If you’re like most people, your produce consumption peaks during the summer months due to abundant availability, freshness, and the lure and trendiness of the mid-summer farmers’ markets. Before you know it, winter is here and the appeal of the couch and the fireplace seem so much better when paired with mac and cheese rather than an arugula salad with tomatoes.Enter what I call the winter color drain—the cold months between December and March where most vegetables are a blah color (think potatoes), your refrigerator rarely sees the color green, and the thought of a stroll through a farmers market is about as inviting as firing up the outdoor grill to make some fish in the frigid air. The truth is, your selection of fruits and vegetables doesn’t have to go away during the winter months—it may just need to come in a different form: frozen. It’s the winter months that you’ll really need to focus on knockout food selections to keep your immune system as beautiful as ever.First, let’s start with availability. Just because spring and summer are gone doesn’t mean that fresh, delicious and available produce is no longer an option. Fall and winter produce selections include apples, pears, cruciferous vegetables such as Brussels sprouts and broccoli, collard greens, sweet potatoes, butternut squash, kale and leeks. Also, remember that any vegetable can be enjoyed year round in the frozen section. These vegetables are frozen at peak ripeness, which means they contain the highest amounts of antioxidants. Just make sure your frozen vegetables are plain and void of added salt, sugars or sauces.Next, let’s look at immunity. The top vitamins for keeping your immune system at peak performance are vitamins C, E, B6, A, D and folic acid, as well as iron, selenium and zinc. Here’s a breakdown of where you can find the best sources of these immune-boosting gems:• Vitamin C: green leafy vegetables, bell peppers, citrus, papaya• Vitamin E: almonds and spinach• Vitamin B6: coldwater fish such as tuna, as well as chicken breast and bananas• Vitamin A: foods high in carotenoids such as carrots, sweet potatoes, pumpkin, cantaloupe and squash• Vitamin D: fatty fish, low-fat milk, eggs and certain varieties of mushrooms• Folic acid: beans, lentils, ready-to-eat cereals and green leafy vegetables• Iron: tofu, beans, broccoli, kale, shrimp and turkey• Selenium: sardines, barley, Brazil nuts, tuna• Zinc: shellfish, chicken, cashews, baked beansKeep in mind though, that the best “immune boosting” diet is really one that incorporates a balanced amount of fruits, vegetables, whole grains, healthy fats and lean sources of protein. In other words, the overall quality of your diet may be more important than pinpointing specific foods for immune-boosting. Other major factors for a healthy immune system include getting adequate sleep and following a regular exercise routine.Finally, let’s look at preparation. Winter is a tempting time to indulge in comfort food favorites. The good news is that you can easily incorporate nutrient-dense vegetables into your winter regulars. To make a healthier chili, substitute ground beef for ground turkey breast and throw in a whole bag of kale. Because kale absorbs so much water, it’ll become nothing more than green specs in your pot—not really noticeable on the spoon but oh so noticeable to the body. Longing for mashed potatoes? Mix ¼ of the entire pot with pureed cauliflower. It’s got the same color and similar texture when pureed, yet gives the potatoes a cruciferous cancer-fighting boost. Want to indulge in a little immune-boosting vitamin A? Mix carrot puree into muffin mixes, soups and even spaghetti sauce. Finally, add some fungus in your wintery mix by folding mushrooms into scrambled eggs in the morning or simply sauté them in olive oil and add them to a panini.Just because the snow shows up more than the sun doesn’t mean your diet has to suffer. Stay beautiful this winter by improving your immune system with the same nutrient-dense produce that keeps you healthy all summer long!