Cold and flu season is here, which means it’s more important than ever to keep your immune system in fighting form. While you’ve probably seen the powders and pills and other miracle shortcuts to boosting your immune system, the truth is that because of the link between gut health and immune system function, the best way to bolster your immunity is with foods that help your immune system. We all think about immunity after we’re already sick, but in terms of staying well, it’s much more important to boost your immune system beforehand. That means learning to identify superfoods for immune system function to keep disease at bay, and if you do get sick, choosing the right foods to fight a cold or other infection.
To help you navigate the topic of foods for immunity, we gathered together a panel of experts to weigh in. The panel included board-certified internist, functional medicine doctor, and author of Happy Gut, Dr. Vincent Pedre; health coach and author of The Real Food Grocery Guide, Maria Marlowe; and INDAY founder Basu Ratnam. They each gave us their experience and science-backed insights on what you should eat to keep disease at bay all year long. Watch the panel discussion above, or read on to learn more.
Would you rather listen than read? Get an audio version of this guide on The WellBe Podcast.
The Link Between Gut Health and Immune System Function
If you’re not sick to your stomach, it might feel counterintuitive to focus on foods to fight a cold or other illness. But, as we explore in-depth in our gut health guide, there’s a strong connection between gut health and immune system function, which means that what you eat has a direct relationship on how often you get sick (and how long you stay sick), regardless of whether your illness has any gut-related symptoms.
Dr. Vincent Pedre explains that 70% of your immune system is found in the lining of your gut, where microbes patrol everything that comes through. “If you think about it, what we’re putting in our mouths is our biggest interaction with the outside world,” he says. He also points out that this interaction includes more than just the foods you choose to eat — there’s also a lot of unseen matter, like fungi and bacteria that’s on your food.
In an ideal world, our immune system does a great job of protecting us against harmful invaders from the outside world. But when gut health breaks down, that changes. Any number of things can break down gut health, including antibiotics and inflammatory foods. When gut health is compromised, it means that foods that normally wouldn’t have been an issue can trigger an immune response. That, in turn, makes you susceptible to getting sick, because as Dr. Pedre explains, “if your immune system is fighting a war in your gut, it doesn’t have the resources to deal with other issues.”
In other words, when your gut health is out of whack, your immune system is too distracted and busy dealing with that problem to prevent other things — like viruses, pathogens, infections — from getting in. On the flipside, if you heal your gut lining, your immune system can get back to doing what it’s supposed to do: fend off disease-causing invaders. The link between gut health and immune system function can’t be overstated, which is why it’s so effective to focus on foods that help your immune system.
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What are the Best Foods to Fight A Cold?
If you want to heal your gut to boost your immunity, you need to look at your diet. So, what are the best foods to fight a cold, virus, or other infection? Well, if you want to sum up our experts’ thoughts on food for immunity in one sentence, it would be “eat the rainbow.” What that means is that you should eat a wide range of diverse food that delivers your body all the nutrients you need to boost your immune system.
Marlowe recommends that at least 50 percent of your plate at each meal be veggies, and that you do your best to eat across the color spectrum (different colored produce generally indicate different vitamins, so eating a rainbow of colors ensures you’re getting all the vitamins you need). At INDAY, their brightly colored Indian dishes are not only Instagram-friendly, but the different colors and varying textures also make the meals nutritious, as well as engaging. The diverse colors, flavors, and textures (Crunch! Spice! Creaminess!) help you pay attention while you’re eating, so you tune in to how your body responds to the food.
If you’re looking for more specific, in-depth guidelines on foods that help your immune system, here are some of the stand-out foods for immunity:
- Bone broth. It contains minerals, and is also very healing for the gut lining, which in turn helps boost the immune system.
- Cruciferous veggies. Marlowe explains that these vegetables support your body’s detox system. They include things like broccoli, cauliflower, and Brussels sprouts.
- Ginger. Known to have antibacterial and antiviral properties.
- Garlic. Known to have antibacterial and antiviral properties.
- Onion. Known to have antibacterial and antiviral properties.
- Mushrooms. Marlowe explained that mushrooms are known as one of the best immune system-boosting foods, but they must be cooked for you to feel the benefits. Pedre recommends shiitake, chaga, or reishi mushrooms, and notes that they have certain properties that increase natural killer cells, which fight viruses.
- Turmeric. Known to have antiviral and anti-inflammatory properties.
- High-fiber foods. Fiber is great for digestion, which helps boost gut health. High-fiber foods include leafy greens, beets, artichokes, apples, mangoes, and lentils, as well as whole, unprocessed grains.
- Zinc-rich foods. Zinc has powerful disease-fighting properties, and while you can take a supplement, it’s always better to choose whole food sources. Oysters, pumpkin seeds, sunflower seeds, and sesame seeds all have high zinc content.
What Are the Worst Foods for Your Immune System?
Just as certain foods support our immune system and help us fight off pathogens, infections, and viruses, other foods will suppress our immune system and make us more susceptible to things like colds and the flu. So what should you avoid if you’re looking to improve your immunity? The answer is short and sweet: Sugar is definitely the bad guy when it comes to immunity.
“Sugar is the biggest immune suppressor,” Dr. Pedre says. “A diet that’s rich in sugar is a going to be a diet that inhibits your immune system.” He goes on to explain that if you incubate white blood cells (they’re the ones that fight against infection) with sugar, it stuns them for about six hours so they can’t function.
Pedre also emphasizes the fact that sugar doesn’t mean just dessert or cane sugar. It can come from a lot of different places, like starches (white rice, white bread, crackers) and many processed foods. He also notes that artificial sweeteners have their own detrimental effect, because they alter the way your gut flora functions and increase your blood sugar as a result.
Besides sugar, some of the worst foods for immunity include those grown with pesticides or not grown organically; toxic metals such as cadmium, lead and mercury are immunosuppressive. Too much sodium causes dehydration, which can also impair immune function, as can inflammatory foods (foods that commonly cause inflammation include fried foods, excessive red meat, refined carbs, margarine, and soda). And of course, any foods to which you’re allergic or have a sensitivity will put your gut into battle mode, thus leaving your immune system unable to fight off illness.
So to sum up, the worst foods for your immune system are:
- Excess sugar
- Produce grown with pesticides
- Foods that contain heavy metals (different heavy metals can occur in a number of different foods, but some examples include some fish, rice, and leafy greens, as well as unfiltered water)
- Excess sodium
- Fried foods
- Red meat
- Refined carbohydrates
- Margarine
- Soda
What Are the Superfoods for Immune System Function?
While eating the right foods for immunity is essential, many of us also want to supplement that with a little boost. A lot of people swear by certain immune boosters, but many of the commonly held beliefs about how to boost your immune system aren’t based on any evidence. Still, there are some true superfoods for immune system function — luckily, our expert panel members helped us discern the difference.
Two superfoods for the immune system that you’ll often hear mentioned are ginger and cayenne pepper. According to Dr. Pedre, these natural immune boosters are legit, and work best for nipping a sore throat in the bud. Ginger is antimicrobial, so it’ll kill the bad stuff as it goes down your throat, while cayenne can promote vascular and metabolic health. Try one of these recipes for homemade ginger shots.
The news isn’t so good when it comes to perhaps the most famous of natural immune boosters, vitamin C. As it turns out, when it comes to foods to fight a cold, vitamin C supplementation isn’t that effective. According to one study, taking a daily vitamin C supplement did not reduce the risk of getting a cold among the general population.
Instead, trade your vitamin C supplement for zinc or elderberry. Zinc can help reduce cold duration, and elderberry has been shown to reduce the duration of colds by 3 or 4 days.
Taking an Ayurvedic Approach to Foods that Help Your Immune System
One of our experts on the panel, Basu Ratnam, spoke to a specific approach to eating foods for immunity: Ayurveda.
Ratnam grew up with an Ayurvedic tradition, which meant that both his parents preached from an early age that food was medicine. “I grew up in a household where the emphasis was always on looking at food as a source of healing,” he says.
The philosophy behind Ayurveda is that food is meant to be at the center of your life balance. This belief is one that makes sense intuitively, given the powerful role diet plays in both physical and mental well-being, and it’s also a belief that has stood the test of time. Ratnam says that one of his biggest frustrations with the wellness and healthy eating movement was that he felt like he always needed to be caught up with the latest trend to know what was “healthy” to eat. Ayurveda, on the other hand, has been around for thousands of years, regardless of trends.
These days, Ratnam explains, eating with an Ayurvedic approach is “in vogue” because it draws from dietary principles that have become more mainstream as the wellness movement grows and people become more educated about what to eat. That approach includes eating whole foods, eating seasonally, and using spices that enhance the relationship between your gut health and immune system. It adjusts spices seasonally, using cooling herbs in the summer and in the wintertime, choosing spices that boost immunity and circulation and reduce inflammation. Ayurvedic eating also focuses on avoiding universal irritants like gluten, dairy, processed foods, sugar, and preservatives. “We start with the highest quality ingredients and then try to activate them or use spices that enhance their healthful qualities,” Ratnam says.
And while you definitely don’t need to follow an Ayurvedic diet to eat foods that help your immune system, it just so happens that there’s quite a big overlap between the two!
The WellBe Takeaway: What to Remember About Gut Health, Diet, and Immunity
We’re all about preventing illness through diet and lifestyle, rather than waiting to get sick and treat it with pharmaceutical medicine. That’s why it’s such great news that you can use foods that help your immune system, and even eat certain foods to fight a cold or virus if you do come down with something.
Here are the key WellBe takeaways when it comes to foods that help your immune system:
- 70% of the body’s immune system resides in the gut’s lining.
- The link between gut health and immune system function explains why what we eat is so important for immunity.
- When gut health is compromised, your immune system is preoccupied and thus can’t properly protect the body from disease.
- Healing the gut lining through proper diet can return your immune system to optimal function.
- Vegetables, especially cruciferous veggies, are some of the best foods for immunity. Other foods that help your immune system include garlic, onions, ginger, bone broth, mushrooms, and turmeric.
- When it comes to the worst foods for immunity, sugar is at the top of the list.
Watch the video above for the first part of our chat with the trio, which also covered: eating healthy while traveling, supplement safety tips, supplementation for plant-based diets, what your sugar cravings mean, the benefit of eating salad before the main course, the downside of juice, food sensitivity tests, nightshade sensitivity, the benefits of cooked vegetables vs. raw, parasites in foods, food-based vs. supplement-based probiotics, why you should avoid carrageenan (is it in your dairy-free milk?), the new trend in smoothies, signs you should skip coffee (and what you should drink instead), Bulletproof coffee, colonics, and the panelists share their go-to breakfasts. (Click the links to jump right to the specific topic!)
What are your favorite foods to fight a cold? Tell us in the comments below!
Would you rather listen than read? Get an audio version of this guide on The WellBe Podcast.
Citations:
- West, C. et al. “The gut microbiota and inflammatory noncommunicable diseases: Associations and potentials for gut microbiota therapies.” The Journal of Allergy and Clinical Immunology. Volume 135, Issue 1, p3-13, January 1, 2015.
- Dai, X et al. Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults, Journal of the American College of Nutrition, 34:6, 478-487. 2015.
- Minich DM. A Review of the Science of Colorful, Plant-Based Food and Practical Strategies for “Eating the Rainbow” [published correction appears in J Nutr Metab. 2020 Nov 28; 2020:5631762]. J Nutr Metab.
- Singh, Reena et al. “Heavy metals and living systems: An overview.” Indian journal of pharmacology vol. 43,3 (2011): 246-53. doi:10.4103/0253-7613.81505.
- Montonen J, et al. Consumption of red meat and whole-grain bread in relation to biomarkers of obesity, inflammation, glucose metabolism and oxidative stress. Eur J Nutr. 2013 Feb;52(1):337-45.
- McCarty, Mark F et al. “Capsaicin may have important potential for promoting vascular and metabolic health.” Open heart vol. 2,1 e000262. 17 Jun. 2015.
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