Some fruit and vegetable peels are rich in nutrients, such as those of tomatoes, pears, and apples, so many people eat them without peeling. However, there are four types of fruit and vegetable peels that are best not eaten.
1. Potato peels. Potatoes contain glycoalkaloids, a toxic substance that is almost entirely concentrated in the potato peel, especially in the green-sprouted parts. Some people like to cook beef with potatoes in their skins, but the cooked peels still retain the glycoalkaloids. Consuming large amounts can cause symptoms such as vomiting, dizziness, and diarrhea.
2. Persimmon peels. The peels of ripe persimmons contain a large amount of tannic acid, which gives them a astringent taste. Under the action of gastric acid, tannic acid will react with the protein in food to form a precipitate, known as a persimmon stone. This substance can easily cause symptoms such as upper abdominal discomfort, bloating, and loss of appetite. Therefore, do not eat unpeeled persimmons, and do not eat them on an empty stomach.
3. Sweet potato peels. Sweet potatoes grow underground for a long time, and their peels are in direct contact with the soil, so many harmful substances are absorbed into the peel. Moreover, sweet potato peels contain more alkali, and excessive consumption can cause gastrointestinal discomfort. In addition, many vendors selling roasted sweet potatoes on the street use coke as fuel to save costs, and harmful substances such as sulfur dioxide produced can easily accumulate on the peel. Therefore, eating roasted sweet potatoes with their skins poses a cancer risk.
4. Water chestnut peels. Water chestnuts grow in paddy fields, and their peels absorb many harmful and toxic biological excretions, and also contain parasites. Eating raw water chestnut peels can cause symptoms such as diarrhea and vomiting. Additionally, it should be noted that water chestnut peels contain a lot of starch, so diabetic patients should be cautious when consuming them.