"Boiling Won't Remove Them"... Rushing Instant Noodles with Hot Tap Water Poses Kidney Damage Risk

Using Hot Tap Water to Cook Instant Noodles for Speed
Heavy Metal Leaching Risk as Water Passes Through Pipes
Lead and Copper Not Removed by Boiling ? Caution Needed

Many people use hot tap water when cooking instant noodles, as it boils faster and is more convenient. However, there is a warning that this seemingly trivial habit could be detrimental to your health. The reason is that hot water does not come directly from the water treatment plant but flows through household boiler or water heater pipes, increasing the likelihood of various metal substances leaching into the water.

Different pipes for cold and hot water supply... Copper, lead, nickel, iron, zinc, and more can mix in

Reference photo to aid understanding of the article. Getty Images Bank

Recently, the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA) have recommended that only cold tap water be used for drinking or cooking. This is because the pathways for hot and cold tap water are different. Cold water is supplied directly from the water treatment plant to homes through water pipes, whereas hot water passes through boiler or water heater pipes before reaching the tap.

This process increases the risk of metals such as copper, lead, nickel, iron, and zinc leaching into the water, and the risk is even higher at elevated temperatures. In particular, it is known that the amount of lead leaching increases sharply in aging pipes. In fact, in 2022, a case was reported in an apartment complex in Mapo-gu, Seoul, where the level of phenol, a toxic substance, in hot water exceeded the drinking water standard.

Heavy metals that do not disappear even after boiling... Especially dangerous for children and pregnant women

Heavy metals mixed in hot water are not removed by boiling. While most organic compounds such as trihalomethanes (THMs), which are produced during chlorination of tap water, are eliminated through boiling, heavy metals like lead and copper are not affected by physical changes. As a result, cooking instant noodles or soups with hot water means you are ingesting these heavy metals directly.

Experts warn that if heavy metals accumulate in the body, they can damage major organs such as the nervous system, kidneys, liver, blood, and respiratory system, and may also act as carcinogens. Special caution is advised for children and pregnant women, as even small amounts of exposure can cause developmental disorders or negatively affect fetal health.

Reference photo to aid understanding of the article. Pixabay

Lead can cause neurodevelopmental disorders, learning disabilities, behavioral problems, kidney damage, and high blood pressure, and has a particularly severe impact on children's brain development. Mercury can result in central nervous system damage, memory loss, tremors, impaired vision and hearing, and kidney damage. Cadmium can lead to decreased kidney function, skeletal weakening (early-onset osteoporosis), lung damage, and an increased risk of cancer. Chronic exposure to heavy metals can cause neurological disorders, weakened immunity, chronic kidney disease, increased cancer risk, and reproductive and developmental abnormalities.

To safely consume tap water, always use cold water for cooking. If the tap has not been used for an extended period, it is also advisable to let the water run for 10 to 30 seconds to flush out any impurities that may have accumulated in the pipes before use.