译者：因为担心水果冰沙里面的纤维素被破坏，以及果糖造成血糖飙升，我很久不敢喝水果冰沙了。

水果冰沙会影响其营养成分吗？（双语）

我们为冰沙爱好者带来了好消息和一些建议。

爱丽丝·卡拉汉

2023 年 8 月 29 日

问：如果我将水果和蔬菜做成冰沙，它们会失去营养或纤维吗？

新鲜冰沙有很多优点：它可以快速得到，易于食用，并且是你手头上任何水果和蔬菜的“大杂烩”（a versatile base for whatever fruits and veggies you have on hand）。

宾夕法尼亚州立大学营养科学副教授克里斯蒂娜·彼得森说，如果农产品冰沙可以帮助你吃更多（蔬菜），那是一件好事。 根据 2017 年至 2018 年进行的调查，86% 的美国成年人没有每天摄入建议的 4.5 杯水果和蔬菜。

但是，当水果和蔬菜被搅拌机刀片切成小碎块时，营养会损失吗？ 我们请专家来帮助解释，以便你可以充分利用你的冰沙。

混合（机刀片）如何影响营养成分。

与榨汁不同，混合（机刀片）可以融合水果和蔬菜的所有可食用部分，包括果皮、种子和果肉，因此冰沙在营养上与直接食用整个农产品非常相似，北卡罗来纳州立大学食品、生物加工和营养科学专业教授玛丽·安·莉拉 (Mary Ann Lila，food, bioprocessing and nutrition sciences at North Carolina State University.) 说。 

莉拉博士说，混合（机刀片）不应降低水果和蔬菜中的维生素或矿物质。 她说，它也不会立即损害某些抗氧化剂和抗炎化合物，例如花青素和黄酮醇。

水果和蔬菜也是纤维的良好来源，我们大多数人都可以通过多摄入纤维受益。 伦敦国王学院的肠道生理学家巴拉兹·巴伊卡 (Balazs Bajka) 说，无论你吃整个苹果还是作为冰沙的一部分，“你摄入的纤维量都是完全相同的”。

然而，混合（机刀片）确实会将纤维分解成更小的碎片，这会影响它们通过消化系统的方式，他说。 某些类型的纤维，当切成小块时，可能会在肠道内更快地分散，并减缓消化和吸收——通常是一件好事——而其他类型的纤维可能会失去一些“粗粮”作用，而这种“粗粮”作用可以使食物在消化道中移动并防止便秘 。

但巴伊卡博士说，关于这方面的研究并不多，具体效果可能取决于人和水果或蔬菜。 无论如何，“吃任何种类的纤维都是好的，”他说。

混合水果如何影响血糖。

加工食物通常会破坏其自然结构，从而加快消化和吸收。 法国国家农业、食品和环境研究所的营养科学家安东尼·法代特说，因此有理由怀疑将水果制成水果泥是否会导致血糖升高。

但在一些测量成年人食用混合水果或整个水果后血糖的小型研究中，研究人员发现了令人放心的结果。 例如，芒果的制备方式似乎对血糖反应没有影响。 当研究人员测试含有西番莲果、覆盆子或猕猴桃等带籽水果的冰沙时，参与者的血糖比直接吃相同水果时的升高更缓慢。

这一结果令英国普利茅斯大学人类营养学高级讲师盖尔·里斯 (Gail Rees) 感到惊讶，他领导了其中两项研究。 她推测，在混合机中捣碎水果种子可能会释放一些纤维、蛋白质和脂肪，这可能会减缓营养吸收并导致血糖逐渐升高。

法德特博士说，尽管如此，流质食物通常比固体食物更没有饱腹感——目前还不清楚为什么会这样，但它可能会导致你想吃更多东西，或者可能会让你更快地想吃零食。

最有营养的冰沙的秘诀。

彼得森博士说，除了冰沙中使用的水果和蔬菜之外，其他成分也会影响它们的营养价值。 如果你想吃点小吃，水是一种很好的液体。 她补充说，为了制作更均衡、更饱腹的冰沙，低脂或无脂牛奶或不加糖酸奶、开菲尔或强化植物奶（kefir or fortified plant-based milks ）可以提供蛋白质、钙和维生素 D。

“放入一些坚果”，或者鳄梨，莉拉博士建议。 两者都提供健康的脂肪和纤维，奇亚籽或亚麻籽也是如此； 小米或燕麦片等全谷物也是很好的纤维来源。

莉拉博士说，冰沙还提供了使用冷冻产品的绝佳机会，冷冻产品通常与新鲜产品一样有营养。 她建议将冷冻水果和蔬菜存放在冰箱的后面，以尽量减少打开冰箱门时可能导致营养损失的轻微解冻和重新冷冻。

最后，请记住，一旦水果被混合成为冰沙，其有益健康的化合物就会逐渐变得不稳定，莉拉博士说。 她说，昨天的冰沙已经分离并变得有点灰色，可能已经失去了一些抗氧化和抗炎的价值。 她补充说，出于同样的原因，预包装的冰沙可能没有那么有益，而且它们通常还含有添加糖。

换句话，莉拉博士说，享受你的冰沙——但要新鲜并马上喝掉。

Does Blending Fruit in a Smoothie Affect Its Nutrients?

We have good news and a little advice for smoothie lovers.

By Alice Callahan

Aug. 29, 2023

Q: If I blend fruits and vegetables into a smoothie, do they lose nutrients or fiber?

A freshly blended smoothie ticks a lot of boxes: It’s quick to prepare, easy to consume and a versatile base for whatever fruits and veggies you have on hand.

And if blending your produce can help you eat more of it, that’s a good thing, said Kristina Petersen, an associate professor of nutritional sciences at Pennsylvania State University. According to surveys performed between 2017 and 2018, 86 percent of adults in the United States didn’t get the recommended 4.5 cups of fruits and vegetables each day.

But are nutrients lost when fruits and vegetables are chopped into bits by a blender blade? We asked experts to help us break it down so you can get the most out of your smoothie.

How blending affects nutrients.

Unlike juicing, blending can incorporate all of the edible parts of fruits and vegetables — including the skin, seeds and pulp — so a smoothie can be nutritionally very similar to eating the produce whole, said Mary Ann Lila, a professor of food, bioprocessing and nutrition sciences at North Carolina State University.

And blending shouldn’t degrade the vitamins or minerals found in fruits and vegetables, Dr. Lila said. Nor will it immediately harm certain antioxidant and anti-inflammatory compounds, like anthocyanins and flavonols, she said.

Fruits and vegetables are also good sources of fiber, which most of us could benefit from eating more of. And whether you eat an apple whole or as part of a smoothie, “you’ve consumed exactly the same amount of fiber,” said Balazs Bajka, a gut physiologist at King’s College London.

Blending does, however, break the fibers into smaller pieces, which will affect how they move through your digestive system, he said. Some types of fibers, when chopped into bits, may disperse more quickly within your gut and slow digestion and absorption — usually a good thing — while others might lose some of the “roughage” effect that keeps things moving in your digestive tract and prevents constipation.

But there’s not much research on this topic, Dr. Bajka said, and specific effects may depend on the person and the fruit or vegetable. Regardless, “eating any kind of fiber is good,” he said.

How blended fruit affects blood sugar.

Processing food often disrupts its natural structure, which can lead to faster digestion and absorption. So it’s reasonable to wonder if puréeing fruit could cause a bigger spike of blood sugar, said Anthony Fardet, a nutrition scientist at the National Research Institute for Agriculture, Food and the Environment in France.

But in a few small studies that measured adults’ blood sugars after they consumed fruit blended or whole, researchers have found reassuring results. The preparation style of mango, for instance, seemed to make no difference in blood sugar response. And when researchers tested smoothies containing seeded fruits like passion fruit, raspberries or kiwi fruit, participants had more gradual rises in blood sugars than when they ate the same fruits whole.

That result surprised Gail Rees, a senior lecturer in human nutrition at the University of Plymouth in Britain who led two of the studies. She hypothesized that mashing up the fruits’ seeds in the blender might release some fiber, protein and fat, which could slow nutrient absorption and cause a more gradual rise in blood sugars.

That said, liquid meals are generally less satiating than those composed of solid foods, Dr. Fardet said — it’s not clear why this is, but it may result in a desire to consume more, or it may leave you hungry for a snack sooner.

Tips for the most nutritious smoothies.

Beyond the fruits and vegetables you use in your smoothies, other ingredients also affect their nutritional value, Dr. Petersen said. Water is a good liquid base if you’re aiming for a light snack. For a more balanced and filling smoothie, low-fat or fat-free dairy milk or unsweetened yogurt, kefir or fortified plant-based milks can provide protein, calcium and vitamin D, she added.

“Throw some nuts in there,” or avocado, Dr. Lila suggested. Both provide healthy fats and fiber, as do chia or flax seeds; whole grains like millet or rolled oats are good fiber sources, too.

Smoothies also provide a great opportunity to use frozen produce, which is generally just as nutritious as when it is fresh, Dr. Lila said. She recommended storing frozen fruits and vegetables at the back of your freezer to minimize the slight thawing and refreezing that can cause nutrient losses when you open your freezer door.

Finally, keep in mind that once fruit is blended, its healthful compounds gradually become less stable, Dr. Lila said. Yesterday’s smoothie that has separated and turned a bit gray has probably lost some of its antioxidant and anti-inflammatory value, she said. For the same reason, prepackaged smoothies may not be as beneficial, she added, and they also often contain added sugars.

In other words, Dr. Lila said, enjoy your smoothie — but make it fresh and drink it right away.