“Let medicine be thy food and let food be thy medicine” – Hippocrates

Centuries ago the earliest known doctors and health practitioners across the world imparted the benefits of using food as medicine to heal the body. Now based on research it is clearly evident that food plays a major role in health and how you feel on a day to day basis. Hippocrates believed that illness stemmed from inadequate nutrition and bad eating habits and that if people were to learn good eating habits then optimum health would be restored.

I can’t say that I disagree with this. For a lot of us, our diets are based on convenience foods which are processed and stripped of nutrition. We should be placing more emphasis on the quality of our diets, especially during the winter months, when illness rates sore.

Okay so let’s say I’ve convinced you to pay attention to your diet. You travel to your local drugstore and you turn down the supplement aisle, looking for the right supplements to boost your immune system. You are overwhelmed by the claims on the packages. You also wonder which claims are purely marketing tactics and which claims are based on science and worth taking? This is where I come in.

With the help of two wonderful nutrition students – Colleen Farrell, BASc (c) and Kelsey Hamilton, BSc, MScFN (C),  I’ve reviewed and compiled research around common nutrients that claim to boost immunity and prevent the winter cold.

Vitamin C

15825973_10157874813725136_350829060849695721_n.jpgYou’ve probably heard it before: taking a vitamin C supplement can prevent you from catching the winter bug. Is this fact or fiction?

Vitamin C plays a big role in immune system, meaning that it helps the body’s natural defense system fight against disease and infectious invaders. There has been conflicting evidence to prove that vitamin C supplements can prevent you from catching the common cold, but research has shown that vitamin C can help lessen symptoms and reduce the duration of this winter illness. However, taking vitamin C after experiencing common cold symptoms has not been shown to affect cold duration or severity of symptoms.

Instead, how about focusing on including Vitamin C-rich foods in your diet around flu season? Vitamin C is commonly found in many fruits and vegetables. You need at least 200mg per day to fight colds. Some foods that have this amount of Vitamin C:

  • 1 guava fruit
  • 2 papayas
  • 2 cups of strawberries
  • 1.5 bell peppers
  • 2.5-3 medium oranges
  • 3 kiwis



Zinc is a mineral that helps with cell growth and the immune system. Zinc has been used to help treat the common cold and can be consumed as a lozenge or syrup. Taking a supplement within 24 hours of contracting a cold may lessen your symptoms, but do not exceed 40 milligrams per day. On the downside, zinc lozenges don’t taste so good!

Vitamin D

This nutrient increases the body’s production of proteins that destroy viruses, including the influenza virus. Given that vitamin D is synthesized in our skin on exposure to sunlight, 15895283_10157874813845136_2954132885408406000_n.jpglow blood levels of vitamin D in the winter months may make us more susceptible to getting the flu.
Take 1000 IU (international units) of vitamin D each day throughout the winter. Older adults, people with dark skin, those who don’t go outdoors often and those who wear clothing that covers most of their skin should take the supplement year-round. Children should supplement with 400 IU per day.

Omega 3

15871703_10157874813860136_8960133067233397056_n.jpg The Omega 3 fatty acids found in oily fish—such as salmon, trout, halibut, and tuna—help boost our immune systems, by increasing the activity of phagocytes, which are white blood cells that combat harmful bacteria. Omega 3 also decreases inflammation, which may help to protect the lungs from infection and colds. Many varieties of shellfish also contain a substantial amount of Selenium, which can help prevent or clear flu viruses out of your body. If you’re not a fish eater, you could supplement with omega 3 – take a 1,000 mg daily dose of purified fish oil or krill oil.


Ginseng is an herb that has been used to treat medical conditions for centuries. In some studies, ginseng has been shown to boost the immune system and release chemicals that can fight off viruses. Although it may boost the immune system, research hasn’t shown that this immune boost is significant enough to conclude that ginseng can reduce the duration and severity of cold symptoms or prevents the common cold.





15965743_10157874813850136_3678450173461718626_n.jpgProbiotics are bacteria found in fermented milk products that promote a healthy digestive system and reduce the growth of harmful bacteria. There has been poor evidence to suggest that probiotics help to reduce the duration or symptom severity of common colds, but probiotics have been shown to have some benefit in children.

Buy a product that contains both lactobacilli and bifidobacteria, the two main types of probiotic bacteria. Take one to 10 billion live cells per dose.  Children’s products typically contain one-quarter to one-half the adult dose.

Allicin (Garlic)

15941314_10157874813865136_8816039552637615802_n.jpgAllicin is the biologically active component of garlic and has been known for its anti-cancer, antioxidant, and anti-microbial benefits. One study found that a high dose (180mg) of allicin extract (a typical garlic clove has 5-9mg of allicin) reduced the number of colds and duration of cold symptoms in the study participants. However, not much is known about the safety of high-doses of allicin and more research is needed.

Alright, I hope you survived navigating through the above synopsis of our research.  Here are some additional take-aways to help prevent the winter cold!

  1. Eat the rainbow! Since there isn’t one food that can completely prevent you from getting sick, it’s important to eat a variety of fruits and vegetables during the winter months. Colourful fruits and veggies contain an abundance of powerful nutrients and antioxidants that can help build a strong immune system and fight infection!
  2. Get enough rest. Being sleep deprived can exacerbate your immune system, making you more prone to catching a cold or flu. Turn off the Netflix and try to hit the hay at a reasonable hour!
  3. Drink water to stay hydrated. Water is important for many functions in the body, especially removing toxins. If you’re not staying hydrated, this can lead a buildup of toxins which can weaken your immune system, making you more susceptible to catching a cold. In addition, drink hot fluids! During a cold, drink plenty of hot liquids such as hot water, tea, soup an broth to relieve nasal congestion and prevent dehydration. Fluids also keep the upper respiratory track moist which can ease sore throat symptoms.
  4. Get moving! Not only does physical activity reduce the likelihood of cardiovascular disease and diabetes, being active can also strengthen your immune system.

In conclusion, there isn’t a one quick fix to fully prevent or treat the common cold from a nutrition perspective. Be sure to keep an open mind when learning about the latest flu-stopping remedy. Herbal medicines and supplements may help treat your cold, but maintaining a balanced and healthy lifestyle can do a lot more for your immune system and overall health. Now, go out and enjoy the snow!


  1. Great information in this post. It shows the importance in providing essential nutrients for the body to help sustain healthy FUNCTION (including immune function) to prevent or shorten the duration of diseases. It also discusses the non food components which are equally important to maintain HEALTH. Achieving a BALANCE among all these components maximizes the chances for achieving and maintaining quality health.
    Great post!

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