Fruits and vegetables are good for your health.
Some of them even reduce your risk of chronic diseases, such as heart disease and cancer (
Juicing, a process that involves extracting the nutritious juices from fresh fruits and vegetables, has become increasingly popular in recent years.
Many people use it to detox or add more nutrients to their diet.
Supporters claim that juicing can improve nutrient absorption from fruits and vegetables, while others say it strips away their important nutrients like fiber.
This is a detailed review of juicing and its health effects — both good and bad.
Juicing is a process that extracts the juices from fresh fruits and vegetables.
It usually strips away most of the solid matter, including the seeds and pulp, from whole fruits and vegetables.
The resulting liquid contains most of the vitamins, minerals, and antioxidants naturally present in the whole fruit or vegetable.
Juicing methods vary, from squeezing fruit by hand to motor-driven juicers.
Two common types of juicers include:
- Centrifugal. These juicers grind fruits and vegetables into pulp through a high-speed spinning action with a cutting blade. The spinning also separates the juice from the solids.
- Cold-press. Also called masticating juicers, these crush and press fruits and vegetables much more slowly to obtain as much juice as possible.
The nutritional quality of juice obtained from centrifugal and cold-press juicers is similar (
Purpose of juicing
Juicing is generally used for two purposes:
- Cleansing or detoxification: Solid food is eliminated and only juice is consumed for 3 days to several weeks. Some people believe drinking juice cleanses their bodies of toxins. However, no evidence supports its effectiveness.
- Supplementing a normal diet: Fresh juice can be used as a handy supplement to your daily diet, increasing nutrient intake from fruits and vegetables that you wouldn't otherwise consume.
Summary Juicing involves extracting and drinking the juice from fresh fruits and vegetables. Some people do this to detox, while others do it to supplement their current diet.
Many people don't obtain enough nutrients from their diet alone (
Nutrient levels in the foods you eat are also much lower than they used to be.
Polluted environments and high stress levels can also increase your requirements for certain nutrients.
If you find it difficult to get the recommended amount of fruits and vegetables into your diet each day, juicing can be a convenient way to increase your intake.
Furthermore, a review of 22 studies found that drinking juice made from fresh fruits and vegetables or blended powder concentrate improved folate and antioxidant levels, including beta carotene, vitamin C, and vitamin E (
Summary If you struggle to eat enough fruits and vegetables each day, juicing is a convenient way to get a wide range of important nutrients.
Plenty of evidence links whole fruits and vegetables to a reduced risk of disease, but studies on fruit and vegetable juices are harder to find.
The health benefits of fruits and vegetables are partly due to their high antioxidant content, but fiber also plays an important role. Many antioxidants are bound to fiber and get released in your digestive system (
A high intake of fruits and vegetables shows promise in many areas of health. For example, juices may reduce your risk of heart disease. Apple and pomegranate juices have been linked to reduced blood pressure and cholesterol levels (
Additionally, consuming fruit and vegetable juices in liquid form (or blended concentrations) may reduce homocysteine levels and markers of oxidative stress, both of which are linked to improved heart health (
One large study observed a reduced risk of Alzheimer's disease among those who drank fruit and vegetable juices three or more times per week, compared with those who drank them less than once per week (
The reduction in Alzheimer's risk may be due to the high levels of polyphenols in the juices. These are antioxidants found in plant foods and believed to protect brain cells.
Despite these results, more studies are needed to better understand the health effects of fruit and vegetable juices (
Summary Limited evidence links fruit and vegetable juice to a reduced risk of diseases like cancer, Alzheimer's, and heart disease.
Juicing advocates often claim that drinking juice is better than eating whole fruits and vegetables.
They assert that removing the fiber makes nutrients easier to absorb.
However, there isn't any scientific research to support this.
In fact, you may need the fiber content of the fruit or vegetable to experience the plant's full health benefits (
For example, the antioxidants that are naturally bound to plant fibers are lost during the juicing process. They may play an important role in the health benefits of whole fruits and vegetables (15,
Notably, up to 90% of fiber is removed during the juicing process, depending on the juicer. Some soluble fiber will remain, but the majority of insoluble fiber is removed.
Potential health benefits of fiber
One study compared eating whole apples to drinking apple juice. It found that drinking clear apple juice increased LDL (bad) cholesterol levels by 6.9%, compared with eating whole apples. This effect is thought to be due to the fiber content of whole apples (
What’s more, an observational study showed an increased risk of type 2 diabetes in people who consumed fruit juices, whereas whole fruits were linked to a reduced risk (
One study compared the effects of blending and juicing on the nutrient content of grapefruit. Results showed that blending, which retains more fiber, is a better technique for obtaining higher levels of beneficial plant compounds (
Should you add fiber to your juices?
The level of fiber in your juices will depend on what type of juicer you use, but some sources suggest adding leftover pulp to other foods or drinks to increase fiber intake.
Although this is better than throwing the fiber away, evidence suggests that re-adding fiber to juice doesn't give you the same health benefits as simply eating whole fruits and vegetables (
Additionally, a study found that adding naturally occurring levels of fiber to juice did not enhance feelings of fullness (
Summary Eating whole fruits and vegetables is better for your health. Juicing causes you to miss out on beneficial fiber and antioxidants.
Many people use juicing as a weight loss strategy.
Most juice diets involve consuming 600–1,000 calories per day from juices only, resulting in a severe calorie deficit and fast weight loss.
However, this is very difficult to sustain for more than a few days.
While juice diets may help you lose weight in the short term, such a severe calorie restriction can slow your metabolism in the long term (
Juice diets are also likely to lead to nutrient deficiencies in the long term, as juices lack many important nutrients.
Summary Most juicing diets involve severe calorie restriction, which is generally unsustainable in the long term and can lead to a slower metabolism.
Using juices as a meal replacement can be bad for your body.
This is because juice on its own is not nutritionally balanced, as it does not contain sufficient protein or fat.
Consuming enough protein throughout the day is necessary for muscle maintenance and long-term health (
Additionally, healthy fats are important for sustained energy, hormone balance, and cell membranes. They may also provide the fat-soluble vitamins — vitamins A, D, E, and K.
That said, replacing one meal per day with juice is unlikely to cause harm, as long as the rest of your diet is more balanced.
You can make your juice more nutritionally balanced by adding protein and healthy fats. Some good sources are whey protein, almond milk, avocados, Greek yogurt, and peanut butter.
Summary Juices are nutritionally unbalanced because they do not contain adequate amounts of protein or fat. Adding protein and fat sources to your juices can help with this.
Regularly consuming high amounts of fruit juice has been associated with an increased risk of metabolic syndrome and obesity (
In addition, there is no evidence that your body needs to be detoxified by eliminating solid food.
Your body is designed to remove toxins on its own, using the liver and kidneys.
Furthermore, if you're juicing with non-organic vegetables, you can end up consuming other toxins that come along with them, such as pesticides.
More extreme juice cleanses are associated with negative side effects, including diarrhea, nausea, dizziness, and fatigue.
Summary There is no evidence that juice cleanses are necessary for detoxifying the body. Also, juicing may harm people who have kidney problems or take certain medications.
What you choose to juice matters, and fruits contain much more sugar than vegetables.
About 3.9 ounces (114 ml) of 100% apple juice contains almost zero grams of fiber but packs 13 grams of sugar and 60 calories (
Similarly, 100% grape juice has 20 grams of sugar in a 3.9-ounce (114-ml) serving.
To keep the sugar content of your juices low, trying juicing vegetables and then add a small piece of fruit if you want more sweetness.
Summary Juices based mainly on fruit are much higher in sugar than vegetable-based ones.
Fresh juices contain important vitamins and antioxidants that can benefit your health.
However, fruits and vegetables are still the healthiest and most nutritious when consumed whole.