TIME Diet/Nutrition

Processed Food Hurts Your Immune System—And Your Kids’ Too

Poor dietary habits get passed down in DNA

Society’s over-indulgence on foods full of sugar, salt and fat may be ruining our immune systems, a new study says.

A study published in Nutrition Journal looked at the impact the Western diet and lifestyle has on people’s immune function. It found that the large number of calories in processed and fast food may lead to health problems such as increased inflammation, reduced control of infection, increased rates of cancer, and increased risk for allergic and auto-inflammatory disease.

And we’re not only harming ourselves. The study authors point to research that poor dietary choices get “encoded” into both DNA scaffolding and into the gut microbiome, meaning that food and lifestyle choices can permanently change the balance of bacteria in our bodies and can weaken the immune system. It also means those changes can be passed onto offspring.

The study’s author, Dr. Ian Myles, says he was surprised by how heavily gut bacteria determined a child’s health. “Our bodies are a kind of mini-ecosystem, and anything that disturbs our bacteria can alter our health in profound ways,” he adds.

Myles, a doctor at the National Institute of Allergy and Infectious Diseases, said the only way for people to avoid these immune effects is to improve their diets.

“Things that most people know—but do not feel confident in their ability to accomplish right now: eliminate processed sugars, eliminating homogenized fats,” he said. “I always tell people there’s a big difference between fat in a piece of fish or meat, and eating fat as a part of processed foods.”

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