While 'gut-friendly' foods like sourdough bread and kimchi are widely recognized for their potential to enhance digestion, immunity, and overall well-being, experts highlight that what we drink can equally significantly impact gut health. Certain beverages can foster a healthy gut microbiome, while others may subtly undermine it, leading to symptoms such as bloating, discomfort, fatigue, and potentially contributing to long-term health issues. This concern extends beyond typical culprits like alcohol and sugary fizzy drinks, as nutritionist Rhiannon Lambert emphasizes that our gut microbiome is influenced by various factors, including our fluid intake. Research increasingly suggests that some drinks, when consumed frequently or in high amounts, can negatively affect gut health.

The gut hosts trillions of microorganisms, primarily bacteria, alongside viruses and fungi, collectively known as the gut microbiome. These microbes are crucial for breaking down food, supporting the gut lining, and producing compounds vital for digestion, inflammation regulation, metabolism, and immune function. A balanced microbiome, where beneficial bacteria maintain stability and suppress harmful strains, is key to health. However, an imbalance, termed dysbiosis, can manifest as bloating, irregular bowel habits, and has been linked to conditions like weight gain, type 2 diabetes, and heart disease. The choices we make regarding beverages can either support or hinder this delicate balance.

Nutritional therapist Hanieh Vidmar stresses that consistency in drink choices is more important than following trends. Generally, the most beneficial drinks for gut health are often the simplest: water, herbal teas, lightly brewed green tea, and fermented options such as kefir or kombucha. These are typically low in additives, sweeteners, and are easily processed by the digestive system. Conversely, several popular drinks are identified as potentially detrimental to gut health.

Drinks to reconsider for optimal gut health:

• Trendy Juice Shots: Often marketed as 'gut shots,' these can be counterproductive. They are usually high in concentrated sugars, low in fiber, and acidic, potentially triggering reflux or stomach irritation. Nutritionist Rob Hobson notes their high concentration, acidity, and lack of fiber can irritate the stomach lining, especially on an empty stomach. While ingredients like ginger and turmeric have benefits in food form, there's limited evidence that small, concentrated liquid shots meaningfully improve gut bacteria, and for some, they may cause more harm than good.

• Oat Milk (Commercial Barista Versions): While not inherently unhealthy, many commercial 'barista' oat milks are highly processed, containing added oils, thickeners, gums, and enzymes that can irritate sensitive digestive systems. Certain emulsifiers are also being investigated for their potential to disrupt the gut's protective mucus layer and increase intestinal permeability. Additionally, they tend to be high in rapidly absorbed carbohydrates, which can lead to blood sugar spikes and indirectly affect gut health.

• Unfiltered Coffee: Coffee can stimulate stomach acid production and accelerate gut motility. While this helps some individuals with regularity, for others, it can exacerbate reflux, cramps, or IBS symptoms. Dr. Federica Amati points out that unfiltered coffee, such as French press or Turkish coffee, contains compounds like cafestol and kahweol, which can elevate LDL cholesterol.

• 'Diet' or 'Zero Sugar' Drinks: Despite being marketed as healthier alternatives, the impact of sugar-free fizzy drinks on gut health is complex. Rhiannon Lambert explains that responses to artificial sweeteners vary depending on the type, dose, and an individual's existing gut bacteria. Some studies show changes in gut microbes and glucose control, while others show no effect, suggesting individual differences. Many ultra-processed diet drinks also contain additives like emulsifiers, which are being studied for their effects on gut bacteria. These are best consumed occasionally, with water as the primary source of hydration. Rob Hobson adds that sweeteners such as sucralose, saccharin, and aspartame have been shown in studies to alter gut bacteria composition and function, potentially impairing glucose tolerance and causing bloating or altered bowel habits for some.

• Beer and Lager: Alcohol has a strong evidence base for causing gut-related harm. Regular consumption can increase intestinal permeability ('leaky gut') and disrupt the balance of gut bacteria, promoting inflammation. The effects are dose-dependent. Beer, in particular, combines alcohol with carbonation and fermentable carbohydrates, a mix that can worsen bloating and trigger symptoms in sensitive guts. Alcohol-free options should also be checked, as many contain high sugar levels.

• Sugar-Sweetened Drinks: These can significantly alter the balance of gut bacteria, reducing beneficial strains and shifting the microbiome towards a less healthy state, leading to reduced bacterial diversity. High sugar diets are associated with inflammation and metabolic disease. Their acidity can also irritate the gut lining, and carbonation may worsen bloating and gas, especially in individuals with sensitive digestion or IBS. Registered dietitian Nichola Ludlam-Raine suggests kombucha as a healthier swap, offering fizziness with live cultures.

• Energy Drinks: Rob Hobson describes energy drinks as a 'perfect storm' for gut health due to their combination of caffeine, sweeteners, acidity, and additives. High caffeine intake can stimulate gut motility, potentially worsening diarrhea and cramping in sensitive individuals. The sugar or sweetener content can disrupt the gut microbiome and increase bloating, while acidity may aggravate reflux and upper gut symptoms, particularly when consumed on an empty stomach. Unsweetened tea or coffee, which contain polyphenols that support gut bacteria diversity, are recommended alternatives.

• Protein Shakes (Some): While convenient, many protein shakes contain artificial sweeteners, sugar alcohols, and thickeners that can cause bloating, gas, and diarrhea. Whey protein can also cause issues for those sensitive to lactose. Hanieh Vidmar recommends choosing powders with minimal additives or opting for whole food sources of protein like eggs, chicken, or tofu instead.

Ultimately, a healthy gut thrives on simplicity and consistency: ample fluids, minimal added sugars, moderate alcohol, and a diet rich in whole foods, rather than relying solely on functional drinks. An occasional fizzy drink or alcoholic beverage is unlikely to undermine an otherwise balanced diet, emphasizing a balanced approach rather than strict prohibitions.