Many people across the country are still experiencing winter. We are still in the grips of cold and flu season. Looking to boost our immune systems, we know that sleep, exercise and diet all play a role. Vitamin C aids your immune system and can help your body protect itself from infection, but what is it, why does it help and what are the best sources?

If you are vitamin C deficient, getting more can boost your immune system back to a healthy level and help prevent you from getting a cold. According to most studies, vitamin C in and of itself can’t stop you from getting sick if you are healthy. However, it can lower the severity of an illness, and reduce the duration of a cold by up to 18 percent. And the benefit was seen even more strikingly in people who were already run down. Vitamin C is found in great abundance in immune cells and decreases when you’re ill, so boosting the amount of it can aid your immune response. Vitamin C supports bone, skin and tissue growth and healing. And, it helps your body absorb other nutrients like iron, allowing you to get more out of your food.

Foods lose vitamin C when heated, so it might be better to enjoy vitamin-c rich foods raw or lightly steamed. While we all think of oranges the moment we talk about vitamin C, many fruits and veggies — like strawberries, tomatoes, bell peppers, broccoli, kiwis and Brussels sprouts — are good sources.

Potatoes are excellent sources of vitamin C though they are also high in carbs. But, turnips are a much lower carb option when it comes to root vegetables with high amounts of the vitamin. And cauliflower (our go-to replacement for spuds) is much higher in vitamin C than either potatoes or turnips. Kale, other leafy greens and cabbage are great sources that can go in a salad along with the tomato. And guava — perhaps difficult to locate at this time of year — packs over 280 percent of your daily vitamin C.

Frozen peas and berries can be a great way to get vitamin C in the winter. But broccoli, kale, Brussels sprouts and other green veggies are in your produce department. We avoid orange juice because of the sugar, but we’ll never turn down an orange. In fact, recently, we shared some tasty orange recipes. However, as we said before, heat can damage the vitamin, so eating an orange raw will give you the most benefit.

You can also get vitamin C from supplements. You should speak to your doctor before adding anything to your routine or making significant changes in your diet. What is right for some people might not be healthy for you.