Vitamin A is one of the four fat soluble vitamins. These are also called fat soluble retinoids. This means that it needs fat for it to be available to the body. Another important fact to remember about this vitamin and the others in its group is that if taken in excess, it can lead to toxicity as it can accumulate in the body. This is unlike the water soluble vitamins that are usually excreted in urine when the body has taken the amount it requires. Naturally it is almost impossible to develop vitamin A toxicity when following a vegan diet. It can however, happen with animal sources of the vitamin. A good example is the liver of the cod fish. The other possible cause of toxicity is the consumption of vitamin A supplements above what the manufacturer recommends.
TYPES OF VITAMIN A
There are two main groups of vitamin A.
Provitamin A
Preformed vitamin A
Provitamin A is sourced from plants while preformed vitamin A is derived from animals. The provitamin A has to go through some process in the body for it to offer its benefits. When taking supplements, how can you tell whether a vitamin ingredient is from plants or animals? Plant-based vitamin A ingredients are shown as retinal while those from animals are retinol. Synthetic vitamin A is a third type that you need to be aware of. This type is mostly used in skin care cosmetic products.
SOURCES OF PROVITAMIN A
The main sources of this vitamin are plants that contain carotenoids. These are the substances in some fruits and vegetable that give them their bright colors of red, orange, dark green and others. A specific type of carotenoids called alpha-carotene, beta-carotene and beta-cryptoxanthin are the only groups that can be converted into active vitamin A. Sources include:
Carrots
Lettuce
Bell peppers
Sweet potatoes
Dark green vegetables
Cantaloupe
Mangoes, papaya, pineapples, passion fruits, pitaya and many other tropical fruits
As much as it is possible, all your vitamin A needs should be met from your diet. But for various reasons, dietary supplements containing the vitamin may be recommended.
WHY YOU MIGHT STILL BE DEFICIENT IN VITAMIN A
Please note that you can consume foods rich in vitamin A but still you suffer from symptoms of the vitamin A deficiency. The reasons for these include:
A low fat diet. There are many healthy fats/oils for vegans. These include coconut, olive and avocado oils.
Poor absorption from the gut due to gut disorders that interfere with nutrient absorption
Infections
Food intake combination
Drug interactions. Some cholesterol lowering medications and the antibiotic Neomycin can reduce the absorption of vitamin A.
With this overview of vitamin A, let us now look at its specific health benefits.
10 BENEFITS OF VITAMIN A
Vitamin A has been known as the vision vitamin. This is because one of the earliest signs and symptoms of its deficiency is observed in the eyes. Xerophthalmia is a condition that makes the eyes abnormally dry. Adequate intake and utilization of the vitamin prevents this problem that can lead to impaired vision and even blindness. Other conditions that can be managed with the vitamin include
Prevention of cataracts
Reduces the risk of age-related macular degeneration (AMD)
May improve symptoms of hereditary retinitis that causes poor night vision
Supports the immune system Many studies have suggested that vitamin A offers support to the treatment of many immunity related health disorders. One search study suggested that the vitamin can be used as an added measure to immunity modulating medications used in the management of conditions search as rheumatoid arthritis and inflammatory bowel disease.
It is a powerful antioxidant High levels of freely circulating free radicals (reactive oxygen species – ROS) are a risk factor for many health disorders including cancer and degenerative health conditions. Vitamin A supports the control of these metabolic products and keeps them within healthy levels where they are not a risk to cellular damage.
Healthy embryos Vitamin A deficiency in pregnancy can lead to serious fetal abnormalities. These include both physical and neurological defects. This was proven in the 1930s when experiments were carried out in farm animals. Worth noting is the fact that, excessive consumption of vitamin A also leads to fetal congenital malformations. These facts have been observed by many study authors. Healthy levels of vitamin A helps in cell differentiation during fetal development. This means that cells develop properly to form specific and well-formed tissues and organs.
Male and female fertility The rate of conception is greatly reduced when a male and or the female has deficiency of vitamin A. For the mother the vitamin supports good placenta development and implantation. For the male the vitamin promotes good spermatogenesis.
Promotes healthy bones Together with other vitamins such as D and K, vitamin A helps to make the bones strong and healthy. However, if too much of it is consumed, it leads to bone loss and increases the risk of fractures among other problems.
Reduces the risk and severity of some childhood diseases. Measles is a serious communicable childhood infection that mostly occurs in poor living conditions and regions. The WHO recommends that all children in parts of the world with widespread vitamin A deficiency or where at least 1% of children with measles die, be given vitamin A supplementation as a precautionary and preventive measure of vitamin A deficiency.
Supports a healthy skin. It offers properties that delays or slows down skin aging and onset of wrinkles and other skin signs and symptoms of aging. In addition to this it promotes faster wound healing.
Lowers cholesterol levels Healthy cholesterol levels have added health benefits that include cardiovascular, renal and even good metabolic mechanisms.
Lowers the risk of cancer Research suggests that vitamin A reduces the risk of tumor development. This could be partly due to it immunity modulating properties. Promising results have been observed in colon, breast, skin and liver cancers.
The benefits of vitamin A are many and are backed by reliable studies. If you are considering supplementing your diet with the vitamin, it is advisable to talk to your healthcare provider. The reason being, as seen in this article, too little or too much of the vitamin can lead to serious health problems.
REFERENCES
Institute of Medicine (US) Panel on Micronutrients. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington (DC): National Academies Press (US); 2001. Available from: https://www.ncbi.nlm.nih.gov/books/NBK222310/ doi: 10.17226/10026 4 Vitamin A." Institute of Medicine. 2001. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: The National Academies Press. doi: 10.17226/10026. Mactier, H., & Weaver, L. (2005). Vitamin A and preterm infants: what we know, what we don’t know, and what we need to know. Archives of Disease in Childhood. Fetal and Neonatal Edition, 90(2), F103–F108. http://doi.org/10.1136/adc.2004.057547 Vitamin A Deficiency and Xerophthalmia", Sommer, Alfred, M.D., Archives of Ophthalmology, March 1990;108:343-344 Ross AC. Vitamin A and retinoids. In: Shils M, ed. Nutrition in Health and Disease. 9th ed. Baltimore: Williams & Wilkins; 1999: 305–327. Clagett-Dame, M., & Knutson, D. (2011). Vitamin A in Reproduction and Development. Nutrients, 3(4), 385–428. http://doi.org/10.3390/nu3040385 Jeyakumar, S. M., Vajreswari, A. and Giridharan, N. V. (2007), Impact of Vitamin A on High-Density Lipoprotein-Cholesterol and Scavenger Receptor Class BI in the Obese Rat. Obesity, 15: 322–329. doi:10.1038/oby.2007.534
