Juice Cleanses Likely Good for Nothing, Bad forMuch

Marilynn Larkin

May 28, 2025

“It’s a great way to get those fruits and vegetables into my diet, especially

since I can’t be bothered peeling or preparing them…” “I lost weight and felt

lighter…” “I’m helping my body detox, and that’s a good feeling.”

Social media is rife with statements like the above about juice cleanses. It’s

a favorite topic as well as something patients often ask about. The

perception is that by doing a juice cleanse, they’re doing something healthy

for themselves — yet experts agree that in most cases, they’re not. But if

they’re having a conversation or asking about it, it offers an opportunity to

provide evidence-based guidance.

American Gastroenterological Association Spokesperson Fazia Mir, MD,

clinical assistant professor at the University of New Mexico and a

gastroenterologist with Presbyterian Healthcare Services, both in

Albuquerque, New Mexico, said some of her patients ask about juice

cleanses because they’re interested in doing a liver detox or helping their

gut inflammation.

“I tell them that, in fact, it does the opposite,” she told Medscape Medical

News.

“The majority of juice cleanses impact gut health negatively. They can cause

bowel habit irregularity and even precipitate inflammatory bowel disease, as

the gut microbiota is disrupted due to the lack of fiber in these cleanses. And

we see patients all the time whose irritable bowel syndrome worsens after

they’ve embarked on a juice cleanse.” 

What the Evidence Says

There’s little evidence to support the use of juice cleanses for eliminating

toxins from the body, according to the US National Center for

Complementary and Integrative Health. Furthermore, some juices used in

“detoxes” and “cleanses” haven’t been pasteurized or treated in other ways

to kill harmful bacteria, meaning they can expose individuals to toxigenic E

coli, Salmonella, hepatitis A, and Cryptosporidium.

In addition, some juices are made from foods high in oxalate, such as leafy

green vegetables and beets. Individuals susceptible to kidney stone

formation should limit their consumption of high-oxalate foods, which can

present a health threat.

In fact, a case report published several years ago documented acute oxalate

nephropathy caused by a “green smoothie cleanse” prepared from juicing

oxalate-rich green leafy vegetables and fruits.

‘Reality Check’

Two recent studies highlight the negative impact of juice cleanses. In a small

randomized, three-arm intervention study with 14 healthy

participants published online in Nutrients, “a 3-day exclusive juice cleanse

(800-900 kcal/d) led to shifts in the oral and gut microbiome, with increases

in taxa linked to inflammation, gut permeability, and even cognitive decline

after juice consumption,” said principal author Melinda Ring, MD, executive

director, Osher Center for Integrative Health at Northwestern University in

Chicago.

Participants followed one of three diets — juice only, juice plus food, or

plant-based food — for 3 days. Microbiota samples (stool, saliva, and inner

cheek swabs) were collected at baseline, after a pre-intervention elimination

diet, immediately after the juice intervention, and 14 days after the

intervention. Gene sequencing was used to analyze microbiota taxonomic

composition.

The juice-only group showed the most significant increase in bacteria

associated with inflammation and gut permeability, as well as associated

changes in the saliva and cheek microbiota — particularly in the relative

abundances of proinflammatory bacterial families. These changes are potentially due to the high sugar and low fiber intake of the juice-related products, the authors suggested.

Ring said the study “offers a reality check” on juice cleanses. “Whether a

cleanse is ‘healthy’ depends on the individual and the intent behind it,” she

told Medscape Medical News. “A short, structured cleanse, ideally lasting no

more than 1-3 days, can be safe for many people if it focuses on polyphenol-

rich, low-sugar vegetables rather than fruit, retains some fiber (as in

blended rather than pressed juices), and avoids extreme calorie restriction.” 

Pediatricians should also be aware that a high-sugar, low-fiber diet may

promote the growth of pro-inflammatory taxa, first author Maria Luisa Savo

Sardaro, PhD, a professor of food microbiology at San Raffaele University in

Rome, Italy, told Medscape Medical News.

“Families often rely on juice boxes in lunch packs, believing they’re a healthy

substitute for whole fruit, and school cafeterias frequently offer sugary

drinks throughout the day,” she said. “Together, these habits may contribute

to an early life increase of inflammation in children.”

Change Dietary Guidelines?

Although it did not address juice cleanses per se, a new review published

online in Nutrition Bulletin specifically compared evidence on whole fruit and

100% fruit juice with regard to nutrient composition, impact on hunger and

satiety, and association with chronic health conditions.

Lead author Hemangi Mavadiya, a PhD candidate at the Joe C. Wen School of

Population & Public Health, University of California Irvine, Irvine, California,

said that, like the Nutrients study, the review of 83 studies found juicing

does indeed remove much of the dietary fiber that has beneficial effects on

the gut. In addition, processing and/or storing 100% fruit juice reduces

vitamins and other antioxidant contents and transforms intrinsic sugars in

the whole fruit into free sugars, which have little nutritional benefit.

Furthermore, fruit consumed in solid form provides greater satiety due to

delayed gastric emptying and related physiological reactions, and “the

synergistic effects of polyphenols and fiber in whole fruit benefit the gut

microbiome by acting as prebiotics and producing short-chain fatty acids

that reduce inflammation,” the authors wrote.

The review also showed that consuming high amounts of fruit juice is

associated with increased risks for certain types of cancer, while results were

mixed for type 2 diabetes and hypertension. 

As a result of their findings, the authors recommended that the next

version of the next set of Dietary Guidelines for Americans, coming out at

the end of 2025, be updated to better reflect the amount of whole fruit and

100% fruit juice adults and children should consume. Current guidelines

recommend that at least half of the daily recommended fruit intake of two

cups a day should come from whole fruits, potentially allowing the other half

to be fulfilled by 100% fruit juice.

Tips for Patients

What are clinicians telling their patients regarding juice cleanses? “When

used as a bridge to more sustainable, whole-food, high-fiber eating habits, a

brief cleanse might serve as a motivational tool,” Ring said. “However,

clinicians should counsel patients that detoxification is a natural, ongoing

function of the liver and kidneys, not something that requires commercial

juice products.” 

Patients should also be told that juice cleanses may temporarily disrupt the

body’s microbial balance, likely due to their high sugar and low fiber content

and may not support long-term gut health. “Cleanses may offer a

psychological ‘reset,’ but without adequate fiber and protein, they could

undermine microbial diversity and resilience, especially if repeated or

prolonged.” 

Patients who love juicing can consider blending instead, to keep the fiber

intact, or pairing juices with whole foods to balance the impact on the

microbiome, she suggested.

Mavadiya advises patients read food labels, which can help distinguish

between fruit juice and fruit drinks, since the latter “is loaded with added

sugars,” and it’s easy to confuse the two.

“Ultimately, the healthiest path forward is not a periodic cleanse, but a

consistent, nutrient-dense, fiber-rich diet that supports gut and systemic

health over the long term,” Ring concluded. Furthermore, clinicians should

assess for underlying conditions such as diabetes, eating disorders, or frailty,

which may make juice cleanses inadvisable.

No conflicts of interest were declared.

Marilynn Larkin, MA, is an award-winning medical writer and editor whose

work has appeared in numerous publications, including Medscape Medical

News and its sister publication MDedge, The Lancet (where she was a

contributing editor), and Reuters Health.