Study finds skim milk more hydrating than water for summer heat

Researchers at the University of St Andrews in Scotland published a study in the American Journal of Clinical Nutrition that ranks skim milk as the most hydrating beverage, surpassing water. The analysis used a Beverage Hydration Index (BHI) and showed that the combination of sugars, lactose, protein and fat in skim milk helps the body retain fluid longer than water alone. Experts recommend drinking two to three litres of water daily during heat waves, but the study suggests skim milk can be a superior alternative, especially when oral rehydration solutions are unavailable. The findings come as European health advisers warn of increased risks of heat‑related illnesses during the summer season.

The research highlights that, after skim milk, oral rehydration solutions rank next in hydration efficacy. The study also notes the high consumption of dairy products in countries such as India, the EU, the United States and China, underscoring the global relevance of dairy as a hydration source.