The question of whether consuming distilled water can cause digestive issues, such as diarrhea, is common for those seeking the purest form of hydration. Distilled water is a highly purified form of H2O, and its unique characteristics prompt concerns about how the body reacts to it. This article examines the science behind this query and clarifies the potential effects of this ultra-pure water on the digestive system and overall health.
Understanding Distilled Water
Distilled water is defined by its near-total lack of dissolved solids, minerals, and contaminants. The purification process involves boiling source water until it turns into steam, leaving behind virtually all impurities, such as minerals, heavy metals, and organic matter. The steam is then cooled and condensed back into a liquid state, creating ultra-pure water with a total dissolved solids (TDS) concentration often less than one part per million (PPM).
This process removes both harmful substances and beneficial minerals, distinguishing it from filtered or purified water which often retains some mineral content. The absence of these components means distilled water is highly hypotonic compared to the water found in human cells and bodily fluids. This lack of solutes is the defining characteristic that drives its interaction with the body.
Addressing Digestive Concerns
The direct answer to whether distilled water causes diarrhea is no. However, consuming it can potentially lead to digestive discomfort, especially when taken rapidly or in large amounts. This potential for upset stems from the water’s hypotonic state, meaning it has a lower concentration of dissolved particles than the fluid in intestinal cells.
When hypotonic distilled water enters the stomach and intestines, the body attempts to equalize the concentration. It does this by moving water out of the digestive cells and into the intestinal lumen. This influx of water into the gut can irritate the intestinal lining and upset the normal digestive rhythm, sometimes leading to bloating, mild stomach distress, or loose stools resembling temporary osmotic diarrhea. This effect is usually acute and subsides quickly, unlike diarrhea caused by infection.
The Risk of Systemic Mineral Loss
A larger concern with long-term, exclusive consumption of distilled water is the risk of systemic mineral loss. The hypotonic nature of this water continues to seek equilibrium within the body’s internal environment. When it enters the bloodstream and contacts cells, it can draw essential electrolytes out to achieve osmotic balance.
Over time, this continuous leaching effect depletes the body’s reserves of necessary minerals, including sodium, potassium, and calcium. Chronic electrolyte imbalance manifests through symptoms such as muscle cramping, fatigue, and weakness. A sustained lack of these minerals may also be associated with cardiovascular health issues. Relying on distilled water as a sole source of hydration requires careful dietary compensation.
Appropriate Use of Distilled Water
Given its composition, distilled water is best suited for non-consumption applications requiring mineral-free purity. It is the preferred choice for use in medical devices, such as continuous positive airway pressure (CPAP) machines, to prevent mineral scale buildup in humidifiers. It is also used in steam irons, car batteries, and automotive cooling systems to avoid corrosion or mineral deposits.
For daily drinking and hydration needs, tap water or bottled water containing natural or added minerals is a safer and healthier alternative. These sources contribute trace amounts of essential electrolytes that help the body maintain internal balance. Distilled water is useful for specific industrial and household uses, but it is not recommended as the primary source of hydration for the average person.