It’s nothing new that all the fat, sugar, and salt in fast foods are hurting our health and immune systems. But a new study has highlighted the significant impact poor dietary choices can have on our gut microbiomes and DNA, which can then be passed onto our children.

Published in the Nutrition Journal, the study found that fast food consumption could lead to a higher chance of inflammation, infection, cancer, and allergic and auto-inflammatory diseases. And when we eat large amounts of unhealthy foods, these dietary choices become etched into our DNA and our gut microbiome. Food and lifestyle choices can permanently upset the balance of bacteria in our guts, and work against our immune system. “Our bodies are a kind of mini-ecosystem, and anything that disturbs our bacteria can alter our health in profound ways,” said Dr. Ian Myles, author of the study and a physician at the National Institute of Allergy and Infectious Diseases, according to Time.

The Western diet, in particular, was pinpointed as the culprit when it came to upsetting our immune systems and gut microbiomes. The authors write that it is also a “potential contributor to the increase in immune-mediated diseases.” They continue in their conclusion, saying that it "appears unlikely that synthetic supplements or probiotics will be able to fully counterbalance the damage of our dietary choices, let alone undo them, if they are not accompanied by lifestyle modifications. Of potentially greatest concern, our poor dietary behaviors are encoded into both our DNA scaffolding and gut microbiome, and thus these harmful immune modifications are passed to our offspring during their most critical developmental window.”

Previous research has shown that you are what you eat in the sense that the “gut flora” in your stomach adapts depending on your diet. The bacteria in our gut are “surprisingly responsive” to diet changes, the researchers found. They saw adjustments in both the types of bacteria and their gene expressions. Other studies have focused on how a mother's diet could impact her baby's DNA. Myles' study is just another reminder that improving lifestyle and eating habits could have an effect not only on our own health and well-being, but that of our offspring as well. Individuals need to do “[t]hings that most people know — but do not feel confident in their ability to accomplish right now: eliminate processed sugars, eliminating homogenized fats,” Myles 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.”

Source: Myles I. Fast food fever: reviewing the impacts of the Western diet on immunity. Nutritial Journal. 2014.