Shopping, planning, extended family visits all contribute to a challenging season full of icky viruses. We often see patients seeking help boosting their immune system before, during and after the holidays.
The immune system provides a robust anatomical barrier that serves as a host defense mechanism. One of these anatomical barriers is the gastrointestinal tract, full of digestive enzymes, bile acids and gut flora to name a few.
All of these essential defense mechanisms rely heavily on the entire gastrointestinal tract functioning efficiently.
Planning meals that benefit the immune system is a great way of fighting off infection. Avoiding infection promoting foods such as potato chips, sugar and soda is also a key to enrich the microbiome and boost immunity.
6 types of foods that boost the immune system
1. Yellow Bell Peppers
Contrary to popular belief, oranges are not particularly high in vitamin C when compared to other fruits. One orange provides 78% DV of vitamin C, which is ok. The reason that yellow bell peppers are top of our list is they are easy to get in most parts of the world and contain 152%DV of vitamin C. Yellow bell peppers contain more vitamin C as they mature (up to a point). Green bell peppers have half the amount of vitamin C, about the same amount as an orange.
Vitamin C boosts the immune system by influencing the development and functioning of lymphocytes. About half a cup of yellow bell peppers will provide 152% DV of vitamin C.
Guava is a perfect source of nutrients and we are right in the middle of the winter ‘guava season’. Peeled guava contains 140% DV of vitamin C and is also rich in lycopene. Lycopene is a powerful antioxidant and plays an important role in the enzyme activities of the immune system.
One randomized controlled study found that eating 400g of guava per day lowered blood pressure as well as serum total cholesterol, triglycerides and LDL cholesterol.
Other foods that are rich in lycopene include: Tomatoes (sun-dried, pureed, fresh and canned), watermelon and red/ pink grapefruit.
Broccoli is high in phytonutrients like vitamin A, C and E. Ensuring high-quality intake of essential nutrients boosts the immune system. It’s important to note that raw broccoli or broccoli sprouts contain the highest levels of sulforaphane. Minimizing boiling or cooking and eating sulforaphane-rich foods as raw as possible will provide maximum health benefits.
Sulforaphane has been found to support healthy inflammation pathways and blood pressure in animal models. Sulforaphane has a wide range of health benefits that include cognitive protection and blood stabilization. In one study, fasting blood sugar was significantly reduced (by 6.5%) in participants that consumed sulforaphane.
Other foods that contain sulforaphane include: Kale, cabbage, Brussels sprouts, bok choy, watercress and cauliflower
Turmeric is a great immune-boosting food due to its support of healthy inflammatory pathways. Inflammation is implicated in the pathophysiology of many health-compromising situations, so consuming pro-healthy-inflammation foods is an ideal way to boost the immune system.
Turmeric has a host of other beneficial health-promoting mechanisms, including its anti-oxidative, anti-cytotoxic, neurorestorative properties, as well as having metal-chelating properties, making it an important staple in an immune-boosting pantry. Curcumin is the active component in turmeric that offers all of the health benefits of this ancient golden root.
Turmeric is the only food that contains curcumin.
5. Green Tea
Green tea contains L-theanine, which promotes relaxation and the formation of healthy T-cells. Black tea also contains L-theanine (sometimes in higher doses). However, black tea is often fermented, reducing the L-theanine properties.
Green tea is packed with flavonoids and epigallocatechin gallate (EGCG). Flavonoids are one of big the reasons plants are good for you as flavonoids boost the immune system.
Other flavonoid rich foods include: Cranberries, apples, blueberries, broccoli, and strawberries
Almonds are rich in fat-soluble vitamin E. Vitamin E boosts the immune system as it’s a free radical scavenging antioxidant. Almonds are easy to find and store in any season, making them a great winter pantry staple.
Additional immune boosting foods
Vitamin E rich foods include: Sunflower seeds, hazelnuts, peanuts and wheat germ oil. Prebiotic foods; garlic, leeks and onions and probiotic foods like miso, pickles, sauerkraut and tempeh go a long way toward good health.
Eating a varied diet bursting with plant-based nutrition is the key to boosting the immune system.
As cold and flu season (the stress season) approaches, be sure to stock your fridge with foods that will fight for your health.