Canada AM nutrition expert Leslie Beck offers a Q and A on how eating healthy can help keep you from becoming sick this season.
Question: Can eating properly actually boost your immune system?
Absolutely, the right diet can certainly help build a strong immune system. A healthy diet that includes protein and plenty of fruits and vegetables will help your body produce white blood cells and immune compounds that fight infection. Staying hydrated can also help prevent infection from taking hold in the first place. When you're dehydrated, tiny cracks form in your nasal membranes in which virus-filled droplets take up residence and promote infection.
So make sure you include protein at all meals. Include foods like fish, poultry, lean meat, eggs, beans, soy, and dairy products. And be sure to meet your daily fluid requirements. In cooler weather you might not feel thirsty, but drink anyway. Men need 3 litres of water per day; women need 2.2. litres. Kids need roughly 2 litres. Certain supplements, like vitamin D, are also important for immunity.
Question: How can vitamin D help?
Vitamin D plays an important role in immunity. It increases the body's production of proteins that destroy viruses, including influenza virus. Given that vitamin D is synthesized in our skin when exposed to sunlight, low blood levels of vitamin D in the winter months may make us more susceptible to getting the flu. Canadian researchers are currently investigating vitamin D for swine flu protection. Adults should take 1000 IU of vitamin D each day from a supplement; kids should get 400 IU.
Question: Are any other supplements worth taking to prevent getting sick - for kids too?
Probiotics, the healthy bacteria in yogurt and supplements, may also be useful in preventing colds and flu in children. A study published earlier this year in Pediatrics found that healthy children, aged 3 to 5, who took a probiotic supplement during the fall and winter suffered significantly less fever, coughs, antibiotic use, and missed school days. Studies do show that regular consumption of probiotic foods and supplements enhance the activity of the immune system.
Buy a product that contains 1 billion to 10 billion live cells per dose (capsule). Choose a probiotic supplement that contains both lactobacilli and bifidobacteria strains. Children's products are available on the market; these usually contain one-quarter to one-half of the adult dose.
Question: Do any foods or supplements harm your immune system?
Sure. Too much alcohol and too much sugar can depress your immune system. Parents should ration the Halloween candy over the next week or two.
When it comes to supplements, taking zinc in high doses can also depress your immune system. Zinc is interesting - it's a mineral that is very important for a healthy immune system, but in high doses, it has the opposite effect. So avoid taking too much zinc from a supplement; stick to your diet and what you get in a multivitamin and mineral supplement - which I do recommend for adults and kids over the age of 2.
Question: What if you have the flu or a cold - which foods can help you recover?
Drink Fluids. During a cold, drink plenty of hot liquids such as hot water, tea, soups and broths to relieve nasal congestion and prevent dehydration. Fluids also help keep the lining of your upper respiratory tract moist which can ease sore throat symptoms.
Chicken Soup. A recent study from the University of Nebraska Medical Center suggests that good old fashioned chicken soup has anti-inflammatory powers which could ease a sore throat. In the study, researchers added 14 varieties of chicken soup to samples of white blood cells that trigger inflammation and found the soups inhibited their activity. The chicken soup also appeared to stop the flow of mucous in the lungs and nasal passages. And it's thought that the spicier the soup the better. Hot peppers contain capsaicin, a natural compound that has the ability to act as a decongestant.
Zinc Losenges. Sucking or chewing zinc lozenges seems to decrease the duration of cold symptoms, especially cough and runny nose. Most studies show a significant reduction in cold symptoms when adults take zinc gluconate or zinc acetate lozenges every two hours while awake, within the first 48 hours of the onset of symptoms. When zinc lozenges dissolve in your mouth, zinc is released and able to bind to cold viruses. This renders the virus unable to attach to cells in your throat, interrupting the infection process.
Most zinc lozenges contain 10 milligrams of zinc each. Do not take more than 50 milligrams (5 lozenges) of zinc per day; too much zinc can depress immune function.
It is important to ensure your daily diet contains zinc rich foods since the mineral is vital to a healthy immune system. Zinc rich foods include oysters, seafood, red meat, poultry, yogurt, wheat bran, wheat germ, whole grains, and enriched breakfast cereals. Your diet and a multivitamin and mineral supplement will provide all the zinc you need to stay healthy.
Question: What about vitamin C?
Although vitamin C promotes the body's production of immune compounds, there's little evidence that taking vitamin C can prevent colds and flu in the general population. However in individuals under physical stress, such as marathon runners, supplementing with vitamin C cut the risk of developing a cold in half.
Vitamin C does seem to lessen cold symptoms in adults and kids. To reduce cold symptoms, 2000 milligrams of vitamin C per day, taken in divided doses appears to be most effective. Children, people under physical stress and those with low dietary intakes of vitamin C tend to respond best to vitamin C.
Question: Any other tips?
It is critical to remember that your first defence against the flu is good personal hygiene. We are hearing this over and over but there is a reason for that. Proper sleep is also critical to guard against infection. Sleep deprivation disrupts immune function and increases levels of proteins in the body associated with inflammation. Aim for seven to eight hours of sleep each night; children and teenagers need nine to 10 hours. And wash your hands!
