1. Vegetables, fruits, nuts, and seeds
We can’t talk about improving your ability to fight diseases without a diet full of these basic foods: vegetables, fruits, nuts, and seeds. They are rich in vitamins, minerals, and antioxidants that boost the immune system like vitamin C, vitamin E, selenium and zinc. Antioxidants support normal lung function and lower inflammation, both of which help you fight infections.
I tell my patients to eat vegetables at least 3 times a day, for a total of 5 cups at minimum. It’s not enough to just eat some broccoli at dinner.
A steady consistent supply of antioxidants from vegetables is key. When you eat an antioxidant-rich food, the level of antioxidants rises in your blood, helping you fight disease-causing free radicals, and then it drops after 3-4 hours.
At each meal, aim for half of your plate to consist of non-starchy vegetables. The more variety in types and color the merrier. When it comes to fruit, I suggest 2-3 servings a day, which is about one apple or orange or pear, 1 cup of berries, 2 clementines, or 1/2 banana. For nuts and seeds, aim for about 1/4 cup a day and up to 1/2 cup a day if you’re more active.
2. Focus on Cruciferous vegetables
Cruciferous vegetables support your liver so it can do its job of detoxifying and flushing out toxins and chemicals properly. This will provide a healthy environment for healthy immune cells. Kale, broccoli, cauliflower, cabbage, Brussels sprouts, collards, and bok choy are in this category. You can enjoy them raw in salads or smoothies or cooked like roasted, steamed, or stir-fried. If you have hypothyroidism, it’s better to eat your cruciferous vegetables cooked. Check out this delicious lemon roasted broccoli recipe from my colleague Lily Nichols.
Japanese mushrooms, such as shitake or oyster mushrooms, boost the immune system. They contain the antioxidant ergothioneine that survives cooking. Add mushrooms (and onions, garlic, and ginger–read below) to homemade chicken stock for a dose of natural defenses.
4. Homemade Broth and Gelatin Protein
When you make chicken or beef broth with bones, you’re extracting all the gelatin (collagen) protein surrounding the joints and ligaments. This protein can help with wound healing and cell generation on the outside (your skin) and the inside (your gut). The amino acids (arginine, alanine, and others) strengthen the immune system and help produce antibodies that help fight foreign substances. When you got sick, your mother (or grandmother) may have made you homemade chicken soup. In Vietnamese culture, pho, broth made with bones, is a cold and flu-fighting remedy.
I talk more about geletin protein here. Read more on its other health benefits and recommendation for a clean, kosher gelatin product that will make it easier for you to incorporate this health food on daily basis.
This kitchen staple is a health boosting powerhouse. Garlic improves the immune function and fights bacteria, viruses, parasites, and fungi. It also helps lower blood pressure, cholesterol, blood sugar, and arthritis pain and prevents tumor growth, platelet accumulations (aka, plaques in your arteries), and atherosclerosis (hardening of your arteries) (studies here and here). Garlic’s health benefits come from its sulfuric compounds, which are also found in kale, cabbage, Brussels sprouts, and onions.
Heat and water can deactivate sulfur enzymes and garlic’s antibiotic effect. Consider adding it just before serving instead of early in the cooking process (most of us do the opposite). If you–and your significant other!–can tolerate the odor of fresh garlic, consider eating it raw. You can blend fresh garlic cloves with olive oil in a food processor and make a garlic dip that’s great with chicken, vegetables, and potatoes.
Onions contain two key nutrients: sulfuric compounds and quercetin. Sulfuric compounds in onions are the same ones found in garlic that help fight viruses and bacteria. Quercetin is a flavonoid (antioxidant) that is involved in protection from the type of asthma that’s caused by toxic chemicals, cold air, exercise, and infections. Cell studies also found that quercetin can treat rhinovirus (RV) infection, the cause of the majority of the common cold cases and can trigger flare ups in people with chronic lung conditions like asthma, cystic fibrosis, and COPD.
7. Ginger, Lemon, and Honey
The combination of these antimicrobial foods is an immune booster. I talk more about their health benefits and share my homemade cough remedy of ginger, lemon, and honey here.
You can also make them into a hot tea. Shred about 1/2 inch cube ginger root into a cup of hot water. Squeeze fresh lemon juice. Add a little bit of honey and mix. Drink warm. I often chew on the ginger that remains in the cup for extra nutrition (and I just love the taste!)
Do you want to learn how to shred ginger root and other tips to spend less time cooking without eating junk? Get my free guide now here.
8. Fermented Foods and Probiotics
The research is mounting on the health benefits of probiotics. Your gut is inhabited by millions of bacteria that help you fight foreign substances and toxins, including harmful bacteria, viruses, fungi, parasites, and their toxic by-products. For many reasons, an imbalance can occur in your gut flora, decreasing the number and variety of healthy bacteria. This is called gut dysbiosis. To allow your immune system get a helping hand from a healthy gut flora, incorporate naturally fermented foods. Some of the common ones are sauerkraut, kimchi, salt-fermented pickles, yogurt, labneh cheese, kefir, and miso.
Should you take a probiotic supplement? I recommend probiotic supplements to many of my patients, give them to my kids, and take them myself. A therapeutic dose of probiotics is necessary if you end up on antibiotics, since many antibiotics wipe out the good and the bad bugs, leaving room for the bag bugs to grow. I don’t usually make supplement recommendations online since each person may benefit from a different type of product. In general, look for something that has more than 4 species, high quality (refrigerated), and about 20 billions units as a starting point.
9. Green Tea
The catechin polyphenols (antioxidants) in green tea have antiviral effects against the influenza viruses (this study investigated A/H1N1, A/H3N2 and B viruses). Green tea boosts the number of certain types of immune cells, improving the immune system’s ability to fight foreign substances. It may also help suppress some autoimmune conditions (word of caution–it may have an opposite effect on some autoimmune conditions too so avoid extracts or concentrated pills unless working with a health practitioner). Green tea also fights tumors, heart disease, diabetes, and obesity, conditions that trigger inflammation and put a toll on the immune system (review here).
10. Tulsi Tea
In India, Tulsi, commonly known as sacred or holy basil, is an Ayurvedic medicinal herb. It has been used for generals for health reasons. Tulsi contains phytochemicals, one type of antioxidants, and have the ability to boost adrenal and immune function. It can support the respiratory system, fight free radicals, calm your adrenals, improve digestion, and improve blood sugars. Enjoy tulsi in the form of tea and sweeten with some local raw honey if needed.
You can find Tulsi tea on amazon here.
11. Raw Whey Protein
Whey protein promotes the production of glutathione, the body’s master antioxidant. Glutathione maximizes the activity of vitamins C and E, CoQ10, and alpha lipoic acid. It’s also necessary for detoxification, the process in which liver clears toxic compounds (even things like acetaminophen) from your body. Read more about whey here and what products I recommend.
12. Vitamin D
Having adequate vitamin D level will help maintain your immune function, especially in the winter when most of us aren’t getting enough quality sun to produce this vitamin in our skin. Small amounts of vitamin D can be found in fortified milk and canned salmon and sardines in bones, but the majority of people need a supplement to get their vitamin D level to a healthy optimal level. I recommend ALL my patients to check their vitamin D level before considering a supplement. If your vitamin D level is low, a typical 1,000 IU dose is not going to be enough. However, if your level is normal, a high therapeutic dose can be harmful. Test first, supplement next.
Your doctor might tell you that your vitamin D is fine when it’s not.
Optimal vitamin D level is between 50 and 70 ng/ml. Most lab references consider 30 ng/ml to be just fine. If you want to be in the OPTIMAL range, not just ‘I-don’t-have-a-deficiency’ range, more than 50 is where you want to be. Consult with your dietitian or physician.
Other Lifestyle Habits that Bust your Immune System
Don’t forget these non-food related habits that will wreck your immune system and hinder its ability to fight diseases. Most us engage in at least one or two! Do your best to move away from these:
- You’re under too much stress (physical like unhealthy diet or excessive exercise, mental, emotional, etc). Think of your perceived stress. Is the situation really stressful, or are you having a hard time adjusting? Is it as bad as you think it is? We can talk about that for hours!
- You don’t get enough sleep. Most people need at least 7 hours of sleep and 8 hours would be even better. Think of sleep hygiene–a dark room, no noise, and comfortable clothing and temperature.
- You don’t exercise. Are you engaging in moderate-intense exercise few times a week? Balance that with adequate rest. Again, another topic to talk about for hours!
- You drink too much alcohol. Even red wine that is claimed to have heart-healthy benefits, your liver still has to detoxify the alcohol. Putting more strain on your liver is not going to help your immune system. The American Heart Association and the American Cancer Society do not recommend alcohol–even red wine–for improved health.
- You’re exposed to tobacco. Smoking or being exposed to smoke is going to hinder your ability to fight diseases, especially respiratory conditions.