Decades of research have shown that fiber-rich diets offer a range of health benefits, including healthier guts, longer lives and reduced risks of chronic conditions like heart disease, diabetes and some types of cancer.

数十年的研究表明，富含纤维的食物对健康有一系列好处，包括更健康的肠道、更长的寿命，以及降低罹患心脏病、糖尿病和某些癌症等慢性疾病的风险。

Yet time and again, national surveys have found that few people in the United States are consuming enough fiber. Between 2015 and 2018, one study showed, just 4 percent of men and 12 percent of women met fiber recommendations — at least 21 to 38 grams per day, depending on a person’s age and sex.

但全国性调查一再发现，在美国，纤维摄入量达标的人很少。一项研究显示，在2015年至2018年期间，仅有4%的男性和12%的女性达到了纤维摄入的建议量——一个人每天至少要摄入21至38克纤维，具体视年龄和性别而定。

That’s far less fiber than what our ancestors likely consumed, said Dr. Stephen O’Keefe, a gastroenterologist and professor of medicine at the University of Pittsburgh. Contemporary hunter gatherers in Tanzania, for example, were estimated to have consumed as much as 100 grams per day.

匹兹堡大学的胃肠病专家、医学教授斯蒂芬·奥基夫博士说，这远远少于我们的祖先可能摄入的纤维量。例如，据估计，生活在坦桑尼亚的当代狩猎采集者每天摄入的纤维量多达100克。

Our collective fiber deficiency is partly because of modern food processing that strips foods of much of their fiber, he said. And as a result, we’re probably missing out on many benefits.

他说，我们之所以整体缺乏纤维，在一定程度上是因为现代食品的加工过程去除了许多食物中的纤维。因此，我们可能会错过膳食纤维的许多益处。

We asked experts to explain what fiber is, why it’s so beneficial and how we can add more to our diets.

我们请专家解释了什么是膳食纤维，为什么它好处多多，以及如何增加饮食中的纤维摄入量。

What is fiber?

膳食纤维是什么？

Dietary fibers belong to a large group of carbohydrates that our digestive systems can’t break down, said Joanne Slavin, a professor of food science and nutrition at the University of Minnesota. Unlike sugars and starches, which are digested and absorbed in the small intestine, fiber travels on through the gut, and affects the body differently depending on what type of fiber it is, she said.

明尼苏达大学食品科学与营养学教授乔安妮·斯莱文说，膳食纤维属于一大类我们消化系统无法分解的碳水化合物。她说，与在小肠中被消化和吸收的糖和淀粉不同，膳食纤维会继续在肠道中移动，并且根据纤维的类型，对身体产生不同的影响。

Some fibers, for example, form a gel-like substance that slows the movement of food through the digestive tract and can reduce blood sugar spikes and lower cholesterol, said Kevin Whelan, a professor of dietetics at King’s College London.

伦敦国王学院饮食学教授凯文·惠兰说，比如，一些纤维会形成凝胶状物质，减缓食物在消化道中的移动，并且能起到降低血糖峰值和胆固醇的作用。

Other fibers can feed our gut microbes, he said, contributing to a healthy gut microbiome; and still others can add bulk to digestive material and prevent constipation.

他说，有一些纤维可以滋养我们的肠道微生物，促进肠道菌群的健康；还有一些纤维可以增加消化物质的体积，预防便秘。

How does fiber benefit health?

食物纤维是如何促进健康的？

In one review of 185 studies published in 2019, researchers compared people who followed higher fiber diets with those who followed lower ones. They found that those who consumed the most fiber were 16 percent less likely to develop Type 2 diabetes or colorectal cancer and 31 percent less likely to die of coronary heart disease during the study period. Consuming 25 to 29 grams per day was enough to reap most of those benefits, the study authors concluded.

在2019年发表的一篇对185项研究的综述中，研究人员比较了遵循高纤维饮食和低纤维饮食的人群。结果发现，在研究期间，摄入纤维最多的人患2型糖尿病或结直肠癌的可能性降低了16%，死于冠心病的可能性降低了31%。研究论文的作者得出的结论是，每天摄入25至29克纤维就足以获得这些益处中的大部分。

In clinical trials, high-fiber diets also lowered people’s blood pressures, cholesterol levels and body weights.

在临床试验中，高纤维饮食还能降低人们的血压、胆固醇水平和体重。

Fiber-rich diets tend to be high in vitamins, minerals and healthful plant-based compounds, which may explain why fiber supplements are unlikely to offer as many benefits as high-fiber diets, said Emily Haller, a registered dietitian nutritionist at Michigan Medicine.

密歇根医学院注册营养师艾米丽·哈勒说，富含纤维的饮食往往含有大量维生素、矿物质和有益健康的植物性化合物，这或许可以解释为什么纤维补充剂不太可能像高纤维饮食那样带来那么多益处。

A growing body of evidence also suggests that diets high in fiber-rich, plant-based foods could support a healthy gut microbiome, Dr. O’Keefe said, which has been associated with improved appetite regulation, reduced inflammation and anticancer effects.

奥基夫说，越来越多的证据还表明，富含纤维的植物性食物可以支持肠道菌群的健康，这与改善食欲、减少炎症和抗癌效果有关。

How can you increase your fiber intake?

如何增加纤维摄入量？

First, take a “low and slow” approach, Ms. Haller said. If you typically consume about 15 grams of fiber each day, for example, try increasing that to 20 grams and giving your body a week or so to adjust before adding more. Drinking plenty of water can help ease the transition. Too much fiber at once can result in bloating and gas, leaving a mistaken impression that you can’t tolerate much fiber, she said.

哈勒说，首先要采取“少而慢”的方法。打个比方，如果你一般每天的摄入量在15克左右，那么可以尝试将摄入量增加到20克，让身体有一周左右的时间来适应。多喝水有助于缓解摄入量的增加所带来的不适。她说，一次摄入过多的纤维会导致腹胀和胀气，给人留下太多纤维让人吃不消的错误印象。

You can find fiber in any whole or minimally processed plant-based foods, including legumes, whole grains, nuts, seeds, fruits and vegetables. Eating a variety of these foods will give you the benefits of the different fiber types, Dr. Whelan said.

你可以在任何天然的或最低限度加工的植物性食物中找到纤维，包括豆类、全谷物、坚果、种子、水果和蔬菜。惠兰说，多吃这些食物能让你从不同类型的纤维中获益。

12 Fiber-Rich Foods

富含纤维的食物

Ms. Haller offered ideas for quick fiber boosts: Add a half cup of beans or chickpeas to a soup or salad; swap regular pasta for whole wheat or legume-based varieties; sprinkle a tablespoon of flax or chia seeds on yogurt or in a smoothie; toss broccoli into soup or pasta; or snack on almonds, popcorn or fresh fruit.

哈勒提供了快速增加纤维的方法：在汤或沙拉中加入半杯豆类或鹰嘴豆；将普通意大利面换成全麦或豆类意面；在酸奶或冰沙上撒一汤匙亚麻籽或奇亚籽；在汤或意大利面中加入西兰花；或者以杏仁、爆米花或新鲜水果作为零食。

What about fiber supplements?

纤维补充剂如何？

If you can’t meet your fiber goals with whole foods alone, “by all means, add a supplement,” Dr. Whelan said. For the most health benefits, choose a supplement that contains several fiber types rather than just one, he suggested.

如果你仅靠天然食物无法达到纤维摄取目标，“请务必服用补充剂，”惠兰说。为了获得最大的健康益处，他建议选择含有多种纤维类型的补充剂，而非单一类型。

To address a specific concern, like constipation or high cholesterol, consult your health care provider about the most appropriate fiber supplement for you, Ms. Haller said. And know that some fiber supplements, such as psyllium, can interfere with the absorption of certain medications, so they should be taken several hours apart.

哈勒说，为了解决特定问题，例如便秘或高胆固醇，请咨询你的医生，了解最适合你的纤维补充剂。要知道，一些纤维补充剂，如车前草，可能会干扰某些药物的吸收，因此它们应该在不同时间服用。

It’s also common for people to lean more on fiber supplements as they age, Dr. Slavin said. Older adults may be more susceptible to constipation if they’re less physically active or have a more limited diet, and a daily fiber supplement can be a big help, she said.

斯莱文说，随着年龄的增长，人们也更倾向于依赖纤维补充剂。她说，如果老年人的体力活动不足或饮食比较有限，他们可能容易出现便秘，而每天补充纤维素会有很大帮助。

“If we keep our gut happy, we can be happy,” Dr. Slavin said. “And fiber is a big piece of that.”

“保持肠道健康，我们就能健康，”斯莱文说。“而纤维是其中的重要组成部分。