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Is it good to juice kale and spinach?

Juicing vegetables like kale and spinach has become increasingly popular in recent years. Proponents claim that juicing is an easy way to pack more nutrients into your diet. However, some worry that important fiber is lost in the juicing process. This article explores the benefits and downsides of juicing kale and spinach.


Kale and spinach are two of the most nutritious vegetables around. Both are packed with vitamins, minerals, and antioxidants. Juicing them allows you to consume larger quantities than you could typically eat whole. This floods your body with micronutrients that support health and wellbeing.

However, the juicing process removes the insoluble fiber content from kale and spinach. Fiber provides many benefits and some worry the trade-off isn’t worth it. This article looks at the advantages and disadvantages of juicing these nutritious greens.

Nutrition in Kale and Spinach

Kale and spinach have stellar nutrition profiles. They contain high levels of vitamins, minerals, and disease-fighting antioxidants. Juicing is an easy way to get a concentrated dose.

Kale Nutrition

Kale contains:

  • Vitamin K: Needed for blood clotting. Just one cup provides over 1000% of your daily needs.
  • Vitamin A: Key for eye and skin health. A cup has over 200% of the RDI.
  • Vitamin C: An important antioxidant that supports immune function. A cup contains 134% of the RDI.
  • Calcium: Necessary for bone health. Kale provides 9% of the RDI per cup.
  • Potassium: Supports heart health and metabolism. A cup contains 9% of the RDI.
  • Iron: Required to transport oxygen via red blood cells. A single cup provides 6% of the RDI.

Additionally, kale is loaded with powerful antioxidants like quercetin and kaempferol. These compounds fight damage by unstable molecules called free radicals, which can harm your DNA and lead to chronic disease.

Spinach Nutrition

Spinach is also very nutrient dense, providing:

  • Vitamin K: A cup contains over 600% of your daily needs.
  • Vitamin A: A single cup has 56% of the RDI.
  • Folate: Crucial for cell growth and development. Provides a quarter of the RDI per cup.
  • Iron: A cup of cooked spinach provides 36% of the RDI.
  • Vitamin C: Cooked spinach provides 22% of the RDI per cup.
  • Calcium: Spinach contains 10% of the RDI per cup.
  • Potassium: You get 9% of the RDI in a single cup.

Spinach also contains beneficial plant compounds like lutein and zeaxanthin. These support eye health by protecting your retina from damage by blue light.

Benefits of Juicing Kale and Spinach

There are several benefits to juicing kale and spinach:

Increases Nutrient Intake

Juicing makes it easy to consume larger quantities of these nutrient-dense veggies. This flood your body with a variety of important vitamins, minerals, and antioxidants.

For example, drinking two 16-ounce (473-mL) green juices per day provides the vitamin K, vitamin A, and iron that the average person needs in an entire week.

Boosts Antioxidant Intake

Antioxidants are compounds that reduce oxidative damage from free radicals. Research shows that they protect your cells and may lower your risk of chronic diseases like cancer and heart disease.

Since kale and spinach are rich in antioxidants like beta carotene, vitamin C, quercetin, and kaempferol, juicing them is an excellent way to increase your antioxidant intake.

Aids Weight Loss

Some research shows that higher intakes of fruits and vegetables are linked to lower body weights.

In one study, each daily serving of fruits or vegetables was associated with a 0.25-pound (0.11-kg) lower weight over 4 years.

Juicing is an easy way to increase your fruit and vegetable intake, which may support weight loss over time.

Easy to Absorb

Juicing breaks down fruits and vegetables into an easily absorbed liquid form. This makes their nutrients more bioavailable than when consumed whole.

Your digestive system can extract nutrients from juices more easily than digesting whole fruits and vegetables.

May Promote Gut Health

Kale and spinach both contain prebiotics that help feed the beneficial bacteria in your gut microbiome. Prebiotics are a type of fiber that your body cannot digest. However, your gut bacteria ferment them, stimulating growth.

Since juicing removes most fiber, adding kale or spinach juice to smoothies is an easy way to promote gut health.

Delicious and Refreshing

Green juices made with kale and spinach are nutritious and refreshing. They can be an excellent alternative to less healthy beverages like soda, sports drinks, or juices with added sugars.

Downsides of Juicing

Despite the benefits, there are some downsides to juicing kale and spinach:

Nutrient Loss

Although juicing vegetables increases absorption of certain nutrients, important insoluble fiber is removed in the process. Fiber supports gut health, weight control, and more.

Juicing also reduces levels of some antioxidants, such as flavonoids, which are bound to plant cell walls. These get left behind when the produce is extracted into juice.


Juice begins losing nutrients as soon as it’s made. This is due to oxidation, which happens when compounds in the juice are exposed to air.

Storing green juices properly by keeping them cold in an airtight container and consuming them within 24 hours can minimize nutrient loss.

High in Sugar

Spinach and kale contain naturally occurring sugars. These sugars become more concentrated when produce is juiced.

Drinking too much fruit and vegetable juice may raise your calorie intake, which could contribute to weight gain.

May Cause Digestive Issues

Drinking more than one small glass of vegetable juice per day may cause digestive problems due to the removal of fiber during juicing.

Fiber is important for regular bowel movements and healthy digestion. Without it, consuming lots of juice may cause issues like diarrhea.

May Spike Blood Sugar

In addition to being high in sugar, fruit and vegetable juices are very low in protein and fat, which helps slow the absorption of sugar into your bloodstream.

As a result, drinking a lot of juice on an empty stomach may spike your blood sugar levels.

Maximizing Benefits While Minimizing Downsides

Here are some tips to maximize the nutrition you get from kale and spinach juice while minimizing potential downsides:

  • Consume juices in moderation. Limit to around 8 ounces (237 mL) per day.
  • Drink your juice slowly to avoid an insulin spike.
  • Store juices properly in an airtight container and drink within 24 hours.
  • Pair juices with protein and healthy fats to slow sugar absorption.
  • Add a squeeze of lemon to juices to help preserve vitamin C and antioxidants.
  • Add juices to smoothies along with fiber sources like chia seeds, hemp seeds, and oats.
  • Consume the pulp from juicing to get additional fiber.
  • Make sure to still eat plenty of whole fruits and vegetables.

Kale and Spinach Juice Recipes

Here are a few tasty, nutritious juice recipes featuring kale and spinach:

Green Revitalizer Juice

  • 1 cucumber
  • 5 leaves kale
  • 1 cup spinach
  • 1 green apple
  • 1 lemon
  • 1-inch piece ginger

Mean Green Juice

  • 1 cucumber
  • 1 cup kale
  • 1 cup spinach
  • 1 Granny Smith apple
  • 1/2 lemon
  • 1-inch piece ginger

Green Pineapple Juice

  • 1 cup kale
  • 1 cup spinach
  • 1 cup pineapple chunks
  • 1 green apple
  • 1-inch piece ginger

Kale Celery Cleansing Juice

  • 4 stalks celery
  • 1 cucumber
  • 1 cup kale
  • 1 lemon
  • 1-inch piece ginger

The Bottom Line

Juicing kale and spinach allows you to consume more of these nutrient powerhouses. Their juice is packed with vitamins, minerals, antioxidants, and plant compounds that support health.

However, fiber is lost in the process. For the greatest nutritional benefit with the least drawbacks, juice in moderation and pair it with whole fruits, veggies, protein, and healthy fats.

Overall, incorporating some green juices into a balanced, healthy diet can be a nutritious addition for most people.

Benefits Downsides
  • Increases nutrient intake
  • Boosts antioxidant intake
  • May aid weight loss
  • More easily absorbed
  • May promote gut health
  • Delicious and refreshing
  • Nutrient loss from lack of fiber
  • Oxidation decreases nutrients
  • Concentrates natural sugars
  • May cause digestive issues
  • Can spike blood sugar
Kale Spinach
  • Vitamin K
  • Vitamin A
  • Vitamin C
  • Calcium
  • Potassium
  • Iron
  • Antioxidants like quercetin and kaempferol
  • Vitamin K
  • Vitamin A
  • Folate
  • Iron
  • Vitamin C
  • Calcium
  • Potassium
  • Antioxidants like lutein and zeaxanthin