German health experts advise on safe morning drinks

Lemon water is promoted as a simple morning habit that supplies vitamin C, improves hydration and may aid digestion, but it should be consumed lukewarm and followed by a water rinse to protect tooth enamel.

A study by researchers at the University of St. Andrews measured a Beverage Hydration Index and found that oral rehydration solution, whole milk and skim milk lead to lower urine output and higher fluid retention than plain water, while most sugary, caffeinated or alcoholic drinks performed similarly to water.

Other health guides warn that fruit juices, soft drinks, alcohol and caffeine can increase thirst in hot weather because of their sugar, diuretic or vasopressin‑inhibiting effects, recommending water, diluted fruit‑juice spritzes or unsweetened iced tea instead.

Finally, German water‑industry officials note that water left standing in taps can pick up microbes or trace chemicals such as BPA. They advise running the tap for 20‑30 seconds until the flow is cold before drinking, and regularly cleaning faucet aerators.