Abstract

Food grade titanium dioxide (TiO₂) containing nanofractions, is commonly applied to whiten and brighten food products, which put consumers under health risks of ingesting TiO₂ nanoparticles (NPs). Although the oral toxicity of TiO₂-NPs has been evaluated in several studies, gaps in knowledge exist regarding interactions between NPs and food components. Therefore, this study aimed to estimate the influence of TiO₂-NPs on nutrient absorption and metabolism through an in situ intestinal loop experiment which conducted on adult Sprague Dawley (SD) rats after 30-d gastrointestinal exposure to TiO₂-NPs of two different sizes (N-TiO₂ and M-TiO₂). Results showed that exposure to TiO₂-NPs caused flat apical membranes with sparse and short microvilli and inflammatory infiltration in small intestine. Both particles were absorbed into small intestinal cells, but N-TiO₂ with smaller size could more easily be transported through gut and raise the blood titanium (Ti) levels. Changes in serum levels of amino acid were also different after exposure to these two particles. After injecting mixed solution of nutrients into in situ intestinal loop, the N-TiO₂ exposure groups displayed significant absorption inhibition of the added histidine (His) and metabolism disorder of some non-added amino acid. However, no influence was observed on metal elements or glucose levels. This study identified TiO₂-NPs with small sizes could affect nutrient absorption and metabolism by inducing intestinal epithelium injury, and amino acids were more susceptible than metal elements and glucose. These findings suggested that foods supplemented with TiO₂-NPs should be carefully consumed by people with high protein requirements, such as children, the elderly, and patients with high metabolic disease or intestinal inflammation.

摘要

包含纳米级成分的食品级二氧化钛（TiO ₂）通常用于增白和增亮食品，使消费者面临摄入TiO ₂纳米颗粒（NPs）的健康风险。尽管已经在数项研究中评估了TiO ₂ -NPs的口服毒性，但是关于NPs和食品成分之间相互作用的知识仍然存在空白。因此，本研究旨在通过对成年Sprague Dawley（SD）大鼠进行30天胃肠道暴露于两种不同的TiO ₂ -NPs后的原位肠loop实验来评估TiO ₂ -NPs对养分吸收和代谢的影响。尺寸（N-TiO ₂和M-TiO ₂）。结果表明，暴露于TiO ₂ -NPs会导致小肠顶膜扁平，微绒毛稀疏，短小以及炎症浸润。两种颗粒均被吸收到小肠细胞中，但是较小尺寸的N-TiO ₂可以更容易地通过肠道运输并提高血液中的钛（Ti）水平。暴露于这两种颗粒后，血清中氨基酸水平的变化也不同。在将营养液的混合溶液注入原位肠in后，N-TiO ₂暴露组显示出对添加的组氨酸（His）的明显吸收抑制和一些未添加的氨基酸的代谢紊乱。然而，未观察到对金属元素或葡萄糖水平的影响。这项研究确定了小尺寸的TiO ₂ -NPs可以通过诱导肠上皮损伤来影响营养物质的吸收和代谢，并且氨基酸比金属元素和葡萄糖更易受影响。这些发现表明，补充蛋白质TiO ₂ -NPs的食物应由蛋白质需求量高的人（如儿童，老年人和高代谢疾病或肠道发炎的病人）小心食用。