If I blend fruits and vegetables to make a smoothie, do they lose nutrients or fiber?
A freshly made fruit smoothie ticks a lot of boxes: It’s quick, easy to consume, and can make a versatile base for whatever you have on hand.
If churning your produce helps you eat more, it’s a good thing, says Kristina Petersen, associate professor of nutritional sciences at Pennsylvania State University. According to research conducted between 2017 and 2018, 86% of adults in the United States did not consume the recommended 4.5 cups of fruits and vegetables per day.
But are nutrients lost when fruits and vegetables are cut and blended in a blender? We asked experts to help us explain, so you can get the most out of your shake.
How the blender affects nutrients
Unlike juice, a shake can incorporate all of the edible parts of fruits and vegetables — including the skin, seeds and pulp — so the drink can be nutritionally very similar to eating the whole product, says Mary Ann Lila, professor of nutrition. , bioprocessing, and nutritional sciences at North Carolina State University.
And the beating action should not degrade the vitamins or minerals found in fruits and vegetables, points out Lila. Nor will it immediately harm certain antioxidant and anti-inflammatory compounds, such as anthocyanins and flavonols, according to her.
Fruits and vegetables are also good sources of fiber, which most people should eat more of. And whether you eat a whole apple or a smoothie, “you get exactly the same amount of fibre,” says Balazs Bajka, an intestinal physiologist at King’s College London.
Processing, however, breaks the fiber into smaller pieces, which will affect how it passes through the digestive system, he says. Some types of fiber, when cut into pieces, can disperse more quickly in the gut and slow down digestion and absorption — generally a good thing — while others can lose some of the “bulky” effect that keeps things moving along in the digestive tract. and prevents constipation.
But there isn’t much research on this subject, Bajka points out, and the specific effects may depend on the person and the fruit or vegetable. Regardless, “eating any type of fiber is good,” he says.
How whipped fruit affects blood sugar
Processing food often disrupts its natural structure, which can lead to faster digestion and absorption. So it’s reasonable to question whether pureed fruit can cause a greater rise in blood sugar, says Anthony Fardet, a nutritional scientist at the National Research Institute for Agriculture, Food and the Environment in France.
In a few small studies that measured adults’ blood sugar after consuming blended or whole fruit, researchers found reassuring results. Mango preparation style, for example, appears to make no difference in blood sugar response. And when researchers tested smoothies containing fruit with seeds, such as passion fruit, raspberry or kiwi, participants experienced more gradual increases in blood sugar than when they ate the same fruit 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 grinding the seeds of the fruit in a blender might release some fiber, protein and fat, which may slow nutrient absorption and cause a more gradual rise in blood sugar.
That said, liquid meals are generally less satiating than those made up of solid foods, points out Fardet. It’s not clear why this happens, but it can result in a desire to consume more or leave you wanting a snack sooner.
Tips for more nutritious smoothies
In addition to the fruits and vegetables you use in your shakes, other ingredients also affect their nutritional value, says Petersen. Water is a good liquid base if you want a light snack. For a more balanced and satisfying shake, low-fat, skim milk, unsweetened yogurt, kefir or fortified plant-based milks can provide protein, calcium and vitamin D, she adds.
“Throw some nuts in there” or avocado, suggests Lila. Both provide healthy fats and fiber, just like chia or flaxseed. Whole grains like corn or rolled oats are also good sources of fiber.
Smoothies also offer a good opportunity to use frozen products, which are generally just as nutritious as fresh, says Lila. She recommends storing frozen fruits and vegetables in the back of the freezer to minimize the slight thawing and refreezing that can cause nutrient loss when you open the freezer door.
Finally, keep in mind that once the fruit is mixed, its healthy compounds gradually become less stable, says Lila. Yesterday’s shake that separated and turned a little gray has probably lost some of its antioxidant and anti-inflammatory value. For the same reason, industrial shakes may not be as beneficial, she adds, and they often also contain added sugars.
In other words, says Lila, enjoy your shake — but make it and drink it right away.
Translated by Luiz Roberto M. Gonçalves
