Supporting the Immune System with Vitamin C

Supporting the Immune System with Vitamin C

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





The Power of Berries To Support Your Immune System

The Power of Berries To Support Your Immune System

The Power of Berries Koru Nutrition

Anthocyanins are a type of flavonoid, a class of compounds with antioxidant effects. Anthocyanins are the pigments that are responsible for giving fruits and vegetables their red, purple, and blue colours, which is commonly found in berries such as pomegranates, grapes, bilberryelderberry, black currants, blueberries, raspberries, blackberries, and cranberries.

Anthocyanins may offer anti-inflammatory, anti-cancer and even anti-viral, benefits. In fact studies show that there is a positive relationship between antiviral activity and polyphenol content of the berries, indicating the possibility that polyphenol is one of the key factors in the antiviral effects of berries (1,2). Studies have shown that anthocyanins can prevent influenza viruses from penetrating human cells and may inhibit viral release once the cell is infected (5).

With this in mind let’s have a look at how berries can help support our immunity.


Based on certain studies, the Vitamin C content in a bilberry is five times higher than that in an orange.

Researchers at the Washington University School of Medicine in St. Louis focused on the effects of flavonoids — antioxidants found in dark chocolate, bilberries and red wine — on intestinal microbiota, researchers found that these nutrients could “collaborate” with certain microbiota bacteria to combat influenza and other viral infections. The results of the study indicate that interaction between the bacteria and the flavonoids does not target flu viruses directly, but rather stimulates a response that prevented the immune system from harming lung tissue (3) while fighting the illness.

Black Currant

Black currant seed oil contains a chemical called gamma-linolenic acid (GLA). Some research suggests that GLA might improve the immune system, making it more able to fight off disease. Blackcurrants are also one of the densest known sources of the polyphenol antioxidant class called anthocyanins, which have been shown to help our immune system defend us against other viral infections, such as those that cause enteritis and common colds (4).

Researchers at Japan’s Asahikawa Medical College examined the effects of blackcurrants against influenza virus A and B (IVA and IVB).  The results showed both viruses were inactivated up to 99.9%. When IVA-infected cells were treated with blackcurrant extracts, the virus was completely suppressed in six hours. This study showed that not only can blackcurrant extracts inhibit IVA and IVB on contact, they also may prevent further infection by blocking the viruses’ ability to leave infected cells (4).

Increasing evidence suggests anthocyanins may support immunity by making the immune system more efficient at fighting and clearing a virus when it does encounter one (6,7). The way the polyphenol anthocyanins in blackcurrants work with the immune system means that if we do get sick, the severity and subsequent tissue damage from the infection may be decreased (8), thus allowing us to recover faster.


Limited studies have been conducted on the antiviral activities associated with pomegranate and its extracts. Despite this, the studies that have been completed have identified anti-viral effects against clinically relevant influenza virus, herpes virus, poxviruses, and human immunodeficiency (HIV-1) virus [10–12].

Haslam (13) suggested that plant polyphenols exert a direct action on the viral particles, inhibiting the adsorption of the virus to the host cell receptors.

The tannins and anthocyanins are the main compounds associated with the beneficial effects of pomegranate consumption. In one study, the flavonoid, punicalagin found in pomegranate was shown to have inhibitory effects on influenza virus [15].  It is possible that pomegranate juice and extracts could be potentially useful in inhibiting viruses transmitted via infected food products, bodily fluids, and so forth (16).


The elderberry is reputed by some to be effective in treating the common cold, flu, and sinus infections. It also has antiviral properties that may prevent or reduce the severity of certain common infections. In fact, a study completed in 2012 suggested that elderberry could help prevent influenza infection by stimulating an immune response (17) and a 2019 study on elderberry for both cold and flu suggested that the fruit substantially reduced upper-airway symptoms (18).

A 2016 study from Australia reported that, among 312 long-haul airline passengers, those who used elderberry extract 10 days before and five days after their flight had 50 percent fewer sick days resulting from a cold than those who didn’t. What elderberry did not appear to do was reduce the risk of getting a cold; both the elderberry group and placebo group had more or less the same number of infections (19), but in the passengers who used elderberry symptoms were less severe based on a scoring of upper respiratory tract symptoms.


The study, published in Nutrition Journal, found that individuals who drank a low calorie cranberry beverage with similar polyphenol content to cranberry juice cocktail every day for 10 weeks had nearly five times more growth of immune-boosting cells and significantly fewer cold and flu symptoms than non-cranberry consumers. Researchers observed that the fruit’s immunity benefits came from the presence of yδ-T cells, which are the body’s first line of defence against harmful bacteria. By improving their function, scientists believe we can reduce the number of symptoms associated with the common cold and flu (20).


To support your immune system and potentially help reduce respiratory virus symptom severity, make sure you consume your berries every day! Put them in salads, smoothies, yogurt or oatmeal, or even on their own as a healthy snack.

For inspiration to include more berries in your diet, check out our Berry Beet Smoothie Bowl.

Or, if you struggle to get berries into your diet or to eat enough variety of berries you may want to explore a whole food berry supplement.



  1. Duymuş HG, Göger F, Başer KH. In vitro antioxidant properties and anthocyanin compositions of elderberry extracts.Food Chemistry. 2014 Jul 15;155:112-9. doi:10.1016/j.foodchem.2014.01.028
  2. J Sci Food Agric. 2013 Jul;93(9):2239-41. doi: 10.1002/jsfa.6031. Epub 2013 Jan 28. Relationship between polyphenol content and anti-influenza viral effects of berries. Sekizawa H1, Ikuta K, Mizuta K, Takechi S, Suzutani T.
  3. Ashley L. Steed, George P. Christophi et al The microbial metabolite desaminotyrosine protects from influenza through type I interferon, Science 04 Aug 2017:Vol. 357, Issue 6350, pp. 498-502
  10. Haidari, M. Ali, S. W. Casscells, and M. Madjid, “Pomegranate (Punica granatum) purified polyphenol extract inhibits influenza virus and has a synergistic effect with oseltamivir,” Phytomedicine, vol. 16, no. 12, pp. 1127–1136, 2009.View at: Publisher Site | Google Scholar
  11. Neurath, N. Strick, Y. Y. Li, and A. K. Debnath, “Punica granatum (pomegranate) juice provides an HIV-1 entry inhibitor and candidate topical microbicide,” in Natural Products and Molecular Therapy, G. J. Kotwal and D. K. Lahiri, Eds., vol. 1056, pp. 311–327, New York Academy of Sciences, 2005.View at: Google Scholar
  12. J. Kotwal, “Genetic diversity-independent neutralization of pandemic viruses (e.g. HIV), potentially pandemic (e.g. H5N1 strain of influenza) and carcinogenic (e.g. HBV and HCV) viruses and possible agents of bioterrorism (variola) by enveloped virus neutralizing compounds (EVNCs),” Vaccine, vol. 26, no. 24, pp. 3055–3058, 2008.View at: Publisher Site | Google Scholar
  13. Haslam, “Natural polyphenols (vegetable tannins) as drugs: possible modes of action,” Journal of Natural Products, vol. 59, no. 2, pp. 205–215, 1996.
  14. Aviram, N. Volkova, R. Coleman et al., “Pomegranate phenolics from the peels, arils, and flowers are antiatherogenic: studies in vivo in atherosclerotic apolipoprotein E-deficient (E-o) mice and in vitro in cultured macrophages and upoproteins,” Journal of Agricultural and Food Chemistry, vol. 56, pp. 1148–1157, 2008.View at: Google Scholar
  15. G. Kasimsetty, D. Bialonska, M. K. Reddy, C. Thornton, K. L. Willett, and D. Ferreira, “Effects of pomegranate chemical constituents/intestinal microbial metabolites on CYP1B1 in 22Rv1 prostate cancer cells,” Journal of Agricultural and Food Chemistry, vol. 57, no. 22, pp. 10636–10644, 2009.View at: Publisher Site | Google Scholar
  17. Kinoshita E, Hayashi K, Katayama H, Hayashi T, Obata A. Anti-influenza virus effects of elderberry juice and its fractionsBiosci Biotechnol Biochem. 2012;76(9):1633–1638. doi:10.1271/bbb.120112
  18. Hawkins J, Baker C, Cherry L, Dunne E. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials. Complement Ther Med. 2019;42:361–365. doi:10.1016/j.ctim.2018.12.004
  19. Tiralongo E, Wee S, Lea R. Elderberry supplementation reduces cold duration and symptoms in air-travellers: A randomized, double-blind placebo-controlled clinical trial. Nutrients. 2016;8(4):182. doi:10.3390/nu8040182.
Why Your Child May Be A Picky Eater

Why Your Child May Be A Picky Eater

Why is My Child a Picky Eater? Koru Nutrition

As a mom it is not uncommon to get frustrated with your kid’s fussy eating patterns. However for moms with kids on the autism spectrum picky eating is an even more common issue.

You may think your child is just being stubborn and unreasonable at mealtime, but there are actually a number of biochemical reasons why a child might have a very limited repertoire of foods that they will consume or are refusing to eat certain meals altogether. In fact, a child’s picky eating could be based on a number of reasons, including:

  • sensory issues
  • oral motor problems
  • nutrient deficiencies
  • anxiety
  • food addictions/cravings
  • chemical addicitions to additives, preservatives and colourings

Food Addictions

Children often become “addicted” to foods that their body has difficulty processing. When certain, specific, “addicted” food proteins enter the blood stream, the body creates a compound that mimics the effect of morphine. Common foods that may cause this effect include dairy and gluten as they can create opiate-like response in the brain, making the child feel good in the short term. Unfortunately, that opiate-like response causes the child to restrict other foods to help fuel the addictive cycle and creates very picky eating.

Fear/Anxiety of New food

Being nervous about consuming a new food is a common developmental step in children between the ages of 2 to 3, but if this continues after this then there maybe an underlying issue such as oral motor issue, sensnory issue, or anxiety. One study identified that caregivers tried offering a new food a maximum of 3-5x before deciding that the child disliked it. However, the research shows that a caregiver needs to provide many more repeated exposures up to 8-15 times before the child would accept the new food. (Carruth, Ruth, Ziegler, Gordon, Barr, 2004). So, persevere it might not be enough exposures before the child feels comfortable consuming it.

Nutrient Deficiencies

Zinc is a nutrient that helps increase the sense of taste, smell and appetite. If your child has a nutrient deficiency, food may taste bad or bland, which can take away the pleasure of eating. A Survey of parent’s rating the efficacy with supplementing identified that austistic symptoms improved in 54% of children when the child was supplemented with zinc. It is recommended that blood tests be done to dtermine if there is a defeciencey before considering supplementing with zinc, but if that can not be done then taking a children’s multivitamin with a smaller dose might be a step in the right direction. Foods high in zinc to incorporate into the diet include: mushrooms, spinach, grass fed beef, lamb, summer squash, shrimp, pumpkin seeds, pumpkin seed oil, broccoli and sesame seeds.

Addictions to Chemicals (MSG, artificial additives)

Artificial food additives are often consumed in a typical Standard American Diet diet which consists mainly of processed foods that have a long shelf life. Addictions to these chemicals can cause restriction to specific brands or a large preference for processed foods. Addictions to salicylates, amines or glutamates can lead to a focus on foods high in these food chemicals, such as a diet high in fruit or fruit juice, tomato sauce, ketchup, and/or soy sauce (as examples), and avoidance of other food not high in them. MSG, in particular is neurodegenerative and contains glutamate that can excite the brain making the food taste more palatable, so subsequently the child craves that food. Removing these processed foods from your child’s diet may cause some withdrawal symptoms in the short-term, but the pay-off will be well worth it in the long-term with improvements in behaviors and mood

Yeast, Viral and Microbial Overgrowth

in the gut can cause a child to gravitate toward high carbohydrate foods such as breads, pizza, pasta and sugar-based foods. Refined grains such as white bread, pizza and pasta are broken down in the body quickly (due to minimal fiber content which would slow the release down) into glucose. These pathogens thrive on glucose to help them proliferate and flourish. These “bad” or “opportunistic bacteria and microbes” in the gut can affect your child’s brain chemistry causing them to crave refined carbohydrates and sugar, which as a result can lead to avoidance of other foods.


Helpful Strategies

  1. Make food fun! You can create pictures on the plate with food and create stories from it.
  2. Get your child involved in the grocery shopping, meal preparation or even in growing foods at home. This can build comfort and familiarity with the food and a sense of accomplishment
  3. Remember you need to expose your child to a new food 8-15 times before they may accept this into their diet. So keep trying!
  4. Don’t get anxious or hung up on the outcome when trying new foods. Kids sense stress and anxiety and will feed on this and not the food.
  5. Sneaking or hiding foods inside other foods can be either a benefit or a detriment, depending on the child. Most childrem prefer to eat foods they are familiar, so pureeing vegetables inside muffins, pancakes, meatballs, or pasta sauce may sneak in a bit of extra nutrition undetected. However, for some children with severe difficulty feeding, this strategy may cause them to lose trust or refuse a previously accepted food because there was something different about it. Hiding new foods or trouble foods inside other recipes is only recommended if that is a strategy has worked before or parents feel confident it won’t be a problem.

If you would like more information on this or would like to speak to one of our nutritionists specialized in working with kids on the autism spectrum please contact us.

How Nutrition Can Support or Hinder Brain Injury Recovery

How Nutrition Can Support or Hinder Brain Injury Recovery

Top 5 Foods to Boost Brain Power Blueberries Koru Nutrition

The human brain requires a huge amount of energy to function efficiently. After a traumatic brain injury, the brain requires even more energy to allow repair to occur. Following a brain injury one major key to recovery is to promote neuroplasticity – that is, enabling the brain to make new connections and pathways to regain function.

Nutrition is often overlooked as a factor that can either support or hinder brain injury recovery, depending on an individual’s eating habits. We know there are specific compounds in foods that effect the production of Brain-Derived Neurotropic Factor (BDNF), which is a protein in the family of growth factors that is produced by the human body and plays an integral role in the survival and growth of brain cells.¹ BDNF contributes to the plasticity of neurons, which is essential for recovery, learning and memory.

Let’s look more closely at how food can support or hinder brain injury recovery!

Top 2 Foods To Avoid Post-Brain Injury

These Foods Reduce Neuroplasticity

1. Alcohol

We’ve probably all heard the adage that “alcohol kills brain cells”. The science is a bit more complicated than that, but it’s true that even moderate alcohol intake can decrease neuroplasticity as well as increasing inflammation within the brain.² This is important to know because sustained inflammation within the brain leads to further damage and impairments in cognitive function.

2. Sugar

Sugar increases inflammation and oxidative stress (an imbalance of free radicals and antioxidant in the body that can lead to tissue damage). Diets high in refined sugar down-regulate several key factors needed for brain function and repair including neurotransmitters. A diet high in refined sugars also impairs the gut microbiome (the bacteria and fungi that live in our guts), which directly impacts the brain via the gut-brain axis. Put plainly, anything damaging the gut is also harming the brain, and vice versa.³

Top 4 Foods To Consume Post-Brain Injury

These Foods improve Neuroplasticity

1. Berries

Berries as a group are high antioxidants and known for their protective effects. The antioxidants present in berries can help protect the brain from secondary damage and functional decline, as well as reduce inflammation.

2. Egg Yolk

Egg yolk is high in the nutrient choline, which is an essential component of all cell membranes and especially critical for communication between brain cells. Choline has neuroprotective effects and promotes rapid repair of damaged cells – exactly what is required post-brain injury!4

3. Non-starchy vegetables

Caloric restriction may benefit individual’s post-brain injury as their body focuses on recovery. In fact, research shows that calorie restriction has beneficial effects on brain plasticity and neuronal vulnerability to injury and can stimulate production of BDNF.5 As such, vegetables like kale, broccoli, asparagus, celery, or cucumber, that provide dense nutrition and satiety without an abundance of calories should be considered as the base of an individual’s diet.6

4. Oily Fish

One of the most important and well-researched dietary factors that relates to brain health is fish-derived Omega 3 fatty acids. Not only do Omega 3 fats assist in reducing inflammation within the brain and helping to prevent secondary damage, but DHA (one specific Omega 3 fat) is known to facilitate brain cell recovery and the development of new brain pathways post-injury.7

If you or someone you know has suffered a traumatic brain injury, please consider the significant positive impact that changes in nutrition can have on recovery. A skilled dietitian or nutritionist, like those at Koru Nutrition, can help you navigate what dietary changes are best for you, and provide you with the tools and skills to implement new habits. Get in touch by email or book a session now, we’re here to help!






Best Foods To Manage Your Stress

Best Foods To Manage Your Stress

stress busting foods koru nutrition

The key to busting stress is making sure that you look after YOU. Have a look at your work life, your personal life and social life to see if there are any areas you can create more happiness. You might be surprised on what you find.

Stress Busting Foods

What are some of the best foods to eat for stress?

  • Fatty fish such as wild salmon and sardines contain omega-3 fats which have anti-inflammatory properties that may help counteract the negative effects of stress (vi).
  • Dark leafy greens such as kale, spinach and Swiss chard are rich in folate that is needed to produce dopamine and serotonin- pleasure inducing neurotransmitters that helps keep you calm (vii).
  • Fermented foods such as kimchi, kombucha, and sauerkraut contain beneficial bacteria that may positively impact your mood and brain health (viii).
  • Seeds such as flaxseeds, sunflower seeds, and pumpkin seeds are great sources of Magnesium, which acts as a precursor for neurotransmitters like serotonin, important for improving mood (viiii).

To find out more about how nutrition impacts your health, Koru offers comprehensive individualized nutrition programs.



vi. Antidepressant-like effects of uridine and omega-3 fatty acids are potentiated by combined treatment in rats Carlezon, William A. et al. Biological Psychiatry , Volume 57 , Issue 4 , 343 – 350

vii. The association of folate and depression: A meta-analysis.

viii. Stress & the gut-brain axis: Regulation by the microbiome.

viiii. Role of Magnesium supplementation in the treatment of depression: A randomized clinical trial