“Does blending a green smoothie destroy the fiber in whole fruits and greens? Should I add a fiber supplement to my smoothies to get extra fiber?” – Amy
Blending does not destroy fiber. A high-speed, professional blender might break it down, but you don’t get less fiber in a blended smoothie than you would if you ate the whole fruit. If anything, you are more likely to enhance nutrient absorption and speed up digestion. The fiber will still be in there to provide its health benefits.
Juicing, on the other hand, removes fiber. Because of this, I don’t recommend long-term juice fasts or juice diets. I also don’t recommend drinking lots of juice every day (especially fruit juice) since fiber is such an important part of a healthy diet. Consuming adequate dietary fiber has been associated with better health, proper bowel function and the evidence suggests that adequate fiber intake may help protect against colon cancer.
Green Smoothies Have Enough Fiber Already
As far as adding a fiber supplement to a green smoothie, I advise against doing this for a couple reasons.
First of all, a green smoothie provides a rich source of soluble (in the “flesh” part of a fruit) and insoluble (usually in the peel or skin) fiber. In general, people should get at least 14 grams of fiber per 1,000 calories consumed. If you eat a 2,000 calorie diet, you should aim for getting at least 28 grams of fiber per day.
A simple green smoothie made with one medium banana, one medium pear, four large strawberries and two cups of fresh spinach will contain about 12 grams of fiber (245 calories, about 16-18 ounces). That’s almost 50% of the recommended daily intake of fiber in just one green smoothie!
A plant-based, whole foods diet will provide ample fiber without the need to supplement. Obtaining fiber from whole foods like fresh fruits and vegetables is, in my opinion, much better than taking an extracted, isolated fiber supplement since you are also getting important vitamins, minerals and antioxidants as well.
The Problem With Excess Fiber
Secondly, a possible negative with adding a fiber supplement to an already fiber-rich green smoothie is that you could be taking too much fiber. Excess fiber consumption may lead to mineral loss. It may also lead to constipation, digestive discomfort, gas, bloating and other problems.
Excess fiber consumption is unlikely from food sources, but can happen when supplemented. As with most nutrients, it is always best and safest to take them in the form nature provides – whole, fresh foods. Green smoothies are an excellent source of dietary fiber.