“Micronutrient deficiency is an epidemic,” says functional nutritionist Dee Harris, RDN, noting that the standard American diet, typically high in processed foods and low on fiber, causes nutrient depletion and stress on the body. A diet rich in vegetables, fruits, and whole grains will deliver many of the nutrients your body and immune system need, but certain supplements can offer extra support and help you reach optimal levels of vital nutrients.
1. Multivitamin: “For a healthy immune system, I think about the first part of the alphabet — vitamins A, B, C, D, and E,” says Rountree. “A quality multivitamin is the star.”
Harris recommends brands containing an active form of B12 and B9 (folate).
2. Vitamin D: Deficiency of vitamin D has been linked to both common and more severe upper-respiratory infections. While conventional medicine says vitamin-D blood levels over 30 ng/ML are adequate, Harris says that, from a functional-medicine perspective, optimal levels are much higher — between 60 and 80.
The sun is a generous provider of vitamin D: Those with fair skin may need as little as 10 to 15 minutes of direct sun exposure daily to make several thousand IUs, while those with darker skin tones may require up to two hours of exposure. Alternatively, most adults can supplement with up to 5,000 IUs of vitamin D3 daily, particularly in the dark winter months. (Work with your healthcare provider to check your D levels every few months.)
3. Zinc: “Zinc is important to the function of lymphocytes that defend against viruses,” says preventive-medicine specialist David Katz, MD. He recommends taking up to 30 mg of zinc daily, whether in a multivitamin or on its own. (See “Zinc Essentials” to learn more about how to optimize this vital mineral.)
4. NAC: Short for N-acetyl-L-cysteine, NAC helps the body make the antioxidant glutathione, which plays an important role in protecting against cellular damage and supporting immune health. In one clinical study, elderly people receiving 600 mg of NAC daily experienced fewer days of sickness from the flu than a placebo group, and showed fewer symptoms, despite similar infection rates.
5. Probiotic: The microbiome plays a critical role in immunity, says Katz. You can support a diverse and healthy microbiome by taking a quality probiotic. Harris recommends brands that contain a blend of Bifido and Lactobacillus bacteria and offer at least 100 billion CFUs.
6. Herbs: Herbs such as astragalus, echinacea, Chinese skullcap, and ashwagandha have been used as immuno-regulators in Ayurveda and Traditional Chinese Medicine for millennia. (For more on their protective and healing properties, see “9 Healing Herbs”.)
This originally appeared as “Supplement Wisely” in “6 Ways to Boost Your Immune System” in the January/February 2021 issue of Experience Life.