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科学家发现母亲饮食与糖尿病的联系
怀孕期间，糟糕的饮食给孩子带来的后果 科学家说，他们已经发现了一种机理方式，这也许可以解释为什么在怀孕期间不良的饮食习惯可能增加后代在以后的生活中患糖尿病的风险。 他们说，用老鼠实验，发现母体饮食不均衡，就会使幼鼠——与胰岛素有关——的基因变“沉默”。 该剑桥大学的研究刊登在《国家科学院学报》。 专家说怀孕期间，健康饮食很重要。 沉默的基因 科学家早先怀疑，怀孕期间糟糕的饮食，会在后代成长中，加重健康问题，如糖尿病等。剑桥大学的研究成果或许能解释该问题。 他们相信孕妇饮食不均衡，从长期来说，将危及孩子的基因功能。 据认为，基因Hnf4a在胰腺发育和胰岛素分泌中起作用。 在孕妇身上验证该理论，存在困难。因此，他们给老鼠提供缺乏蛋白质的食物，同预料一样，幼鼠中2型糖尿病的发病率很高。 他们还发现，随着幼鼠长大，Hnf4a基因变得“沉默”，或者“关掉”了。研究人员说，这两种情况都会引发糖尿病，并且追溯到母体饮食。 该研究的牵头人，剑桥大学的苏珊·欧撒尼医生说，需要进一步用老鼠研究：高脂肪饮食或其他不均衡饮食，是否会产生类似后果。 她认为该研究中发现的机制，同样适用人类，而且感觉不仅仅影响下一代。 “生活中，随时保持健康均衡饮食，真的很重要，”她说，“尤其怀孕期间，健康均衡饮食特别重要，因为将长期影响孩子，还可能影响孙子辈。” 早期阶段 通常将2型糖尿病与肥胖联系，但有几项遗传基因也与此有关。 最新研究集中在“后生”机制，该机制影响基因。其他研究还发现，这些变化将传递多代，而且核心DNA没有任何改变。 英国心脏协会的杰瑞米· 但他说该研究 “为——有时候，母亲饮食会改变未出世孩子的基因控制力——增加了证据”。 生物技术和生物科学研究会的道格拉斯·凯尔教授说，该研究轻松地充实了某些分子程序。 “通过后生生物学和分子生物学研究，该研究揭示了一个重要环节，明确告诉我们：早期发育，细胞内的细微变化，都会在以后的岁月中，对健康产生巨大的影响。”他说。
Scientists say they have found a mechanism which may explain why a poor diet during pregnancy can increase the risk of offspring developing diabetes in later life. They say rat studies indicate an imbalanced diet in the mother can lead to the "silencing" of a gene linked to insulin production in the child. The Cambridge study is in Proceedings of the National Academy of Sciences. Experts said it showed a healthy diet was important during pregnancy. Scientists already suspect that a poor diet during pregnancy can result in health problems such as diabetes for the offspring in later life. What the researchers at the University of Cambridge have come up with is a possible explanation. They believe an imbalanced diet in the expectant mother can compromise the long-term functioning of a gene in the child. The gene, called Hnf4a, is thought to play a role in the development of the pancreas and in insulin production. Because of the difficulties of testing the theory on pregnant women, they fed rats a protein-deficient diet and found higher rates of type 2 diabetes in the offspring, as expected. What they also found in the offspring was that this Hnf4a gene appeared to be "silenced" or "switched off" as the rats aged. The researchers suggest this may both cause diabetes, and can be linked back to the maternal diet. Dr Susan Ozanne of the University of Cambridge, who lead the study, said further research would be needed to establish whether high-fat diets or other imbalanced diets had similar consequences in rats. She believes similar mechanisms to those seen in the study could occur in humans, and that the effects might be felt by more than just the immediate offspring. "Having a healthy well-balanced diet any time in your life is important for your health," she said, "but a healthy well-balanced diet during pregnancy is particularly important because of the impact on the baby long-term and potentially even on the grandchildren as well." Type 2 diabetes is often associated with obesity, although several inheritable genes have also been linked to the condition. This latest study focuses on what are called the "epigenetic" mechanisms which can affect whether a gene is expressed or not. Other studies have shown that these changes can be passed across generations without any modifications to our core DNA. Professor Jeremy Pearson of the British Heart Foundation said the research did not change the advice to pregnant women to eat a healthy, balanced diet, and said there was no reason for expectant mothers to be unduly worried. But he said the study "adds to the evidence that a mother's diet may sometimes alter the control of certain genes in her unborn child". Professor Douglas Kell of the Biotechnology and Biological Sciences Research Council said the research fleshed out some of the molecular processes at play. "This study uncovers - through epigenetics and molecular biology research - an important piece of this puzzle and shows us how apparently minor changes within cells at the very earliest stages of development can have a major influence on our health into old age," he said.
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