If You Want to Boost Immunity, Look to the Gut

If You Want to Boost Immunity, Look to the Gut

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You likely know that what you eat affects your weight and energy. But did you know it also shapes your immune system? In fact, 70% of your immune cells live in the gut, making gut health one of the most powerful ways to defend your body against illnesses.

The Gut–Immunity Connection

"Nutrition is a key modulator of immune function," says Dr. David Heber, professor emeritus of medicine at UCLA Health. The gut microbiome – trillions of bacteria and fungi living in your digestive tract – directly communicates with immune cells. A healthy, diverse microbiome trains immune cells to fight infections while keeping inflammation in check.

Dr. Jonathan Jacobs from UCLA adds, "What’s present in the gut determines what education immune cells get." In simple words, healthy gut bacteria = smarter immune cells.

Why Diet Matters

The food you eat directly feeds your gut bacteria. A diet rich in fiber and plant-based foods helps beneficial bacteria thrive, boosting immunity. On the other hand, a typical Western diet – high in sugar, processed foods, and saturated fats – reduces gut diversity and promotes inflammation, increasing the risk of chronic diseases.

“Gut bacteria subsist on complex carbohydrates and fiber that our own cells can’t digest,” says Dr. Jacobs. Fruits, vegetables, whole grains, and legumes are their favorite foods.

Gut health and immunity

Extra Weight and Immunity

Carrying extra fat can weaken immunity. “Obesity affects the immune system directly,” says Dr. Vijaya Surampudi. Fat tissue, once thought to be inactive, is now known to release chemicals that trigger low-grade inflammation, putting stress on immune cells.

Maintaining a healthy weight through a fiber-rich, plant-based diet helps reduce inflammation and strengthens immune defenses.

Doctor-Recommended Strategies to Boost Gut Health

  • Eat plenty of plants: Aim for 7 servings of colorful fruits and vegetables daily.
  • Choose healthy fats: Use olive oil, avocado oil, or add avocado slices to salads. Healthy fats support immune cell function.
  • Include wild-caught fish: Rich in omega-3s, which lower inflammation. 2–3 servings weekly is ideal.
  • Get protein at every meal: Muscle, made from protein, is an endocrine organ that supports immunity. Opt for plant-based proteins like lentils, chickpeas, and nuts when possible.
  • Use spices and herbs: Garlic, turmeric, and ginger are rich in phytochemicals that nourish gut bacteria.

The Bottom Line: If you want stronger immunity, start with your gut. Feed it with fiber-rich, diverse plant foods, maintain a healthy weight, and your immune system will thank you.