【营养青年会】全球对话｜哈佛大学营养系前系主任 Walter Willet 教授专访
哈佛大学营养系前系主任 Walter Willet 教授专访
文章来源：营养青年会
已授权《中国临床营养网》转载
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Walter C. Willett 教授
Walter C. Willett 教授简介
M.D., Dr. P.H.
Walter C. Willett, M.D., Dr. P.H., is Professor of Epidemiology and Nutrition at Harvard T.H. Chan School of Public Health and Professor of Medicine at Harvard Medical School. He chaired the Department of Nutrition at Harvard for 25 years. Dr. Willett studied food science at Michigan State University, and graduated from the University of Michigan Medical School before obtaining a Masters and Doctorate in Public Health from Harvard T.H. Chan School of Public Health. Dr. Willett has focused much of his work over the last 40 years on the development and evaluation of methods, using both questionnaire and biochemical approaches, to study the effects of diet on the occurrence of major diseases. He has applied these methods starting in 1980s in the Nurses’ Health Studies I and II and the Health Professionals Follow-up Study. Together, these cohorts that include nearly 300,000 men and women with repeated dietary assessments, are providing the most detailed information on the long-term health consequences of food choices.
Dr. Willett has published over 1,700 original research papers and reviews, primarily on lifestyle risk factors for heart disease, cancer, and other conditions and has written the textbook, Nutritional Epidemiology, published by Oxford University Press, now in its third edition. He also has written four books for the general public. Dr. Willett is among the most cited nutritionist internationally. He is a member of the National Academy of Medicine and the recipient of many national and international awards for his research.
Walter C. Willett（医学博士，公共卫生学博士）是哈佛大学陈曾熙公共卫生学院流行病系和营养系教授，同时也是哈佛大学医学院医学教授。Willett教授在密歇根州立大学学习过食品科学，毕业于密歇根大学医学院，在哈佛大学陈曾熙公共卫生学院取得公共卫生学硕士及博士学位，并任该学院营养系主任长达25年。Willett教授近40年的研究主要集中在建立和评价膳食问卷及生物标记物的方法，并用于阐明营养与重大疾病的关系。他于1980年开始将这些方法学应用到著名的‘护士健康研究 I, II’，与‘健康从业人员随访研究’中。迄今为止，这两大队列共有30万参与者定期提供饮食评估及详细的长期健康信息。
Willett教授在心血管疾病及癌症的生活方式危险因素领域共发表了1700多篇文章，并由牛津大学出版社出版发行了教科书《营养流行病学》，现在已经是第三版。他也发表了面向大众的四本书。Willett教授是国际上被引用最多的营养学家之一。他是美国国家科学院院士，并被多次授予国家（美国）和国际奖项。
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采访精彩摘要
1
First, thanks for taking the time to be interviewed by International Chinese Nutrition Young Scholar Network (ICNYSN). As a pioneer in nutritional epidemiology, your work has provided direction for mechanistic research and has greatly impacted policy-making. Could you briefly introduce the development of this discipline and its importance?
首先感谢Willett教授接受世界华人青年营养学者发展促进会(微信公众号：“营养青年会”，或ICNYSN）的专访。您作为营养流行病学的先驱，为研究饮食与疾病的关系提供了重要思路，为营养政策的制定提供了卓越的贡献。可否简单介绍下营养流行病这门学科的发展阶段及重要性？
Walter Willet
教授
When I started working in this area in 1970s, research in nutrition and epidemiology was completely separate. Nutrition departments focused on in vitro and animal studies, and short-term feeding studies in humans. There were very few studies looking directly at what people ate in relation to their long-term well-being. There was a huge gap between nutrition and epidemiology. The most important question of nutrition is how does diet influence long-term well-being? So, I started realizing this huge gap and had some experience in nutrition and epidemiology, which provided a way for me to start working on building this bridge. The first obstacle was being able to measure diet. In epidemiology if we can’t measure the exposure, we can’t really study the exposure. So in my early years I was devoted to standardizing a dietary questionnaire and eventually integrating it into the Nurses’ Health Study, which was the largest study at that time to look at diet.
当我自上世纪70年代开始在这个领域工作时，营养学和流行病学两个领域是完全分离的。营养系专注于体外和动物研究，以及人类的短期饮食研究。很少有研究直接观察人们吃什么与他们长期健康的关系，而且当时营养学和流行病学之间存在着巨大的鸿沟。最重要的营养学问题是“饮食如何影响人们的长期健康”。所以我开始意识到这个巨大的差距，并且在营养和流行病学方面有一些经验，这为我提供了一种方法来开始建立两者之间的联系。我遇到的第一个问题是如何去测量饮食。在流行病学中，如果我们不能测量暴露因素，我们就不能真正地研究暴露。所以在我最初的几年里，我致力于使调查问卷标准化并最终将其纳入到当时最大的研究——护士健康研究中。
One key issue we faced when measuring diet was its validity. Luckily, I had a background in physics which made me realize that everything we measured has errors. So instead of trying to eliminate the errors, we tried very hard to understand them, and measure their magnitude, type, and of course the source of the errors. Lots of work in nutritional epidemiology has been trying to find methods to measure dietary intake, including the use of both reported food intakes and biomarkers. We learned a lot since our investigation in 1980s and many other studies. Now we have a great deal more knowledge about diet and health than forty years ago.
我们在测量饮食时面对的一个关键问题是它的有效性。幸运的是我有物理学的背景，这让我意识到我们所测量的一切都会出现误差。因此我们不是试图去消除误差，而是努力去理解它们，并测量它们的大小、类型，当然还有来源。许多营养流行病学的工作一直在努力寻找测量饮食摄入量的方法，包括对于食物摄入量和生物标记物的使用标准。我们从上世纪80年代的研究中发现了许多这方面的相关知识。现在，我们对饮食和健康的了解比四十年前多了很多。
2
In your opinion, what are the most important nutrition findings during the past decades?
您认为过去几十年营养界最重要的发现是什么？
Walter Willet
教授
We have had many findings. I think the most important finding is in regard to the type of fat and carbohydrate, in other words, the quality of fat and carbohydrate. When we began our work, there was a general belief that all fat in the diet was bad. Dietary advice was focusing on reducing all type of dietary fat. By default, that means eating large amounts of carbohydrate. People didn’t pay much attention to what type of carbohydrate. What we see is that for both fat and carbohydrate, the quality is much more important than the amount. The first finding when we started looking at fat was that trans-fat strongly correlated to heart disease, which was a very big problem in the United States (U.S.) and many other countries. The majority of vegetable fat at that time was being subjected to partial hydrogenation, which creates trans-fat. And we found that not only is trans-fat correlated to heart disease, but subsequently diabetes and other conditions as well. Due to these findings, now there is almost a complete elimination of trans-fat in the U.S. and some other countries. We also saw that unsaturated fats, particularly polyunsaturated fats were correlated to lower risk of heart disease, when you compared them to same amount of carbohydrate. It’s really important because many people were eliminating those healthy fats because they were told that all fats were bad. We also found that saturated fat was actually very similar to typical carbohydrate in relation to heart disease and other health outcomes. So, replacing saturated fat was also healthy. Interestingly in China, from the evidence we see, including blood samples from different parts of China, there was never a lot of trans-fat in people’s diet, which was very fortune as it was not common practice in China to partially hydrogenate vegetable oils. But it’s also very important to make sure that it will not come back in the diet.
我们有过很多发现。我认为最重要的发现是关于脂肪和碳水化合物类型的研究。换句话说，也就是脂肪和碳水化合物的质量。当我们刚开始工作时，有一个普遍的说法，那就是所有的脂肪都是有害的。饮食建议的重点是减少所有类型的膳食脂肪，在默认情况下这意味着摄入大量的碳水化合物。人们当时不太注意碳水化合物的种类。现在我们看到的是对于脂肪和碳水化合物，质量比数量重要得多。我们开始研究脂肪之后的第一个发现是反式脂肪与心脏病密切相关，这在美国和许多其他国家是一个非常大的问题。当时大多数的植物来源脂肪都会进行部分氢化，这就产生了反式脂肪。我们发现，反式脂肪不仅与心脏病有关，而且还会导致糖尿病和其他疾病。由于这些发现，现在美国和其他一些国家几乎完全消除了反式脂肪。我们还发现，与相同数量的碳水化合物相比，不饱和脂肪尤其是多不饱和脂肪与较低的心脏病风险相关。这个发现很重要，因为当大家被告知所有的脂肪都是有害的时候，很多人同时也避免了健康的脂肪的摄入。我们还发现饱和脂肪在对心脏病和其他健康结果的关系上，表现出的影响和典型的碳水化合物非常类似。因此，替换掉饱和脂肪也是健康的。有趣的是，在中国，从我们所看到的证据，包括来自中国不同地区的血液样本来看，人们的饮食中从来没有大量的反式脂肪。这是非常幸运的，因为在中国部分氢化的植物油并不常见。但这个研究同样也很重要，因为要确保它以后也不会在大家的饮食中出现。
In terms of carbohydrate quality, again, there are some forms of carbohydrate particularly refined grain and sugar, which had many adverse metabolic effects related to a higher risk of heart disease, diabetes and other health outcomes. Another important development has been documentation of the roles of glycemic load and glycemic index, a concept initially developed in Canada. Though I thought it made sense, glycemic index was controversial and rejected by most the nutrition community, but we have seen that GL and GI predict risk of heart disease and diabetes. But we also saw that whole grains like brown rice, oats, whole oats are correlated to a reduction in the risk of diabetes and CVDs. We also began the investigation surrounding the correlation between sugar sweetened beverages and diabetes and CVDs. Sugar sweetened beverage is actually a very serious problem. Except in the U.S., which has shown a reduction by about 25% in the last 10 or 15 years, sugar sweetened beverage consumption grows every year around the world. Harvard healthy diet plate developed in our department tries to communicate these findings.
就碳水化合物的质量而言，还有一些形式的碳水化合物尤其是精制谷物和糖有很多不良的代谢效应，这些效应与心脏病、糖尿病和其他健康结果的高风险相关。另一项进展是对血糖负荷和血糖指数作用的研究，这两个概念最开始是在加拿大发展起来的。虽然我认为这两个概念是有道理的，但血糖指数还是存在争议，并且被大多数营养团体拒绝了。但我们发现血糖指数和血糖负荷可以预测心脏病和糖尿病风险。同时我们也看到了像糙米、燕麦、全燕麦这样的全谷物与糖尿病和心血管疾病风险的降低相关。我们也开始研究含糖饮料与糖尿病和心血管疾病之间的相关性。含糖饮料实际上是一个非常严重的问题。在过去的10年或15年里，除了美国显示含糖饮料消费量减少了约25%，其他世界各地的含糖饮料消费量每年都在增长。由我们营养系开发的哈佛健康饮食餐盘一直在试图向公众传达这些发现。
3
What is the transition between nutrition discovery and nutritional policy? What are the common steps between them?
一项新的营养发现转化为一项营养政策会经历些什么？
Walter Willet
教授
We like to think just doing our research and coming up with strong evidence will translate into nutrition policy. But we realize that in fact it’s not a straight-line relationship. There are many factors influencing nutritional policy. Sometimes it’s other people in the nutrition community who are making it hard to change public opinion. And also very powerful industries trying to influence nutritional policy, who often have more power in government policy making than us as scientists. So, there are many different factors behind translating nutritional discovery into policy. In the end, I think it’s really essential to have the strongest evidence possible. Because in the long run I think strongest evidence will always win. For example in regards to trans-fat, there was opposition for everybody at the beginning. But once people started to reproduce our findings it made for a really strong case to eventually change the policy.
我们习惯认为只要做好自己的研究并从中提出强有力的证据就可以使这些发现转化为营养政策，但我们意识到事实上这并不是一种直线关系。影响营养政策的因素有很多，有时是营养界的其他人在使改变舆论的观点变得困难，还有一些是非常强大的产业试图影响营养政策，这些产业在政府政策制定中往往比我们科学家更有影响力。因此将营养发现转化为政策有许多不同的影响因素。最后一点，我认为有最有力的证据是非常必要的。因为从长远来看，我认为最有力的证据总会获胜。例如一开始所有人都反对关于反式脂肪的观点，但是一旦人们开始在不同的研究中重现我们的发现，我们的发现就为最终改变政策做出了强有力的解释。
Sometimes policies are created with very little evidence. The whole idea that we try to reduce all types of fat that is built into nutritional policy was based on very little evidence. So making policies on bad or limited evidence is dangerous.
有时候政策制定的时候只有很少的证据。当时将减少所有类型的脂肪的摄入这一观点纳入到营养政策之中时，这个观点是建立在很少的证据基础上的。因此在不对的证据或有限的证据上制定政策是危险的。
4
In the field of nutrition communication, is there a best way to marry nutrition research and outreach to the public?
您认为在营养传播领域，如何可以将科研和科普更好地结合呢？
Walter Willet
教授
This is very important and we always need partners, because we ourselves don’t own strong connections with the large public. There are many ways to ensure evidence-based messages are communicated effectively. One is to work with journalists whose job is to communicate research findings. Try to find good partners who do have communication pathways with the public, through print media and television. Sometimes our partners can be in the government, which does have a role in disseminating nutrition policy. So working with partners in government or governmental organizations like Consumer Advocacy Groups is beneficial for communicating research findings. In this country, we work with Center for Science and Public Interest quite a bit. We have to be careful when working with industries because their objective is usually making money, not to promote health. But we have found some good industrial partners who are trying to make healthy products. Of course, in our university, there are lots of partners too. There are lots of people who teach nutrition, and other health professional groups like dietitians. Ideally, physicians should be good partners to communicate nutrition information. But unfortunately, historically most medical school more or less ignored nutrition. Some people are currently trying to correct this by working with medical schools. However, in general, physicians are often reimbursed more by prescribing drugs and doing procedures when in many cases nutrition will be more powerful. So, we need to better partner with people in medical field.
这是非常重要的，并且我们总是需要合作伙伴，因为我们自己与广大公众少有非常紧密的联系。其实有很多方法可以有效地把有根据的科研成果普及给大众。一种是与记者合作，他们的工作是传达研究成果。试着去找可以通过印刷媒体和电视与公众进行沟通的好伙伴。有时我们的合作伙伴可能在政府中，这在传播营养政策方面有一定作用的。因此与政府或政府机构合作伙伴的合作比如消费者权益保护组织，对交流研究成果是有益的。在美国，我们与科学和公共利益中心有很多的合作。但是在与产业合作时我们必须谨慎，因为他们的目的通常是赚钱，而不是促进健康。但是我们也发现了一些优秀的产业合作伙伴是想努力生产健康的产品的。当然在我们的大学里也有很多合作伙伴。我们学校有很多人是教营养学的，还有其他健康职业的团体比如营养师。在理想的情况下，医生应该是传达营养信息的良好合作伙伴。但遗憾的是，从历史上来看，大多数医学院或多或少地忽视了营养。因此有一些人目前正试图通过与医学院合作来纠正这一现象。然而总的来说，虽然在很多情况下可能营养方面的改善对病症会更加有效，但是医生通常还是通过开处方和走程序来完成治疗，以得到更多的补偿。因此，我们需要更好地与医疗领域的人合作。
5
Conflicts are commonly observed in nutrition evidence. What are the challenges if these conflicts are brought to the public attention?
营养研究存在相互矛盾现象，您认为这些矛盾会给公众认知带来什么问题?
Walter Willet
教授
There are lots of contradictions and conflicts in nutritional research. But some of them are exaggerated in part by nutrition researchers. It’s more interesting for us to talk about where we disagree than where we agree. From the standpoint of a journalist, they definitely like to magnify disagreements rather than agreements, because disagreements create more headlines.
营养研究中存在许多矛盾和冲突，但其中一些研究是被营养研究者部分夸大了。我们更感兴趣的是讨论与我们观点分歧的地方，而不是我们一致的地方。从记者的立场来看，他们肯定更喜欢放大与舆论不一致的观点，而不是一致的观点，因为不一致的观点可以创造更多的新闻头条。
I think it’s also important that we emphasize many big areas of agreements. For example, there are strong agreements amongst the nutrition community including eating more whole grains instead of refined grains and sugar-sweetened beverage, eating more healthy types of fat, and limiting trans-fat. But those big areas we agree upon don’t get much attention. In those areas, there are always some uncertainties or room for disagreements like how many servings of fruit and vegetables, what’s the optimal amount of whole grains in diet. Those are just details. We should emphasize the big picture. Unfortunately, all these factors create the sense of more disagreement. The Internet magnifies everything because everyone believes themselves to be a nutrition expert, saying anything without any evidence to support it. So that creates more confusion.
我认为我们强调许多重要领域相同的观点也是很重要的。例如，在营养界有很多的共识，包括吃更多的全谷物而不是精制谷物和含糖饮料，吃更健康的脂肪，以及限制反式脂肪。但是我们在那些重要领域达成的共识并没有得到太多的关注。在这些领域，总有一些不确定因素或存在分歧的地方，比如水果和蔬菜的数量，还有在饮食中最理想的全谷类食物的摄入量是多少。然而这些都是细节，而我们应该强调的是大方向。遗憾的是，所有这些因素都造成了有很多分歧的感觉。互联网放大了一切，因为每个人都相信自己是一个营养专家，说着一些没有任何证据支持的话。因此这造成了更多的混淆。
It’s important and it’s our responsibility as researchers to not overstate our findings in journals. That’s critical. Medical journals are part of the problem too. Because they want to have new findings, they will often not publish confirmatory studies because it’s not new. But in fact, confirmatory studies are very important and really solidify the knowledge in the area. So, there is a level of bias all the way from researchers, to the journals, to the journalists, with the public always advertising contradiction and disagreement.
作为研究人员，重要的是不要在期刊上夸大我们的发现，并且这也是我们的责任。这是至关重要的。医学期刊也是这个问题的一部分。因为他们想要有新的发现，所以他们通常不会发表验证性研究，因为这不是新的发现。但事实上，验证性研究非常重要，并且确实巩固了这一领域的知识。因此，从研究人员到学术期刊，到记者，总是可能倾向于向公众宣传与前人存在矛盾和分歧的观点，然而这些宣传多少是存在一定偏见的。
6
In your opinion, is there a best way to combine the forefront of nutritional discoveries with industrial application in order to promote human health?
如何将营养科学前沿和实际产业服务结合起来，更好地为人类健康发展做贡献？
Walter Willet
教授
I am not so sure we need to pay as much attention to that, because industry will always be trying to capitalize the new information to make money. The biggest issue is usually with industries who are promoting unhealthy products like Coca cola. They spend billions of dollars a year trying to promote a product that is actually unhealthy. So, most of our relationship with industry is actually in disagreement. There is real danger for the nutrition community to get too close to the industry.
我不确定我们是否需要关注太多这方面的事情。因为行业总是试图利用这些新信息赚钱。最大的问题通常是那些推销像可口可乐这样不健康产品的行业。他们每年要花费数十亿美元来推销一种实际上不健康的产品。因此，我们与工业的大部分关系实际上是存在分歧的。在许多情况下，营养领域与产业过于接近是很危险的。
Sometimes, part of the industry tries to make healthy products. It’s important to communicate our findings to them. But also again, getting too close is a problem even when the product is healthy. Because the public will then distrust the information fundedby the industry. It’s important to retain our trust by the public.
有时该产业的一部分人试图生产健康的产品，这时把我们的发现传达给他们是很重要的。但同样的，即使产品是健康的，过于接近也是一个问题，因为公众将会对企业资助所发现的营养信息不再于信任。但保持公众对我们的信任是很重要的。
Communicating with industry is important but also remaining independent is also very important.
与产业沟通很重要，但保持独立也是非常重要的。
7
What is the trend of personalized nutrition in this era? What are challenges that may come along with these opportunities?
未来几年个性化营养会如何发展，在实际应用中具体面临的机遇与挑战有哪些？
Walter Willet
教授
This idea of personalized nutrition is gaining a lot of attention. But I think we have to be careful about putting too much attention in this area. We certainly know that different people may metabolize nutrients and other components of foods at different rates. But the major differences are rare mutations and they are very rare. In general, the same diet that affects one person is going to affect another person in the same way. The same generally healthy diet is likely to be healthy for the majority of population. I also think personalized prevention is different from personalized treatment. By analogy, if we have a car and get it checked routinely, we want to make sure that all of the components are working properly. That’s the same thing with our body. We have all of our different systems that need to be working properly. The car usually stops working when there is one component failing. Then we want to find out what it is and have a very specific treatment for that component. It's the same thing when we have a disease, we do want to understand what’s wrong so we can fix it. As generally healthy people, we really have to prevent every possibility from going wrong. That means we really want to find a diet that will be healthy for the large majority of people. Like tobacco, some people may be more susceptible to lung cancer if they smoke. That doesn’t mean we just prevent smoking to help people who are more susceptible to lung cancer. Everybody should not be smoking. I think on the prevention side, the personalized concept is more likely to be important on a social/logical/cultural basis rather than a genetic basis. For example, helping people eat a healthy diet may be more effective if done on a personalized basis that takes into account their life situation. What we see is some people in our studies have dietary allergies and may not be able to eat milk, nuts, or other foods They can benefit perhaps by individual evaluation and counseling in order to improve their diet. That’s personalization but it’s a different thing than analyzing their genome.
个性化营养的理念正在得到广泛的关注。但我认为我们在这个领域投入过多的注意力时必须要小心。我们当然知道不同的人可能会以不同的速率代谢营养和其他食物成分，但主要的区别是一些非常罕见的突变。一般来说，可以影响一个人的饮食也会以同样的方式影响另一个人。一般健康的饮食对大多数人来说都是健康的。同时我认为个性化预防与个性化治疗是不同的。用类推法，如果我们有一辆车并定期检查它，我们是为了确保所有的部件都能正常工作。这和我们的身体是一样的，我们有各种不同的系统需要正常工作。当汽车有一个部件出现故障时，通常会停止工作。然后我们想知道它是什么地方出现故障并且对这个部件制定一个非常具体的修理方法。同样的当我们有疾病时，我们确实想知道什么地方出了问题，这样我们可以针对那个地方给予治疗。作为大多数健康人，我们必须防止一切可能的问题。这意味着我们确实想要找到一种对大多数人来说都是健康的饮食。像烟草一样，一些人吸烟之后可能更容易患肺癌。这并不意味着我们只是为了帮助那些容易罹患肺癌的人而让他们不要吸烟。每个人都不应该吸烟。我认为在预防方面，个性化概念可能更多地体现在社会/文化基础上，而不是遗传层面。例如，将一个人的生活环境纳入考虑后，帮助人们吃健康的饮食可能会更有效。我们所看到的是我们研究中的一些人对一些食物过敏，他们无法喝牛奶，吃坚果等其他一些食物。他们可以通过个人的评估和咨询来改善他们的饮食。这是一种“个性化”，但这不同于分析他们的基因组。
8
In your opinion, what is the direction of nutrition research in the future? What will be the biggest challenge?
您怎么看未来营养研究的发展方向？将来最大的挑战是什么？
Walter Willet
教授
Probably most important in nutrition research is having long-follow-up prospective studies, and looking how diet early in life influences health later in life. It’s important to keep in mind that many diseases like cancer and Alzheimer Disease develop over many decades. And many studies only last a few years, like ten or fifteen years, which may be quite short. For smoking, you need to smoke for about 30 years before you start seeing the health consequence, so short-term studies can’t see many of these effects. Therefore long-term studies are critically important to see the full impact of diets on health. For example, we have been investigating “early life” diets in NHS2, where we retrospectively collected data in early life and look prospectively at disease risk. Much evidence suggests that for some cancers we are particularly susceptible to environmental influences during those early years.
在营养学研究中，最重要的可能是进行长期跟踪的前瞻性研究，并观察生命早期饮食对一生健康的影响。重要的是要记住，许多疾病如癌症和阿尔茨海默病，需要几十年才发展出来。许多研究只持续了几年，比如10年或15年，这样子的研究时间可能还是相对有点短。对于吸烟，你需要吸烟30年才能开始看到对健康的影响，因此短期研究无法看到这些影响。因此，长期的研究对于了解饮食的全面影响是至关重要的。比如，我们通过回顾早期的生活，并前瞻性地收集了数据去研究护士研究II中 “生命早期” 的饮食。大量的证据表明，一些癌症的发病特别容易受到生命早期环境的影响。
I think expanding the range of diet will also be important. For example, international studies are really important. We rarely have a chance in U.S. population to look at soy consumption and its long-term health consequence. So it’s really helpful that there are studies in China, which are able to look at that issue, because soy is more commonly consumed in parts of the China. Many parts of the world do not have prospective studies, like in South America and Africa. So there are a lot of big missing pieces. Besides, there are a lot of exciting things in omics, incorporating genomics, metabolomics and the microbiome into nutrition research, which I think is very interesting and we will certainly learn a great deal from those areas. But I still think the major focus should be on what people eat and what happens to them in the long run, and also improvements in the quality of our data. That’s the most important. For example with genomics, in reality we haven’t learned nearly as much as people thought we would learn, such as being able to strongly predict disease risk by genetic analysis. In fact, it doesn’t add very much to what we already know about the diet and other risk factors for almost all these diseases. The relative risks for SNPs (single nucleotide polymorphisms) are small, even when we combine many different SNPs together we still can’t get a very strong stratification of the risk. Epidemiologist already knew that, because it’s very clear that genetics was not the primary factor to determine high rates of disease that we have in some places. How much we will learn from metabolomics is still open to question. I think we won’t really be able to interpret the metabolomic study without good quality dietary data. We do use metabolomics, but it’s really important to have good quality dietary data.
我认为扩大饮食的范围也很重要。例如，国际研究是非常重要的。我们很少有机会在美国人口中看到大豆消费及其长期健康后果。所以在中国有这方面的研究是很有帮助的，他们能够通过研究了解这个问题。因为在中国的部分地区，大豆非常常见。世界上许多地方还没有前瞻性的研究，比如南美和非洲，所以有很多缺失的部分。除此之外，还有很多令人兴奋的领域，包括结合基因组学、代谢组学和微生物组学在营养中的研究，我觉得这些很有趣，我们肯定也会从这些领域学到很多东西。但是我仍然认为主要关注应该放在人们的饮食中，从长远看他们会产生什么影响，以及提高我们的数据质量，这些是最重要的。例如，在基因组学方面，现实中我们并没有像人们想象中那样知道那么多东西，比如能够通过基因分析来明确地预测疾病的风险。事实上，它并没有增加我们对已经知道的饮食和其他几乎所有这些疾病的风险因素的了解。SNPs(单核苷酸多态性)的相对风险很小，即使我们将许多不同的SNPs组合在一起，我们仍然无法得到非常明显的风险分层。流行病学家已经知道遗传很明显并不是决定某些地方疾病高发病率的主要因素。对于我们能从代谢组学中学到多少东西仍然有待商榷。我认为，如果没有高质量的饮食数据，我们无法解释代谢组学的研究。我们确实要使用代谢组学，但是拥有高质量的饮食数据是非常重要的。
In terms of specific topics, I do think the brain in some way is the biggest frontier in biomedical research. So, learning how diet affects brain health is a major topic and I think will continue to be for a while.
就具体的话题而言，我确实认为关于大脑的研究在某种程度上是生物医学研究领域中最大的尚待开发的领域。因此，了解饮食对大脑健康的影响是一个主要的话题，我认为这将会持续一段时间。
9
For young scholars, what are the focuses of career development at early stage? What would you tell a young scholar who just starts graduate school?
您认为青年学者在研究生阶段和早期研究阶段分别应该注意哪些能力的培养？
Walter Willet
教授
I think every area of science does emphasize depth, that deep understanding of a research area is very important. But also, especially in nutrition or health, learning more broadly and having a greater breadth of understanding of health is also really important. To ask the most important questions is to visualize the biggest picture of how what we are doing may influence health. I would encourage people to have a deep understanding in the area they are working on, but also try to gain as much as experience in other parts of life, even outside science. Because those experiences often generate perspectives and questions. And even within science, frontiers and new developments often come from the interfaces of different research areas. We learn from what’s happening in another area. Even those seemly non-related areas can be brought into our own areas of interest, or sometime we may change our direction of research. So, I would encourage both depth and breadth in whatever we are doing. One area I briefly mentioned before pertains to China, and the importance of considering how rapidly diet and lifestyles are changing. For some aspects of diet, it may take forty or fifty years before we really see the influence on health outcomes. Again like tobacco, it may take forty or fifty years of follow up before we see the full impact. For example, people are eating more red meat now in some places, but we may not see the consequence for thirty or forty years, as atherosclerosis develops gradually or cancers that are initiated may not appear until decades later. Thus we need to be a little extra careful when making conclusions on limited follow-up. The same thing applies here, people are start eating more soy products in US, but we may not see the full impact for thirty or forty years. We probably have a better understanding by looking at data from China or other places in Asia where soy has been used for a long time.
我认为科学的每个领域都强调深度，对研究领域的深刻理解是非常重要的。但是尤其是在营养或健康领域，更广泛地学习或更广泛地理解这些知识也是非常重要的。要问最重要的问题，那就要想象我们的工作在大局上是怎么影响人们健康的。我鼓励人们对他们所从事的领域有深刻的理解，同时也要努力获得生活中其他方面的经验，甚至是在科学之外的经验。因为这些经验通常会帮助我们产生观点和问题。 甚至在科学领域，前沿和新的发展往往来自不同研究领域的交界面。我们可以从另一个领域中的一些情况学习到东西。即使是那些看起来不相关的领域的东西也会被带入到我们自己研究的领域或引起我们的兴趣，或者有时可能会改变我们的研究方向。因此，无论我们做什么，我都会鼓励注意研究的深度和广度。前面我曾简要提到过一个点同样适用于中国，就是对饮食和生活方式正在快速变化的思考的重要性。对于有些饮食来说，可能要花上四十年或五十年的时间才能真正看到它们的影响。再一次以烟草为例子，在我们看到它对人类健康的所有的影响之前，大概需要跟进研究大约40或50年的时间。再例如现在某些地方的人会吃更多的红肉，我们可能不会在30或40年内就能看到后果，因为动脉粥样硬化会慢慢发展，或癌症在几十年后才开始，因此当我们利用有限随访年限的研究进行下结论时需要多加小心。同样的事情也适用于这里，美国人开始吃更多的豆制品，我们可能不会在30或40年内看到它对人体健康的所有影响。通过中国或亚洲其他地区的数据我们可能会更好的了解豆制品对人健康的影响，因为这些地区已经食用大豆很长时间了。
Beside nutrition, learning about agriculture and food technology is important. People often don’t get much training. Also, clearly, climate change and other environmental influences of food systems are very important now. Those are related to culture and politics. All these things directly impact what people eat and what will be available for people to eat. The more we can learn about all these areas the better, including our own history. We don’t want to repeat the same mistakes, and learning what works is best based upon our previous mistakes and can be very helpful.
除了营养，学习农业和食品技术是很重要的。人们通常不会接受太多这方面的培训。而且很明显的，气候变化以及其他一些环境对食物系统的影响现在也变得非常重要。这些都与文化和政治有关。所有这些都会直接影响人们的饮食还有人们以后可以食用的东西。我们对所有这些领域的了解越多越好，包括我们自己的历史。我们不希望重复同样的错误，并且最好的学习什么有效的方法就是基于前面犯的错误，这也是非常有帮助的。
Take-home message for young scholars:
Make your experiences as broad as possible. This will enhance your research in the long run, and make your work more interesting and enjoyable.
尽可能地丰富你的经历。从长远来看这会有助于你的研究，并会使你的研究更有乐趣。”
—— Walter C. Willett 教授
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