Listen to social media and you would think that juice cleanses are a great way to detox your body and/or your liver … and that they help with gut inflammation. Many believe it’s the perfect way to get fruits and vegetables into their diet or to lose weight and feel lighter.
But, According to American Gastroenterological Association Spokesperson Dr. Fazia Mir, “The majority of juice cleanses impact gut health negatively.” As clinical assistant professor at the University of New Mexico and a gastroenterologist with Presbyterian Healthcare Services, she is an expert on the topic. “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
According to the U.S. National Center for Complementary and Integrative Health, there is scant evidence that juice cleanses eliminate toxins from the body. Even worse, some juices used in cleanses and detoxifiers haven’t been pasteurized, meaning individuals risk exposure to E coli, Salmonella, hepatitis A, Cryptosporidium, and other toxins.
In addition, certain ingredients in these juices are high in oxalate, generally from green leafy vegetables and fruits; individuals susceptible to kidney stone formation should limit their consumption of high-oxalate foods, as they present a health threat, including acute oxalate nephropathy.
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 unhealthy shifts in the oral and gut microbiome, with increases in taxa linked to inflammation, gut permeability, and even cognitive decline after juice consumption.” These changes were likely due to the high sugar and low fiber intake of the juice-related products, the authors suggested.
The second study did not address juice cleanses per se, but it compared evidence on whole fruit versus 100% fruit juice with regard to nutrient composition, impact on hunger, and association with chronic health conditions.
Lead author Hemangi Mavadiya, a PhD candidate at the Joe C. Wen School of Population and Public Health, University of California Irvine, said that, like the Nutrients study, the review of 83 studies found “juice cleansing” removes much of the dietary fiber that has beneficial effects on the gut. In addition, processing and storing 100% fruit juice reduces the beneficial effects of vitamins and other antioxidant contents and transforms intrinsic sugars in the whole fruit into free sugars, which offer little nutritional benefit.
What if I really want to try a juice cleanse?
The best type of juice cleanse would be short (1-3 days) and structured, and it would consist largely of polyphenol-rich, low-sugar vegetables that retain some fiber (as in blended rather than pressed juices). The cleansing regimen would also avoid extreme calorie restriction.
How all of this relates to children
Parents with children should be aware that a high-sugar, low-fiber diet may promote the growth of pro-inflammatory taxa. As such, those juice boxes in the daily lunch pack and other sugary drinks may contribute to an unnecessary increase of inflammation early in life for children.
The bottom line
Detoxification is a natural, ongoing function of the liver and kidneys; it is NOT something that requires commercial juice products.
The healthiest path forward is a consistent, nutrient- and fiber-rich diet that supports long-term gut health.