好英语网睡眠质量差？可能是饮食的原因
This has not been a very good year for sleep.
今年不是个睡觉的好年头。
With the coronavirus pandemic, school and work disruptions and a contentious election season contributing to countless sleepless nights, sleep experts have encouraged people to adopt a variety of measures to overcome their stress-related insomnia. Among their recommendations: engage in regular exercise, establish a nightly bedtime routine and cut back on screen time and social media.
由于新冠疫情，学校和工作的中断，还有充满争议的大选季导致了无数个失眠之夜，睡眠专家鼓励人们采取各种措施来克服压力导致的失眠。他们的建议包括：定期锻炼、养成每晚的睡前习惯、减少看屏幕和社交媒体的时间。
But many people may be overlooking another important factor in poor sleep: diet. A growing body of research suggests that the foods you eat can affect how well you sleep, and your sleep patterns can affect your dietary choices.
但很多人可能忽略了导致睡眠质量差的另一个重要因素：饮食。越来越多的研究表明，人们所吃的食物会影响睡眠质量，睡眠模式也会影响饮食选择。
Researchers have found that eating a diet that is high in sugar, saturated fat and processed carbohydrates can disrupt your sleep, while eating more plants, fiber and foods rich in unsaturated fat — such as nuts, olive oil, fish and avocados — seems to have the opposite effect, helping to promote sound sleep.
研究人员发现，糖分、饱和脂肪和加工碳水化合物含量高的饮食会扰乱睡眠，多吃蔬菜、纤维和富含不饱和脂肪的食物——比如坚果、橄榄油、鱼和牛油果——似乎会产生相反的效果，有助于促进良好睡眠。
Much of what we know about sleep and diet comes from large epidemiological studies that, over the years, have found that people who suffer from consistently bad sleep tend to have poorer quality diets, with less protein, fewer fruits and vegetables, and a higher intake of added sugar from foods like sugary beverages, desserts and ultra-processed foods. But by their nature, epidemiological studies can show only correlations, not cause and effect. They cannot explain, for example, whether poor diet precedes and leads to poor sleep, or the reverse.
我们大部分关于睡眠和饮食的知识都来自大型流行病学研究，多年来，这些研究发现，长期睡眠不好的人往往饮食质量较差，摄入的蛋白质、水果和蔬菜较少，而从含糖饮料、甜点和精加工食品等食物中摄入的添加糖较多。但就其性质而言，流行病学研究只能显示相关性，不能说明因果关系。例如，它们无法解释究竟是饮食不良先于并导致睡眠不良，还是睡眠不良先于并导致饮食不良。
To get a better understanding of the relationship between diet and sleep, some researchers have turned to randomized controlled trials in which they tell participants what to eat and then look for changes in their sleep. A number of studies have looked at the impact of a diverse array of individual foods, from warm milk to fruit juice. But those studies often have been small and not very rigorous.
为了更好地理解饮食和睡眠的关系，一些研究人员转向了随机对照试验，告诉参与者该怎么吃，然后观察他们睡眠的变化。许多研究考察了从热牛奶到果汁等各种单独食物的影响。但这些研究往往规模较小，不够严谨。
Some of these trials have also been funded by the food industry, which can bias results. One study funded by Zespri International, the world’s largest marketer of kiwi fruit, for example, found that people assigned to eat two kiwis an hour before their bedtime every night for four weeks had improvements in their sleep onset, duration and efficiency. The authors of the study attributed their findings in part to an “abundance” of antioxidants in kiwis. But importantly, the study lacked a control group, so it is possible that any benefits could have resulted from the placebo effect.
其中一些试验还得到食品行业的资助，这可能会使结果产生偏差。例如，世界上最大的猕猴桃经销商Zespri国际公司(Zespri International)资助的一项研究发现，被安排连续四周每晚睡前一小时吃两颗猕猴桃的人，其睡眠的开始时间、持续时间和质量都有所改善。该研究的作者们将其发现部分归因于猕猴桃中“富含”的抗氧化剂。但重要的是，该研究缺少对照组，因此起到效果的可能是安慰剂效应。
Other studies funded by the cherry industry have found that drinking tart cherry juice can modestly improve sleep in people with insomnia, supposedly by promoting tryptophan, one of the building blocks of the sleep-regulating hormone melatonin. Tryptophan is an amino acid found in many foods, including dairy and turkey, which is one of the reasons commonly given for why so many of us feel so sleepy after our Thanksgiving feasts. But tryptophan has to cross the blood-brain barrier to have any soporific effects, and in the presence of other amino acids found in food it ends up competing, largely unsuccessfully, for absorption. Studies show that eating protein-rich foods such as milk and turkey on their own actually decreases the ability of tryptophan to cross the blood-brain barrier.
樱桃产业资助的其他研究发现，喝酸樱桃汁可以适度改善失眠症患者的睡眠，据说这是通过增加色氨酸——调节睡眠的荷尔蒙褪黑素的成分之一——来实现的。色氨酸是一种氨基酸，存在于许多食物中，包括乳制品和火鸡，这也是为什么我们很多人在感恩节大餐后会觉得昏昏欲睡的原因之一。但色氨酸必须穿过血脑屏障才能起到催眠作用，而且由于食物中存在其他氨基酸，色氨酸在竞争中往往不会被成功吸收。研究表明，单独摄入蛋白质丰富的食物，如牛奶和火鸡，实际上会降低色氨酸穿过血脑屏障的能力。
One way to enhance tryptophan’s uptake is to pair foods that contain it with carbohydrates. That combination stimulates the release of insulin, which causes competing amino acids to be absorbed by muscles, in turn making it easier for tryptophan to cross into the brain, said Marie-Pierre St-Onge, an associate professor of nutritional medicine at Columbia University Irving Medical Center and the director of the Sleep Center of Excellence at Columbia.
哥伦比亚大学欧文医学中心(Columbia University Irving Medical Center)营养学副教授、哥伦比亚大学卓越睡眠中心(Sleep Center of Excellence)主任玛丽·皮埃尔·圣安琪(Marie-Pierre St-Onge)表示，提高色氨酸吸收的一个方法是将含有色氨酸的食物与碳水化合物搭配食用。这种结合能刺激胰岛素释放，导致竞争的氨基酸被肌肉吸收，从而使色氨酸更容易进入大脑。
Dr. St-Onge has spent years studying the relationship between diet and sleep. Her work suggests that rather than emphasizing one or two specific foods with supposedly sleep-inducing properties, it is better to focus on the overall quality of your diet. In one randomized clinical trial, she and her colleagues recruited 26 healthy adults and controlled what they ate for four days, providing them regular meals prepared by nutritionists while also monitoring how they slept at night. On the fifth day, the subjects were allowed to eat whatever they wanted.
圣安琪博士多年来都在研究饮食和睡眠的关系。她的研究表明，与其强调一到两种特定食物具有催眠作用，还不如把重点放在饮食整体质量上。在一次随机临床试验中，她和同事们招募了26名健康成年人，对他们的饮食进行了四天的控制，为他们提供营养学家准备的常规膳食，同时监测他们晚上的睡眠情况。第五天，受试者可以想吃什么就吃什么。
The researchers discovered that eating more saturated fat and less fiber from foods like vegetables, fruits and whole grains led to reductions in slow-wave sleep, which is the deep, restorative kind. In general, clinical trials have also found that carbohydrates have a significant impact on sleep: People tend to fall asleep much faster at night when they consume a high-carbohydrate diet compared to when they consume a high-fat or high-protein diet. That may have something to do with carbs helping tryptophan cross into the brain more easily.
研究者发现，摄入更多饱和脂肪，更少蔬菜、水果和粗粮等食物中的纤维，会导致慢波睡眠减少，慢波睡眠是一种深度的恢复性睡眠。总的来说，临床试验也发现碳水化合物对睡眠有显著影响：人们在晚上吃高碳水化合物食物时，往往比吃高脂肪或高蛋白食物时入睡更快。这可能与碳水化合物能帮助色氨酸更容易进入大脑有关。
But the quality of carbs matters. In fact, they can be a double-edged sword when it comes to slumber. Dr. St-Onge has found in her research that when people eat more sugar and simple carbs — such as white bread, bagels, pastries and pasta — they wake up more frequently throughout the night. In other words, eating carbs may help you fall asleep faster, but it is best to consume “complex” carbs that contain fiber, which may help you obtain more deep, restorative sleep.
但碳水化合物的质量也很重要。事实上，它们对睡眠可能是把双刃剑。圣安琪博士在研究中发现，当人们吃更多食糖和单一碳水化合物（如白面包、百吉饼、糕点和意大利面）时，夜间醒来的频率会更高。换句话说，吃碳水化合物可以帮助你更快入睡，但最好是吃含有纤维的复合碳水化合物，这能让你获得更深的恢复性睡眠。
“Complex carbohydrates provide a more stable blood sugar level,” said Dr. St-Onge. “So if blood sugar levels are more stable at night, that could be the reason complex carbohydrates are associated with better sleep.”
“复合碳水化合物能让血糖水平更稳定，”圣安琪博士说。“因此，血糖水平在夜间更稳定，可能就是复合碳水化合物与更好的睡眠相关联的原因。”
One example of a dietary pattern that may be optimal for better sleep is the Mediterranean diet, which emphasizes such foods as vegetables, fruits, nuts, seeds, legumes, whole grains, seafood, poultry, yogurt, herbs and spices and olive oil. Large observational studies have found that people who follow this type of dietary pattern are less likely to suffer from insomnia and short sleep, though more research is needed to confirm the correlation.
地中海饮食可能是提升睡眠质量的理想饮食模式之一，它主打蔬菜、水果、坚果、豆类、全谷类、海鲜、家禽、酸奶、草药、香料和橄榄油等食材。大量观察性研究已经发现，遵循这种饮食模式的人患失眠和睡眠时间短的可能性较小，不过还需要更多的研究来证实这种相关性。
But the relationship between poor diet and bad sleep is a two-way street: Scientists have found that as people lose sleep, they experience physiological changes that can nudge them to seek out junk food. In clinical trials, healthy adults who are allowed to sleep only four or five hours a night end up consuming more calories and snacking more frequently throughout the day. They experience significantly more hunger and their preference for sweet foods increases.
但不良饮食和糟糕睡眠之间的关系是双向的：科学家发现，当人们缺乏睡眠时，会出现生理上的变化，从而促使他们去寻找垃圾食品。在临床试验中，每晚只允许睡四到五小时的健康成年人最终会消耗更多卡路里，并在一天中更频繁地吃零食。他们的饥饿感明显增加，对甜食的偏好也有所增加。
In men, sleep deprivation stimulates increased levels of ghrelin, the so-called hunger hormone, while in women, restricting sleep leads to lower levels of GLP-1, a hormone that signals satiety.
对男性来说，睡眠不足会刺激被称为“饥饿激素”的胃促生长素水平的上升，而对女性来说，睡眠不足会导致GLP-1的水平下降，这是一种标志着饱腹感的激素。
“So in men, short sleep promotes greater appetite and desire to eat, and in women there is less of a signal that makes you stop eating,” said Dr. St-Onge.
“所以，对男性来说，睡眠时间短会促进更强烈的食欲和进食欲望，而对女性来说，则是让停止进食的信号变少，”圣安琪博士说。
Changes also occur in the brain. Dr. St-Onge found that when men and women were restricted to four hours of nightly sleep for five nights in a row, they had greater activation in reward centers of the brain in response to pepperoni pizza, doughnuts and candy compared to healthy foods such as carrots, yogurt, oatmeal and fruit. After five nights of normal sleep, however, this pattern of stronger brain responses to the junk food disappeared.
他们的大脑也会发生变化。圣安琪博士发现，当男性和女性连续五晚的睡眠时间被限制在四个小时，他们大脑的奖赏中心对帕帕罗尼披萨、甜甜圈和糖果的反应，会比对胡萝卜、酸奶、燕麦和水果等健康食品的反应更活跃。但在五晚的正常睡眠之后，大脑对垃圾食品的更强烈反应就消失了。
Another study, led by researchers at King’s College London, also demonstrated how proper sleep can increase your willpower to avoid unhealthy foods. It found that habitually short sleepers who went through a program to help them sleep longer — resulting in their getting roughly an hour of additional sleep each night — had improvements in their diet. The most striking change was that they cut about 10 grams of added sugar from their diets each day, the equivalent of about two and a half teaspoons.
由伦敦国王学院(King’s College London)的研究人员领导的另一项研究也证明了适当的睡眠如何能增强避免摄入不健康食品的意志力。研究发现，习惯性睡眠不足的人在完成帮助延长睡眠的项目后——结果是他们每晚大约能多睡一小时——饮食都有所改善。最显著的变化是，他们每日饮食减少了约10克的添加糖，相当于两茶匙半的量。
The takeaway is that diet and sleep are entwined. Improving one can help you improve the other and vice versa, creating a positive cycle where they perpetuate one another, said Dr. Susan Redline, a senior physician at the Brigham and Women’s Hospital and a professor of sleep medicine at Harvard Medical School who studies diet and sleep disorders.
布莱根妇女医院(Brigham and Women's Hospital)高级医师、在哈佛大学医学院(Harvard Medical School)研究饮食及睡眠紊乱的睡眠医学教授苏珊·雷德琳(Susan Redline)表示，这说明了饮食和睡眠是密切相关的。提升一方可以帮助你改善另一方，反之亦然，这创造了一个良性循环，让提升互相延续下去。
“The best way to approach health is to emphasize a healthy diet and healthy sleep,” she added. “These are two very important health behaviors that can reinforce each other.”
“获得健康的最好办法，就是强调健康饮食和健康睡眠，”她补充道。“这两个非常重要的健康习惯是可以相互促进的。”