Juicing : How Healthy is It?

Reviewed by Laura J. Martin, MD

Juicing is popular. But before you give it a whirl, you might want to know what it may -- and may not -- do for your health.

What are the nutritional benefits and drawbacks? Can you juice for weight loss? What about food safety and claims about cleansing your system? Here's what you need to know.

Pros and Cons

Jennifer Barr, a Wilmington, Del., dietitian, occasionally makes fresh juice as a snack for her kids. Her favorite juice combines kale, carrots, ginger, parsley, and apples. She then adds the leftover pulp from her juicing machine into muffins.

“If you’re not big into fruits and vegetables, it’s a good way to get them in. It can help you meet daily recommendations in one drink” and be part of a healthy diet, says Barr, MPH, RD, LDN, who works at Wilmington's Center for Community Health at Christiana Care Health System.

But you shouldn't count on juicing as your sole source of fruits and vegetables.

"Don’t think because you’re juicing that you’re off the hook with eating fruits and vegetables,” says Manuel Villacorta, MS, RD, CSSD, an Academy of Nutrition and Dietetics spokesman and founder of Eating Free, a weight management program.

Aim to eat two whole fruits, and three to four vegetables a day. They should come in different colors, as the colors have different vitamins and minerals, Barr says.

What's Left Out

A juicing machine extracts the juice from whole fruits or vegetables. The processing results in fewer vitamins and minerals, because the nutrient-rich skin is left behind. Juicing also removes the pulp, which contains fiber.

You can add some of the leftover pulp back into the juice or use it in cooking.

Besides muffins, Barr uses other combinations -- such as spinach, pears, flaxseed, celery, and kale -- to make broth for cooking soup, rice, and pasta. She calls it "going the extra step to fortify your meals."

Juicers can be expensive, ranging from $50 to $400. Some more expensive juicers will break down a lot of the fruit by grinding the core, rind, and seeds, Barr says.

You may not need a juicing machine to make juice. You can use a blender for most whole fruits or vegetables to keep the fiber -- add water if it becomes too thick, Villacorta says.

You’ll also want to remove seeds and rinds, and some skins.

What to know before adding fresh juice to your diet.

Calorie Count

As with any food, it’s important to consider calories and sugar content.

A medium piece of fruit has about 60 calories. A cup of vegetables has about 25 calories, and 3 cups of leafy greens have about 25 calories. Each 60-calorie serving of fruit equals about 4 ounces of juice. A typical juice is usually 12 to 16 ounces.

Those calories add up.

"You could be taking up to four fruits and now the calories start adding up. If you use vegetables to juice, the calories are a lot less. If they use mainly vegetables, add an apple or kiwi for flavor. Calories are a concern if it’s pure fruit juice," Villacorta says.

To make a juice more balanced with protein, some good sources are almond milk, Greek yogurt, flaxseed, or peanut butter.

Food Safety and Juicing

When juicing, follow these food safety guidelines:

• Wash your hands before touching the fruits and vegetables.
• Thoroughly clean the produce.
• Use hot, soapy water if you have to hand wash the juicer or blender. Let all parts completely dry before putting away, to prevent bacterial growth.
• Use your dishwasher's sanitize cycle if the juicer is dishwasher safe.
• Don’t keep juice longer than a week. It’s best to drink it the same day, since the juice isn’t pasteurized.

Juicing Health Claims

There are many health claims about juicing on the Internet. For instance, juicing fans say that juicing can reduce your risk of cancer and boost your immune system.

It's true that eating a plant-based diet is linked to lower risk of heart disease or cancer. But there hasn't been a lot of research done that's specific to juicing.

There is some research on juicing and immune system, but any immune system benefits probably come from eating fruits and vegetables, whether it's in juice or not, Barr says.

Fans of juicing also say that juicing is better than eating whole fruits and vegetables because the body can absorb the nutrients better and it gives the digestive systema rest from working on fiber.

But "the nutrients might not have the same potential because you’ve processed them," Villacorta says. "There’s nothing like eating the whole fruit or vegetable."

It's true that too much fiber can sometimes block the absorption of nutrients. But most people don't even get the recommended amount of fiber per day, Villacorta says.

It’s important to speak with your health-care provider before integrating juicing into your diet to avoid any potential food and drug interactions.

For instance, large amounts of foods high in vitamin K, such as kale and spinach, may change how an anti- blood clotting medication works, Barr says.

Juicing for Weight Loss and Cleansing

Juicing as an extreme weight loss measure is a fad diet. You can't stick to it for long -- and you shouldn't.

On a juice-only diet, you may not get enough fiber to make you full. And it's so limited that you may rebel.

“If you’re doing a juicing diet, you’ll be so tempted to eat something like a cake or donut because you’ve restricted yourself,” Barr says.

You may also not get enough protein. If you are trying to lose weight by only juicing, then you are putting yourself at risk to lose muscle mass. Research shows that adding protein is essential to preserve muscle mass during weight loss.

By the end of any extreme diet, your metabolism may have temporarily slowed down. Once you start eating a more normal diet, you’ll be prone to building fat cells, Villacorta says.

What about juicing as a way to detox or cleanse your body? “I haven’t seen any research or science paper to support that cleansing is happening from juicing,” Villacorta says.

Your liver and kidneys take care of that -- whether you're juicing or not.