Introduction: Influenced by Western diets, more and more people are eating vegetables raw, either in cold dishes or as fruit and vegetable salads, feeling that they are nutritious and have a unique flavor. However, be careful, not all fruits and vegetables are suitable for eating raw. Some raw vegetables can lead to nutrient loss, indigestion, and even food poisoning!
Cold vegetable dishes and fruit and vegetable salads are popular favorites. Many people feel that raw vegetables have a refreshing taste and reduce nutrient loss. But in fact, not all vegetables are suitable for eating raw. These vegetables, when not cooked, not only easily lead to nutrient loss but may also cause some adverse consequences.
1. Legume Vegetables
In the beans of legume vegetables such as edamame, fava beans, kidney beans, and lentils, and in the tubers of potatoes, there is a toxic protein called lectin that can cause the red blood cells in the blood to agglutinate. When eating these vegetables that are not thoroughly cooked, it often causes symptoms such as nausea and vomiting, and in severe cases, it can be fatal.
These vegetables also contain a toxic protein called trypsin inhibitor. Its toxicity manifests as inhibiting the activity of proteases, causing pancreatic enlargement. The grains of fava beans (and pollen) contain a vicine called vicine, which can destroy red blood cells. When eating undercooked fava beans, it can induce hemolytic anemia, which is the well-known "favism".
The toxic substances in legume vegetables become inactive after heating, so they must be stir-fried or thoroughly cooked before consumption.
2. Tuber Vegetables
The reason why tuber vegetables are not suitable for raw consumption is due to their toxic glycoside content.
The high-starch cassava roots contain cyanogenic glycosides. If not soaked and cooked, they can cause cyanide poisoning after consumption. As for the solanine (also called solanine) contained in potato tubers, the content is extremely high in the greened skin exposed to light (can be 10 times higher than normal tubers), and it is not destroyed even after cooking, making it completely inedible.
3. Vegetables High in Nitrates, Such as Spinach and Mustard Greens
Vegetables like spinach and mustard greens can easily accumulate nitrates. Nitrates themselves are of low toxicity to the human body, but under the action of microorganisms in the body, they are converted into nitrites, which combine with nitrogen-containing compounds in the gastrointestinal tract (such as secondary amines, tertiary amines, amides, etc.) to form strong carcinogenic nitrosamines, posing a risk of inducing digestive system cancer.
Such vegetables should not only be eaten raw, but must also be thoroughly cooked before consumption. Therefore, the "hot pot" method of just briefly blanching them in soup before eating is not advisable.
4. Vegetables High in Oxalic Acid
Vegetables high in oxalic acid, such as spinach, bamboo shoots, and water bamboo, should be blanched in boiling water first to remove most of the oxalic acid, even if they are to be served in a cold dish.
Oxalic acid combines with calcium in the intestines to form calcium oxalate, which is difficult to absorb, interfering with the body's absorption of calcium and leading to calcium deficiency.
5. Daylilies
Fresh daylilies contain a substance called colchicine. Colchicine itself is non-toxic, but after being absorbed by the gastrointestinal tract, it oxidizes into a highly toxic colchicine dioxide, which can irritate the stomach and intestines, causing symptoms such as a sore throat, heartburn, thirst, abdominal pain, and diarrhea.
Since colchicine is water-soluble, it is destroyed during the steaming and drying process of fresh daylilies. Furthermore, dried daylilies must be soaked in clear water before consumption, so there is no risk of poisoning.
6. Wild Vegetables
Wild vegetables, such as purslane, need to be blanched to thoroughly remove dust and small insects to prevent allergies.
In addition, before eating raw vegetables like lettuce and water chestnuts, it is best to peel, wash, and blanch them in boiling water first. This is more hygienic and will not affect the taste or nutritional content.
7. Starchy Vegetables
Starchy vegetables such as potatoes, taro, and Chinese yam must be cooked. Otherwise, their starch granules will not break down, and the human body cannot digest them.
8. Wood Ear Mushrooms
9. Leafy Greens Growing Close to the Ground
Under conventional cultivation conditions, these vegetables are often irrigated with human and animal manure and pesticides, causing contamination that cannot be washed off no matter how much you rinse them with water. Of course, if the vegetables are produced in a soilless cultivation system, they can be eaten raw with peace of mind.
10. Water Chestnuts
Eating raw water chestnuts often can lead to the ingestion of fasciolopsis worms, which enter the human body and attach to the intestinal mucosa, causing intestinal ulcers, diarrhea, or facial edema.