Natural Immune Boosters That Work

Natural Immune Boosters That Work

Fall is around the corner, and that means another flu and cold season is about to kick off. As the weather cools and the days shorten, we all have to take a little better care of ourselves to stay healthy. While there’s no proven cure for the common cold, and no fail-safe prevention against getting it, you can at least do your best to keep your immune system strong while it puts up the good fight. 

The better you treat your body, the better prepared it will be to defend itself against extra threats. General healthy lifestyle habits like eating right, drinking moderately, exercising, and getting good sleep will help keep your immune system in fighting shape. Certain nutrients and herbs have also been shown to provide crucial support to your immune system when it needs it most. Here are some tried-and-true natural immune boosters to keep on hand this season.

Vitamin D

Why do colds and flus increase in the winter months? It’s not just the colder, wetter may also be the lack of sunshine, which deprives us of vitamin D. Vitamin D is crucial for a healthy functioning immune system, and low levels of vitamin D are linked with an increased risk of colds and flus. 1 Research also shows that vitamin D deficiency is surprisingly common, especially in the winter. If you are spending a lot of time indoors, it’s smart to take a vitamin D supplement.

Vitamin D influences your body’s antimicrobial response2 and is crucial for activating your T “killer” immune cells, which help fight off foreign bacteria and viruses.3 One large review of clinical trials found that taking vitamin D supplements can reduce the risk of developing upper respiratory infections by as much as 42% for people with low vitamin D levels, and by 10% in those with higher vitamin D blood levels.2


Zinc is an essential trace mineral that’s crucial for healthy immune function. Like vitamin D, zinc plays an important role in activating those killer T cells that help protect the body from foreign invaders.4,5 A little zinc goes a long way for everyday immune health, but research shows it’s safe to take high doses of zinc temporarily to help fight off a cold.6 Studies have shown that taking zinc within the first 24 hours of cold symptoms can shorten the duration of your cold by as much as 40%.7,8


Elderberry fruit has been used as a traditional folk remedy for colds and flus for thousands of years. Now, science is starting to uncover why it has stood the test of time. Research shows that elderberry has direct antiviral action, not just in the early stages of infection, but even more powerfully during later stages of the virus.9 Multiple studies have shown that taking elderberry significantly reduces both the symptoms and the duration of colds and flus10,11,12. It’s even been shown that people have more antibodies against the flu virus after taking elderberry.13

Vitamin C

One of the most important vitamins for overall immune health, vitamin C supports your immune system in multiple ways. It encourages the production of white blood cells, helps them function more effectively, and protects them from free radical damage.14 Its antioxidant activity also helps prevent tissue damage from excess inflammation.15 Lack of vitamin C leads to a weakened immune system and increased risk of infection.16

Getting enough vitamin C on a regular basis is important for supporting general healthy immune function. But it’s when you are under physical or psychological stress that vitamin C really goes to work for you. Vitamin C is highly concentrated in immune cells, as well as in the adrenals, which produce your body’s stress response hormones. When your body is fighting an infection or dealing with stress, vitamin C levels are quickly depleted,17,18 so your need for vitamin C is increased. Taking extra vitamin C during periods of physical or emotional stress has been shown to improve immune function and stress recovery, helping you bounce back better17,19,20,21. 

All these natural immune boosters can help give your immune system some extra support when you need it most. Our NATURELO Immunity Support supplement combines the powers of elderberry, zinc, and vitamin C together in one supplement to help keep your immune function strong this season. Make sure you have a vitamin D supplement on hand for those days of little sun, and if you are stressed out or under the weather, taking some extra vitamin C is a good idea, too. Stay safe and healthy!


1.  National Institutes of Health. “Low Vitamin D Levels Associated with Colds and Flu.” NIH website. Published March 9, 2009.

2. University of Queen Mary London. "Vitamin D protects against colds and flu, finds major global study." ScienceDaily. ScienceDaily, 16 February 2017.

3. University of Copenhagen. "Vitamin D crucial to activating immune defenses." ScienceDaily. ScienceDaily, 8 March 2010.

4. Kaltenberg J, Plum LM, Ober-Blöbaum JL, Hönscheid A, Rink L, Haase H. “Zinc signals promote IL-2-dependent proliferation of T cells.Eur J Immunol. 2010;40(5):1496-1503. doi:10.1002/eji.200939574

5. Federation of American Societies for Experimental Biology. "Got Zinc? New Zinc Research Suggests Novel Therapeutic Targets." ScienceDaily. ScienceDaily, 31 July 2009.

6.  “Zinc.” Micronutrient Information Center, Linus Pauling Institute, Oregon State University.

7. Singh M, Das RR. “Zinc for the common cold.Cochrane Database Syst Rev. 2011;(2):CD001364. Published 2011 Feb 16. doi:10.1002/14651858.CD001364.pub3

8. Hemilä, Harri. “Zinc lozenges may shorten the duration of colds: a systematic review.The open respiratory medicine journal vol. 5 (2011): 51-8. doi:10.2174/1874306401105010051

9. Golnoosh Torabian, Peter Valtchev, Qayyum Adil, Fariba Dehghani. “Anti-influenza activity of elderberry (Sambucus nigra).Journal of Functional Foods, 2019; 54: 353 DOI: 10.1016/j.jff.2019.01.031

10. Hawkins, Jessie, et al. “Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials.” Complementary Therapies in Medicine, Volume 42, February 2019, Pages 361-365.

11. Zakay-Rones Z, Thom E, Wollan T, Wadstein J. “Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections.J Int Med Res. 2004;32(2):132-140. doi:10.1177/147323000403200205

12. Tiralongo, Evelin et al. “Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial.Nutrients vol. 8,4 182. 24 Mar. 2016, doi:10.3390/nu8040182

13. Roschek Jr. B, Fink RC, McMichael MD, et al. “Elderberry flavonoids bind to and prevent H1N1 infection in vitro.Phytochemistry. 2009;70(10):1255-61. doi: 10.1016/j.phytochem.2009.06.003. 

14. Raman, Ryan. “7 Impressive Ways Vitamin C Benefits Your Body.” Healthline, Feb 2020.

15. Nordqvist, Joseph. “Vitamin C: Why is it important?” Medical News Today, April 2017.

16. Carr, Anitra C, and Silvia Maggini. “Vitamin C and Immune Function.Nutrients vol. 9,11 1211. 3 Nov. 2017, doi:10.3390/nu9111211

17. Wintergerst ES, Maggini S, Hornig DH. “Immune-enhancing role of vitamin C and zinc and effect on clinical conditions.Ann Nutr Metab. 2006;50(2):85-94.

18. “Got Stress? You Need Vitamin C.” Adrenal Fatigue, Jan 2018.

19. Hemilä H. “Vitamin C and Infections.Nutrients. 2017;9(4):339. Published 2017 Mar 29. doi:10.3390/nu9040339

20. American Chemical Society. "Scientists Say Vitamin C May Alleviate The Body's Response To Stress." ScienceDaily. ScienceDaily, 23 August 1999.

21. “Vitamin C: Stress Buster.” Psychology Today, April 2003.