Elderberry

The berries and flowers of elderberry are packed with antioxidants and vitamins that may boost your immune system. They could help tame inflammation, lessen stress, and help protect your heart, too. Some experts recommend elderberry to help prevent and ease cold and flu symptoms.

Vitamin C

Vitamin C is one of the safest and most effective nutrients, experts say. Though it may not be the cure for the common cold, the benefits of vitamin C may include protection against immune system deficiencies, cardiovascular disease, prenatal health problems, eye disease, and even skin wrinkling. The tolerable upper intake level (or the maximum amount you can take in a day that likely won’t cause harm) is 2000 mg a day for adults.

Vitamin D

Vitamin D is a nutrient your body needs for building and maintaining healthy bones. That's because your body can only absorb calcium, the primary component of bone, when vitamin D is present. Vitamin D also regulates many other cellular functions in your body. Its anti-inflammatory, antioxidant and neuroprotective properties support immune health, muscle function and brain cell activity.

Zinc

Zinc plays a key role in maintaining vision, and it is present in high concentrations in the eye. Zinc deficiency can alter vision, and severe deficiency can cause changes in the retina (the back of the eye where an image is focused). Zinc might also have effects against viruses. It appears to lessen symptoms of the rhinovirus (common cold), but researchers can’t yet explain exactly how this works. In addition, there is some evidence that zinc has some antiviral activity against the herpes virus. Low zinc levels can be associated with male infertility, sickle cell disease, HIV, major depression, and type 2 diabetes, and can be fought by taking a zinc supplement.