Cold and flu season is once again upon us, and it seems everyone turns to vitamin C as a first line of defense. However, there are other natural immune boosting supplements which should be incorporated to support a healthy immune system.

People eating a healthy diet of fruits and vegetables may still not be getting enough of the vitamins they need due to agricultural elements such as herbicides and pesticides used on crops.

Dr. Kiera Smialek, ND, of Natural Kid Doc, said supplementing your diet with certain herbs, minerals, vitamins, and probiotics is beneficial in supporting a healthy immune system. 

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“There is research to support specific vitamins, minerals and herbs regulate immune system function,” she said. “Having a combination of these vitamins, minerals and herbs can also help fight off the viruses causing colds and the flu.”


Zinc is an important mineral for the development of immune cells. These immune cells help target infections in the body and fight viruses. Taking zinc at the onset of a cold often decreases the symptoms if it is taken within the first 24 hours of infection, according to research by the Mayo Clinic.

Foods containing zinc include shellfish, meats, whole grains, legumes, egg yolk, nuts, and seeds.

“Vegetarians and vegans often need to supplement zinc due to the lack of zinc in their diet,” she said.


Garlic is an exceptional antiviral and antimicrobial food due to a heavy concentration of sulfur-containing compounds such as allicin. Allicin has immune boosting properties which help prevent the common cold and flu. 

Garlic has been shown to treat chronic bronchitis, sore throat, sinus problems and respiratory infections, according to the University of Rochester Medical Center. 

“Garlic can be eaten as a food, infused into tea or herbal cough syrups, or taken as a supplement in capsule or tablet form,” Smialek said.

Vitamin D

There are studies that show a deficiency in vitamin D is associated with an increased susceptibility to infections in general.  

Vitamin D is one of the most important vitamins during cold and flu season because it helps boost the immune system, Smialek said. Supplementing vitamin D is often necessary during cold and flu season because most of the vitamin D people receive comes through sunlight, which can be lacking in certain areas of the country during the winter season.

“I typically recommend vitamin D supplementation during cold and flu season,” Smialek said. “During the colder months there is less exposure to sunlight, which is a main source of vitamin D. It is recommended to be outdoors with most of your skin exposed for at least 15 to 20 minutes a day to receive enough vitamin D from the sun.” 

Vitamin D can also be found in the skin of fatty fish. There are small amounts found in cheese, egg yolk and beef liver. Many foods are now fortified with vitamin D, including milk, orange juice, breakfast cereal and bread.  


Elderberry is a plant that produces berries with medicinal properties. 

“Elderberries are high in antioxidants and have immune modulating benefits,” Smialek said. “These antioxidants help fight viruses and support healthy immune system function.” 

Elderberry is often formulated into a palatable syrup, or the extract is put into capsules.

“Most people buy elderberry syrup because it tastes good and can be taken easily,” Smialek said. “Elderberry tea is another popular option for those who enjoy drinking tea.”


Probiotics are live beneficial bacteria in the gut, which play a major role in immune health. Probiotics work by enhancing digestive and immune system function. People often think of eating yogurt as a good source of probiotics. 

 “Yes, yogurts have some good bacteria, but a lot of yogurts have a high amount of sugar in them,” Smialek said. “The number of beneficial bacteria in yogurt is generally low and consuming a large amount of sugar can be inflammatory, which can have a detrimental effect on our immune system. Fermented foods like kimchi, kefir, and sauerkraut are preferred over dairy based products as a source of dietary probiotics.”

Smialek said she recommends people supplement high quality blends of probiotics in a powder or capsule form to receive all the benefits.

Appropriate Dosing

Taking the right dosage of a vitamin is the most important aspect in receiving the therapeutic benefits. The recommended daily amount on packaging for vitamins is the bare minimum a person should take. 

“Taking more than the recommended dose is not always beneficial,” she said. “For example, if you take too much vitamin C you will pass it out of your body through urine. Taking more than recommended amount of vitamin A, D, and K can be dangerous and have detrimental health effects.”

Smialek recommends consulting with a healthcare provider, such as a naturopathic doctor, functional medicine doctor or nutritionist, to determine the correct dose of nutritional supplements.   

“In general, I encourage people to eat a healthy diet high in antioxidant foods during cold and flu season,” she said. “Eating more fruits and vegetables, and less inflammatory foods like dairy and sugar, is beneficial in keeping the immune system healthy.” 

Keep in mind you should always consult a physician before starting any supplement regimen.


Joey Hancock is a freelance writer living in Tempe, Arizona. He has reported on health, politics, sports, engineering, and education at multiple publications throughout Southern Arizona.