Can Nutrition Help Prevent Colds and Flu?


Around this time every year, I often get asked, “what can I do to prevent getting a cold or the flu?” When you become exposed to a cold or flu, the chances of getting it are incredibly likely. Everyone wants to do and know as much as they can to prevent it altogether or lower their risk of getting ill.

I get the concern; you don’t want to miss work and then have to play catch up. I don’t want my children not feeling well because, as a parent, I want nothing more than for them to feel well again. And if the whole family gets it, gosh, the amount of extra cleaning, laundry and disinfecting that needs to be done can be exhausting and overwhelming.

While both the “common” cold and flu are caused by viruses that infect our respiratory cells and trigger a response (or fight) from our immune system, there are different types of viruses.

According to the National Institute of Allergy and Infection Disease, there are approximately 200 different types of cold viruses, rhinovirus often being the most prevalent, and the peak season for contracting cold viruses is between April to May and again in September. Children in the U.S. tend to have 6-10 colds each year and teens and adults have 2-4 annually.

There are three different types of flu viruses – influenza A, B and C. Influenza A is the one that causes most flu outbreaks each year, with its peak season ranging from December-February but can last all the way until May.

{Myth Buster: It’s a myth that cold weather or wet weather can cause you to get sick. During these times, you are more likely to be cooped up inside along with others and it’s easier for viruses to spread from one to another}
Best Prevention
The flu virus has two different proteins on its surface which is what causes the virus to spread within your respiratory system, and these proteins can change or adapt over time. When your body comes in contact with the adapted virus, it looks like a new invader that your immune system hasn’t seen before. So even if you had been vaccinated against the flu last year, you do not have antibodies built up to protect you from these new versions of the flu virus. This is why we need a flu vaccine each year.

Speaking of the flu vaccine, every year we hear moans and groans about the need for the flu vaccine. It’s not only a matter of your protection but for everyone else’s, especially young children or older adults, as each year the flu causes numerous hospitalizations and even deaths across the country.

The flu vaccine is essentially a prediction from the U.S. Public Health Advisory Committee regarding what the upcoming year’s flu virus will be. As there are different strains of flu, you can imagine the difficulty in making this prediction, especially knowing the virus is smart and can modify its structure over time.

The flu vaccine is an inactive or non-living version of the predicted virus, at least for the injection, meaning you cannot get sick from it. Your body can utilize this as an identifier and start to build antibodies to protect yourself. Those that receive the flu vaccine, again since it’s a prediction, may still contract the flu, but if you do get it, it is likely not as severe and does not last as long.
In addition to getting the flu vaccine, the best way to prevent contracting the cold or flu virus is through frequent hand washing.

Both the cold viruses and the flu are spread by contact with secretions that contain the virus. Likely culprits for the virus would be doorknobs, faucets and toilet handles. The virus may then enter your body if you touch your eyes, mouth or nose after coming in contact with the virus. Therefore, in addition to getting the flu vaccine every year, frequent hand washing is the next best method to prevent getting sick. The more you wash your hands, the more likely you are cleaning them from potentially carrying the virus around and getting yourself sick or spreading it to other surfaces and exposing others.

Airborne transmission is also possible, sneezing and coughing may expel droplets that you or someone else might breathe in. I know it sounds disgusting, but it just helps illustrate how easily and almost secretly we are being exposed to these pathogens.

Nutritional Supplements
Since our modern day medicine may not offer the best prevention at this time, we often look for additional or supplemental sources to help protect us.

{Always check with your provider before beginning any supplement regimen}.

Some evidence suggests taking garlic may help prevent colds or reduce the number of colds; however, the research is limited to really recommend it. Garlic may have immune supporting properties, but it can interact with a variety of different medications.

Asian ginseng may have immune stimulant properties that may help prevent getting a cold and even help boost the effectiveness of the flu vaccine by increasing antibody response. Taking 100 mg daily for four weeks prior to the vaccine and eight weeks after may reduce the risk of getting sick.

American ginseng – and specifically an extract of it called Cold fX – can be taken twice daily at 200 mg over three-four months. It may decrease the risk of getting multiple colds in one season and have reduced severity and duration.

While there’s some support that zinc prevents the rhinovirus from replicating in a lab, there’s no evidence of zinc supplements actually preventing a cold. Some initial research suggests taking zinc with selenium may improve response to the flu vaccine and reduce the chance of getting sick in the nutrition deficient elderly individuals, this does not carry through for healthy adults with a sufficient diet.

Vitamin C
Vitamin C is probably the most well-known, well-promoted (but misconceived) nutrient for preventing colds and flu. Vitamin C may be helpful with immune function by increasing some antibody activity, function, mobility and production but most studies do not conclude that vitamin C prevents colds, even with amounts of up to 1 gram per day. Unfortunately, even eating foods rich in vitamin C does not lessen your chances of getting colds or flu.

Vitamin D
In 2017, some clinical research demonstrated a 12% reduction in respiratory tract infections in adults taking supplemental vitamin D. For individuals who had lower levels of vitamin D, the risk reduction was even greater (42%). The exact recommended dose was not clear, but taking vitamin D daily or weekly seemed more effective than taking larger doses at a single time. The findings seemed to be supportive in younger populations as well. Children ages one to sixteen had 40% less risk of infection. Additional studies, with larger sample sizes, are still needed.

Some of the newer, more promising and safest use of supplements stems from research supporting beneficial bacteria called probiotics in preventing upper respiratory tract infections. Not all supplemental varieties of probiotics are the same – ranging from the amounts and types of various bacterial strains.

Milk fortified with a few probiotic varieties (Lactobacillus rhamnosus GG  or Culturelle Every Day Health, Lactobacillus acidophilus and Bifidobacterium animalis) reduced rates of respiratory tract infection in children in daycares. The probiotics seem to simulate immunity, reducing symptoms and shortening its duration.

Bifidiobacterium is another strain that seems promising in additional age groups. College students seemed to benefit the most from a specific variety of three billion bacteria, bifidiobacterium bifidum, for six weeks reduced the number of students with cold and flu by 35%.

While we all have an interest in preventing the incidence and spread of colds and flu, the best prevention is scheduling an annual flu vaccine. Frequent hand washing as well as avoiding those who are ill are also at the top of the list for preventable measures.

If you’re looking for additional support that’s evidence-based, safe and effective, vitamin D and probiotics top my list for potential supplements. Despite the research suggesting that vitamin C containing foods (fruits and vegetables like citrus, pineapple, kiwi, strawberries, peppers, greens, potatoes) does not support preventing colds and flu, it can’t hurt to add these nutrient-rich foods into your diet. While your nutrition may not prevent you from getting colds and flu, it can help lessen the severity of your symptoms and shorten the length of the illness.

Rebecca Miller, MPH, RDN, LDN is a registered dietitian nutritionist who shares recipes + inspiration on her blog, Twisted Nutrition. She can be reached at or via email

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