5 Types of Vegetables That “Naturally Contain Toxi.ns” — Always Blanch Them Before Eating

Few people realize that certain vegetables naturally contain toxins. Eating them raw or without blanching in boiling water can potentially harm your health.

According to nutrition experts, blanching vegetables not only removes natural toxins and reduces bitterness but also washes away pesticide residues, and even kills bacteria and parasite eggs on the surface. More importantly, studies have shown that blanching vegetables properly can help reduce nitrites — compounds that may be harmful if they accumulate in the body over time.

So, which vegetables should always be blanched before eating?

1. Vegetables High in Oxalic Acid

Plants like purslane and bitter melon contain high levels of oxalic acid, which can hinder calcium absorption and increase the risk of kidney stones over time. Blanching these vegetables in boiling water for 15–30 seconds can remove most of the oxalic acid, making the dish lighter and easier to eat.

2. Beans That May Cause Food Poisoning

Green beans, string beans, and kidney beans can cause stomach pain, nausea, or vomiting if eaten raw or undercooked because they contain saponins and lectins. To ensure safety, they should be blanched or boiled thoroughly for 5–10 minutes until their raw green color fades and their pungent odor disappears.

3. Vegetables That Are Hard to Wash Clean

Broccoli and cauliflower have many crevices that can trap dirt, pesticides, or insect eggs. The best method is to soak them in salted water or flour water for about 10 minutes, then blanch quickly in boiling water for 1–2 minutes to ensure cleanliness and food safety.

4. Vegetables Prone to Nitrite Formation

Pickled vegetables such as sauerkraut or fermented mustard greens can contain high levels of nitrites if consumed immediately. Before cooking, blanch them in boiling water for 30 seconds to 1 minute. This not only reduces nitrites but also mellows the sharp taste, making the pickles more fragrant and pleasant.

5. Wild Edible Plants That Can Be Toxic

Certain wild or foraged vegetables, such as dandelion greens or daylily buds, naturally contain toxins. These must be blanched in boiling water and then soaked in cold water afterward to remove most of the toxins before being cooked.

Expert Recommendations

When blanching vegetables, always wait until the water is fully boiling before adding them. Use plenty of water, keep the blanching time appropriate, and immediately place the vegetables in cold water to preserve their color and crisp texture.

What may seem like a small extra step is, in fact, an important safeguard for your family’s health.