Juice cleanses have surged in popularity, often marketed as methods to detoxify the body, improve digestion, and promote weight loss. However, recent research indicates that these regimens may pose health risks, particularly concerning the disruption of the gut microbiome.
Impact on the Gut Microbiome
A study published in Nutrients in January 2025 examined the effects of a three-day juice cleanse on participants’ oral and gut microbiomes. The findings revealed that individuals who adhered to a juice-only diet experienced significant increases in bacteria associated with inflammation and gut permeability. In contrast, participants who consumed juices alongside whole foods exhibited less severe microbial changes, while those on a plant-based whole food diet demonstrated beneficial shifts in their microbiota. These results suggest that the absence of dietary fibre in juice-only cleanses may disrupt the gut microbiome, potentially leading to long-term health consequences.
Dr. Melinda Ring, director of the Osher Center for Integrative Health at Northwestern University Feinberg School of Medicine, commented on the study: “Most people think of juicing as a healthy cleanse, but this study offers a reality check. Consuming large amounts of juice with little fibre may lead microbiome imbalances that could have negative consequences, such as inflammation and reduced gut health.”
The Role of Fiber
Juicing often involves extracting the liquid from fruits and vegetables while discarding the pulp, which contains essential dietary fibre. Fiber plays a crucial role in feeding beneficial gut bacteria that produce anti-inflammatory compounds like butyrate. Without adequate fibre, sugar-loving bacteria can proliferate, leading to an imbalance in the gut microbiome. The high sugar content in juices further fuels these harmful bacteria, exacerbating the disruption. Reduced fibre intake may also impact metabolism, immunity, and mental health.
Expert Recommendations
Given these findings, experts advise caution when considering juice cleanses. Dr. Ring suggests alternatives to traditional juicing: “If you love juicing, consider blending instead to keep the fibre intact, or pair juices with whole foods to balance the impact on your microbiome.”
Lisa Froechtenigt, RD, senior program management associate in the Baylor College of Medicine Bariatric Surgery Program speaking to Health.com, emphasises the importance of a balanced diet: “The human body is not designed to consume only one type of nutrient or food. It requires a balance of macronutrients (proteins, fats, and carbohydrates, including fibre) daily. When important food groups are removed from someone’s diet, the body may go into a type of survival mode.”
Regulatory Warnings
The U.S. Food and Drug Administration (FDA) has issued warnings regarding detox and cleansing products, noting that some may contain illegal or potentially harmful ingredients and are marketed with unproven health claims. The FDA also highlights that juice-only diets are unlikely to provide sufficient energy or nutrients and rarely lead to lasting weight loss.
Lack of Scientific Evidence
While anecdotal reports often tout the benefits of juice cleanses, scientific evidence supporting their efficacy is limited. The body’s natural detoxification systems, primarily the liver and kidneys, effectively remove toxins without the need for restrictive diets. Moreover, the restrictive nature of juice cleanses can lead to nutrient deficiencies, muscle loss, and other health issues.
Conclusion
While incorporating fresh juices into a balanced diet can increase fruit and vegetable intake, relying solely on juice cleanses may disrupt the gut microbiome and pose other health risks. Maintaining a diet rich in whole foods, including adequate fibre, is essential for supporting gut health and overall well-being. Consulting with healthcare professionals before undertaking any restrictive diet regimen is strongly recommended.
