It’s no secret that respiratory illnesses, including the common cold, the flu, and other viruses peak during winter. What may be lesser known? Which nutrients can boost your immune system.

“As far as immune-boosting substances go, natural sources should be your first line of defense,” says Dr. Theresa Sheridan, a primary care physician. “Eating a balanced diet of nutrient-dense foods will supply your body with vitamins and minerals it can easily absorb.”

Supplements to consider

If you are not getting enough nutrients from diet alone, supplements can help you meet recommended daily intake levels.

These nutrients can help keep illness at bay:

• Vitamin D: “The number one nutrient to consider is vitamin D,” says Dr. Sheridan. “Since sunlight is one of the most abundant sources of vitamin D, many Midwesterners are vitamin D deficient. When vitamin D levels fall below 30, your immune system drops off.”
  
  Your primary care provider should check your vitamin D level before you start taking a vitamin D supplement. Ingesting too much vitamin D can be harmful to your health.

• Vitamin C: “Vitamin C is the second most important nutrient when it comes to immune health,” says Dr. Sheridan. The recommended daily level of vitamin C is 500-1000 mg.

• Fish Oil: “Fish oil helps your body absorb vitamins and nutrients so your cells can use them to fight off illness,” Dr. Sheridan explains.

• Pro- and prebiotics: “We have more bacteria in our gut than cells in our body,” says Dr. Sheridan. “People with a variety of bacteria in their gut are healthier than people with limited gut bacteria.”

“When you are fighting an infection, you are detoxifying your body of the virus or bacteria,” explains Dr. Sheridan. “Substances that replenish your liver, the organ that filters toxins, will help you fight viruses more effectively.” Nutrients like zinc, quercetin, and berberine can be found in foods or taken as supplements to offer additional immune support.

Before beginning any supplement, talk with your primary care physician to make sure it won’t interact negatively with medications or other supplements you’re already taking, or health conditions you may have. Your doctor can recommend the best and safest combination of supplements for your health.