Many people often think that drinking water is a simple habit that shouldn’t be a concern. However, the reality is that not paying attention to how we drink water can negatively impact our health and even cause cancer.
Is it safe to boil water or leave it overnight?
According to Associate Professor Fan Zhihong of the Department of Nutrition and Food Safety at China Agricultural University, nitrites—carcinogens—are only formed in the presence of nitrates. Most bottled or purified water we use daily does not contain nitrates, so leaving it overnight does not pose a cancer risk.
Two Types of Water That Actually “Feed” Cancer Cells
Contrary to popular belief, water repeatedly boiled or left overnight does not directly cause cancer. Instead, consider the following two types of water:
1. Water that is too hot
Water that is too hot (above 50–60°C) for an extended period can severely damage the lining of the esophagus. This constant stimulation can lead to hyperplasia of the lining of the esophagus, increasing the risk of esophageal cancer. To ensure safety, wait until the water temperature drops to approximately 18–30°C before drinking.
2. Unboiled tap water