How to Boost Your Immune System with Food

The change of seasons has many of us looking for ways to boost our immune systems. And while it’s not a surefire way to prevent viruses, a healthy diet is essential to keeping those natural defences strong. Here’s how to use your diet to take better care of yourself this cold and flu season.

There’s no magic food or single nutrient that can prevent or cure ailments, so it’s important to eat a varied diet of mostly unprocessed foods like fruits and vegetables. It’s the best way to get all the nutrients your body needs to work properly. Here are some key nutrients that play a vital role in supporting the immune system:

Antioxidants are molecules that protect the body’s cells from being damaged by free radicals—unstable molecules produced as a result of stress, pollution, or even the natural process of digestion. When free radicals build up in the body, they can weaken our cells and make our immune system less effective. Antioxidants work by neutralizing these harmful molecules, helping our immune cells stay strong and ready to defend the body. By eating antioxidant-rich foods often, we can help keep our immune systems healthy and reduce our risk of developing diseases related to chronic inflammation.

Antioxidants are mainly found in fruits and vegetables: citrus fruit, peppers, carrots, broccoli, sweet potatoes, cabbage, beets, grapefruits, kiwis, and strawberries and other berries. Fun fact: A single bell pepper contains the full recommended daily dose of the antioxidant vitamin C! Zinc and magnesium, which also play important antioxidant roles, are found in legumes, nuts and seeds.

Nicknamed the sunshine vitamin, vitamin D is mainly produced by the skin in response to UV exposure. As fall and winter bring greyer and shorter days and a lack of sunlight, it can be a good idea to get vitamin D through diet and/or supplements.

Vitamin D plays an important role in immune cell activation, and studies have shown that vitamin D deficiency makes us more susceptible to infection. The body also needs vitamin D to activate immune cells knows as T-cells. This means that having low vitamin D has a direct effect on the immune system.

Foods high in vitamin D include milk, eggs, fortified plant-based beverages, and oily fish like salmon, herring and sardines. In Canada, a daily supplement of 400 IU (10 micrograms) is recommended for adults over 50, since our skin becomes less able to produce vitamin D as we age.

Omega-3 fatty acids have anti-inflammatory properties. They help regulate the immune response by limiting excessive inflammation, which can weaken the body’s ability to defend itself. Omega-3 fatty acids are also beneficial for the gut microbiome.

Incorporating more omega-3 into your diet is a natural way to boost immunity, and it’s great for your overall health. Omega-3-rich foods include seeds, nuts, and oily fish like salmon, mackerel and sardines.

Probiotics are the “good bacteria” found in fermented foods such as yogurt, kefir, kimchi, miso and sauerkraut. They play a major role in supporting the immune system by strengthening the gut microbiome, that ecosystem of billions of micro-organisms living in our intestines that constitutes one of the first lines of defence against infection. Did you know that 75% of our immune cells are found in the digestive tract? By keeping our intestinal barrier strong, probiotics help keep unwanted bacteria and viruses from entering our bodies.

When it comes to supporting the immune system, hydration is just as important as diet. Water helps the body transport nutrients, eliminate waste, and hydrate its mucous membranes—the front lines of infection prevention. The recommended daily intake of water is about two litres, adjusted for individual needs and levels of physical activity.

Besides getting essential nutrients and staying hydrated, there are plenty of important lifestyle factors that keep the immune system healthy. Sleep is a big one, as lack of sleep can weaken the immune system. The recommendations are to get seven to nine hours of sleep a night and avoid caffeine and screens before bed. Stress management is also crucial, as chronic stress disrupts the immune system. Relaxing activities like meditation and yoga can help with that. And of course, regular physical activity is good for circulation and helps immune cells flow more freely throughout the body.

If you want to optimize your immune health, it’s important to take a holistic approach that combines a varied and nutritious diet with a healthy lifestyle. When you eat foods like citrus fruit, oily fish, probiotics, and colourful produce, you’re giving your body the fuel it needs to fight off infection. So enjoy these delicious immune-boosting foods every day. Your body will thank you!