普特英语听力练习mp3材料

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The Dangers Of Vitamin Supplements

Do you take your vitamins everyday? Be careful. Just as vitamin deficiency can make you sick, so can vitamin toxicity. Indeed, vitamins can be very dangerous if you take them in high quantities.

What “A” And “D” Have In Common
Though vitamins A and D are the most likely to make you sick if you take too much of them, they aren’t the only vitamins that can be dangerous. All vitamins have the potential to be toxic if you ingest too much of them.

Part of the reason why A and D put you at higher risk than Vitamin C and others has to do with the way vitamins are dissolved. Vitamin C dissolves in water. Thus, if you take excess Vitamin C, your body can flush it out through urine. Vitamins A and D, however, dissolve in oils and melted fat.

The Consequences
So, when you take too much of one of these vitamins, rather than flushing the excess out, the body stores the surplus in fat or in fatty tissues such as the liver and the brain.

Accumulation of water in the brain, severe headaches, and birth defects are just three of the problems toxic levels of Vitamin A can cause. If you keep a relatively well-balanced diet, you’ll most likely get the vitamins your body needs without the use of supplements.
过量补充维他命的危险

你每天都补充维他命么？小心点。就如缺乏维他命会使你生病一样，维他命中毒也会令你生病。事实上，如果摄入剂量太大，维他命会变得非常危险。

维他命A和维他命D的共同点。

尽管维他命A和维他命D是最有可能因为服用过量导致生病的，但是它们不是仅有的两种会造成危险的维他命。如果你服用剂量过高，所有的维他命都有成为毒药的可能。

服用维他命A和维他命D比维他命C以及其他维他命存在更高风险的部分原因在于维他命的分解方式。维他命C溶于水，因此，如果你服用了过量的维他命C，你的身体可以通过尿液将其排出体外。而维他命A和维他命D却是溶于油和脂肪的。

后果

因此，如果你过量摄入这几种维生素的话，身体会将剩余部分存入脂肪或脂肪组织，比如肝脏和大脑，而不会排出体外。

脑积水、严重的头痛和先天畸形仅仅是维他命A中毒会造成的众多疾病中的几种。如果你保持饮食均衡，那么你也许已经摄取了身体所需的维他命，不需要补充。

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