Nutrition for a Strong Immune System: What Works and What Doesn’t

Hey Peak Performer,

We’ve all been there: a scratchy throat, a sniffle, and the immediate desire to load up on anything that might keep us from getting sick. Whether it’s downing orange juice or considering a trendy detox, we all want to know how to keep our immune system strong. But what actually works, and what’s just hype? Let’s dive into some science-backed tips and bust a few myths along the way.

The Science-Backed Basics for Immune Health

Eat a Variety of Nutrient-Dense Foods The best thing you can do for your immune system? Eat a diverse, colorful diet. It’s not just about one “superfood” but a combination of vitamins and minerals that keep your immune defenses strong.

-- Vitamin C: It’s a classic for a reason. Vitamin C supports multiple immune functions, so getting enough from foods like oranges, strawberries, bell peppers, and broccoli is essential. While vitamin C may not stop a cold from happening, it can help shorten the duration if you consistently get enough (Carr & Maggini, 2017).

-- Vitamin D: Your body’s immune response relies on adequate vitamin D, which you can get from sunlight or foods like salmon, egg yolks, and fortified dairy. Low vitamin D levels are linked to a higher risk of infection, so a supplement might be helpful if you’re not getting enough (Aranow, 2011).

-- Zinc: This mineral is key for immune cell function. You’ll find zinc in foods like red meat, shellfish, seeds, and legumes. Taking zinc supplements may help shorten the length of a cold if you start early, but don’t overdo it (Hemil?, 2017).

Take Care of Your Gut Did you know that roughly 70% of your immune system lives in your gut? A healthy gut microbiome helps keep your immune system balanced, so prioritize foods that promote good gut bacteria. Think fermented foods like yogurt, kefir, kimchi, and sauerkraut. Foods high in fiber, like whole grains, fruits, and vegetables, are also great for gut health (Zmora et al., 2019).

Stay Hydrated Hydration is often overlooked, but it’s crucial. Water helps carry nutrients to your cells and flushes out toxins. Aim to drink plenty of water throughout the day, and don’t forget that hydrating foods like cucumbers and watermelon count, too.

Common Myths About Immune Nutrition

1. “Mega-Doses of Vitamin C Will Keep You Healthy” Vitamin C is essential, but taking massive doses won’t make you invincible. Research shows that while vitamin C might shorten a cold slightly, it won’t prevent it altogether. You’re better off focusing on a balanced intake through fruits and vegetables rather than supplements (Carr & Maggini, 2017).
2. “You Need to Do a Detox to Boost Your Immunity” Detoxes and juice cleanses sound appealing, but they’re mostly marketing. Your liver and kidneys already do an excellent job of detoxifying your body. Instead, support these organs by eating whole, unprocessed foods and drinking plenty of water. Skip the expensive cleanses and focus on nutrient-dense meals instead.
3. “Avoid Fat to Keep Your Immune System Healthy” Fats have gotten a bad reputation, but healthy fats are essential for your immune system. Omega-3 fatty acids, found in fatty fish, walnuts, and flaxseeds, help reduce inflammation and support immune function. So, don’t shy away from these healthy fats—they’re an important part of your diet.
4. “Supplements Are the Best Way to Boost Immunity” Supplements can be helpful if you’re deficient in something, but they’re not a replacement for a balanced diet. Whole foods offer a complex mix of nutrients that work together in ways that a pill can’t replicate. Supplements should only fill in gaps, not be your main defense.

Foods to Include More Often During Cold and Flu Season

When cold and flu season hits, what you eat can make a difference in how your immune system handles potential threats. Including certain foods in your daily diet can help ensure you’re giving your immune system the tools it needs to function at its best. Here are some nutrient-packed options to keep in mind:

1. Citrus Fruits We’ve all heard about vitamin C and its role in immune health, and citrus fruits like oranges, grapefruits, lemons, and limes are some of the best sources. Vitamin C helps stimulate the production of white blood cells, which are key to fighting infections. Try adding citrus slices to your water or tossing orange segments into a salad for a refreshing boost.
2. Leafy Greens Kale, spinach, Swiss chard, and other leafy greens are packed with vitamins A, C, and E—nutrients that are critical for maintaining a healthy immune system. These greens are also loaded with antioxidants, which can help reduce inflammation. Add them to smoothies, sauté them as a side dish, or mix them into soups.
3. Garlic Garlic does more than add flavor to your meals—it also has immune-boosting properties. Its power comes from allicin, a sulfur-containing compound known to enhance the immune response. Studies have found that regular consumption of garlic may help reduce the severity of colds and flu (Percival, 2016). Try incorporating fresh garlic into your cooking, from pasta sauces to roasted vegetables.
4. Ginger Ginger has long been used for its anti-inflammatory and antioxidant properties. It can also help soothe a sore throat and reduce nausea, making it especially helpful when you’re already feeling under the weather. Add fresh ginger to tea, soups, or stir-fries for an immune-friendly kick.
5. Yogurt and Other Probiotic-Rich Foods Remember how important gut health is for immunity? Probiotic-rich foods like yogurt, kefir, kimchi, and sauerkraut promote a healthy gut microbiome, which in turn supports immune function. Look for yogurts labeled with “live and active cultures,” and aim for options low in added sugars. You can also make a habit of adding a spoonful of sauerkraut to your sandwiches or enjoying a bowl of probiotic-rich miso soup.
6. Berries Berries like blueberries, strawberries, and raspberries are full of antioxidants and vitamin C. They can help protect your immune cells from damage caused by free radicals. Enjoy them in smoothies, mixed into oatmeal, or simply as a sweet snack. Frozen berries are a great option too, especially when fresh ones aren’t in season.
7. Mushrooms Certain types of mushrooms, like shiitake, maitake, and reishi, contain beta-glucans, compounds that may enhance immune function. Mushrooms also provide vitamin D, especially when exposed to sunlight. Add mushrooms to soups, stir-fries, or as a savory topping for toast.
8. Almonds and Other Nuts Vitamin E is a powerful antioxidant, and almonds are one of the best sources. Just a small handful provides a good portion of your daily needs, helping to keep your immune system strong. Walnuts, Brazil nuts, and sunflower seeds are also great choices, as they contain healthy fats and other immune-supporting nutrients like selenium and zinc.
9. Fatty Fish Salmon, sardines, and mackerel are rich in omega-3 fatty acids, which help lower inflammation in the body and support immune health. They also contain vitamin D, which plays a role in activating immune cells. If you don’t eat fish, consider getting your omega-3s from plant-based sources like chia seeds, flaxseeds, and walnuts.
10. Green Tea Green tea contains antioxidants called catechins, which are known to have immune-boosting properties. It also provides a small amount of L-theanine, an amino acid that may aid in immune response. Sip on green tea throughout the day, or try adding a squeeze of lemon for an extra dose of vitamin C.

Quick Tip: Make It Easy to Include These Foods

• Breakfast: Add berries and a sprinkle of nuts to your oatmeal or yogurt.
• Lunch: Make a hearty salad with spinach, kale, and citrus segments, and add a dressing with garlic and ginger.
• Dinner: Cook up some fatty fish and serve it with a side of roasted mushrooms and garlic-infused veggies.
• Snacks: Keep a stash of almonds or whip up a green tea to sip on during the afternoon.

By making these immune-friendly foods a regular part of your diet, you’ll be setting yourself up to feel strong and resilient, even when everyone around you is reaching for tissues.

The Bottom Line

There’s no magic pill or one-size-fits-all solution to keep your immune system strong. The key is a healthy, consistent lifestyle: eating a balanced diet, exercising, sleeping well, and managing stress. If you’re thinking of adding supplements to your routine, make sure to talk to a healthcare professional first.

Focus on whole, unprocessed foods, prioritize variety, and remember that small, consistent habits often make the biggest difference. Your immune system works hard to protect you—support it the best you can!

Have questions or your own immune-boosting tips? Drop them below—I’d love to hear how you stay healthy!

Your Sports Dietitian,

Jordan

Sources:

• Carr, A. C., & Maggini, S. (2017). Vitamin C and immune function. Nutrients, 9(11), 1211.
• Aranow, C. (2011). Vitamin D and the immune system. Journal of Investigative Medicine, 59(6), 881–886.
• Hemil?, H. (2017). Zinc lozenges and the common cold: A meta-analysis. Journal of the Royal Society of Medicine Open, 8(5), 2054270417694291.
• Zmora, N., Suez, J., & Elinav, E. (2019). You are what you eat: Diet, health, and the gut microbiota. Nature Reviews Gastroenterology & Hepatology, 16(1), 35–56.