Why should you not drink overnight tea?

Generally speaking, the claim that "overnight tea cannot be consumed" is too absolute. For some individuals, drinking overnight tea may carry certain risks. These include food poisoning, disrupted sleep, loss of nutrients, yellowing of teeth, and an increased risk of cardiovascular disease. If any abnormalities occur, prompt medical attention is recommended. A detailed explanation is as follows:

1. Food poisoning: Overnight tea is usually stored in relatively humid conditions, and tea left exposed to air can easily breed bacteria or fungi. If contaminated by these microorganisms, drinking the tea may cause food poisoning, leading to symptoms such as headache, diarrhea, and vomiting. Especially in warm and humid weather, overnight tea is more prone to mold growth, increasing health risks after consumption.

2. Sleep disruption: The caffeine content in overnight tea may increase, potentially causing insomnia and palpitations after consumption. Long-term consumption of overnight tea before bedtime may lead to difficulty falling asleep or maintaining sleep, potentially triggering neurasthenia and other issues.

3. Nutrient loss: Antioxidants in overnight tea, such as tea polyphenols and vitamin C, gradually oxidize and degrade, reducing the nutritional value of the tea.

4. Yellowing of teeth: Pigments in tea leaves fully dissolve into the tea when steeped for extended periods. Over time, these pigments can adhere to teeth, potentially causing yellowing and affecting aesthetics.

5. Increased cardiovascular disease risk: Oxidation products of tea polyphenols in overnight tea may adversely affect the cardiovascular system, increasing the risk of cardiovascular diseases. This may be related to oxidative damage to blood vessel walls, although the exact mechanism requires further research.

In daily life, attention should be paid to proper tea storage methods to avoid moisture or prolonged exposure to air.