Fresh cut vegetables served at Kellogg Conference Center

Although we typically talk about food first, when it comes to the immune system, the mouth is a first-line immunological barrier and proper hydration is key to a healthy mouth. Many viruses and bacteria enter the body through the mouth, and our saliva acts as a barrier to help keep them out. Therefore, staying well hydrated decreases dry mouth, keeping salvia plentiful. Dehydration may also increase the stress hormone, cortisol, which has been linked to immunosuppression. To maintain proper hydration, drink enough fluids (water, unsweetened tea, seltzer, milk) throughout the day to ensure you never feel thirsty and your urine is pale in color.

 A huge proportion of your immune system (nearly 70%!) is in your gut thanks to your intestinal flora. A healthy digestive system relies on the balance of healthy bacteria to not only help you absorb nutrients from food, but also to support the immune system and enhance overall health. The millions of bacteria in the gut work symbiotically with the immune system to ensure the body is protected and can eliminate any harmful pathogens it encounters. If the balance of healthy bacteria in the gut is thrown off, it can result in decreased immunity, leaving the body vulnerable to harmful invaders. Luckily, we can improve the healthy bacteria in the gut through diet.  Consuming foods with ‘good’ bacteria, i.e.  probiotics found in kefiryogurt and sauerkraut, may enrich intestinal flora to improve immune function. Since bacteria cannot flourish without food, a colorful, fiber-rich diet including fruits, vegetables and legumes feeds microbes to build a healthy gut.

The micronutrients and plant chemicals found in fruits and vegetables are as good as gold to a healthy immune system. Many of these vitamins and minerals have antioxidant properties that help regulate the millions of biochemical processes that keep this system shining bright. Vitamins and minerals specifically exhibit important immune-modulating functions by entering cells and regulating gene expression. Vitamins A, C, D, and E, minerals zinc and selenium, and antioxidant compounds like beta-carotene and flavonoids play important roles in immune function. It is best to get these nutrients from whole foods rather than supplements as they tend to work in combination with other nutrients and plant chemicals also found in food. There is no specific fruit or vegetable that’s best; focus on a variety of colors such as greenorangewhiteredblue and purple, and incorporate nutsseedswhole grains, and lean protein from beefpoultry and seafood to ensure a well-rounded micronutrient intake.

A diet rich in healthy unsaturated fats has been shown to support a healthy immune system. Long-chain polyunsaturated fats can help modulate immune function, and omega-3 fatty acids have been shown to alter the fat composition of cell membranes, help regulate immune cell function, suppress over activity, and act as anti-inflammatory agents. These healthy fats can be found in fish (salmontuna, anchovy), nuts and seeds (chiaflaxwalnuts) and vegetable oils (olive, soybean and canola). 

THE POWER OF PROTEIN Proteins (made of amino acids) don’t just build strong muscles, they are elemental in the structure of every cell, tissue, and organ working to keep you well. Protein molecules assist immune cells (i.e. white blood cells, B cells, phagocytes, and antibodies) to carry out their jobs, like distinguishing between normal body chemicals and foreign invaders, destroying harmful organisms, and mounting an immune response to infection. Ensure your diet is rich in quality proteins from both plant and animal sources including lean cuts of beefpoultry and pork, fish, eggs, beans, and whole grains.  

A healthy immune system starts with a healthy diet, so this winter focus more on whole foods rich in vitamins and minerals, and less on supplements and processed foods to ensure your immune system is in tip-top shape.