If there is one health concern that has dominated our consciousness in recent years, it’s immune function. More than ever before, people are looking for natural ways to support their immune system and protect themselves and their families.
As naturopathic physicians who focus on prevention, wellness, and enhancing the body’s inherent healing power, we have been inundated with questions about natural therapies for boosting immunity. We hope our responses to the most common queries will answer some of the questions you may have about this important and timely topic.
What Are the Best Immune Health Supplements?
This is the question we get the most often. People want to take supplements that can help to naturally increase their resistance to infections, but they are overwhelmed by all the conflicting information and the sheer number of immune supplements out there.
There are dozens of promising natural ingredients, but these are the immune enhancers we recommend most often:
- Elderberry extract: Since the days of Hippocrates, the flowers and berries of Sambucus nigra have been used to support immune health, especially during the winter months. To this day, elderberry is a popular and effective remedy for colds and flu. Suggested daily dosage: 50 mg of a concentrated elderberry extract.
- Beta-glucan: Derived from brewers’ yeast, beta-glucan contains bioactive compounds that boost overall immune function. It is particularly supportive of upper respiratory health and has been shown to improve inflammation, breathing, and other symptoms. Suggested daily dosage: 250 mg of beta-glucan.
- Probiotics: About 70% of your immune cells are located in your gut and they closely interact with your gut microbiome. Supplemental probiotics, which contain selected species of live beneficial bacteria, help to replenish, diversify, and balance your gut microbiome. Plus, they help to protect against respiratory infections and support overall health. Suggested daily dosage: a minimum of 6.5 billion CFU of Lactobacillus, Bifidobacterium, Saccharomyces (probiotic yeast), and Bacillus (soil-based organisms).
- Vitamin C: It’s been more than 50 years since Dr. Linus Pauling wrote about the immune benefits of vitamin C, and it’s still going strong. When taken at the first signs of an upper respiratory infection, vitamin C can help to shorten symptom duration and severity. Suggested daily dosage: 1,000–2,000 mg of vitamin C.
- Zinc: This mineral protects the skin and mucous membranes, which are your body’s frontline defense against germs. Low zinc status can depress the immune system and increase the risk of respiratory infections. Studies also suggest that zinc lozenges can help to speed recovery. Suggested daily dosage: 10–15 mg of zinc.
- Vitamin D3: A meta-analysis of 25 clinical trials involving 11,000 participants revealed that vitamin D supplements protect against acute respiratory tract infections. About 40% of Americans have a suboptimal blood level of vitamin D, so supplementation is critical. Suggested daily dosage: 1,000 IU (25 mcg) of vitamin D3.
A special note about vitamin D: Sun exposure, geographic location, time of year, age, skin color, and genetics all influence how much vitamin D your body produces. To determine the best dosage for you, have your blood level of 25-hydroxy vitamin D tested and take enough vitamin D3 to keep it in the 50 ng/ml range. This may require 4,000–5,000 IU or even more. As long as your blood level is in the normal range, even higher dosages are safe and well tolerated.
What Should You Eat to Boost Your Immune System?
We also get a lot of questions about food and other lifestyle factors. This is encouraging because it suggests people are looking to improve their overall health. The dietary advice we offer to most everyone is pretty much the same: healthy fats like olive oil, adequate protein including omega-3-rich fish, and lots of fresh, high-fiber organic produce. That said, we want to mention a few of our family’s favorite immune-boosting foods:
- Onions & garlic: These pungent vegetables are loaded with sulfur compounds that support your body’s production of glutathione, an important antioxidant involved in immune function. Onions are also a good source of quercetin, which has antihistamine properties and is particularly protective of the lungs. One of garlic’s main claims to fame is allicin, a compound with antiviral, antibacterial, and antifungal effects. Both are also prebiotics that support your gut microbiome.
- Cruciferous vegetables: These vegetables—including broccoli and Brussels sprouts—also contain sulfur compounds. Plus, they are nature’s richest source of sulforaphane, a phytonutrient with antioxidant and detoxification properties that promote immune health. Raw or cooked, broccoli is one of our favs.
- Leafy greens: In addition to their high content of vitamins C, K, and folate, spinach, kale, and other leafy green vegetables are excellent sources of beta-carotene and other immune-enhancing carotenoids. Beta-carotene is converted in the body to vitamin A, which, like zinc, supports your skin, mucous membranes, and overall immune health.
- Berries: Blueberries, raspberries, strawberries, and blackberries are a concentrated source of polyphenols, which are famous for their antioxidant and anti-inflammatory effects. They’re also low in calories and high in fiber and vitamins—a cup of strawberries has nearly 100 mg of vitamin C! At our house, we often snack on berries, including pomegranates (yes, they are berries), which our kids love.
- Chicken soup: Nothing beats chicken soup for immunity. One of our go-to meals is to simmer all of the above (save the berries for dessert) plus other vegetables you have on hand in organic chicken broth. In addition to the nutrients we’ve discussed, chicken soup also contains cysteine, an amino acid that helps loosen mucus. Spiking your soup with hot peppers further reduces congestion and coughing. Here's the full recipe for a great chicken soup.
Our final advice on food: Sugar suppresses the immune system, so try to avoid it. This may be easier said than done, especially if you have children who can’t seem to get enough of the sweet stuff! You can’t police what your kids eat 24/7, but you can control what you keep in the house.
What Are the Effects of Exercise on the Immune System?
You know that exercise helps to protect against obesity, heart disease, diabetes, depression, and other chronic conditions that increase your risk of infection. Plus, here are a few additional ways exercise supports the immune system:
- Increases the circulation of cytokines, antibodies, lymphocytes, and other white blood cells, which can improve their ability to detect and dispatch viruses and bacteria.
- Stimulates the lymph system—an important but overlooked part of the immune system that removes toxins, wastes, and infectious agents from the body. (Rebounders and mini-trampolines are especially good for lymphatic circulation.)
- Promotes deeper, more forceful breathing, which may help to flush out viruses and bacteria from the lungs and airways.
- Raises body temperature, both during and after exercise, which can have an infection-fighting effect similar to a fever.
- Reduces cortisol and stress, which have a negative impact on your immune system.
Aim for some type of physical activity every day, whether it’s taking a brisk walk, going to the gym, or participating in a favorite sport. Be aware that overexercising can dampen the immune response, so take care to avoid overtraining.
How Does Sleep Improve the Immune System?
Regular sleep is essential for optimal immune function. Your immune system is on constant patrol, looking for foreign invaders and neutralizing them before they can make you sick. But certain immune functions—including the production of infection-fighting antibodies and T cells and the release of cytokines that play a role in inflammation—rev up when you sleep.
Sleep deprivation profoundly affects immune function. In addition to reducing your resistance and increasing the likelihood of getting sick, poor sleep is also linked with systemic inflammation, which is a risk factor for many health problems.
For overall health and a strong immune system, aim for seven to nine hours of sleep each night. And if you do happen to come down with something, there’s a lot of truth to the old saying, “Sleep is the best medicine.”