Study Guide: Essential Vitamins
A healthy immune system depends on a balanced healthy diet over time. Maintaining a strong immune system is like preparing your body to be ready when attacked by viruses, bacteria or toxins. With some exceptions, it’s best to get vitamins and minerals from healthy food rather than pills or supplements. Other lifestyle choices, such as regular exercise and good sleep will also prepare you for the battle.
Vitamin C
Vitamin C may help prevent infections or shorten their duration. Citrus fruits are great, but there are many other good sources.
- Spinach
- Kale
- Bell peppers
- Brussels sprouts
- Strawberries
- Papaya
Vitamin E
Like vitamin C, vitamin E is a powerful antioxidant that helps us fight off infection. This important vitamin, which is part of nearly 200 biochemical reactions in the body, is critical to immune system functions. To get your vitamin E, think of high-fat plant foods such as:
- Almonds
- Peanuts/peanut butter
- Sunflower seeds
- Oils such as sunflower, safflower, and soybean oil
- Hazelnuts
Vitamin A
Vitamin A is an infection-fighter and comes in two forms:
- Preformed in animal foods, including
- Fish
- Meat
- Dairy
- Plant carotenoids, such as from
- Carrots
- Sweet potatoes
- Pumpkin
- Butternut squash
- Cantaloupe
- Dark green leafy vegetables
Vitamin D
Known as the sunshine vitamin, it’s one of the most important and powerful nutrients for the immune system. In general, it’s best to get vitamins from healthy foods, but because food sources of vitamin D are limited, it may be the exception to that rule. Vitamin D can be found in fortified milk, orange juice and cereals.
- Salmon
- Mackerel
- Tuna
- Sardines
Folate/Folic acid
Folate is the natural form and folic acid is the synthetic form of this vitamin. To get more folate, eat more beans, lentils, leafy green vegetables, and avocados. Folic acid is often added to fortified foods.
- Enriched pasta
- Enriched bread
- Enriched rice
Iron
Iron helps the blood carry oxygen to every cell, and plays a part in the immune system. Iron comes in different forms. Humans can most easily absorb heme iron (aka iron from animal products), which is abundant in:
- Beans
- Broccoli
- Kale
- Red meat (eat small amounts, not too often).
- Chicken
- Turkey
- Canned sardines
- Oysters
- Clams
- Mussels
- Canned light tuna
- Iron-fortified cereals
Selenium
Selenium helps prevent infections. Animal foods are the best sources, with the exception of Brazil nuts, that offer a whopping greater than 100% daily value in one nut. However, too much selenium can be a problem, so keep to no more than one to two of these in a day. Look for selenium in:
- Seafood (tuna, halibut, sardines)
- Meat (in particular liver)
- Poultry
- Cottage cheese
Zinc
Zinc is needed for the production of new immune system cells. It’s found primarily in animal foods but can be also found in some vegetables.
- Oysters
- Crab
- Lean meats and poultry
- Baked beans
- Yogurt
- Chickpeas
Frozen foods
Depending on the time of year and the dominance of industrial mono-crop agriculture, we can’t always find high-quality fresh produce. In such situations, frozen food is a good choice. Food is frozen at peak ripeness, and packs a similar nutritional value as fresh. When selecting frozen foods, remember to choose pure foods, not those with added sugar or sodium.