Fiber & Smoothies: Does Blending Destroy the Benefits? - Ask a Nutritionist

Transcript:

Alyssa: Welcome to Dishing Up Nutrition's Midweek “Ask a Nutritionist” program. If you are enjoying the show, let us know by leaving a rating and reviewing it on your favorite podcast platform. Your feedback is appreciated and helps others find the podcast.

Now onto today's show of answering a question from a fellow Dishing Up Nutrition listener. The question is all about smoothies. They asked “Is it true that when I use my Cuisinart to cut up various vegetables to put into my smoothie that I lose things such as fiber content?” This is a great question and one that I have been asked as a dietitian a handful of times over the years.

Hello, I am Alyssa, a dietitian here at Nutritional Weight & Wellness. I provide nutrition therapy counseling to clients both in person and virtually from our Eagan and St. Paul, Minnesota offices.

So eating the recommended amounts of daily vegetables and fruits is not always easy. According to the CDC, in 2019, most surveyed adults did not meet daily fruit and vegetable intake recommendations.

Specifically, only 12.3% of surveyed adults ate the recommended daily amounts of fruit, and only 10% of surveyed adults met vegetable intake recommendations. Also important to note the recommended amounts referenced in the survey were for one and a half to two cup equivalents of daily fruit and two to three cup equivalents of daily vegetables.

Smoothies: a great way to pack in nutrition

Smoothies, a blended drink with fruit and vegetables can be a quick, delicious and portable way to enjoy both vegetables and fruits, helping to boost overall daily intake of both. A smoothie can pack plenty of nutrition when you know how to make them, and they can be a whole meal, a part of a meal or a snack. Some smoothies even taste like dessert.

Blending does NOT destroy fiber & nutrients

Today's listener is specifically wondering whether the blending process destroys the fiber and other nutrients from the vegetables and fruits being added to the smoothie. The short answer is no. Blending your vegetables and fruits into a smoothie does not destroy the fiber in them. Using a blender to make a smoothie just breaks up the fiber into smaller pieces.

Benefit of blending fruits & vegetables

In some instances, like for people living with different digestive challenges, getting vegetables and fruits in the form of a smoothie can actually be an easier way to tolerate them and not have the same uncomfortable symptoms they may have if they ate those same vegetables and fruits in their whole versions.

Juicing DOES remove fiber from fruit & vegetables

Now, unlike smoothies, juicing does remove the fiber from the fruit and the vegetables. The juicing process removes the fiber contained parts, which is why if you look at the food label for a juice at the store, you'll typically not see any fiber listed.

Blending fruit and vegetables also does not have a significant impact on other nutrients either. The nutritional content of blended fruit and vegetables will be very similar to the nutritional content of the whole versions of the same fruit and vegetables. The blending process does increase the oxidation of the added plants, but that is not going to trigger a great loss of nutrients.

What is oxidation & does it affect anything negatively?

Oxidation is a chemical reaction that occurs when the inside of the fruits and vegetables are exposed to oxygen after being cut or in the case of a smoothie blended up into many tiny pieces. This often results in browning or discoloration of the smoothie. Oxidation is also the reason apple slice lists will turn brown, or the other half of your avocado that is exposed to air will turn brown over time.

The loss of nutrients by oxidation is going to be minor regardless of how long a smoothie is blended in the blender. Oxidation is important to remember, it takes time. You may notice if you make a smoothie and you do not promptly drink it, let's say maybe you put it in the fridge in the morning and you drink the smoothie later at lunch, the smoothie will become discolored over time due to the oxidation.

By lunchtime, it's not going to be the same color as it was when you first made it in the morning before work. The longer the smoothie is exposed to air, the more antioxidants it will slowly lose. For maximum nutrient density, drink or eat your smoothie in a bowl with a spoon sooner rather than later after you make it.

If you want to save time in the morning making your smoothies, try making several smoothie packs in advance. In freezer safe containers or bags assemble all your smoothie ingredients minus your liquid. Then each individually portioned smoothie pack is put back in your freezer for safekeeping. The morning of you take one of those smoothie packs, you dump the contents of your smoothie pack into your blender, and you add your liquid, blend it up and enjoy.

Several stores also offer pre-made smoothie pack options that have a mix of different fruits and vegetables pre-portioned and designed to be added to the blender with a liquid.

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Components of a great smoothie

So what exactly goes into making a great smoothie? When I build a smoothie, I think about four main components. Step one is smoothie making. Choose your liquid base. This can be water, a nut milk, cow milk, coconut milk, even coffee. It is important to consider the amount of energy, sugar, protein, and fat that's in the liquid and how it fits into your own personal energy needs.

My go-to liquid choices are either water, ultra filtered lactose free milk or plain kefir. Step two of smoothie making: choose your plants, fruits and vegetables. Frozen is great. The freezing process locks in nutrition and will eliminate the need to add ice to the smoothie, preventing a watered down smoothie.

Berries are a great fruit option. Go-to fruits at my house tend to be wild blueberries, strawberries, cherries, raspberries, pineapple and kiwi fruit. In general, berries like your raspberries are going to provide more fiber and less sugar by volume or less carbohydrates compared to most other fruits. Berries are also a rich source of antioxidant nutrients and they're delicious.

Popular vegetable options to add include veggies such as spinach, kale, cauliflower, beets, and zucchini. Something additional to consider: there is some research that shows bananas can slightly lower the absorption of some nutrients like flavonols from the berries. The difference is not a huge deal when you look at the big picture. If you want to maximize the antioxidants from your berries, you may consider skipping the banana when choosing what fruits to add to the smoothie.

Step three of that smoothie making process: add a protein source. The protein could be from a high protein milk, kefir, Greek yogurt, a protein powder such as whey protein isolate, a pea protein, collagen, egg white, or even pasteurized liquid egg whites. Flavored protein powders can add some additional taste to a smoothie. Most people wanting to have a smoothie for a meal will want to aim to get at least 25 grams or more of protein into the smoothie they're going to drink for the meal.

Step four of the smoothie making process: add fat and fiber. Having fat in the smoothie and added fiber will help to slow down digestion, keep blood sugar levels more stable, and help to keep you full longer. Fat and fiber help your smoothie be more filling.

Options I often use and recommend that contain both fat and fiber include seeds such as chia seeds, milled flax seeds, nut butters, such as peanut butter, almond butter, cashew butter, and avocados. It's important to be mindful of portions and remember what your individual needs are.

Usually I aim to have around eight to 10 grams of fiber in a smoothie meant for a meal and between about 14 to 20 grams of fat if it's going to be for a meal. But that's based on my own personal needs, and it'll vary depending on who I'm working with and what their energy needs are.

Avocados are a great option in smoothies providing beneficial monounsaturated fats, fiber, and heart healthy nutrients like magnesium and potassium. Avocados are also not very strong in flavor when added to a smoothie and can add some creaminess to the smoothie, especially if you're just using water for your liquid and you're not having any other creamy ingredients.

You can enjoy your smoothie from a cup or try a smoothie bowl and enjoy the smoothie with a spoon. For a smoothie bowl, add a little less liquid so you have a thicker consistency in your smoothie. And then consider adding a few extra toppings for added flavors and textures and nutrition. Popular smoothie bowl toppings I often think about are those seeds like the chia seeds, hemp hearts, sunflower or pumpkin seeds and chopped nuts like walnuts, pecans, or slivered almonds.

Following those four steps, you can assemble a smoothie in limitless ways. You can create and enjoy tasty smoothies for a meal, as part of a meal, for a snack or as a dessert, maybe even try freezing a smoothie into popsicle trays. That can taste really delicious and refreshing in the summer.

Bottom line: blending vegetables and fruit into a smoothie is a convenient and tasty way to boost your intake of both vegetables and fruit. The blending process does not destroy the fiber found in the vegetables and the fruit. If you enjoy a smoothie, you can have one every day. Be mindful of portions to make sure the smoothie meets your energy and nutritional needs.

If you're not sure what you need, it's great to meet with a nutritionist such as myself or one of my colleagues at Nutritional Weight & Wellness. Thank you to the listener who asked today's question, and thank you for listening today to Dishing Up Nutrition's “Ask a Nutritionist”.

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