Is it safe to eat sodium metabisulfite?

Sodium metabisulfite in food is safe for most people. However, people with sulfite allergies and asthma should avoid anything that contains sulfites.

Sodium metabisulfite is an organic salt commonly used in the healthcare and food industries. As a food additive, it is used as a preservative. When used as a health product, it is most often used in hair care products. Another common use of sodium metabisulfite is as a disinfectant. So, is this bad for you? Well, it all depends on the exposure. Sodium metabisulfite keeps your food fresh for longer without causing harm to you. Multiple studies have been conducted and no carcinogenic effects have been found. There are some studies showing that sulfites can cause elevated copper levels in the kidneys, but any sulfites you get from sodium metabisulfite are diluted much more than what was used in the experiments. In fact, reactions to sodium pyrosulfite are likely to only occur in people who are allergic to sulfites or who have been exposed to pure sodium pyrosulfite.

When pure sodium metabisulfite is ingested, it releases sulfite upon contact with stomach acid, which can cause gastrointestinal damage. Inhaled sodium metabisulfite is a strong irritant that can cause shortness of breath and coughing. Sodium metabisulfite is also an irritant to the skin and eyes.

Another danger is its decomposition. Although sodium metabisulfite is nonflammable, when heated, it releases toxic gases including sulfur oxides. Additionally, sodium metabisulfite is known to inactivate some drugs, especially those in the epinephrine family.

While sodium metabisulfite is safe for most people who are not allergic to sulfites, it has been shown to worsen asthma symptoms. Additionally, sulfites are known to destroy thiamine (vitamin B1).

Still, if you're wondering if sodium metabisulfite in food causes premature death, the answer is unlikely. Remember, it's not pure sodium metabisulfite in your food, other chemicals can neutralize its toxicity.