Department of Pharmacology, Medical University of Silesia, Katowice, Poland.
Mol Nutr Food Res. 2013 Oct;57(10):1772-84. doi: 10.1002/mnfr.201300123. Epub 2013 Jun 10.
Caffeine, a methylxanthine present in coffee, has been postulated to be responsible for an increased risk of osteoporosis in coffee drinkers; however, the data are inconsistent. The aim of the present study was to investigate the effects of a moderate dose of caffeine on the skeletal system of rats with normal and decreased estrogen level (developing osteoporosis due to estrogen deficiency).
The experiments were carried out on mature nonovariectomized and ovariectomized Wistar rats, divided into control rats and rats receiving caffeine once daily, 20 mg/kg p.o., for 4 wk. Serum bone turnover markers, bone mass, mass of bone mineral, calcium and phosphorus content, histomorphometric parameters, and bone mechanical properties were examined. Caffeine favorably affected the skeletal system of ovariectomized rats, slightly inhibiting the development of bone changes induced by estrogen deficiency (increasing bone mineralization, and improving the strength and structure of cancellous bone). Moreover, it favorably affected mechanical properties of compact bone. There were no significant effects of caffeine in rats with normal estrogen levels.
In conclusion, results of the present study indicate that low-to-moderate caffeine intake may exert some beneficial effects on the skeletal system of mature organisms.
咖啡因是咖啡中存在的一种甲基黄嘌呤，有人推测它会使喝咖啡的人骨质疏松的风险增加；然而，数据并不一致。本研究的目的是研究中等剂量的咖啡因对正常和雌激素水平降低（因雌激素缺乏而发生骨质疏松症）的大鼠骨骼系统的影响。
实验在成熟的未去卵巢和去卵巢 Wistar 大鼠上进行，分为对照组和每天接受咖啡因 20mg/kg 灌胃 4 周的大鼠。检测了血清骨转换标志物、骨量、骨矿物质量、钙和磷含量、组织形态计量学参数和骨力学性能。咖啡因对去卵巢大鼠的骨骼系统有良好的影响，轻度抑制了由雌激素缺乏引起的骨变化的发展（增加骨矿化，改善松质骨的强度和结构）。此外，它还对皮质骨的力学性能有良好的影响。在雌激素水平正常的大鼠中，咖啡因没有显著影响。
总之，本研究结果表明，低至中等剂量的咖啡因摄入可能对成熟生物的骨骼系统有一些有益的影响。
