The recommended amount of vitamin C for the following gender and age groups is (9):
- Men: 90 milligrams (mg) per day
- Women: 75 mg per day
- Pregnant and/or breastfeeding women: 85 to 120 mg per day
- Infants up to 6 months old: 40 mg per day
- Infants up to 12 months old: 50 mg per day
- Children up to 3 years old: 15 mg per day
- Children up to 8 years old: 25 mg per day
- Children up to 13 years old: 45 mg per day
- Teenage boys aged 13 to 17: 75 mg per day
- Teenage girls aged 13 to 17: 65 mg per day
When sick, that dose should increase to 1 to 2 grams daily until symptoms subside (10).
Since humans aren’t able to make their own vitamin C, it’s essential that you eat the following fruits and vegetables in order to maintain adequate levels...
Foods Rich in Vitamin C Include:
- Kiwi: 1 cup (273% DV*)
- Bell Peppers: 1 cup (200% DV)
- Orange: 1 cup (160% DV)
- Strawberries: 1 cup (149% DV)
- Broccoli: ½ cup cooked (84% DV)
- Brussels Sprouts: ½ cup cooked (81% DV)
- Tomato: 1 medium, raw (28% DV)
- Potato: 1 medium, cooked (45% DV)
- Spinach: 1 cup (15% DV)
- Kale: 1 cup (134% DV)
*DV = Daily Value
Note: A total of 5 to 9 servings of fresh or frozen fruit and vegetables per day is estimated to equal ~200 milligrams of vitamin C (10).
Summary: Vitamin C may boost immunity by helping white blood cells function more effectively and strengthening your skin’s defense system. In turn, it may reduce symptoms and shorten the duration of respiratory tract infections.
3. Vitamin E
Like vitamin C, vitamin E is an impressive antioxidant. And getting enough of this antioxidant is crucial for the health of your immune system, especially if you’re older.
The antioxidants in vitamin E have the ability to (11, 12):
- Reduce free radical damage
- Fight inflammation
- Naturally slow aging in your cells
- Increase immunity
- Prevent common illnesses and serious conditions from forming
How Much Vitamin E Should I Take?
The recommended amount of vitamin E for both men and women is 15 milligrams (mg) per day; with the Tolerable Upper Intake Level being 1,000 mg per day (13).
To ensure you’re maintaining adequate levels of vitamin E, eat two to three of the following foods…
Foods Rich in Vitamin E Include:
- Sunflower Seeds: 1 cup (220% DV*)
- Almonds: 1 cup (218% DV)
- Hazelnuts: 1 cup (133% DV)
- Mango: 1 whole, raw (20% DV)
- Avocado: 1 whole, raw (18% DV)
- Butternut Squash: 1 cup, cooked (17% DV)
- Broccoli: 1 cup, cooked (12% DV)
*DV = Daily Value
Summary: Vitamin E is a powerful antioxidant that helps the body reduce free radical damage, fight inflammation, and defend against infections and illnesses.
4. Omega-3 Fatty Acids
It’s rare to find a nutrient with as many health benefits as omega-3s. The most commonly known benefit is a reduced risk of heart disease, but that’s not the only perk...
They can boost your immune system, too.
Omega-3 fatty acids enhance immunity by increasing the activity of B cells—a vital part of the body's immune response (14, 15).
In addition to this, omega-3s reduce inflammation—your body’s natural response to infections and imbalances in the body. Reducing inflammation leads to an array of positive outcomes: Decreased risk of cardiovascular disease, diabetes, arthritis, cancer, and other diseases (16, 17).
Foods Rich in Omega-3s Include:
- Atlantic Mackerel: 1 cup, cooked (174% DV*)
- Salmon Fish Oil: 1 tablespoon (119% DV)
- Walnuts: ¼ cup (66% DV)
- Chia Seeds: 1 tablespoon (61% DV)
- Herring: 3 ounces (47% DV)
- Alaskan Salmon (wild-caught): 3 ounces (42% DV)
- Flaxseeds: 1 tablespoon, ground (39% DV)
- Krill Oil: 1 softgel (60mg)
*DV = Daily Value
Summary: Omega-3s can improve the activity of immune cells, help fight several autoimmune diseases, and reduce chronic inflammation—the primary contributor to chronic illness and disease.
5. Collagen
Collagen is the most abundant protein in your body—making up 33% of it, in fact (18).
Out of the 28 different types of collagen, there are two that make up 80 to 90% of the collagen in your body: Type 1 and Type 2 Collagen (19). These types of collagen can be found in your muscles, bones, connective tissue, skin, blood vessels, digestive system, and more.
Collagen is often dubbed as the “glue” that holds your body together. It’s credited to giving your skin its glow and elasticity; your bones their structure and support; and your connective tissue its cushion-like padding.
As if collagen couldn’t get any better, researchers are just beginning to uncover the miraculous effects it has on immunity.
One 2015 study measured the SIV (Scoring of Immunological Vigor) in men and women between the ages of 30 and 59 to determine if collagen ingestion affected immunity.
The 8-week study revealed that through 10 grams of daily collagen supplementation, there was a significant improvement in the comprehensive immunological status of humans. The participants who took the placebo didn’t show any signs of improvement (20).
Another (critical) thing that collagen supports: Your gut.
With nearly 70% of the immune system being housed in your GI tract, your gut is your body's immunity powerhouse (21).
An unhealthy gut is prone to bacteria, viruses, fungi, and parasites. Which can then “leak” through your intestinal wall, causing inflammatory diseases like irritable bowel syndrome, leaky Chron disease, and ulcerative colitis (22).
The amino acids in type 3 collagen (namely glycine, glutamine, and proline) maintain gut lining, helping to prevent toxic leakage and issues like malabsorption of nutrients, autoimmunity, and more (23).
Despite the critical role collagen plays with our immunity and overall health, most adults are highly deficient—for two reasons:
1. Our bodies stop producing it. As you grow older, your body’s collagen production naturally begins to slow down. This results in a degenerative process affecting your joints, bones, skin, and your first line of defense against illness—your gut health.
2. Our modern diets lack it. While our ancestors consumed a collagen-rich diet, our modern eating habits don’t include the same foods as the civilizations before us (think: bone marrow, fish skin, poultry cartilage, and animal organs such as hearts, livers, and eyes).
Although bone marrow and fish skin contain ample amounts of collagen, there are a few other foods that have fair amounts of collagen, too...
Foods Rich in Collagen Include:
- Organic Bone Broth
- Citrus Fruits
- Pasture-raised Egg Whites
- Wild-Caught Fish
- Berries
- Pasture-Raised Chicken
- Red & Yellow Bell Peppers
- Garlic
- White Tea
- Leafy Greens
- Cashews
- Tomatoes
- Beans
- Avocados
- Carrots
Keep this in mind, though: It’s extremely difficult to get the amount of collagen you need with just food...
That’s why I recommend supplementing with a grass-fed collagen powder.
With just two scoops of collagen powder per day, you’ll be equipping your immune system with what it needs to stay sick-free while reinforcing intestinal integrity to keep pathogens from seeping into your bloodstream.
Summary: Daily collagen consumption is proven to boost immunity and improve the strength of the intestinal tract, where 70% of immune function occurs. For those who don’t find collagen-rich foods appealing, you may want to consider taking a grass-fed collagen supplement (ideally with Type 1 & 3 fibers).
