What Are the Worst Ingredients for Your Immune System?

On This Page

    Can the foods you eat impact your immune health? Let’s look into what ingredients can have an adverse effect on your body’s defense system.

    Our immune systems help keep us safe from foreign invaders that exist in the world around us. We all know that practicing good hygiene, staying up-to-date on our immunizations, and taking extra precautions during cold and flu season can help keep us from getting sick. But did you know that the food and beverages you consume have an impact on your immune system too? Studies have shown that some common ingredients can actually hinder our immune systems, keeping it from functioning at its best. Let’s explore the ingredients that research suggests are the worst for our immune responses.

    The Five Worst Ingredients For Your Immune System

    So which ingredients should be avoided for your immune health to thrive? Studies show that the five worst ingredients are sugar, salt, AGEs, phthalates, and artificial sweeteners. These ingredients can all impact your immune system in different ways when consumed in excess.

    Sugar And Immunity

    Who doesn’t love a sweet treat? Sugar is a major part of our diets, even when we try to avoid it. It's added to a lot of processed foods and many dishes in restaurants use it, even when the dish doesn’t taste sweet. While many of us know that sugar is high in calories and can cause damage to our teeth, sugar also has an impact on our immune response. A diet high in sugar can be detrimental to the functionality of our leukocytes, the most vital immune cells in our bodies.

    How Long Does Sugar Suppress The Immune System?

    Leukocytes, also known as white blood cells, are key players in the body’s defenses. They detect invaders in the body and attack them, eliminating threats from the body. When we consume a significant amount of sugar, our white blood cells are slowed. Research says they may be slowed down for up to five hours! Additionally, a high-sugar diet can cause major changes within your gut biome-- which may be another good reason to try and scale back.


    Salt is not only delicious, but an important element of our diets. It’s vital for maintaining our electrolyte balance and helps regulate fluids in the body. However, when too much salt is included in your diet, it can have adverse effects. Dietary Guidelines for Americans recommends adults limit sodium intake to less than 2,300 mg per day—that's equal to about 1 teaspoon of table salt. With the amount of prepackaged, processed foods we consume on a daily basis (which can be extremely high in sodium,) many people are taking in well over that amount of salt per day.

    So what does this mean for our immune health? Studies have found that a high-sodium diet can cause an excessive immune response, which in turn makes it difficult for our immune systems to balance out again and respond properly to illness or injury. Additionally, salt can suppress a type of macrophage that is vital in wound healing, preventing the macrophages from functioning properly.

    AGEs (Advanced Glycation End Products)

    Advanced glycation end products, or AGEs, are commonly found in animal-derived foods, especially those that have high levels of fat and protein. AGEs are formed during the cooking process. When food is cooked at a high temperature (fried, broiled, or grilled) or heavily processed, it is more likely to contain a high amount of AGEs. AGEs have been found to be damaging to kidney health and slow down wound healing. However, if you enjoy eating a diet that’s heavy on meat, you can limit the production of AGEs through cooking for a shorter time at a higher heat, a longer time at a lower heat, or cooking with an acid like lemon juice or vinegar. Additionally, pairing your meats with cruciferous vegetables like broccoli, cauliflower, or brussel sprouts may help manage AGEs because of their high sulforaphane content.


    Phthalates are a man-made chemical that was originally designed to make plastic more durable. While phthalates are not intentionally being added to your food, they can leach into foods that come into contact with plastic during production and packaging. PVC tubing, gloves, bottles or plastic bags all contain phthalates. Additionally, phthalates are found in cookware, toys, personal care items, and many other plastic objects that we use every day. Phthalates have been found to disrupt hormone production in the body, either by mimicking our bodies’ hormones or blocking them completely.

    The way the food industry works now, it’s exceptionally difficult to avoid all phthalates all the time. However, it is possible to limit exposure by making certain choices when it comes to food purchases.

    Artificial Sweeteners

    Artificial sweeteners are commonly praised as an alternative to real sugar because they’re lower in calories. However, artificial sweeteners can be extremely bad for our health. They have been linked to a decrease in liver function and have been found to change your gut biome, which can be detrimental to immune health. Because artificial sweeteners are metabolized differently in our bodies, they may hurt or kill off helpful bacteria in our guts that help protect the digestive tract. Additionally, artificial sweeteners can cause increased production of different hormones in our bodies, including insulin, and have been found to potentially increase body weight as well.

    Is Chocolate Actually Good For Your Immune System?

    Most everyone loves chocolate, but does it impact our immune health? Fortunately, studies suggest that chocolate can help support immune health. Chocolate has a significant amount of antioxidant properties, which can keep our immune systems healthy. Scientists and doctors recommend choosing dark chocolate (70% or higher) as the higher amount of cocoa flavonoids and lower sugar content makes it the healthiest. Of course, consuming chocolate in excess can still have a detrimental effect, so it’s still best to keep it as a treat.

    Key Takeaways

    The important thing to take away from these guidelines is not ‘don’t ever eat these ingredients!’ Instead, consider how you can adjust your diet to minimize the amount of these harmful ingredients you’re consuming. Picking up natural, whole-food ingredients as opposed to processed or pre-packaged foods supports long-term health as well as the immune system. Maintaining your gut health is also an important part of your immune system. So, taking steps to ensure your diet is high in fiber and low in ingredients that compromise your gut biome’s health will ensure that you are doing what you can to support your immune system functioning at its best.

    You're unique. Your supplements should be too.

    Take the quiz
    Dr. Carla Montrond Correia ND, CNS
    Medical Content Manager
    Dr. Montrond-Correia is a licensed naturopathic physician and a certified nutrition specialist (CNS). She holds degrees from University of Bridgeport, Georgetown University, and University of Saint Joseph, and supplemented her education with internships in the health and wellness space. She's focused on research, herbal medicine, nutrigenomics, and integrative and functional medicine. She makes time for exercise, artistic activities, and enjoying delicious food.
    Our Editorial Staff
    Freelance Contributor
    The Care/of Editorial Team is made up of writers, experts, and health enthusiasts, all dedicated to giving you the information you need today. Our team is here to answer your biggest wellness questions, read the studies for you, and introduce you to your new favorite product, staying up to date on the latest research, trends, and science. Each article is written by one of our experts, reviewed both for editorial standards by an editor and medical standards by one of our naturopathic doctors, and updated regularly as new information becomes available.