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本视频由Michael Greger医生于 2016 年 7 月 4 日发布，来自NutritionFacts.org — 能救命的营养学。
Michael Greger 医生是畅销书《How Not to Die》一书作者，中文译本：繁体版书名为《食疗圣经》。简体版书名为《救命》，将于今年5月底出版。 还没有看过维生素D之前系列视频的朋友，请先补看一下： 应该摄取多少维生素D？ 【系列3】 How Much Vitamin D Should You Take?摘要：使大多数人达到最佳水平的维生素D补充剂的安全剂量是每天2,000 IU，但老年人和超重者可能需要更多。 The safe dose of vitamin D supplementation to get most of the population to the optimal level is 2,000 IU a day, but the elderly and overweight may need more. 随机对照临床试验发现维生素D补充剂能延长人的寿命。 Randomized, controlled clinical trials have found that vitamin D supplements extend one’s lifespan. 摄取多少才是最佳剂量？ 多少的血液维生素D水平与最长寿命有关？ What is the optimal dose? What blood level is associated with living longest?
在我的2011年关于维生素D的九集视频系列中，我注意到维生素D水平和死亡率之间的关系似乎是U形曲线 - 意味着维生素D水平低与死亡率增加相关。 但是，维生素D水平太高也与死亡率增加相关，维生素D水平最佳值是75或80 [nmol / L]左右，结论是基于像这样的个体研究。 In my nine-part video series on vitamin D back in 2011, I noted that the relationship between vitamin D levels and mortality appeared to be a U-shaped curve — meaning low vitamin D levels were associated with increased mortality. But so were levels that were too high, with the apparent sweet spot around 75 or 80 nanomoles per liter [nmol/L], based on individual studies like this one. 为什么更高的D水平与更高的风险相关呢？ Why might higher D levels be associated with higher risk?
那么这是一项人口研究。 所以，你不能确定哪个是第一。 也许维生素D导致更高的风险。 或者也许更高的风险导致了维生素D水平高，也就是说那些身体状况不好的人被开了维生素D处方。 Well, this was a population study; so, you can’t be sure which came first. Maybe the vitamin D led to higher risk. Or maybe higher risk led to the vitamin D, meaning maybe those who weren’t doing as well were prescribed vitamin D.
也许这是因为它是斯堪的纳维亚研究，他们往往摄取了大量的鱼肝油作为维生素D补充剂， 其中一勺可能会超过维生素A摄入量的上限，这可能会产生负面后果，即使不把鱼肝油注射入阴茎。 Maybe it’s because these were Scandinavian studies, where they tend to take a lot of cod liver oil as the vitamin D supplement, one spoonful of which could exceed the tolerable upper daily limit of intake for vitamin A — which could have negative consequences, even if you don’t inject it into your penis.
我很惊讶地看到，鱼肝油被列入男人们试图向自己注射的长长的清单中，因为他们认为自己的阴茎太短了，尽管可能在所有重建手术后阴茎反而更短。 I was surprised to see cod liver oil listed among the long list of things men have tried to inject into themselves because they felt they were coming up short, though may have ended up shorter after all the reconstructive surgery.
无论如何，U形曲线是旧数据。 Anyways, the U-shaped curve is old data. 一项更新的荟萃分析显示，随着人们的维生素D水平的提高，死亡率出现下降，并且停了下来 — 这是好事，因为那样我们就不必测试以确定维生素D是否达到了最佳的水平。 An updated meta-analysis has shown that as population vitamin D levels go up, mortality appears to go down, and stay down — which is good, because then we don’t have to test to see if we’re hitting just the right level.
不推荐常规检测维生素D水平。 Routine testing of vitamin D levels is not recommended. 为什么？ 测试需要花钱，而且对大多数人来说，只要有足够的日晒，维生素D就可达到你想要的水平。 所以，他们想测试有什么意义呢？ Why? Well, it costs money, and in most people, levels come right up to where you want them with sufficient sun, or supplementation. So, they figure what’s the point?
但也因为测试结果不是很稳定 — 不同的试验室测试结果不尽相同。 But also because the test is not very good — results can be all over the place.
当你发送一个样本到世界各地一千个不同的实验室会有怎样的结果呢？ What happens when you send a single sample to a thousand different labs around the world?
你可能想到有一点小的变化范围，但不是这样。 同一样本的结果范围从20以下到100以上不等。 You maybe expect a little variation, but not this. Results from the same sample ranged anywhere from less than 20 to over 100. 因此，取决于您的医生将您的血液样本送至的实验室，结果可能会将您置于此处或此处；所以，不一定非常有帮助。 So, depending on what lab your doctor sent your blood sample to, the results could have placed you here, or here; so, not necessarily very helpful. 那么，什么是安全的剂量，其可能会使我们达到所谓的最佳水平？ So, what’s a safe dose that will likely get us to the purported optimal level?
每天 1,000 单位应使大多数人达到目标 75 nmol / L（即 30 ng / mL）。 但“大多数人”，他们的意思是 50％。 1,000 units a day should get most people up to the target 75 nmol/L (which is 30 ng/mL). But by most people, they mean 50%.
为了让 85％的人口达到 75 nmol / L，每天需要 2000 单位。每天 2,000 个国际单位将把曲线从这里（A）转移到这里（B）。这样，我们就可以将普通人变成理想的范围，而不用担心毒性。 To get around 85% of the population up to 75 would require 2,000 a day. 2,000 international units a day would shift the curve from here （A） to here （B）. That way, we can take the average person into the desired range without fear of toxicity. 如果摄入过多的维生素D，但是问题不会显示出来，直到血液水平达到 250 nmol / L左右，这需要持续摄取每天剂量超过 10,000 单位。 You can take too much vitamin D, but you don’t tend to see problems until blood levels get up around 250, which would take consistent daily doses in excess of 10,000.
请注意，如果你超重，你可能要吃3000单位，或者如果肥胖，甚至需要更多。 Note that if you’re overweight, you may want to take 3,000, or if obese, even more than that.
如果你超过 70 岁，并没有获得足够的阳光，则可能需要 3,500 单位才能有 85% 的机会使你的维生素D水平超过目标值。 If you’re over age 70, and not getting enough sun, it may take 3,500 units to get that same 85% chance of bumping your levels past the target.
再次强调，没有必要让普通人进行测试和重新测试，因为每天几千单位维生素D应该使几乎每个人都能够达到维生素D目标值而没有毒性风险。 Again, no need for the average person to test and retest, since a few thousand a day should bring almost everyone up without risking toxicity.
好吧，但为什么医学研究所将每日推荐量（RDA）设置为 600 到 800 单位？ Okay, but then why did the Institute of Medicine set the Recommended Daily Allowance at 600 to 800 units?
事实上，官方的建议范围很广，从每天的 200 到每天的 10000 单位不等。 In fact, official recommendations are all over the map — ranging from just 200 a day, all the way up to 10,000 a day.
我会试图解决困惑。请看下回分解。 I’ll try to cut through the confusion, next. （翻译及字幕制作：老玉米 Karen Chou) 参考文献：
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来自： zhihui2016 > 《健康 饮食》
