#1) Stay Active
Exercise (sweating quite possibly being the most important part) plays a direct role in the human body's immune function. Whether it's running, jogging, playing tennis, or using your preferred machine at the gym, physical activity stimulates white blood cells and antibodies, sending them throughout the body. This improves the immune system's ability to fight off infectious diseases, so be sure to exercise on a regular basis this fall.
#2) Increase Your Vitamin C Intake
Vitamin C is a naturally occurring antioxidant that can improve your health and protect against illness. A study conducted in 2007 found that a daily 200 mg dose of vitamin C when taken at the onset of a cold shortened its duration by 8% in adults and 14% in children. (Some report greater success with zinc, especially zinc lozenges.) With fall and winter being prime time for colds, it might be a good idea to push your daily food intake into the direction of getting a minimum of 75 mg of this powerful antioxidant.
Some sources you might not have considered: Pineapple (fresh) 16mg, asparagus 31 mg, grapefruit 26 mg, broccoli (raw) 89 mg, sundried tomatoes in oil 101 mg, raw parsley 133 mg. The humble apple contains so many phytonutrients that it has an antioxidant equivalent of 1,000 mg (as in 1g) of vitamin C.
#3) Remember the Rainbow ("ROY-G-BIV")
Yet another way to improve your health is to do your best to get every color in your food, every day: red, orange, yellow, especially (dark, bitter) GREENS, blue and purple (violet). (I'm going to substitute white or beige for the indigo. Let's hear it for the beige: cauliflower, leeks, fennel, celeriac, parsnips, rutabagas, the all powerful mushrooms, even potatoes--which I know will be controversial.) With some notable exceptions, the more color you have on your breakfast, lunch or dinner plate, the better. Foods that are bright orange, red and green are all excellent sources of vitamins and antioxidants. Some ideas include squash, bell peppers, broccoli rabe, Swiss chard, bok choi, escarole--all of which will help keep you healthy throughout the darker, drearier, indoor months.
#4 Make a Soup
There's no better time than the chilly fall and winter seasons to lovingly prepare a hearty soup. Avoid store-bought soups (and stocks--or read labels carefully), which are usually loaded in sodium and preservatives. Instead, make your own from scratch. This allows you to include a variety of beneficial vegetables and seasoning, tailoring it to your own personal preference.