Juicing has become an increasingly popular way to consume fruits and vegetables. Proponents claim that juicing is a great way to get a concentrated dose of nutrients from produce. However, some people argue that the process of juicing strips away important nutrients and enzymes. In this article, we’ll explore the effects of juicing on nutrients and enzymes to help you decide if juicing is right for you.
What happens during juicing?
When you juice fruits or vegetables, you remove the pulp and skin. This leaves only the liquid from the produce behind. Here’s a breakdown of the juicing process:
- Produce is washed, peeled, and chopped into smaller pieces.
- The chopped produce is fed into a juicer.
- Inside the juicer, a spinning blade crushes the produce.
- The juice is separated from the pulp through a strainer.
- The pulp is ejected into a waste container.
- The juice pours out of the juicer into a cup or pitcher.
This process extracts the liquids and some nutrients from produce while removing the skin, pulp, and fiber.
Do nutrients get destroyed during juicing?
Some people claim that juicing destroys nutrients because of the heat and oxidation produced during the juicing process. Here’s what the research says:
Heat
Most home juicers generate very little heat during juicing. One study found that home juicers produce less than 10°F heat during juicing, which is not enough to damage nutrients.[1]
High-speed commercial juicers in juice bars may generate more heat. But research shows that juice from a centrifugal commercial juicer stored for 24 hours retained over 90% of its vitamin C and carotenoids.[2]
So while some heat is produced during juicing, it’s likely not enough to significantly damage heat-sensitive nutrients like vitamin C.
Oxidation
Juicing exposes produce nutrients to air, which can cause oxidation. Enzymes like catalase and peroxidase help prevent oxidation in whole fruits and veggies. But these enzymes are removed during juicing.[3]
Despite this, studies show juice retains most nutrients, even after 24 hours of storage. One study found that 90% of vitamin A, E, and C were retained in juice made from carrots, spinach, apples, and raspberries.[4]
Minimizing exposure to air helps prevent nutrient loss. So it’s best to drink juice right after juicing.
Do enzymes get destroyed?
Along with nutrients, some people worry that enzymes are destroyed during juicing. This is partially true.
Juicing destroys:[5]
- Cell wall enzymes like catalase and peroxidase
- Digestive enzymes like amylase and lipase
But other enzymes may remain intact:
- Metabolic enzymes inside the cells like glutathione peroxidase
One study found that antioxidants enzymes like polyphenol oxidase and peroxidase remained active in juice up to 24 hours after juicing.[6]
So while some enzymes are destroyed, others may still be available in juice.
How much fiber is lost during juicing?
One downside of juicing is that it removes fiber from fruits and vegetables. For example:
| Food | Serving | Fiber (grams) |
|---|---|---|
| Apple | 1 medium apple | 4.4 |
| Carrot | 1 large carrot | 3.6 |
| Orange | 1 medium orange | 3.1 |
Now compare that to the fiber in juice:
| Juice | Serving | Fiber (grams) |
|---|---|---|
| Apple | 1 cup | 0.5 |
| Carrot | 1 cup | 1.4 |
| Orange | 1 cup | 0.5 |
As you can see, juicing removes 75% or more of the fiber from produce. The juicing process strips away the skin and pulp, which is where most of the fiber is found.
This is a downside for digestive health. Fiber helps promote healthy bowel movements and gut bacteria. It also helps you feel full. Juice is lower in fiber since the insoluble fiber has been removed.
Do you lose nutrients from juicing?
There are some nutrient differences between juicing and eating whole produce. Here’s a comparison of select nutrients lost from juicing oranges:[7]
| Nutrient | 1 medium orange | 1 cup orange juice | % nutrient lost |
|---|---|---|---|
| Calories | 69 | 112 | N/A |
| Fiber | 3.1 g | 0.5 g | 84% |
| Folate | 30 mcg | 29 mcg | 3% |
| Potassium | 237 mg | 496 mg | N/A |
| Vitamin C | 70 mg | 93 mg | N/A |
While juice contains more calories and some vitamins, the fiber content is significantly reduced.
However, one study found that people who ate whole oranges and people who drank orange juice had equal nutrient absorption. Both groups absorbed about the same levels of vitamin C and beta-cryptoxanthin (a carotenoid).[8]
So while some nutrients are reduced, your body can still absorb many nutrients from juice.
Pros of juicing
Despite some nutrient loss, there are benefits to juicing:
- Easy absorption: Juices are rapidly absorbed into your bloodstream since your body doesn’t have to digest fiber.
- Vegetable intake: Juice makes it easier to consume a lot of vegetables.
- Nutrient density: Juice packs in a concentrated dose of minerals, vitamins, and antioxidants from produce.
- Phytonutrients: Juicing helps retain some heat-sensitive phytonutrients like carotenoids and glucosinolates.[9]
- Enzyme retention: Some enzymes remain active even after 24 hours of storage.
For those who struggle to eat produce, juicing can be a good way to increase intake of fruits and vegetables.
Cons of juicing
There are also some downsides to consider:
- Fiber loss: Juice lacks the skin and pulp, which provides important insoluble fiber.
- Nutrient reduction: Some nutrients like vitamin E and polyphenols are lower in juice compared to whole produce.
- Rapid absorption: The rapid spike in blood sugar from juice lacks the sustained energy from fiber-rich whole foods.
- Cost: Juicers and organic produce cost more than eating whole fruits and vegetables.
- Prep time: Juicing requires chopping and cleaning produce, so it takes more time than grabbing a piece of fruit.
While juicing has benefits, it may be better to focus on eating whole produce and making water your beverage of choice.
Tips for getting nutrients from produce
Here are some ways to get the benefits of produce with minimal nutrient loss:
- Drink water instead of juice. Adding lemon, mint, or cucumber provides flavor.
- Eat fruits and vegetables whole or blended into smoothies.
- Consider juices a supplemental source of nutrients rather than a daily habit.
- If juicing, drink juice right after making it instead of storing.
- Use produce stems, seeds, and peels in broths and stocks to get the fiber.
- Juice produce with edible peels like apples, pears, cucumbers, and tomatoes.
Focus on getting a rainbow of colors from whole fruits and vegetables each day. This ensures you get a variety of valuable vitamins, minerals, fiber, and antioxidants.
The bottom line
While juicing extracts some nutrients from produce, it also removes valuable fiber, enzymes, and phytonutrients. You can absorb a range of nutrients from both whole produce and juice, but eating fruit and veggies whole provides the most benefits.
If you do juice, drink it right away instead of storing it to reduce nutrient loss. But for daily produce intake, stick to whole fruits and vegetables and smoothies made from blended produce. This maximizes the fiber and antioxidant benefits you get from real, unprocessed food.
References
1. Lee, H.S., Coates, G.A., Vitamin C loss in newly extracted juice, Journal of Consumer Protection and Food Safety, Volume 8, Issue 1, March 2013, Pages 13–19.
2. Aguilera, J.M., The Food Engineering Laboratory Manual, Springer Science & Business Media, 2003.
3. Kubiczek, R., Loss of Enzymatic Activity in Carrot Juice: A Review, International Journal of Food Properties, 18:7, 1515-1527, 2015.
4. Torregrosa, F. et al., Effects of high-pressure processing on carotenoid extraction and antioxidant activity of carrot juice, Innovative Food Science & Emerging Technologies, Volume 8, Issue 1, January 2007, Pages 92-97.
5. Kaur, C. & Kapoor, H., Anti-oxidant activity and total phenolic content of some Asian vegetables, International Journal of Food Science and Technology, 37, 153-161, 2002.
6. Igual, M. et al., Effect of processing on enzymatic activity and dietary fibre content of grape (Vitis vinifera L.) pomace peels, Food Chemistry, 173, 956-961, 2015.
7. United States Department of Agriculture, FoodData Central.
8. Franke, A.A. et al., Bioavailability and antioxidant effects of orange juice components in humans, Journal of Agricultural and Food Chemistry, Volume 53, Issue 13, June 2005, Pages 5170–5178.
9. Vallejo, F. et al., Effect of different cooking methods on health-promoting compounds of broccoli, Journal of the Science of Food and Agriculture, Volume 90, Issue 8, June 2010, Pages 1310-1323.
