Does Diet Affect Long Term Brain Health?

饮食对长期大脑健康的影响

In this new series, we discuss ground-breaking research being conducted on human nutrition, paving the way for Americans to lead healthier lives while reducing the risk of diseases. ARS funded research supports human health at all stages of life by better understanding relationships between nutrient intake, eating patterns, exercise, health conditions, disease prevention, and how nutrition promotes health.

在本系列新文章中，我们将探讨人类营养学领域正在开展的突破性研究，旨在为美国人降低疾病风险、迈向更健康的生活铺平道路。美国农业部农业研究局（ARS）资助的研究项目，致力于深入探究营养摄入、饮食模式、运动习惯、健康状况及疾病预防之间的相互关系，以及营养促进健康的内在机制，从而为人生各个阶段的健康提供科学支持。

In this article, we look at possible associations between different dietary patterns and brain aging. Our guests are Dr. Sarah Booth, Center Director and Senior Scientist for the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, MA, and Dr. Paul Jacques, Senior Scientist at the Jean Mayer Center. Drs. Booth and Jacques recently completed a review titled, “Dietary Patterns and Brain Aging: Enthusiasm Before Evidence?”

在本文中，我们将探讨不同饮食模式与大脑衰老之间可能存在的关联。本期嘉宾是萨拉·布斯（Sarah Booth）博士和保罗·雅克（Paul Jacques）博士。布斯博士任职于马萨诸塞州波士顿塔夫茨大学的让·梅耶美国农业部人类营养衰老研究中心，担任中心主任兼高级科学家；雅克博士则是该中心的高级科学家。两位学者近期完成了一篇综述，题为《饮食模式与大脑衰老：热情是否先于证据？》。

Pictured Left to Right: Dr. Sarah Booth and Dr. Paul Jacques

左起：萨拉·布斯（Sarah Booth）博士、保罗·雅克（Paul Jacques）博士

Welcome to Drs. Booth and Jacques to Under the Microscope:

欢迎布斯博士和雅克博士做客《显微镜下》栏目：主要修改点说明：

UM: Before conducting the study, what did you already know from previous research on associations between brain aging and diet?

UM：在开展这项研究之前，关于大脑衰老与饮食之间的关联，既往研究已经有哪些发现？

SB/PJ: Research suggests that what we eat may help slow down memory loss and lower the risk of Alzheimer’s disease and related conditions. In this study, we looked at and summarized existing research on how healthy diets are connected to changes in the aging brain, both normal changes and those linked to disease. We also evaluated how strong and reliable that evidence is and pointed out areas where more research is needed to better understand how diet affects brain aging.

SB/PJ：研究表明，饮食可能有助于减缓记忆力衰退，并降低阿尔茨海默病及相关疾病的风险。在本研究中，我们梳理并总结了现有关于健康饮食与衰老大脑变化之间关联的研究，涵盖正常的生理性变化以及与疾病相关的病理性变化。此外，我们还评估了现有证据的强度与可靠性，并指出了尚需进一步研究的领域，以便更深入地理解饮食对大脑衰老的影响。

UM: What did your study confirm or change about this linkage?

UM：关于这种关联，你们的研究证实了哪些既有认知，又带来了哪些新的改变？

SB/PJ: Our findings support the evidence that healthy dietary patterns, which include higher consumption of vegetables, fruits, legumes, nuts, fish and other seafood, and unsaturated vegetable oils and lower consumption of red and processed meats and sugar-sweetened beverages, are associated with lower risk of age-related neurodegenerative disease.

SB/PJ：我们的研究结果进一步印证了现有证据，即健康的饮食模式与较低的年龄相关性神经退行性疾病风险相关。这类饮食模式的特点是：多摄入蔬菜、水果、豆类、坚果、鱼类及其他海产品、不饱和植物油，同时少摄入红肉、加工肉类和含糖饮料。

Family eating healthy. (Getty stock photo)

家庭健康饮食。（盖蒂图片社供图）

While there is some promising evidence, many of the existing studies have important limitations. For example, researchers use different tests to measure memory and thinking, and study groups vary widely in their health and cognitive status, making it hard to compare results. Some studies may also have biases or inaccuracies—for instance, people may not report their diets perfectly, and early memory problems could already be affecting what they eat. Another issue is that many studies don’t track how people’s diets change over time, so they may miss important shifts in dietary patterns. Finally, much of the research focuses on older adults, which makes it harder to understand whether eating habits earlier in adulthood might have a bigger impact on preventing cognitive decline.

尽管已有一些令人鼓舞的证据，但许多现有研究仍存在重要的局限性。例如，不同研究采用的记忆与认知功能测评工具各不相同，受试群体的健康状况和认知水平也差异较大，导致研究结果难以相互比较。部分研究还可能存在偏倚或误差——比如，受试者的饮食自我报告可能不够准确，而早期的记忆问题也可能反过来影响其饮食行为。此外，许多研究未能追踪受试者饮食模式随时间的变化，因此可能遗漏饮食模式转变这一重要信息。最后，现有研究大多聚焦于老年人群，这使得我们难以判断成年早期形成的饮食习惯是否对预防认知功能衰退具有更重要的影响。

UM: For Americans looking to avoid cognitive diseases later in life, is it as simple as eating more vegetables, fruits, legumes, nuts, fish and/or seafood, and unsaturated vegetable oils/fats and less red and processed meats and sugar-sweetened beverages?

UM：对于希望晚年远离认知疾病的美国人来说，事情是否就这么简单——多吃蔬菜、水果、豆类、坚果、鱼类和海产品、不饱和植物油，少吃红肉、加工肉类和含糖饮料？

SB/PJ: While there are still gaps in our understanding of the role of diet and brain aging, we know that healthy diet patterns lower risk of conditions such as diabetes and other cardiovascular disease risk factors, which are also risk factors for cognitive decline and dementia. However, it is unlikely that consumption of a healthy dietary pattern alone will achieve clinically relevant success in reducing risk of cognitive decline and/or dementia given the many risk factors other than diet that are associated with variation in age-related cognitive decline and dementia risk.

SB/PJ：尽管我们对饮食在大脑衰老中所起作用的认识仍存在空白，但我们已知，健康的饮食模式能够降低糖尿病及其他心血管疾病危险因素的发生风险，而这些因素同样是认知功能衰退和痴呆症的危险因素。然而，鉴于与年龄相关的认知衰退和痴呆风险受多种非饮食因素影响，仅靠健康饮食模式本身，不太可能在降低认知衰退和/或痴呆风险方面取得具有临床意义的效果。

UM: What other risk factors play a part in cognitive decline and associated diseases such as Alzheimer’s and dementia?

UM：除了饮食之外，还有哪些危险因素会影响认知功能衰退以及阿尔茨海默病、痴呆症等相关疾病的发生？

SB/PJ: Age is the single biggest risk factor for Alzheimer’s disease and related dementias—the chances of developing it roughly double every 5 years between ages 65 and 90. Sex also plays a role, with women having about twice the risk of men. Other known risk factors include a history of serious head injury and carrying a certain genetic trait called ApoE4. However, these risks can’t be changed.

SB/PJ：尽管我们对饮食在大脑衰老中的作用仍存在一些认识空白，但我们已知，健康的饮食模式能够降低糖尿病及其他心血管疾病危险因素的发生风险，而这些因素同样也是认知功能衰退和痴呆症的危险因素。然而，鉴于年龄相关性认知衰退和痴呆风险还受多种非饮食因素影响，仅靠健康饮食模式本身，不太可能在降低认知衰退和/或痴呆风险方面取得具有临床意义的效果。

Conversely, some risk factors are modifiable. In addition to diet, these include heart and metabolic health conditions like diabetes, high blood pressure, high cholesterol, and obesity, as well as lifestyle factors such as physical activity, alcohol use, smoking, education level, and social connections.

相反，一些危险因素是可以改变的。除饮食外，这些因素还包括心脏和代谢健康状况，如糖尿病、高血压、高胆固醇和肥胖；以及生活方式因素，如体育锻炼、饮酒、吸烟、受教育程度和社会交往。

UM: Can improving your diet later in life help lower the risk of cognitive decline?

UM：在晚年改善饮食，是否有助于降低认知功能衰退的风险？

SB/PJ: While our study did not directly address this issue, there is limited evidence that individuals in their 60’s and 70’s who consumed a healthier diet have less risk of dementia. However, we are not aware of any studies showing that improvements in diet in individuals in their 80’s and older lowers dementia risk.

SB/PJ：尽管我们的研究并未直接回答这一问题，但有限证据表明，60多岁和70多岁的人群若饮食更健康，患痴呆症的风险较低。然而，目前尚无研究显示，80岁及以上人群改善饮食能够降低痴呆症风险。

Seniors eating healthy. (Getty stock photo)

老年人健康饮食。（盖蒂图片社供图）

Given that the pathological processes that ultimately lead to dementia are believed to start 20 to 30 years prior to the diagnosis of dementia, consuming a healthier diet at younger and middle ages may provide the best opportunity to prevent or delay the onset of pathological cognitive decline. That said, it would be reasonable to suggest that a healthier diet could help maintain cognitive health for older individuals of any age who have yet to experience cognitive decline.

鉴于最终导致痴呆的病理过程被认为在痴呆确诊前20至30年就已启动，在青年和中年阶段采取更健康的饮食，可能是预防或延缓病理性认知衰退发作的最佳时机。尽管如此，提出以下建议仍是合理的：对于任何年龄、尚未出现认知衰退的老年人而言，更健康的饮食有助于维持其认知健康。

UM: Your study discussed a possible link between type 2 diabetes and dementia. Please elaborate.

UM：你的研究探讨了2型糖尿病与痴呆症之间可能存在的关联，请详细说明。

SB/PJ: Type 2 diabetes is a known risk factor for Alzheimer’s disease and related dementias. It develops when the body becomes resistant to insulin, a hormone that helps control blood sugar. Insulin resistance can also happen in the brain itself, and this may play an important role in the development of Alzheimer’s disease. Importantly, insulin resistance in the brain is not the same as insulin resistance in the rest of the body, and it can occur even in people who do not have type 2 diabetes. It is an emerging area but requires more research to unravel the underlying mechanisms that link it to Alzheimer’s disease and related dementias.

SB/PJ：2型糖尿病是阿尔茨海默病及相关痴呆症的已知危险因素。当机体对胰岛素——一种帮助调节血糖的激素——产生抵抗时，2型糖尿病便会发生。胰岛素抵抗也可能出现在大脑本身，这可能在阿尔茨海默病的发生发展中起重要作用。重要的是，大脑中的胰岛素抵抗与身体其他部位的胰岛素抵抗并不相同，即使未患2型糖尿病的人也可能出现脑部胰岛素抵抗。这是一个新兴研究领域，但仍需更多研究来揭示其与阿尔茨海默病及相关痴呆症之间关联的潜在机制。

UM: Do the consumption of individual nutrients, such as polyphenols and vitamins D and K, play a role in reducing the risk of cognitive diseases later in life? If so, are there also risks to overconsuming these nutrients?

UM：摄入多酚以及维生素D、K等单一营养素，是否有助于降低晚年患认知相关疾病的风险？如果是，过量摄入这些营养素是否也存在风险？

SB/PJ: There is evidence that several individual nutrients may play a role in brain health, but adequate intakes of most of these nutrients, including the polyphenols, lutein, vitamin K, choline, polyunsaturated fatty acids, and other dietary bioactive compounds, are readily achieved in healthy dietary patterns that include a variety of plant foods (including whole grains), fish and other seafoods, dairy, healthy oils, and limit refined gain products, saturated fats, and added salt and sugar. While each nutrient might have small individual effects on cognitive function, together in a healthy diet, their combined effects could provide much greater benefits, negating the need for consuming multiple supplements. This is consistent with studies of diet patterns, which generally show stronger and more consistent protective associations than seen with individual nutrients.

SB/PJ：有证据表明，若干单一营养素可能对大脑健康发挥作用，但大多数此类营养素——包括多酚、叶黄素、维生素K、胆碱、多不饱和脂肪酸及其他膳食生物活性化合物——的充足摄入量，在健康的饮食模式下很容易达到。这类饮食模式应包含多种植物性食物（包括全谷物）、鱼类及其他海产品、乳制品和健康油脂，并限制精制谷物制品、饱和脂肪以及添加的盐和糖。尽管每种营养素对认知功能的单独作用可能较小，但在健康饮食中，它们的协同作用可带来更大的益处，从而无需额外服用多种膳食补充剂。这与饮食模式研究的结果一致：饮食模式通常比单一营养素显示出更强、更一致的保护性关联。

Two exceptions where supplements may be beneficial are vitamins B12 and D, particularly for older individuals who may experience greater inadequacies of these vitamins.

维生素B12和D是两个例外，补充这两种维生素可能有益，尤其对于更容易出现这两种维生素缺乏的老年人而言。

UM: Your study mentions several diets, including the Mediterranean-style diet, the Dietary Approaches to Stop Hypertension (DASH) diet, and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet. What were your conclusions from studying these diets?

UM：你的研究提到了几种饮食模式，包括地中海式饮食、得舒饮食（DASH，即终止高血压膳食疗法），以及地中海-DASH干预神经退行性疾病饮食（MIND）。你从这些饮食模式的研究中得出了哪些结论？

SB/PJ: The research shows that all these healthy eating patterns are linked to better brain health and a lower risk of Alzheimer’s disease and related dementias. This isn’t surprising because these diets are quite similar, even though they emphasize slightly different foods. All of these diets encourage eating plenty of plant-based foods like fruits (especially berries), vegetables (especially leafy greens), beans, nuts, seeds, and whole grains. They also recommend using healthy fats like olive oil. Fish and poultry are included in moderate amounts, while red and processed meats, as well as sweets and pastries, should be limited.

SB/PJ：研究表明，所有这些健康饮食模式都与更好的大脑健康以及更低的阿尔茨海默病及相关痴呆症风险相关。这并不令人意外，因为这些饮食模式虽然强调的食物略有不同，但整体十分相似。它们都鼓励大量摄入植物性食物，如水果（尤其是浆果）、蔬菜（尤其是绿叶蔬菜）、豆类、坚果、种子和全谷物，并建议使用橄榄油等健康油脂。鱼类和禽肉应适量摄入，而红肉及加工肉类、甜食和糕点则应限制。

Mediterranean-style food. (Getty stock photo)

地中海风格的食物。（盖蒂图片社供图）

There are a few differences—for example, the DASH diet includes more low-fat dairy, the Mediterranean diet allows moderate dairy, and the MIND diet mainly recommends limiting cheese and butter. The main takeaway is that there isn’t just one “perfect” diet. Healthy eating can look a little different for everyone, but in general, it should focus on mostly plant-based, minimally processed foods; include smaller amounts of healthier animal foods; and limit processed foods that are high in salt, unhealthy fats, and added sugars. This concept that healthy diets can take different forms is important for helping people adhere to dietary recommendations. It allows for cultural, medical, and personal preferences, and shows that there are many ways to eat healthfully—more than we may have previously thought.

这几种饮食模式之间存在一些差异——例如，得舒饮食（DASH）包含更多低脂乳制品，地中海饮食允许适量摄入乳制品，而MIND饮食则主要建议限制奶酪和黄油的摄入。核心结论是：并不存在唯一一种"完美"饮食。健康饮食的形式因人而异，但总体而言，应以植物性、低加工食品为主，搭配少量更健康的动物性食物，并限制高盐、不健康脂肪及添加糖的加工食品。"健康饮食可以有多种形式"这一理念，对于帮助人们坚持饮食建议至关重要。它兼顾了文化、医疗和个人偏好，表明健康饮食的方式多种多样——远超我们此前的想象。

UM: What is the big takeaway for Americans in each age group?

嗯: 每个年龄段的美国人最大的收获是什么？

SB/PJ: The importance of diet in neurodevelopment and cognitive health of infants, children, adolescents, and young adults is established, and evidence is accumulating to suggest that diet may affect brain aging as well. Despite our incomplete understanding of the latter, we know that healthy diets can have important impacts on many different health outcomes across the lifespan so we should not only focus on the role of diet on the brain but also on the role of diet in overall healthy aging.

SB/PJ：饮食在婴儿、儿童、青少年和年轻人的神经发育与认知健康中的重要性已得到证实，且越来越多的证据表明，饮食也可能影响大脑衰老。尽管我们对后者的认识尚不充分，但已知健康饮食会对整个生命周期中的多种健康结局产生重要影响，因此我们不应仅关注饮食对大脑的作用，还应关注饮食在整体健康老龄化中的作用。