Boost your immune system

Samara Felesky-Hunt, For The Calgary Herald

Q: Last winter, I seemed to get sick more often. How can I keep my immune system strong to fight off colds and flu this year?

A: Let's first consider what makes up the immune system, which defends our bodies from bacteria, microbes, viruses and toxins. It's a complex system, made up of bone marrow, the thymus, spleen and lymph nodes, but essentially it produces and sends white blood cells throughout the body to fight off infectious agents.

Your skin is your first defence against agents trying to weaken your immune system. Skin forms a wall against them and can also alert your white blood cells that an infection is coming.

Stress and a lack of sleep or physical activity can take its toll on the immune system.

Most infectious agents, therefore , get inside the body when they are inhaled or swallowed. That's why it's so important to cover your mouth when sneezing or coughing and to wash your hands properly and frequently.

Immunity-Weakening Factors

Many factors can weaken your immune system, including aging, poor nutrition and an unhealthy lifestyle. Natural aging causes a variety of changes in our bodies, including a slowing down of the immune system. As well, our body's ability to absorb nutrients, including vitamins and minerals needed to keep the immune system strong, may be affected.

The immune system needs a variety of vitamins and minerals to stay strong. Poor nutrition can weaken its ability to fight off infectious agents and enable the production of free radicals, which can lead to serious illness such as heart disease.

Not getting enough vitamin C, for instance, can weaken the body's ability to fight off infection. Eating too much sugar can compromise the ability of white blood cells to kill germs.

Stress and a lack of sleep or physical activity can also take its toll on the immune system. When our bodies are stressed, for example, they release a substance called cortisol, which slows the immune system and weakens its ability to fight off infectious agents.

Immunity-Boosting Nutrients

Eating a balanced diet ensures your body gets everything it needs to maintain a healthy immune system. The Nutrients related link (at right) highlights 10 vital nutrients and how they benefit your immune health.

To obtain these nutrients, keep in mind that eating five to 10 servings of fruit and vegetables daily can help you meet your requirements of vitamin C, vitamin A, beta-carotene and folic acid.

Choosing whole grains instead of refined grains will pump your diet with more B-vitamins, iron and zinc. Consuming lean protein choices such as egg whites, lean cuts of red meats, poultry, fish, nuts, seeds and legumes will add selenium, copper, iron and zinc without adding saturated fats.

Consuming two to four servings of milk products will help you meet your daily requirement of vitamin D. And, you can get all the vitamin E you need by eating more nuts, seeds and leafy greens.

Five Immunity-Boosters

Here are five lifestyle tips that can help strengthen your immunity:

1. Eat a balanced diet and don't skip meals. Eat vegetables and fruits between meals.

2. Incorporate immune-boosting nutrients into your meals.

3. Stay active. An active lifestyle can help keep your body strong so you can fight off infectious agents more easily.

4. Get plenty of sleep and rest.

5. Drink plenty of water. Fluids help flush out bacteria and viruses from your body.