Joan Endyke: Take stock of these flu-fighting foods

A healthy diet is essential for a strong immune system, which helps to resist  flu infection, or aids in faster recovery time. Like proper hand-washing and  vaccines, what you put on your plate could go a long way to keep you flu-free  this season.

Don’t wait until your head is throbbing and a fever is spiking to eat well.  It takes time to build up your immune defenses, so start now.

Forget about relying on vitamins and supplements. Research finds they do not  prevent flu or colds, although vitamin C can lessen the duration of illness.  Whole foods provide real benefit. Emphasize those rich in vitamins A, C and E,  as well as selenium, zinc and omega 3 fatty acids. These nutrients work in  conjunction with thousands of other minute plant nutrients in foods to bolster  the immune system. No one has yet been able to package these powerful nutrients  into a supplement in the same mysterious way nature does.

Fruits and vegetables are the powerhouses of protection. Aim to have them at  every meal. Add fruit to breakfast or eat it as a snack. Try warming up frozen  berries in the microwave and topping with vanilla yogurt. Choose vegetable  soups, stews and salads, or oven-roast them. Add a low-sodium V-8 or tomato  juice to breakfast or lunch. Frozen vegetables retain their nutrients and can be  good options for busy days. Throw some in your work freezer to microwave at  lunch. Snack on nuts and dried fruit instead of empty-calorie crackers, fat-free  cookies or the like.

Flu-fighting foods

Vitamin A is critical to the immune system. It enhances white blood cells and  antibodies, and maintains the protective lining of the nose, throat and lungs to  prevent virus entry and serious respiratory infections. Milk, liver and eggs are  good animal sources. Sweet potato, cantaloupe, broccoli, greens, cabbage, kale,  spinach and carrots are good plant sources. Aim for at least one plant serving  daily.

Vitamin C increases the production of white cells and interferon, keeping  viruses from taking over cells. Aim for at least one good source daily of: fresh  orange, grapefruit or equivalent juices, colorful peppers, strawberries,  broccoli, kale, cauliflower, greens, Brussels sprouts, papaya, cabbage, spinach,  kiwi, snow peas, cantaloupe, tomatoes, zucchini, raspberries, asparagus, celery,  pineapple or watermelon.

Selenium protects the thyroid gland and immune cells from damage and keeps  them functioning properly. Brazil nuts are the best source (aim for one a day).  Good sources are fish, mushrooms, eggs, lamb, barley, sunflower seeds, turkey  and oats.

Vitamin E helps in cell signaling and production of antibodies. Green leafy  vegetables, wheat germ, sunflower seeds and almonds are very good sources.

Zinc improves production and response of white blood cells, especially in  children. Calf liver, mushrooms and spinach are the best sources. Pumpkin seeds,  beef, lamb, summer squash, asparagus, chard, collard greens, shrimp, broccoli,  peas, yogurt and sesame seeds are good sources.

Omega 3 fatty acids help to regulate the immune system. Eat cold-water fish,  flax seeds and walnuts.

Patriot Ledger contributor Joan Endyke is a registered dietitian with a master’s degree in nutrition and  food science. She is a certified personal trainer and the nutrition director at  Fitness Unlimited. Readers may send questions about nutrition to Endyke at Fitness Unlimited,  364 Granite Ave., Milton, MA 02186, or by e-mail to jendyke@fitnessunlimited.com. The information in this column is not intended to diagnose individual  conditions. Readers should see their doctors about specific problems.