Blending food into smoothies, juices, and other blended drinks has become increasingly popular in recent years. While there are certainly some benefits to blending fruits and vegetables, there are also some potential downsides to consider.
Loss of Fiber
One of the main negatives of blending is that it can significantly reduce the fiber content of foods. Fiber is an important nutrient that promotes gut health and helps you feel full. When you blend fruits and veggies into smoothies, you break down the plant’s cell walls, releasing the sugars but often removing much of the fiber.
For example, a whole apple with skin contains about 5 grams of fiber. But when you blend it into a smoothie, the resulting beverage has less than 1 gram of fiber. The same goes for blending vegetables like spinach and kale.
| Food | Fiber when whole | Fiber when blended |
|---|---|---|
| Apple with skin | 5 g | 0.5 g |
| Spinach | 2 g per cup | 0.5 g per cup |
| Kale | 3 g per cup | 1 g per cup |
To get the benefits of fiber, it’s best to eat whole fruits and vegetables or add extra high-fiber ingredients like chia seeds, flaxseed, or psyllium husk to your smoothies.
Potential Loss of Vitamins
In addition to fiber, some vitamins and minerals can be degraded and lost during the blending process.
Vitamin C and folate are water-soluble vitamins that can leach out of fruits and vegetables when blended in liquid. The breakdown of plant cell walls also makes these vitamins more susceptible to damage from heat, light, and air.
One study found that up to 51% of vitamin C was lost from spinach when blended into a smoothie compared to whole spinach leaves. Other antioxidants like vitamin E and polyphenols can also degrade when exposed to heat and oxygen.
To limit nutrient loss, try adding the blending liquid and any supplements or powders just before blending rather than making smoothies in advance. Minimize blending time and make sure your blender has a tight fitting lid to reduce oxidation.
High Glycemic Index
Since blending breaks down fiber and plant cell walls, it causes the sugars in fruits and veggies to be absorbed faster and can lead to rapid spikes in blood sugar levels.
For example, a whole apple has a glycemic index (GI) of about 40, while apple juice has a GI of 40. Blends and juices made from higher sugar fruits like mangos, bananas, and pineapples can have an even greater impact on blood sugar.
This is especially important for people with diabetes or prediabetes who need to control their blood sugar response. It’s best to focus on smoothies made with low glycemic fruits and non-starchy vegetables and limit added sugars from juices, agave, honey, etc. Adding protein, fat, and fiber can also help blunt the glycemic response.
| Food | Glycemic Index (GI) when whole | GI when juiced/blended |
|---|---|---|
| Apple | 40 | 44 |
| Grapes | 43 | 59 |
| Orange | 42 | 57 |
| Mango | 51 | 67 |
Potential For Acrylamide Formation
Acrylamide is a potentially carcinogenic compound that can form in certain foods during high-temperature cooking, such as frying and baking. There is also some evidence that acrylamide can form in plant foods during other processing methods like juicing, blending, and grating.
Acrylamide forms when the amino acid asparagine reacts with natural sugars like glucose and fructose at temperatures above 120°C (248°F). Blending can create the perfect storm for acrylamide formation by breaking down cell walls to free up sugars and amino acids while exposing the ingredients to heat and friction.
One study detected acrylamide in several blended drinks made from raw kale, spinach, and other ingredients. While the acrylamide levels were relatively low, it shows the potential is there under certain blending conditions.
To limit acrylamide, avoid overheating blends and don’t blend ingredients that have already been heated. Allow smoothies and blends to sit for a few minutes before consuming to allow heat from the blending process to dissipate.
Potential Loss of Beneficial Compounds
In addition to vitamins and minerals, fruits and vegetables contain a wide array of beneficial plant compounds like antioxidants and polyphenols. These compounds are sensitive to heat, light, and oxygen. Blending can degrade and destroy some of these healthy compounds over time.
For example, a study making blended carrot juice found that more than 50% of total phenolic compounds were lost after 15 minutes of blending. The researchers also found blending had a negative effect on antioxidant activity compared to whole carrots.
Other research shows that the longer blending time, the greater the degradation of beneficial plant compounds. To preserve nutrients, blend only until smooth rather than for extended periods. Consume blends as soon as possible rather than letting them sit for hours before drinking.
Higher Calorie Intake
Blending makes it very easy to consume a large number of calories very quickly. For example, many blended fruit smoothies contain 300-500 calories per 16-24 ounces. While these calories are from natural fruits, it’s very easy to overdo it when you can down a 500 calorie blended drink in just a couple of minutes.
Portion control is key – be mindful of serving sizes when making high-calorie blends and smoothies. Focus on adding low-calorie ingredients like leafy greens and cucumbers rather than just high-sugar fruits. Don’t mindlessly sip on blends all day long. Drinking calories requires less chewing and provides less satiety compared to eating whole foods.
Potential For Contamination
Improper handling of ingredients when making blended drinks can increase the risk of contamination leading to food borne illness. Fresh produce often carries harmful bacteria like Salmonella and E. coli. If ingredients aren’t washed properly, bacteria can transfer to the blades and container of your blender.
Always wash produce thoroughly before blending. Be diligent about cleaning your blender according to manufacturer guidelines after each use. Don’t allow ingredients or leftover smoothies to sit at room temperature for more than 2 hours.
Pre-cut fruits and greens like pre-washed lettuce can harbor even more bacteria. When possible, opt for whole produce rather than pre-cut to reduce risks.
Higher Cost
Blending fruits and veggies into smoothies and juices takes more raw ingredients compared to eating them whole or cooking them. You might go through 5-6 apples to make a 16 ounce apple smoothie compared to just eating one whole apple.
This can raise the cost of your grocery bill, especially if you rely on pricey pre-cut produce. Blending leafy greens like kale and spinach can be pricier than cooking them. You also have to account for the initial investment in a quality blender if you don’t already own one.
To save money, buy whole fruits and vegetables on sale and freeze what you don’t use immediately. Taking a little extra time to prep whole ingredients rather than relying on costly pre-cut produce also helps.
Conclusion
Blending can be a nutritious and convenient way to increase your intake of fruits and vegetables. However, there are some potential downsides to blending that need to be considered.
To maximize nutrition and minimize risks when blending:
-Focus on whole fruits and vegetables rather than juices or pre-cut produce
-Don’t over-blend ingredients as extended blending times degrade nutrients
-Add healthy fats, protein, and extra fiber to blends
-Portion control is key – blends still contain calories.
-Always practice food safety – wash produce and clean blender properly after each use
As with any food, moderation and variety is key. Rotate blended drinks with whole fruits and veggies as well as cooked dishes to get the best nutritional balance. Be mindful of portion sizes and ingredients used. When done properly and in moderation, blending can be a healthy addition to your diet.
