As a dietitian, I am a huge fan of the famous quote by Hippocrates, “Let food by thy medicine,” and during cold and flu season, that couldn’t be more applicable! This time of year, many of my clients ask about ways they can stay healthy and prevent getting sick. So, I thought I would share some of my favorite ways to support the immune system during cold and flu season.
- Eat plenty of colorful fruits and veggies – I always say “food first.” The truth is, no supplement or exercise regimen can take the place of a good quality, whole foods diet. Research has shown that adequate fruit and vegetable intake can reduce susceptibility to colds and flu. Colorful fruits and veggies contain nutrients like vitamin A and C in addition to phytonutrients, all of which are important for immune function. Focus on having at least 5 servings of fruits and veggies daily. Ideally you should have 3-4 servings of fruit and 5 or more servings of vegetables daily. If you have trouble meeting this goal, try having a fruit and veggie smoothie for breakfast or as part of lunch or dinner. It can be a great way to get in extra servings.
- Avoid or limit refined sugar – Sweets, sugary drinks, juice, floury foods and processed grain foods in excess, suppress immune function making us more susceptible to communicable infections. Stick with whole food carbohydrates such as beans, fruit, peas, starchy veggies and whole grains like quinoa and whole oats most often. Unsweetened dairy can also be a good choice however, if you find it creates more mucus, you may fare best avoiding it during cold season.
- Stay Hydrated – Drink at least 2 liters of water daily (About 64 oz). Ideally you should aim to drink half of your body weight. Also opt for unsweetened green or black tea which contain polyphenols and flavanoids that help your body fight pathogens. They also help keep you hydrated. Enjoy several cups of green or black tea throughout the day.
- Get adequate protein – Proteins build our immune system and the antibodies that fight infection. Aim to have a serving of protein about the size of the palm of your hand at each meal. Stick with high quality proteins from fresh poultry, fish, lean pork and beef, eggs, nuts, beans, quinoa and unsweetened yogurt. When incorporating animal proteins, consider the source, as most factory farmed meats contain pesticides and antibiotics that can weaken the immune system.
- Incorporate Healthy Fats – And avoid the processed ones! Stick with healthy fats from avocados, avocado oil, olive oil, olives, fatty fish like salmon, sardines, tuna and trout, nuts, natural nut butters, seeds, grass-fed butter and a good quality cod liver oil like this one which provides vitamins A and D that are important nutrients for immune health. These healthy fats help fight inflammation where as the processed oils contribute to it. The more inflammation we have, the harder it is for our immune system to function at it’s best. Avoid processed oils like corn, soybean, peanut and cottonseed oil and any of the processed foods that contain them like fried foods, margarine, baked goods, chips, coffee creamers and most bottled salad dressings to name a few. Trans fats are also included here so anytime you see the words hydrogenated or partially hydrogenated in the ingredients, that is a big red flag.
- Focus on gut health – Millions of bacteria live in our gut! We now know that much of our immune function, about 80%, is determined by the composition of microbes that live in our gut. For a healthy immune system, we want to have plenty of good bugs in our GI tract to fight off the bad bugs. These good bugs work in a number of ways to boost immunity but the bottom line is, we want plenty of them. Eating fermented foods like sour kraut, kimchi, kefir, probiotic yogurt and apple cider vinegar is one of the best ways to optimize our gut flora. Feeding the good bugs with plenty of plant-based foods (fruits, veggies, whole grains, nuts, beans and seeds) is also key! A good quality probiotic supplement can be beneficial but remember, food first and talk with your dietitian about a good quality probiotic because not all are created equal.
- Get adequate vitamin D – Most of us don’t get enough vitamin D. Since it comes primarily from the sun, this is especially true in the winter months which also happen to be during cold and flu season. Vitamin D is one of the most important nutrients for optimal immune function. It is important to know your vitamin D level. Ask your doctor for this simple test that most are willing to do. If your level is below 40, it is a good idea to supplement with 1,000 to 4,000 IU of vitamin D3 daily to achieve a target range of 50-80. Talk with your doctor or dietitian about the most appropriate dose for you.
- Last but not least… think Zinc – Zinc is an important mineral involved in the development and function of immune cells. Research shows that taking around 30 mg of zinc citrate or zinc gluconate daily when fighting a cold or other respiratory infection can significantly reduce severity and duration of the illness. Taking 1 zinc lozenge like these every 2 hours at the first symptom of a respiratory infection can have a dramatic effect on your ability to fight the infection quickly. I know this first hand as my family relies on these to stay well during cold and flu season. I also like these because they contain elderberry and vitamin C which are beneficial for immunity. They are great for kids too. I give my 3 year old 2 or 3 a day when fighting a cold.
As you can see, you have a lot of control over your susceptibility to colds and flu. Start incorporating these tips now to optimize your immune system and outsmart infections this winter!
