A lack of vitamin A increases the risk of developing several serious health issues.
Vitamin A is heavily involved in the growth and specialization of almost every cell in the human body, known as cell differentiation.
Fortunately, you can find vitamin A in many places, although numerous factors can inhibit its activity. At the bottom of this page we recommend a vitamin A supplement. But first let’s learn about the science behind vitamin A, and how to determine if you have a vitamin A deficiency.
What Is Vitamin A
Vitamin A is an essential fat-soluble vitamin. The liver stores it as retinyl esters, which are then hydrolyzed into all-trans-retinal. This all-trans-retinal binds to retinol binding protein before it is released into the bloodstream. (National Institutes of Health, 2018)
Vitamin A is found in two forms:
- Preformed Vitamin A (retinol and its esterified form, retinyl ester), and
- Provitamin A carotenoids
Retinol is sourced from animal products and can be used directly by the body. Beta-carotene is derived from fruits and vegetables and has to be converted to an active form of vitamin A before the body can use it.
Why Is Vitamin A Important?
Vitamin A is essential to the health of the body, largely in part to its antioxidant properties, which foster cell growth. Eating a well-balanced diet, including fruits, vegetables, and other whole foods, is a great way to ensure you're getting the most health benefits. If you are vegan, consider supplementing with a type of preformed Vitamin A.
Health benefits of Vitamin A include:
- Eye health — Vitamin A aids in keeping eyes healthy and vision at its sharpest. This is due in part to beta-carotene, which prevents macular degeneration. Macular degeneration is one of the leading causes of blindness as you age. Studies have shown that taking high doses of vitamin A every day reduces the risk of macular degeneration by 25%. (Age-Related Eye Disease Study Research Group, 2008)
- Immune system health — Vitamin A is vital to immune health and preventing illness as well as infections. Researchers have shown a link between vitamin A deficiency and lower immunity, in part due to its importance to regulatory T cells and Secretory IgA. (Semba, 1994) In addition, vitamin A deficiency inhibits the growth of mucosal barriers, which increases the risk of infections. (Stephensen, 2001)
- Reduced inflammation — Vitamin A and beta carotene are great for reducing inflammation — as they are powerful antioxidants. Inflammation is a significant contributing factor in chronic and neurodegenerative diseases such as cardiovascular disease, Alzheimer's, Parkinson's, and diabetes. (Hunter, 2012)
- Skin health — Vitamin A is a great boost to skin health. This is because retinol improves fine lines and wrinkles as well as makes the skin more durable and able to resist injury better. (Kafi et al., 2007) Vitamin A's anti-inflammatory properties are also useful in helping skin conditions such as eczema, psoriasis, and acne. (Chivot, 2005)
- Reproductive and prenatal development — Vitamin A is crucial to fetal development and better health outcomes of both mother and baby. It aids in the development and functioning of the lungs of the baby and prevents developmental disorders in pregnant women. (Strobel, Tinz, & Biesalski, 2007)
- Bone health — Vitamin A is a great boost to bone health, much like calcium and vitamin D are. However, finding the right amount and balance is essential. Too little vitamin A can cause a deficiency, which has been linked to reduced bone density and bone health. (Maggio et al, 2006)
In addition, vitamin A has also been shown to help in:
- The regulation of gene expression
- Autoimmune disease prevention
- red blood cell production
- Nutrient interactions (synergy)
- Cancer prevention
- Preventing urinary stones
- Tissue repair and cell regeneration
- Hormonal development
Signs and Symptoms of a Vitamin A Deficiency
Vitamin A deficiency is more prone in people who cannot absorb fats or those not consuming adequate amounts of active Vitamin A or retinol. Malabsorption of fats is often seen in those with IBS and related conditions, celiac disease, inflammatory bowel disease, pancreatic disorders, and autoimmune disorders.
It also stems from an inadequate intake of vitamin A from a proper diet of meat, eggs, milk, fruits, and vegetables. A severe vitamin A deficiency is defined when serum retinol concentrations are found to be below 0.35μmol/L (10 μg/dL).
There are many reasons why provitamin A carotenoids from plant foods are not converted adequately to active forms: hypothyroidism, genetics, nutrient deficiencies such as iron and zinc, and diabetes, among others. This is thought to affect a significant proportion of the population, which means that animal sources containing preformed Vitamin A must be consumed consistently or a supplement should be used. (Minger, 2013)
Vitamin A deficiency is also a concern in low-income countries, affecting predominately young children and pregnant women. This is a serious issue as a lack of vitamin A is responsible for an increased risk of illness, vision impairment, and even blindness.
Common symptoms of a vitamin A deficiency are:
- Night blindness
- Bitot's spots
- Dry eyes
- Dry skin and lips
- Bumpy skin
- Poor immune system functioning
- Stunted growth in children
- Thyroid dysfunction
- Acne and breakouts
Best Vitamin A Food Sources
To get an adequate amount of vitamin A, 900mcg RAE (retinol activity equivalent) per day for adult males and 700mcg RAE per day for adult females is required. These numbers are lower for younger people. Ideally, a combination of animal and plant sources should be consumed.
(National Institutes of Health, 2018)
A lower amount by weight of preformed Vitamin A (animal source) is required compared to provitamin A (plant source) because performed Vitamin A is in an optimal form ready for final conversion for use in the body. This means that animal sources of Vitamin A have a higher RAE by weight than plant sources.
Some people with particular health conditions will need higher amounts than listed above, but this amount should not exceed 3000mcg RAE per day. The lowest amount that resolves deficiency symptoms is the best approach since excess Vitamin A can be toxic.
Preformed Vitamin A food sources include:
- Cod Liver oil, 1 tsp - 1,382mcg RAE
- Beef liver, 1 ounce pan fried - 2,194 mcg RAE
- Chicken liver, 1 ounce pan fried - 1288 mcg RAE
- Egg yolk, 1 - 95-125 mcg RAE
- Hard goat cheese, 50g - 243 mcg RAE
Provitamin A carotenoids food sources include:
- Carrot juice, 1/2 cup - 966mcg RAE
- Sweet potato, cooked with skin, 1 medium - 1096mcg RAE
- Canned pumpkin, 1/2 cup - 1007 mcg RAE
- Butternut squash, 1/2 cup cooked - 604 mcg RAE
- Spinach, cooked, 1/2 cup - 498 mcg RAE
- Dried apricots, 1/4 cup - 191mcg RAE
- Raw mango, 1 whole - 112mcg RAE
Sources: National Institutes of Health 2018, Health Canada 2015
If getting vitamin A through nutritional sources isn't an option, vitamin A supplementation is the next best option. However, be sure to talk to a healthcare provider to find out what your vitamin A status is before supplementing. Vitamin A should always be balanced with Vitamins D and K2.
If you and your healthcare practitioner decide supplementation is right for you, we recommend: