DANA G. SMITH2026年7月9日 Maria HerguetaIn theory, taking an omega-3, or fish oil, supplement makes a lot of sense.从理论上讲，服用欧米伽-3（即鱼油）补充剂是合理的。Omega-3 fatty acids are vital for brain health: They are used to build brain cells, keeping the cell walls flexible and enabling the neurons to sprout new connections and communicate with other cells. Numerous studies have shown that people with higher levels of omega-3s in their blood have better cognition and healthier looking brains, as well as a lower risk of developing dementia. In contrast, people with Alzheimer’s disease have been shown to have lower omega-3 levels.欧米伽-3脂肪酸对大脑健康至关重要：它们被用来构建脑细胞，保持细胞壁的弹性，使神经元能够长出新的连接并与其他细胞交流。众多研究表明，血液中欧米伽-3水平较高的人拥有更好的认知能力和看起来更健康的大脑结构，同时患上失智症的风险也更低。相比之下，阿兹海默病患者已被证实欧米伽-3水平较低。But there’s a catch: The vast majority of clinical trials have found that taking omega-3 supplements offers virtually no benefit for cognition or dementia symptoms.但这里存在一个问题：绝大多数临床试验发现，服用欧米伽-3补充剂对改善认知或缓解失智症症状而言，几乎没有任何益处。“It kind of intuitively makes sense” that neurons need fatty acids for their health, so you should take a fatty acid supplement, said Dr. Kristine Yaffe, a professor of psychiatry, neurology and epidemiology at the University of California, San Francisco. “The problem is that most of the evidence, particularly the trial evidence, just doesn’t support it at all,” she said.加利福尼亚大学旧金山分校的精神病学、神经病学和流行病学教授克里斯汀·雅菲博士表示，神经元的健康需要脂肪酸，因此应该服用脂肪酸补充剂，“这在直觉上是说得通的”。她说：“问题在于，大多数证据，尤其是试验得出的证据，根本不支持这一点。”A study published last month offers a prime example. The scientists who ran the clinical trial tried to cover all their bases: The participants were older adults who didn’t eat a lot of fish (which is rich in omega-3s), suggesting they might benefit the most from a supplement. Roughly half of the participants had an increased genetic risk for Alzheimer’s, which is another group that experts think might need more omega-3s. The researchers even did lumbar punctures on some of the participants to confirm that the supplement caused omega-3 levels in the brain to go up.上个月发表的一项研究就是一个典型的例子。进行该临床试验的科学家们试图面面俱到：参与者是平时不怎么吃鱼（鱼类富含欧米伽-3）的老年人，这表明他们可能最能从补充剂中受益。大约一半的参与者患阿兹海默病的遗传风险在增加，这是专家认为可能需要更多欧米伽-3的另一类人群。研究人员甚至对部分参与者进行了腰椎穿刺，以确认补充剂确实使大脑中的欧米伽-3水平有所上升。But compared with a placebo, the supplement didn’t result in any benefit when it came to people’s cognition or brain structure.但与安慰剂相比，该补充剂在改善认知或大脑结构方面没有带来任何益处。So what’s behind the disconnect? Scientists have a few hypotheses, and most are connected to diet and lifestyle.那么，这种脱节背后原因何在？科学家有几种假设，且大多数都与饮食和生活方式有关。Hypothesis 1: Most people already get enough omega-3s.假设一：大多数人已经摄入了足够的欧米伽-3。There are three main types of omega-3s that are important for health: EPA and DHA, which are primarily found in fish, and ALA, which is in nuts and seeds. The liver can convert small amounts of ALA into EPA and DHA.对健康至关重要的欧米伽-3主要有三种类型：主要存在于鱼类中的EPA和DHA，以及存在于坚果和种子中的ALA。肝脏可以将少量的ALA转化为EPA和DHA。DHA is the most vital for cognition, and there’s a large reserve of it in our brains. According to Richard Bazinet, a professor of nutritional sciences at the University of Toronto, the amount of DHA our brains use every day is just a tiny fraction of that reserve.DHA对认知最为关键，我们的大脑中有大量的DHA储备。多伦多大学营养科学教授理查德·巴齐内表示，我们的大脑每天消耗的DHA仅占该储备中极其微小的一部分。Even if people don’t eat a lot of fish, Dr. Bazinet thinks they still probably get enough omega-3s through their diet, particularly from ALA, to replace the small amount of DHA the brain uses.巴齐内认为，一个人即使不怎么吃鱼，很可能也会通过饮食（尤其是通过ALA）获取足够的欧米伽-3，来补充大脑消耗掉的少量DHA。“We all eat a ton of” ALA, Dr. Bazinet said. And if people’s DHA intake is low, the liver can convert the ALA to DHA and send it to the brain.“我们都会吃很多”ALA，巴齐内说。如果DHA摄入量较低，肝脏就可以将ALA转化为DHA并输送给大脑。In Dr. Bazinet’s mind, since virtually everyone gets enough omega-3s from their diet, the brain benefits that scientists see in people who have high blood levels of DHA are probably caused by something besides omega-3s — most likely from other healthy habits that tend to come with eating a diet rich in fish.在巴齐内看来，既然几乎每个人都能从饮食中摄入足够的欧米伽-3，那么科学家在血液DHA水平高的人群中所看到的大脑益处，可能并不是欧米伽-3本身带来的——而更可能是伴随摄入富含鱼类饮食的其他健康习惯所致。For example, when someone has fish for dinner, they typically pair it with vegetables, not junk food. “If you’re going to have a nice tuna steak, you might have a little bit of salad,” Dr. Bazinet said. And “when you’re eating that meal, you’re not eating something else” that’s less healthy for your brain, he added.例如，晚餐吃鱼时，人们通常会搭配蔬菜，而不是垃圾食品。巴齐内说：“如果你准备吃一盘精美的金枪鱼排，你可能会配上一点沙拉。”他补充道。而且“当你吃那一餐时，你就不会去吃其他对你的大脑健康不那么有帮助的东西了”。Hypothesis 2: It’s how you metabolize omega-3s that really matters.假设二：如何代谢欧米伽-3才是真正关键所在。Dr. Hussein Yassine, a professor of neurology at the University of Southern California’s Keck School of Medicine, thinks it is how the brain uses omega-3s that matters most.南加州大学凯克医学院的神经学教授侯赛因·雅辛(Hussein Yassine)博士认为，大脑如何利用欧米伽-3才是最核心的问题。In the brain, there is a molecule that breaks down and gets rid of omega-3s. Everyone has this molecule, but Dr. Yassine has found that it is more active in people with a genetic risk for Alzheimer’s. It’s possible that their brains metabolize omega-3s more quickly, depleting the levels.在大脑中，存在一种能够分解并清除欧米伽-3的分子。每个人都有这种分子，但雅辛发现，在具有阿兹海默病遗传风险的人群中，这种分子更加活跃。他们的大脑代谢欧米伽-3的速度可能更快，从而导致迅速耗尽。To improve brain health, Dr. Yassine, who also led the recent omega-3 supplement trial, thinks some people need not only to increase their omega-3 intake, but also to decrease the activity of that other molecule. Research is preliminary, but there’s some evidence that this molecule is affected by the gut microbiome and is less active in people who have a diet rich in plants, fiber and fermented foods. In other words, to benefit the brain, you need the nutrients from the tuna, as well as those from the salad or other healthy side dishes.同样主持了近期这项欧米伽-3补充剂试验的雅辛认为，为了改善大脑健康，一些人不仅需要增加欧米伽-3的摄入量，还需要降低那种分子的活性。虽然研究尚处于初步阶段，但有证据表明，这种分子会受到肠道微生物组的影响，并且在饮食富含植物、纤维和发酵食品的人群中活性较低。换句话说，要让大脑获益，你既需要金枪鱼中的营养，也需要沙拉或其他健康配菜中的营养。If someone has a poor diet “and you just give them a supplement where the only thing you change is the level of omega-3s in their blood and in their brain, our study would suggest that it’s not going to work,” Dr. Yassine said.雅辛说，如果一个人的饮食习惯很差，“而你只是给他们提供一种补充剂，其中你唯一改变的是他们血液和脑部的欧米伽-3水平，我们的研究表明这是不会起作用的。”Hypothesis 3: To see benefits, you need to consume large amounts of omega-3s for decades.假设三：要想看到益处，你需要连续几十年摄入大量的欧米伽-3。Not everyone is giving up on omega-3 supplements. Gene Bowman, an assistant professor of neurology at Harvard Medical School, thinks one reason that clinical trials tend to fail is because they only test supplements for a few years, and that may not be enough time to detect changes in the brain. When people have high blood levels of omega-3s, it’s typically because they’ve eaten foods rich in omega-3s — by some estimates three weekly servings of fish — for decades.并非所有人都在放弃欧米伽-3补充剂。哈佛医学院神经学助理教授吉恩·鲍曼认为，临床试验往往失败的原因之一在于，它们只对补充剂进行了几年的测试，而这段时间可能不足以检测出大脑中的变化。当人们血液中含有高水平的欧米伽-3时，通常是因为他们几十年来一直食用富含欧米伽-3的食物——据某些估计，每周要吃三次鱼。“I think the reason for the disconnect or inconsistency, one explanation could be strictly methodological,” Dr. Bowman said.“我认为造成这种脱节或不一致的原因，有一种解释可能纯粹是方法学上的，”鲍曼说。“So we either start much earlier and do much longer trials,” he added, “or we come up with a more powerful treatment that has a larger magnitude of effect.” For instance, omega-3s may work best when combined with other nutrients (the fish-plus-salad theory), particularly in people who have nutritional deficiencies.他补充道：“因此，我们要么更早开始并进行更长时间的试验，要么开发出一种效果更明显的、更强效的治疗方法。”例如，当欧米伽-3与其他营养素相结合时（即鱼加沙拉理论）效果可能最好，尤其是在存在营养缺乏的人群中。Regardless of the reason for why omega-3 supplements seem to fall short, the current research suggests it’s a balanced diet, rather than a pill, that can help keep your brain healthy. That is also likely true for heart health, another reason many people take an omega-3 supplement.无论欧米伽-3补充剂似乎效果不佳的原因为何，目前的研究所表明的都是，通过均衡的饮食——而非吃药——才能有助于保持你的大脑健康。对于心脏健康而言情况很可能也是如此，而这也是许多人服用欧米伽-3补充剂的另一个原因。“The best evidence, as limited as it might be, is that eating foods with omega-3s seems to be a good thing and correlates with better brain outcomes,” Dr. Bazinet said. “But taking the shortcut with the supplements” doesn’t seem to show the same benefit.“最好的证据（尽管它可能还很有限）表明，食用含有欧米伽-3的食物似乎是一件好事，并且与更好的大脑结果相关，”巴齐内说。“但在服用补充剂走捷径这件事上”，似乎并没有表现出同样的益处。Dana G. Smith是《纽约时报》记者，报道个人健康，特别是衰老和大脑健康问题。翻译：经雷点击查看本文英文版。