Department of Nutritional Sciences and the Rutgers Center for Lipid Research, Institute of Food, Health, and Nutrition, Rutgers University, New Brunswick, NJ, USA.
Department of Food Sciences, Rutgers University, New Brunswick, NJ, USA and South China Agriculture University, Guangzhou, China.
Food Funct. 2018 Mar 1;9(3):1809-1815. doi: 10.1039/c7fo01631j. Epub 2018 Mar 7.
In vivo studies measuring true fractional calcium (Ca) absorption have shown that dietary fat is a significant predictor of absorption and is influenced by luminal pH levels. However, whether changes in Ca bioaccessibility (CaB) can explain the effects on absorption has not been examined. In the current study, we examined two high fat diets enriched in either monounsaturated fatty acids or saturated fatty acids (SFA), and a low-fat diet (LFD), each with 50 mg Ca, and measured CaB at different intestinal regions during normal acidic or higher (pH = 7) gastrointestinal conditions using an in vitro gastrointestinal model. During normal pH conditions in the jejunum, there was an interaction between diet and time for CaB (P < 0.02), and CaB during the SFA diet was higher than LFD (P = 0.05). CaB was reduced by 90 ± 3% during higher compared with normal pH under all dietary conditions (P < 0.001). These findings indicate that fat intake, especially SFA enriched, is associated with a greater CaB in the jejunum, and may explain the higher Ca absorption in previous studies. In addition, the marked reduction in CaB under higher pH conditions could have implications in persons taking medications to reduce gastric acid.
体内研究测量真实的钙（Ca）分数吸收表明，膳食脂肪是吸收的一个重要预测因子，并受腔 pH 值水平的影响。然而，Ca 生物利用度（CaB）的变化是否可以解释吸收的影响尚未被检验。在本研究中，我们检验了两种富含单不饱和脂肪酸或饱和脂肪酸（SFA）的高脂肪饮食，以及一种低脂肪饮食（LFD），每种饮食都含有 50mgCa，并在正常酸性或更高（pH=7）胃肠道条件下，使用体外胃肠道模型，在不同的肠道区域测量 CaB。在空肠的正常 pH 条件下，CaB 存在饮食和时间的交互作用（P<0.02），SFA 饮食中的 CaB 高于 LFD（P=0.05）。与所有饮食条件下的正常 pH 相比，较高 pH 时 CaB 降低了 90±3%（P<0.001）。这些发现表明，脂肪摄入，尤其是富含 SFA 的脂肪摄入，与空肠中更高的 CaB 相关，并可能解释先前研究中更高的 Ca 吸收。此外，在较高 pH 条件下 CaB 的明显降低可能对服用药物来减少胃酸的人有影响。
