By Keith Barbalato

Keeping a healthy immune system is always important, especially during colder months when we're often indoors, in closer contact with germs.

The link between strong immunity and nutritional intake is clear: More whole foods, fewer processed foods and a balanced intake of essential vitamins and minerals can keep you and the people around you, from getting sick.

Find these micronutrients in a food near you:

Vitamin D

What it is: A nutrient that fosters production of the proteins that break down the cell membranes of bacteria and strengthens cells that maintain immunity for the body. Deficiency can increase infection, while healthy doses are believed to prevent autoimmune diseases.

Where to get it: Sunshine, milk, mushrooms and oily fish such as salmon, tuna and herring.

Did you know? Vitamin D is the only vitamin with its own Twitter account: @VitaminDCouncil.

Vitamin A

What it is: Fat-soluble compounds vital to the normal functioning of many immune cells including antibody generation and cellular reproduction; plays a crucial role in maintaining the health of your skin and mucous membranes, which act as the first lines of defense against infections.

Where to get it: Animal livers, dark greens and orange and yellow vegetables such as carrots and sweet potatoes.

Did you know? It is possible to get too much vitamin A. Overdose, known as hypervitaminosis A, can cause nausea, vomiting and dry skin. This was a common problem for Arctic explorers whose subsistence diet included seal and polar bear livers.

Zinc

What it is: A mineral required for essential proteins and antioxidants that play a major role in maintaining immunity. Zinc also enhances the function of T cells, which detect and eliminate infectious and abnormal cells in the body.

Where to get it: Oysters, dairy products such as yogurt and dark meats.

Did you know? Two oysters contain the full daily requirement of zinc.

Vitamin C

What it is: A powerful antioxidant that aids in the production and function of white blood cells, helps prevent cell damage and is needed for the function of essential enzymes.

Where to get it: Citrus fruits and drinks, as well as sauerkraut.

Did You know? Vitamin C is a water-soluble nutrient, meaning it is not stored in cells. Excess amounts pass through the body, so vitamin C can be consumed throughout the day.

Probiotics

What it is: Bacteria for your digestive tract that stimulate the production of antibodies and T cells and help cells communicate as they fight off infections.

Where to get it: Yogurt. Check labels for “contains active/live cultures." Also kimchi, kombucha and other fermented foods.

Did you know? In contrast to antibiotics, which means “life-killing" in the Greek etymology, probiotics means “for life" because they are organisms that stimulate growth.

Vitamin E

What it is: An essential antioxidant helping protect cell membranes from atoms that damage cells.

Where to get it: Fatty foods such as seeds, nuts and oils. Add sunflower seeds—one of the best sources—to salads, yogurt or stir-fries.

Did you know? Studies show that 90 percent of Americans don't meet the recommended daily value for vitamin E.

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