Like many people right now, your focus is liking turning towards building a healthy immune system.
With the spread of the coronavirus (COVID-19), in conjunction with flu season, there really is no time like the present to start incorporating some superfoods and essential nutrients into your diet.
Foods that are rich in vitamins, minerals, antioxidants, and bioactive compounds can upregulate your immunity and provide cellular-level support. All real, whole foods provide some level of assistance to your immune system function, but below is a list of the top 15 immune-boosting foods you should be focusing on.
15 Immune-Boosting Foods (That Will Keep You In Ketosis)
In the realm of immune-boosting foods, it’s hard to beat garlic when it comes to research-backed benefits. This small allium plant is packed with nutrients that support a strong immune system in a variety of ways.
To begin with, It’s antimicrobial, antiviral, anti-fungal, anti-carcinogenic, and anti-inflammatory[*].
On a cellular level, the nutrients in garlic support immunity by[*]:
- Stimulating immune cells such as macrophages, lymphocytes, natural killer (NK) cells, dendritic cells, and eosinophils.
- Turning on immune-signaling cells (cytokines) that regulate immune processes like inflammation.
- Enhancing the production of antibodies.
- Supporting phagocytosis, a process in which your immune cells engulf viruses or infected cells to clear them from circulation.
#2 Brazil Nuts
Brazil nuts are one of the best sources of the mineral selenium. Selenium plays a key role in the health of your immune system due to its incorporation in compounds called selenoproteins.
Selenoproteins are crucial for immunity because they regulate the activity of reactive oxygen species (ROS) in almost every tissue in your body.
What’s more, research shows that deficiencies in selenium can enhance the virulence of viruses, while supplementing with selenium can enhance your immune defenses[*][*].
#3 Red Bell Peppers
Red bell peppers are an excellent immunity food due to their high levels of vitamin C. Since citrus fruits like oranges and grapefruits are no-no’s on the keto diet, finding this crucial water-soluble vitamin elsewhere is essential.
Vitamin C is a powerhouse nutrient when it comes to immunity. It not only shortens the duration and severity of a common cold, but research shows that in virus-induced respiratory infections, vitamin C can relieve symptoms up to 85%[*].
Liver is perhaps one of the most nutrient-dense foods out there. This organ meat is loaded with vitamins, minerals, and protein — all you could ask for when looking to boost your immunity.
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Vitamin A, a fat-soluble vitamin, is particularly abundant in liver and plays a crucial role in the expression of immune cells. It’s involved in both humoral and cellular immunity and regulates the mucus integrity in your body[*].
Research shows that supplementing with vitamin A may even reduce mortality in some infectious diseases[*].
#5 Green Tea
Green tea is a fantastic source of flavonoids, powerful antioxidant compounds that have immunomodulatory effects. Specifically, flavonoids support the activity of T-lymphocyte immune cells.
T-lymphocytes (also called T-cells) play a crucial role in protecting your immune system from infection. As part of your adaptive immunity, they tailor your immune response by searching for, and destroying, targeted invaders[*][*].
In green tea, the major flavonoids are catechins, particularly epigallocatechin-3-gallate (also known as EGCG).
#6 Leafy Greens
Leafy greens like spinach, kale, and chard are packed with vitamins and minerals.
What’s more, however, is that green vegetables are the source of a vital chemical signal that regulates immune cells in your gut and skin.
In one study, mice fed green vegetables experienced an upregulation of a specific receptor on their immune cells, which resulted in enhanced immune activation.
Conversely, when they were deprived of green veggies, the immune cell receptors disappeared, resulting in a lack of control over the microbes living on the intestinal surface[*].
Turmeric is a spice that’s been used for thousands of years in Ayurvedic medicine.
The primary bioactive compound in turmeric, curcumin, is well-known for its anti-inflammatory activity and continues to gain popularity as research uncovers its potent healing qualities.
Curcumin not only enhances the activity of several types of immune cells, but it also downregulates the expression of various pro-inflammatory compounds in your body. In doing so, turmeric has become a spice of interest in a number of immune conditions, including rheumatoid arthritis, asthma, atherosclerosis, heart disease, and Alzheimer’s disease[*].
#8 Red Meat
Protein plays a vital role in the health of your immune system. In fact, it’s well understood that protein malnutrition is one of the risk factors for infectious disease[*].
The amino acids found in red meat, arginine, in particular, support immunity by activating a specific cell line called T cells. Other roles of amino acids in immunity include[*]:
- Activation of T-lymphocytes, B-lymphocytes, natural killer cells, and macrophages
- Immune cell expression
- Lymphocyte proliferation
- Production of antibodies, cytokines, and other cytotoxic substances
What sets red meat apart from other forms of protein when it comes to immunity is its high zinc content. Zinc plays a crucial role in your immune system by fighting off free radicals and balancing your inflammatory response.
In addition, zinc can help your body fight viral-induced respiratory infections by inhibiting the replication of viruses[*][*].
Almonds and sunflower seeds are rich sources of vitamin E, a fat-soluble vitamin that protects the outer layer of your cells from oxidative damage.
In your immune system, vitamin E acts as an antioxidant and is able to modulate a host of immune functions. In a vitamin E deficiency, your body becomes more susceptible to infectious disease and cellular immunity plummets.
Conversely, with vitamin E supplementation, your immune system strengthens, and cellular immunity becomes more robust[*].
The bright orange color of carrots comes from the phytonutrient beta-carotene. Beta-carotene is a precursor to vitamin A, which, as mentioned above, is a crucial nutrient for strong immunity.
Furthermore, beta-carotene is a potent antioxidant compound that research shows may play a major role in your immune response against cancer. Beta-carotene seems to work through cell-mediated immunity (as opposed to antibodies) to upregulate immune cell pathways[*][*].
#11 Broccoli Sprouts
Cruciferous vegetables, in general, are rich sources of an antioxidant compound called sulforaphane(SFN). Broccoli sprouts, however, are by far the most abundant source of SFN out there.
SFN helps your immune system by protecting you against inflammatory diseases like cancer, heart disease, rheumatoid arthritis, IBS, respiratory conditions, and diabetes. It exhibits both anti-inflammatory and antioxidant properties, and may even have a protective effect on your DNA[*].
Shellfish, even more so than red meat, are an excellent source of zinc. In fact, 1/4th cup of oysters contains 40 mg of zinc, which is about 400% of the recommended daily intake[*][*].
Other seafood sources of zinc include crab, with ½ can of crab meat coming in at about 25% of your daily needs, and lobster with ½ can packing 30% of your daily needs[*][*].
Spinach is a rich source of the B vitamin folate. Folate, also known as folic acid, is crucial for cell-mediated immunity.
In a folate deficiency, the activity in your thymus is affected, which results in a decreased maturation of T-cells. Since T-cells are vital to adaptive immunity, this creates a back-up in your body’s ability to fight off foreign invaders.
In other words, your body experiences a decreased resistance to infections[*].
Another spice that’s excellent for your immune system is ginger. Ginger is not only warming to your body, but it also has antioxidant and anti-inflammatory properties.
Ginger is particularly helpful for respiratory infections and conditions due to its ability to relax the smooth muscles in your airways. Some research even suggests that extracts of ginger may be useful in treating asthma[*].
Luckily, for the keto dieter, elderberry is typically taken as a dietary supplement as opposed to being consumed as a fruit.
This immune-boosting berry is well-researched for its antiviral activity. In fact, when given to people suffering from the flu, supplementation with elderberry reduced the duration of symptoms to 3-4 days.
Research suggests that the compounds in elderberries activate your immune system by increasing the production of cytokines, which are small proteins secreted by immune cells for interaction and communication between cells[*].
Coronavirus or not, taking care of your immune system is vital to overall health and longevity. Consuming nutrient-rich foods is crucial if you want to be able to fight infection and keep your immunity strong.
In addition to the above-mentioned immune-boosting foods, keep your diet as whole-foods based and clean as possible. While they may give you emotional comfort during these strange times, try to avoid drinking too much alcohol or consuming too many processed foods.
And of course, steer clear of high-carb comfort foods that could kick you out of ketosis.