You've likely heard that breakfast is the most important meal of the day. Not only is it the best time to get immune-boosting nutrients that many Canadians lack, such as vitamins A and D, but it also jump-starts your metabolism and is an excuse to try delicious new foods.

Five-minute prep: If you've been battling a lingering cold, begin your day with a parfait made from plain Greek yogurt and fresh juicy strawberries. This winning combination has the cold-busting triple benefits of vitamin C, protein and probiotics. The vitamin C in the berries helps decrease the length of time and severity of cold symptoms.

Greek yogurt is a smart choice because it has double the protein of regular yogurt; protein can increase the production of immune-boosting T cells and make you less susceptible to colds. Remember to scan the ingredient list for the words "live active cultures." That's your hint that the product contains probiotics, beneficial bacteria that enhance immune defenses.

People who regularly eat probiotic-rich yogurt are less vulnerable to common colds and show a higher resistance to those other nasty pathogens that cause food poisoning.   

If you're on the go, skip fast-food yogurt parfaits. They're often made with sweetened yogurt and syrupy fruit, and may contain a whopping four teaspoons of added sugar. Plus, they don't boast the same levels of vitamin C.

10-minute prep: Rev your immune system with a bowl of oatmeal, which can be ready in as little as one minute. Add dried apricots and almonds to a package of natural quick-cooking oats – a better option than processed, sugar-laden packets. Oats contain zinc, which is crucial: a zinc deficiency can result in reduced T-cell function. Oats also contain selenium and manganese, which help counter inflammation.

The apricots and almonds have vitamin A and E, respectively, both of which are antioxidants that help protect immune cells from damage caused by harmful free radicals (which cause cell damage). Vitamin A is also a vital part of the mucosal cells that line our nasal passages and throats, and defend against infection. (Hello, flu season!) Having a vitamin A deficiency makes you more susceptible to foreign invaders that can make you cough and sneeze.  

If oatmeal isn't your thing, try whole-grain toast with almond butter and dried apricots. Choose bread made with sesame or pumpkin seeds for extra zinc.

20-minute prep: Fancy up your Sunday brunch with a salmon and dill frittata. Fresh salmon and omega-3-enriched egg yolks both contain vitamin D and omega-3 fats, two nutrients that regulate the immune system. Vitamin D deficiency has been linked to an increased risk of multiple sclerosis and certain cancers, so it's crucial that you get enough.  

And while smoked salmon may taste great, you should avoid it if you already have a weakened immune system (if you have cancer, say, or are taking immune-suppressing drugs), because raw fish can carry harmful Listeria bacteria.  

Don't forget to add spinach and peppers to the eggs. Antioxidant-rich vegetables help protect cells and strengthen your immune system, making it easier to ward off colds, flu and other infections. Out of fresh veggies? Use frozen instead. Vegetables are flash-frozen at the peak of freshness to lock in vitamins A and C.

Cara Rosenbloom is a registered dietitian in Toronto and a member of Dietitians of Canada.

If you do get sick, we have 5 natural cold remedies to help you feel better.
                                               

This story was originally titled "Breakfast Boost" in the November 2013 issue.             Subscribe to Canadian Living today and never miss an issue!