This time of year, it seems like everyone you know is either sniffling their way through a cold or completely out-for-the-count with the flu. If you’re lucky enough to have survived winter unscathed so far, you’ll do well to know how you can stay as healthy and strong as possible until springtime.

As you probably know, getting sick stresses your immune system, increases your risk of autoimmune flare-ups and thyroid dysfunction, and can even lead to a longer-term illness. In some cases, doctors may even mistakenly prescribe you antibiotics, which wreak havoc on your gut bacteria. (FYI: Antibiotics can’t treat viruses, which colds and the flu are.)

To keep your immune defenses up, I recommend focusing on the following five natural strategies.

1. Wash Your Hands Frequently and Thoroughly 

The way in which cold and flu viruses spread is no mystery; someone who is sick coughs or sneezes into their hand and then touches the office coffee machine. Hours later, you touch the machine, pick up the germ, and get sick yourself.

Simple as it may seem, washing your hands truly is integral in protecting yourself during cold and flu season. Wash your hands with soap and warm water for at least 30 seconds every four to five hours (and after every human contact you have).

2. Get Plenty of Exercise

Exercise can boost your immune system by increasing your circulation, which transports illness-fighting antibodies throughout your body.

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Exercise also enhances your immune system by relieving stress (which can negatively impact your immunity). In fact, it can help slow your body’s production of stress hormones.

3. Sleep 7 To 9 Hours Per Night

Your body relies on sleep to recuperate from daily stress and inflammation. Unsurprisingly, chronic sleep deprivation can significantly reduce your immune function. Prioritize sleep as much as possible this time of year, and aim for seven to nine hours of rest per night.

4. Load Up On Turmeric

Antioxidants are very important for your immune function. The antioxidant curcumin⁠—the orange pigment in turmeric, in particular⁠—is a potent free radical scavenger that supports joint and cardiovascular health. 

Throughout the winter, incorporate turmeric into your diet however you can. I love to eat daal, a lentil soup colored and lightly flavored with turmeric.

That said, there are also plenty of turmeric teas and even fresh turmeric-containing juices and health shots that you can incorporate into your daily routine.

5. Up Your Intake Of Certain Vitamins

Although healthy habits, exercise, and proper sleep are your best defenses during cold and flu season, you can also support your immune system by upping your intake of certain vitamins.

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Two, in particular, I recommend: vitamin C and vitamin D. You can find vitamin C in produce like citrus fruit, peppers, and tomatoes. D is a little harder to find, though certain fatty fish and UV-treated mushrooms provide some. Consider supplementation if you can’t get your fill through food. 

Dr. Amy Shah, M.D., is a double board-certified physician with training from Cornell, Columbia, and Harvard Universities. With extensive training in health and nutrition, she advises on increasing energy levels, fixing gut issues, managing allergies, and boosting the immune system. Dr. Shah was recently named one of MindBodyGreen’s Top 100 Women in Wellness to Watch and is a member of Genexa‘s Medical Advisory Board.