Supporting the Immune System Koru Nutrition

The world is going through unprecedented times at the moment. Supporting a healthy immune system has never been so crucial for our health and the health of our families. At Koru Nutrition we want to make sure that you have the right information so you can take the steps needed to build a healthy immune system and help protect you and your family.

Influenza, commonly known as “the flu”, is an infectious disease caused by an influenza virus. Symptoms can be mild to severe. The most common symptoms include: a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired. These symptoms typically begin two days after exposure to the virus and last about a week. The cough, however, may last for more than two weeks. Right now, we are living in uncertain times with the immergence of the novel coronavirus, COVID-19. Although part of the cold and flu family, the human race has never been exposed to this virus before.

So is there anything we do to protect ourselves?

The Under-Rated Power of Vitamin C

Health food stores and drugstores have been running out of various immune-supportive supplements as people attempt to strengthen and enhance their immunity. Vitamin C is one supplement that has been in high demand.

But does vitamin C really protect us?

Vitamin C is found in high concentrations in our white blood cells, but is rapidly depleted during infections resulting in reduced immunity (5,6). Vitamin C helps us to upregulate our immune system, and the scientific literature has extensive research on the ability of vitamin C to support the body in recovery from a variety of viruses (4, 5, 7, 8, 9).

A vitamin C deficiency results in a weakened immune system and susceptibility to colds and other infections. Since the lining of the respiratory tract also depends heavily on the protection of vitamin C, respiratory infection and other lung-related conditions may also be a symptom of inadequate vitamin C intake(10).

Research shows that vitamin C in  therapeutic doses  can be very effective at preventing and addressing the common influenza virus, sometimes even after serious complications such as encephalitis have arisen along with many other viral syndromes (4). In spite of this information, vitamin C is still not routinely utilized against this infectious disease, and none of the various forms of vitamin C are included in the formularies of nearly any US hospitals.

One study on individuals that had cold/flu-like symptoms split participants into 2 groups. The control population were treated with pain relievers and decongestants, whereas those in the test population were treated with hourly doses of 1000 mg of Vitamin C for the first 6 hours and then 3 times daily thereafter. Overall, reported flu and cold symptoms in the group that was administered vitamin C decreased by 85% compared with the control group. (1)

In the evaluation of vitamin C, administration of extra therapeutic doses at the onset of cold/flu symptoms has found to help reduce illness duration, shorten the time of confinement indoors and relieve the symptoms associated with it, including chest pain (2).

Unfortunately, because the novel coronavirus has never been seen before, there is little research to date about the impact of vitamin C specifically on the COVID-19 virus. However, because vitamin C has shown success in treating many other viral infections and has a very low risk-profile, it may be one more tool you and your family can use – in addition to social distancing, frequent handwashing, and wearing a facemask and gloves in public – to help protect yourselves.


Currently, for the immune benefits. Vitamin C supplementation is very safe. There is no documented toxicity level for vitamin C because it is a water-soluble vitamin, which means it is flushed out of the body relatively quickly. Vitamin C is also easily lost with stress, and as mentioned above, is rapidly lost when a person is sick or has an infection.

Because vitamin C has a laxative effect at higher doses, often health professionals recommending individualized high-doses for their clients will suggest taking it only to bowel tolerance. Vitamin C is best taken with meals to improve absorption.


Foods High in Vitamin C

Having a diet high in fruits and vegetables is a great step to not only increase your vitamin C intake, but also your intake of many other immune-supportive antioxidants and nutrients. If you are unable to supplement, or simply want to increase your intake, the chart below outlines some foods that are high in vitamin C. However, if you do have flu-like symptoms vitamin C supplementation is highly recommended.

Food Amount (mg) Daily value (DV) %
Bell Peppers (1 cup) 174.8 291%
Parsley (2 tablespoons) 10 16.6%
Broccoli (1 cup) 123.4 205.7%
Strawberries (1 cup) 81.7 136.1%
Tomatoes (1 cup) 34.4 57.3%
Lemon juice (¼ cup) 28.1 46.8%
Oranges (1 fruit) 69.7 116.2%
Kale (1 cup) 53.3 88.8%
Cabbage (1 cup) 30.2 50.3%


If you would like more information about the impact of nutrition on your immunity, please reach out to Koru Nutrition today.

Stay safe and stay home.



  1. Gorton HC, Jarvis K., J Manipulative Physiol Ther. 1999 Oct;22(8):530-3. The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections.
  2. Biomed Res Int. 2018; 2018: 1837634. Published online 2018 Jul 5. doi: 10.1155/2018/1837634 PMCID: PMC6057395 PMID: 30069463 Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold: A Meta-Analysis of 9 Randomized Controlled Trials Li Ran, 1 Wenli Zhao, 1 , 2 Jingxia Wang, 3 Hongwu Wang, 4 Ye Zhao, 3 , 5 Yiider Tseng,corresponding author 5 and Huaien Bucorresponding author 4
  1. Michael J Gonzalez; Miguel J Berdiel; Jorge Duconge; Thomas E Levy; Ines M Alfaro; Raul Morales-Borges, Victor Marcial-Vega, Jose Olalde, University of Puerto Rico, Medical Sciences Campus, School of Public Health,: Gonzalez MJ et al (2018) High Dose Vitamin C and Influenza: A Case Report. J Orthomol Med. 33(3)
  2. Klenner FR. The treatment of poliomyelitis and other virus diseases with vitamin C. South Med J 1949; 3(7):209-214.
  3. Levy, TE.Curing the Incurable: Vitamin C, Infectious Diseases, and Toxins by Henderson, Nevada; Livon Books, 2002.
  4. Pauling L. The significance of the evidence about ascorbic acid and the common cold. Proc Natl Acad Sci U S A. 1971;68:2678–2681.
  5. Stone I. The healing factor: Vitamin C against disease. Grosset and Dunlap, New York, 1972.
  6. Gonzalez MJ, Miranda-Massari JR, Berdiel MJ, Duconge J, Rodríguez-López JL, Hunninghake R, Cobas-Rosario VJ.High dose intraveneous vitamin C and chikungunya fever: A case report. J Orthomolec Med. 2014;29(4):154-156.
  7. Gonzalez MJ, Berdiel MJ, Miranda-Massari JR, Duconge J, Rodríguez-López JL, Adrover-López PA. High dose intravenous vitamin C treatment for zika fever. J Orthomolec Med 2016;31(1):19-22.
  8. Mateljan, George, The Worlds Healthiest Foods, 2007





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