How to Build Your Immune System with a Plant-Based Diet

Posted by Kristen Carli, RD on

After COVID, interest in immunity and building immune strength became top of mind. While there are many things to do to improve your immunity, including hand-washing and basic hygiene, fine-tuning your diet can prove to be especially effective in combination with these efforts.

How to strengthen your immune system?

Your immune system is fighting off infection frequently. It is exposed to various pathogens and innately targets these intruders when possible. Sometimes, the infection is evasive or too strong for your immune system and as a result, you are more prone to getting sick. What can you do to strengthen your own internal defensive army?

Research shows that several factors can play into building and maintaining a healthy immune system. These include the following:

1. Eat a healthy diet

With the myriad of confusing opinions around nutrition and dieting, it is difficult to know what is truly “healthy”. The Dietary Guidelines for Americans, which are health guidelines for American citizens developed by the USDA, recommend that we consume about 2 ½ cups of vegetables and 2 cups of fruits each day. For those not following a plant-based diet, this may be particularly challenging. For experts in plant-based nutrition, this may sound like a piece of cake, as the majority of your diet is already composed of plant based food. Additionally, the Dietary Guidelines recommend 6 ½ ounces of grains and 5 ½ ounces of protein per day. A diet composed of a balance of vegetables, fruits, grains and protein is considered “healthy”.

The Dietary Guidelines also recommend avoiding sources of saturated fat, added sugars and sodium. Where will you find saturated fat in foods? Most saturated fat is found in animal-based products like beef, pork, poultry, dairy and eggs, as well as tropical oils like palm oil and coconut oil. Likewise, what are the top sources of sodium? Sodium is found in a lot of foods, but is especially high in processed meats, dairy, cold cuts, canned soups, pizza, breads, rolls, processed snacks, and poultry. By following a plant-based diet, you are already at an advantage because you do not eat animal products that are high sources of saturated fat and sodium. As a result, you need to be particularly mindful of sources of added sugars and sodium in processed foods. One unsuspecting source of added sugars and sodium is in canned fruits and vegetables. Be sure to always check the nutrition facts label of canned products in order to limit these ingredients.

2. Eat plenty of fruits and vegetables

As a plant-based eater, you may be used to eating a lot of fruits and vegetables, but most people are not eating nearly enough. MyPlate guidelines, which are created by the USDA, recommend aiming for half of your plate at each meal to be composed of fruits and/ or vegetables. Maybe, for you, that looks like fruit with breakfast and vegetables with lunch and dinner. Or maybe you serve both at each meal. However you need to make it fit best into your lifestyle, the goal is to increase total fruit and vegetable consumption.

3. Maintain a healthy weight

Almost half of Americans are living with obesity. Being overweight or obese can increase your risk of developing many diseases. Research shows that a well-balanced plant-based diet can be helpful for achieving weight loss and maintaining an appropriate body weight. In addition to diet, regular physical activity is essential towards maintaining an appropriate body weight. A good rule of thumb is to aim for at least 150 minutes of physical activity per week.

4. Minimize stress

As more and more research is coming out about stress, it is becoming more apparent just how influential stress is on many health outcomes. Stress has a huge role in immune function and development of chronic diseases. In order to minimize daily stressors, it is a good idea to incorporate a regular form of self-care or relaxation into your daily or weekly routine. This may look different from person to person. Meditation has been shown to be a very effective method of reducing stress levels. That being said, it might not be your favorite way to decompress. If that is the case, find something that works better for you. Some of my patients love to decompress with a cup of chamomile tea before bed. Some enjoy journaling. Others prefer going on a walk in nature or playing with their pets. The idea here is to find something that truly works to lower your personal stress levels. Once you find your ideal form of relaxation, schedule it into your routine so that it is prioritized.

Leaky Gut, Intestinal Permeability & Fiber

You’ve likely heard of the term “leaky gut”, but might not know what this actually means. Lining the inside of your gastrointestinal tract are many cells whose job it is to absorb the nutrients for your body meanwhile keeping out potential pathogens from entering your bloodstream. When one’s gut health is weak, the intestinal cells lose their ability to act as a barrier. They start to slip aside and lose their tight grips between one another. This allows for potential pathogens to sneak in between these cells of the gastrointestinal lining, entering your bloodstream. The drooping gut wall allows for these pathogens to “leak” inside. This is why it is called a “leaky gut”.

A plant-based diet is particularly helpful for strengthening gut health. Because fruits and vegetables, as well as other plant foods, are composed of sources of fiber, these foods can provide nourishing energy for the healthy gut bacteria in your gastrointestinal system. Sources of fiber, particularly prebiotic fibers, along with sources of healthy bacteria (aka probiotics) promote gut health.

So where can you find food sources of prebiotic fibers? These prebiotic fibers are not found in any animal-based foods. They can only be found in certain plant-based foods. Seek out dandelion greens, onion, garlic, Jerusalem artichokes, leeks, banana, barley, asparagus, oats, seaweed, apples, and flaxseeds for high prebiotic content. 

Micronutrients & Deficiency

Research shows that being deficient in certain nutrients can lead to a decreased immune system. So how do you know if you are eating enough micronutrients through your diet? Most individuals following the Standard American Diet (SAD) do not receive enough nutrients through food, particularly lacking in some key micronutrients, as they do not eat enough fruits and vegetables. Fruits and vegetables are not only healthy for us because they are low-calorie. They are also very rich in vitamins and minerals, which are micronutrients that our bodies need to function optimally. As a result, a well-planned plant-based diet is often low-calorie but nutrient-dense. In particular, nutrients such as vitamin B6, zinc, vitamin C, vitamin E and magnesium have been shown to be involved in the maintenance of immune function. Eating a well-balanced nutrient-dense plant-based diet will provide plenty of these nutrients.

What constitutes a nutrient-dense plant-based diet?

As a plant-based eater, your diet is composed of plenty of fruits and vegetables, and hopefully a reliable source of vitamin B12. As a result, your diet is very nutrient-dense. To ensure that you are getting enough micronutrients through your dietary intake, be sure to consume produce in a variety of colors. Have you ever heard the phrase “eat the rainbow”? This is what I’m referring to. Each color corresponds with various phytonutrients found in your produce. By ensuring that you consume red, orange, yellow, green, blue, purple, and white colored produce, you will consume a wide variety of phytonutrients.

In summary, to build your immunity with a plant-based diet, focus on the following priorities:

  • Eat a well-planned plant-based diet.
  • Base your meals on fruits and vegetables.
  • Engage in regular exercise.
  • Make stress-relief part of your routine.
  • Seek out food sources of prebiotics.
  • Eat the rainbow.



Kristen Carli is the owner of Camelback Nutrition & Wellness, a private nutrition practice in Scottsdale, Arizona specializing in chronic disease prevention and management as well as vegan/vegetarian nutrition. She is a health & wellness contributor for Momsley, an outlet devoted to serving the modern mom. Having a passion for nutrition communication, she has been featured in InStyle, Bustle, Livestrong, The List, MyFitnessPal and many others. Kristen was selected to act as a Produce for Better Health Foundation Fruit and Vegetable Ambassador in Action, helping to promote the health benefits and importance of consuming fruits and vegetables. She also runs Mostly Green, a blog where she develops and shares simple plant-based recipes

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