During seasons when germs and viruses are circulating heavily, we can all use an extra boost when it comes to our immune systems. A strong, balanced immune system is key to warding off pathogens and recovering from illness quickly.
So let’s start at the very beginning with a look at vitamin A, also called retinol. How does this vitamin work and what benefits does it have for our bodies’ immunity?
What Does Vitamin A Do in the Body?
Vitamin A for Immune Function
One of the big functions of vitamin A in the body is immune support. Among other things, vitamin A:
- Stimulates the production and activity of white blood cells (antiviral and anti-tumor cells);
- Maintains and strengthens epithelial tissues and mucous membranes — the body’s first line of defense against pathogens.
A 2018 article reviewing the scientific literature of vitamin A concluded that vitamin A “has both promoting and regulatory roles in both the innate immune system and adaptive immunity; therefore, it can enhance the organism’s immune function and provide an enhanced defense against multiple infectious diseases.”
In other words, without vitamin A, your immune system is at a disadvantage.
Other Benefits of Vitamin A
It’s worth noting that vitamin A is also necessary for:
- Vision: preserves eyesight and protects the cornea;
- Reproductive system: aids in sperm formation and regulates embryonic development;
- Cellular health: the antioxidant properties of vitamin A prevent oxidative stress of cells, keeping them healthier and protected from damage.
Vitamin A is a critical nutrient that our bodies need.
So, how do we get it?
Sources of Vitamin A
Vitamin A is a fat-soluble vitamin that is naturally present in many foods, and is also available through fortified foods and supplements.
Animal Sources of Vitamin A
Vitamin A from animal sources is retinoid, and you may see it referred to as retinol. This is also known as “preformed” vitamin A, which means it’s in a form that is usable by the body as soon as it is consumed.
Good sources of retinoids are:
- salmon
- eggs
- milk (fortified)
- yogurt
- tuna
- beef liver
- fish oils
Plant Sources of Vitamin A
Vitamin A from plant sources must first be converted from carotenoids. It is often called “proformed” vitamin A or provitamin A. So, to get vitamin A from plant sources, you need to eat fruits and vegetables high in carotenoids, which are typically identified by yellow, orange, and red colors. Beta-carotene is one of the most common carotenoids. Once these carotenoids are digested, the body will convert them to vitamin A as needed.
Good sources of carotenoids include:
- carrots
- sweet potatoes
- pumpkin
- cantaloupe
- mango
- red bell peppers
- apricots
- plums
- tomatoes
- kale
- spinach
- broccoli
Vitamin A Supplements
Vitamin A supplementation is available as a standalone supplement or in a multivitamin. Supplements can contain either or both forms of vitamin A (preformed or proformed), with the most common provitamin A being beta-carotene. It’s important to review the labels of supplements to understand which form and how much vitamin A is included. Supplementing with vitamin A is generally not beneficial unless a person is deficient.
What is the Right Amount of Vitamin A to Consume?
Deficiency and Toxicity of Vitamin A
It is possible to have either deficient or toxic levels of Vitamin A, though deficiencies are not common among otherwise healthy people. Some digestive disorders (Crohn’s disease, cystic fibrosis) as well as extremely poor diets (such as those that may be experienced in developing countries) will cause a vitamin A deficiency.
In the U.S., vitamin A toxicity is much more common than deficiency, due to high levels of preformed vitamin A that can be in supplements. Vitamin A toxicity can be dangerous, particularly for pregnant women, as it can cause serious birth defects in the developing fetus. Vitamin A toxicity can also cause irreversible liver damage, coma, and even death.
Something to keep in mind: vitamin A is fat-soluble. This has two implications for the amount of vitamin A in your body:
- Your body can only absorb vitamin A optimally along with fat. So, plant-based foods rich in vitamin A should be eaten with a healthy fat such as olive oil, nuts, or avocado, in order to maximize absorption of the vitamin.
- Excess vitamin A is stored in the body. Any amount that is not immediately used by the body is stored in the body’s fatty tissue and liver until it is needed. In the case of preformed vitamin A (animal-based and retinoid supplements), this can cause a toxic buildup of vitamin A. Toxicity is not possible with plant-based vitamin A, as beta-carotene is only converted to vitamin A as it is needed.
Optimal Levels of Vitamin A
The amount of vitamin A the body needs depends on a person’s sex and life stage. Average recommended daily amounts are indicated as micrograms of retinol activity equivalents (RAE). Men should get 900 mcg daily, and women should get 700 mcg daily. If women are pregnant or breastfeeding, the recommendation goes up to 770 mcg and 1300 mcg, respectively. The recommended amount for infants and children ranges from 400 – 600 mcg.
If these numbers don’t mean much to you, don’t worry — just eat an assortment of colorful vegetables along with some meat and dairy, and you should be getting an adequate amount of vitamin A.
If you’re wanting to give your immune system a boost, the answer is not in taking a vitamin A supplement. Rather, increase your consumption of leafy green vegetables and red and orange fruits and veggies. Once your body has all the vitamin A it needs, the other health-promoting benefits of these foods will provide an added bonus.
Keep Your Body Strong and Eat Your Vitamins!
Good nutrition keeps us from getting sick and allows our bodies to recover from sickness faster.
Along with adequate sleep and stress-management techniques, a balanced diet can equip your immune system to tackle whatever comes its way!
In case you do need a doctor, In and Out Express Care provides care for individuals and families, serving children as young as two years old. Stop by one of our four urgent care clinics in Hampton Roads to see one of our friendly docs. We’re here when you need us!
