Pickled Vegetables (e.g., pickled cucumbers, pickled eggplants...)
Pickled vegetables are a common and beloved dish in many Vietnamese households. However, overconsumption or using improperly preserved pickles can have severe repercussions for liver health.

The reason for this is that during the pickling process, especially when the brine is not prepared correctly, nitrates in vegetables can be converted into nitrites. When nitrites combine with amino acids in the body, they form nitrosamines, a compound known for its cancer-causing potential, particularly for liver and digestive system cancers.

According to the U.S. National Cancer Institute, nitrosamines are a group of potent carcinogens found in improperly processed or fermented foods.

Furthermore, pickled vegetables tend to be high in salt. A diet high in salt can not only strain the kidneys but also indirectly affect liver function.

Recommendation: Opt for pickled vegetables that have a light yellow color and a balanced acidity level, and avoid consuming them in large quantities. It's best to make them at home to ensure hygiene.

Damaged or Spoiled Vegetables
Some people, in an effort to save food, continue to use vegetables that are bruised or starting to rot, simply cutting away the damaged portions. However, this is a serious mistake.

Damaged vegetables are more likely to produce toxins. When plant cells are broken, they create an environment conducive to bacteria and mold growth. Certain molds can generate mycotoxins, such as aflatoxins, which are among the most potent liver toxins.

The World Health Organization (WHO) warns that aflatoxins are highly toxic and can cause significant liver damage, increasing the risk of liver cancer.

Even if the damaged areas are removed, toxins and bacteria can spread to other parts of the vegetable that are not visibly affected. Consuming such vegetables forces the liver to work harder to detoxify the body, which may cause long-term liver damage.

Recommendation: Never eat vegetables that are damaged, moldy, or rotten. "Saving" food in this case can be detrimental to your health.

Sprouted Potatoes
Sprouted potatoes are a common sight, and many people simply remove the sprouts and continue to use the potato. However, sprouted potatoes can pose a risk to health.

When potatoes sprout or turn green, they produce solanine, a toxic alkaloid. Solanine is most concentrated in the sprouts, the green skin, and near the sprouting eyes. According to the U.S. Food and Drug Administration (FDA), consuming potatoes with high solanine levels can cause symptoms of poisoning such as nausea, diarrhea, stomach pain, headaches, and, in severe cases, neurological and liver damage.

Although the liver has detoxification abilities, regular exposure to solanine, even in small doses, can put stress on the liver and potentially cause long-term harm.

Recommendation: It's safest to discard sprouted or green potatoes. If only a few small sprouts are present, remove all the sprouting eyes and green areas, peel the potatoes thoroughly, and soak them in water before cooking. However, the safest option is to avoid using them altogether.

Over-Soaked Wood Ear Mushrooms
Dry wood ear mushrooms are a convenient ingredient, but if they are soaked for too long or left overnight, they can become a health hazard.

When wood ear mushrooms are soaked for an extended period, especially in warm temperatures, the bacterium Pseudomonas cocovenenans can grow and produce bongkrekic acid – a highly potent toxin. This toxin can cause severe damage to various organs, including the liver, kidneys, and heart, and in some cases, can even lead to death.

There have been reports of food poisoning due to bongkrekic acid from improperly soaked wood ear mushrooms in various countries, with a high fatality rate. Bongkrekic acid is heat-resistant and is not destroyed by boiling at high temperatures.

Recommendation: Only soak wood ear mushrooms for the necessary time (1-2 hours) and cook them immediately after soaking. Never soak them overnight or in large quantities for storage.

Unripe Tomatoes
Green or under-ripe tomatoes can contain toxins that may be harmful if consumed in large quantities. This is because unripe tomatoes contain significant amounts of tomatine, a glycoalkaloid similar to solanine found in green potatoes. While tomatine is less toxic than solanine, consuming large amounts can still cause symptoms such as nausea, vomiting, diarrhea, stomach pain, dizziness, and headaches.

According to the U.S. National Library of Medicine, tomatine can be toxic when consumed in large quantities, especially from unripe tomatoes.

When the body absorbs tomatine, the liver must work to metabolize and eliminate the toxin, which can put pressure on the liver, especially for those with weakened liver function.

Recommendation: Only eat tomatoes that are fully ripe and red. Avoid consuming green or under-ripe tomatoes.