Does Blending Destroy Fiber & Nutrients?
You may have heard that blending fruits and veggies—as you would when making a smoothie—destroys their fiber and may impact other nutrients in these nutritious foods as well. So, does blending destroy fiber and other nutrients?
First, what is fiber?
Fiber is a type of carbohydrate found in plant-based foods like fruits, veggies, legumes, and whole grains. In fact, plant-based foods are the only foods that naturally contain fiber.
Unlike with protein, fat, and the other carbohydrate types (sugars and starches), your body can’t break down fiber and (directly) use it for energy because you don’t have the digestive enzymes needed to do so. Instead, fiber works its magic by sliding through your gut relatively intact but not unnoticed.
Fiber is the MVP of carbs, and getting more of it into your diet can help:
- Lower cholesterol
- Stabilize blood sugar levels
- Keep you regular
- Support gut health
- Support weight loss
- …and more!
Wondering how to get more fiber in your diet? Check out these 10 Easy Ways to Sneak Fiber into Your Diet! And spoiler, sipping on smoothie is one of the ten ideas!
Does blending destroy fiber?
Fiber is one tough cookie. If it can pass through the digestive tract relatively unphased and withstand your molars and digestive enzymes, 20 seconds of being roughed up by blender blades won’t “destroy” it. So, no, blending your fruits and veggies into a smoothie will not “destroy” their fiber.
But does blending impact the fiber structure in any way? Well, fine grinding of other plant foods has been shown to impact the particle size of fibers. One study found that grinding of wheat bran and oat bran reduced the particle sizes of the fibers in them and ultimately changed their functional properties—wheat bran’s water-holding capacities decreased, whereas oat bran’s increased. These changes would likely impact their physiological effects (e.g., stool-bulking abilities and effects on gastric emptying) when consumed.
But again, we’re talking fine grinding of grains here. Is that 20 to 30 seconds in your blender going to greatly impact the properties of the fiber in the fruits and veggies you blend in your smoothies? Probably not.
So, do smoothies have fiber?
Blending is essentially just taking care of that first step of the digestion process, chewing, for you. And it’s certainly not destroying that fiber and leaving you with a fiber-less smoothie. And the little research we do have on commercially-processed smoothies supports this, showing that cell wall structures and fiber are largely preserved after processing.
That said, depending on the fruits you use in your smoothies, blending could actually release some fiber, making it more available to the body. (That’s a good thing).
Does blending fruit make it less healthy?
Here’s where things get really interesting. Studies have found that consuming fruits with seeds that aren’t de-seeded prior to blending, such as raspberries, blackberries, and passionfruit, in blended form yields a lower glycemic response (blood sugar response) than consuming these fruits in their whole form. The authors hypothesized this could be the result of fiber (and, to a lesser extent, fat, protein, and other phytonutrients) being released from the seeds when blended, whereas most seeds remain intact when these fruits are consumed whole.
This theory is supported by a separate study that tested the glycemic responses to a mixed fruit smoothie (raspberries, passionfruit, kiwi, pineapple, mango, and banana) and a mango smoothie versus their whole fruit counterparts. They found a lowering of the glycemic response for the mixed fruit smoothie, compared with the same fruit consumed whole. However, for mango—which, other than its large, removable pit, is seedless—there was no difference in the glycemic response when consumed in smoothie form versus whole.
Bottom line: At-home blending of fruits for smoothies likely has little to no effect on fruit pulp fiber but may ‘grind’ some of the seeds in seed-containing fruits (if used), thus releasing more fiber and making it more available to your body (a good thing)! Ultimately, there is no evidence that blending fruit makes it less healthy. In the case of seed-containing fruits, it may make it more nutritious.
Does blending destroy nutrients?
We now know the answer to the question ‘Does blending destroy fiber?’ is a big no, but what about other nutrients, like vitamins, minerals, and phytonutrients? Does blending destroy nutrients in any way? You may have heard that when blending fruits and veggies, a significant amount of nutrients is lost to oxidation.
Since oxidation occurs when fruits and vegetables are cut and exposed to oxygen, it’s thought that process of blending greatly increases oxidation and therefore greatly increases nutrient loss. But here’s the thing, oxidation takes time. Even if it takes you 15 to 20 minutes to gulp down that smoothie, nutrient losses via oxidation will be minimal.
Does blending unlock nutrients?
You may have also heard the opposite, that blending “unlocks” nutrients, increasing their bioavailability. Popular high-powered blender companies like Vitamix and Nutribullet used to use this messaging in their marketing! In fact, Vitamix used to advertise a “breakthrough” study, which they funded back in 2008, on their website, claiming it found that the high-powered blender had the ability to “disrupt plant cell wall structure and significantly reduce food particle size” which could “enhance the bioavailability of essential nutrients in fruits and vegetables”. The study was never published…
What little research we do have on smoothies suggests cell wall structures are mostly preserved during blending. However, as mentioned above, blending could “unlock” some of the nutrients in the seeds of seed-containing fruits.
Some studies have shown that other, more intense processing methods, like juicing, may make some nutrients more available for absorption. For example, juicing certain vegetables may increase bioavailability of beta-carotene. But this is at least partly due to the removal of fiber, the presence of which can reduce the absorption of carotenoids. Any small increases in the bioavailability of certain micronutrients are probably not worth sacrificing the health benefits of fiber. While you can certainly include fruit juices in the diet, we recommend choosing whole fruits or healthy smoothies over juices for the most part.
Are smoothies healthy?
Absolutely! Smoothies are one of the easiest and most convenient ways to get a hefty daily dose of weight-loss-supporting nutrients, like fiber, protein, vitamins, minerals, and other phytonutrients. Plus, they’re (typically) a healthier, more nutrient-dense alternative to the standard American breakfast—you know, Pop-Tarts, donuts, and bacon, egg, and cheese, breakfast sandwiches.
One study found that offering fruit smoothies as part of a school breakfast program amongst middle and high school children increased the proportion of students eating a full serving of whole fruit from 4.3% to 45.1% over a 10-week period. These findings support the idea that smoothies can help individuals dramatically increase their whole fruit intake. And, despite what you may have heard about fruit on social media, research has consistently shown that fruit intake has an anti-obesity effect.
How to make a high-fiber smoothie
We know that smoothies retain the fiber from their whole counterparts, but it can’t hurt to add a little extra fiber for satiating and blood sugar-stabilizing power! To up the fiber content of your smoothies, add one or two of the following:
- Chia seeds, hemp seeds, or ground flaxseed
- Nut or seed butters, like almond, peanut, cashew, or sunflower seed butters, or tahini
Want to know our secret formula for how to make healthy weight loss smoothies plus 5 recipes for the best smoothies for weight loss? Check out our Ultimate Weight Loss Smoothies Guide!
Does blending destroy fiber and nutrients? No. Does blending fruit make it less healthy? Also no. Blended fruits and veggies are nutritionally comparable to their whole counterparts. So, if making a smoothie helps you get more produce into your day, then by all means continue doing so!
That said, smoothies may be a little less satiating than their whole counterparts. You consume a smoothie at a much faster rate than if you were chewing the whole fruits and vegetables they’re made of, and both the rate of ingestion and act of chewing may impact satiety. So, try not to gulp down your smoothie too quickly, and be sure to incorporate produce in its whole form in the diet, too.
Well, this is the way to say it. Eat it when possible, but it also doesn’t hurt to gulp it if it fits into the routine easily, as neither doesn’t really hurt. You might get something good into your diet instead of skipping it altogether by considering all the other things studies say to eat only the fruit, just the whole fruit.
And yes, still keeping in the mind to only consider buying or making fresh smoothies instead of something being stocked in shelves waiting for days or weeks, or even months.