine, in such way that bone tissue was negatively affected; however, the exercise improved the bone parameters analyzed. In Chapter VII, observed that inadequate calcium intake improved its absorption efficiency in the gut, but reduced calcium balance. It was also observed that the ovariectomy reduced calcium balance and absorption, and that caffeine intake raised calcium balance and intestinal absorption. The exercise improved calcium absorption and reduced its fecal output. In conclusion, the ovariectomy raised body fat deposition and bone calcium resorption; the intake of caffeine did not affect body composition, but when associated with inadequate calcium intake, it is harmful to bone tissue, although the calcium balance was improved; the low calcium intake reduced its balance and was harmful to bone tissue, but did not affect body composition; the exercise mitigated the negative effects of ovariectomy. Thus, the exercise training reduced the risk of obesity and osteoporosis fractures, associated with estrogen deficiency and inadequate calcium intake.

ASSUNTO(S)

physical activity ciencia de alimentos atividade física caffeine calcium cafeína biodisponibilidade de cálcio

ACESSO AO ARTIGO

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