5 Diseases And Health Problems Caused By Vitamin A Deficiency
Vitamin A Deficiency Diseases And Health Issues
A vitamin A deficiency (VAD) is usually triggered by poor nutrition or health problems that interfere with its absorption. VAD can cause eye diseases such as night blindness, Bitot's spots, corneal xerosis or ulcers, and keratomalacia,. Anemia and poor skin and hair health are also common as are frequent infections. Young children and pregnant women are especially vulnerable.
Eat your carrots! Have more broccoli! Drink up your milk! If you’ve grown up hearing this often tiresome monologue from your parents, there’s much to thank them for. These and many other foods commonly found in our diets are rich in vitamin A, a nutrient that we cannot do without.
Vitamin A is a fat-soluble compound that our bodies need:
- For good eyesight (especially at night)
- To maintain skin health
- To stimulate the production of white blood cells that protect us against infections
- To regulate bone growth
- To promote the health of cells lining the inside of our bodies
- To maintain fertility levels in males and females
But when our body is deprived of vitamin A, the health problems that loom are worrisome. Unfortunately, vitamin A deficiency (VAD) is a serious health problem among children and pregnant and lactating women in many developing or low-income countries. In fact, 250 million children across the world suffer from VAD.1 It could even result in death when left untreated.
There are many animal sources (liver, whole milk, cheese, eggs, and oily fish) and plant sources (colorful fruits and vegetables as well as greens) of vitamin A. When we don’t eat enough of these foods, VAD sets in, leading to various diseases.2 3 VAD can also be triggered by inefficient storage, transport, and absorption of vitamin A. Adults with gastrointestinal diseases like celiac, bile duct disorder, or liver cirrhosis may be vulnerable.4 Here are some VAD-related health problems you should be aware of:
1. Eye Diseases
When vitamin A deficiency (VAD) becomes prolonged, other eye infections can set in and lead to blindness or even death. Children with acute VAD are also usually malnourished. Eating vitamin-A rich foods can cut your risk of developing eye problems like age-related macular degeneration and cataract. 5
Xerophthalmia covers the range of eye problems triggered by VAD. These symptoms vary depending on age and the extent of the deficiency. People who are vulnerable to this condition include preschoolers, teenagers, and pregnant mothers. Young children are particularly at risk since they need a higher intake of vitamin A in the growing years. In fact, xerophthalmia is the leading cause of blindness among children worldwide, but especially so in some developing countries if the diet contains insufficient vitamin A. In most cases, this kind of blindness is preventable.6 Some of the eye diseases likely to be triggered by VAD are:
Night blindness is an early symptom of vitamin A deficiency.
Vitamin A works with proteins called opsins to produce a light-sensitive pigment called rhodopsin in our bodies. When there’s a deficiency of vitamin A, rhodopsin production declines, leading to visual impairment in dark conditions. Children between 2–6 years and pregnant and lactating women are most likely to be affected by night blindness.7
Bitot’s spots form when VAD is left untreated.
A widely observed characteristic of VAD, Bitot’s spots are whitish deposits on the thin lining of the lower eyelid. They are usually spotted in children aged 3–6 years.
The conjunctiva, a fine membrane covering the front of the eye and inner surface of our eyelids, keeps these areas moist and friction-free so we can blink our eyes without irritation. Without sufficient vitamin A, the conjunctiva becomes dull and dry (conjunctival xerosis).8 9 This leads to the buildup of keratin protein in the eye, manifesting as dry, triangular lesions with a foamy appearance called Bitot’s spots
If the symptoms of Bitot’s spots are not addressed by treating VAD, it can affect the cornea, the clear front portion of the eye that allows light to enter and which is partially responsible for our eyes’ ability to focus. With corneal xerosis, the tear glands in the eye malfunction and no longer produce tears and mucus to keep the eye surface moist. The cornea then becomes dry and hazy and takes on a parched appearance. It is also more prone to infections at this stage.
Corneal xerosis is a drying up of the eyes. This can happen when Bitot’s spots are left untreated or due to a sudden and acute deficiency of vitamin A.
Corneal xerosis does not always follow from previous symptoms like Bitot’s spots. It can also manifest as a sudden and acute sign of VAD. If left unchecked, it may lead to blindness and, often, death in young children. Clinical studies show that patients, usually children, who receive treatment with vitamin A supplements even at this stage can have their sight fully restored.10
If acute VAD is not treated quickly, ulcers can develop in the cornea. This may look like a part of the cornea has melted away. The ulcer may also develop a secondary infection, leading to the eye appearing highly inflamed. Children between 1 and 4 years are most susceptible to this condition.11
Keratomalacia is an extreme stage of VAD, often precipitated by measles or diarrhea.
Keratomalacia is the last stage of deterioration if corneal erosion and haziness are not addressed in time. Within a few days of the haziness setting in, the cornea softens, liquefies, and breaks down either partially or completely. Keratomalacia also makes an appearance in children aged 1–4. Keratomalacia may also manifest in apparently healthy children who develop measles or bouts of diarrhea (more on that later). This occurs because they already have a low store of vitamin A and the current illness suddenly depletes their store of the nutrient.12 13 14
2. Compromised Immunity
Animal studies show that VAD affects immunity and increases the risk of infectious diseases, often with fatal results. In humans, most studies have involved children rather than adults. In fact, the seriousness of VAD can be estimated from the fact that children’s autopsy studies have shown that VAD can lead to atrophy of the thymus, spleen, and lymph nodes. VAD can also alter mucosal surfaces such as that in the eye, respiratory tract, genitourinary tract, and gastrointestinal tract. Children with VAD have been known to have lowered response to the tetanus vaccination and meningitis vaccination, among others.
Adults of normal health are generally protected from VAD because of the ability of the adult liver to store vitamin A for quite some time.15
Other than eye-related diseases, children with VAD are at high risk of catching common childhood infections such as measles and diarrhea. In fact, sometimes the infections can get severe enough to be fatal.16
More Severe Among Malnourished Children
In countries where VAD is widespread, research has established that children under 2 years are at high risk of developing severe measles infections. What’s more, the measles virus can invade the eye and, in serious cases, cause the conjunctiva to harden and dry, a condition called keratoconjunctivitis. Studies claim that even children immunized against measles can develop a mild form of keratoconjunctivitis if they have VAD and this can take months to disappear.17
The World Health Organization (WHO) recommends that children with measles who live in regions with known VAD be given a daily oral dose of 200,000 IU of vitamin A (100,000 IU in infants) for 2 days. The two-dose treatment appears to be associated with reduced mortality.18 Strangely, vitamin A treatment works only for children with VAD and may not be effective in measles treatment if the child does not have a deficiency. Children should only be given vitamin A supplements under medical supervision to avoid excessive build-up of this vitamin in the body.19
Rare Among The Immunized Population
Measles is rare in developed countries where immunization during childhood is widespread. However, an outbreak of the infection brought into a country, say, by an unvaccinated traveler is possible in areas where too few people have been vaccinated. In such places, vulnerable groups include babies too young to be vaccinated, pregnant mothers, and adults who are malnourished or have weak immune systems.20
Research among vitamin A deficient children in the developing world has thrown up a puzzle. Does vitamin A deficiency – and the consequent low immunity – make children vulnerable to prolonged diarrhea infections? Or do frequent diarrhea infections lead to impaired absorption of vitamin A from food? Most likely, this is a vicious cycle, with one feeding off the other.21
Treating such cases of diarrhea with vitamin A supplements has been found to help. In one study from India on children aged between 2 and 9 years and suffering from severe diarrhea, it was observed that vitamin A supplements dramatically reduced the diarrhea within 48 hours. Many other studies have strongly established the association between vitamin A-related xerophthalmia and gastrointestinal diseases.22
During pregnancy, a woman’s requirement of vitamin A, both for herself and her growing baby, increases considerably. Healthy mothers consuming a nutrient-rich diet normally have a sufficient store of vitamin A in the liver.23 However, studies show that women with insufficient dietary intake of vitamin A during pregnancy – a common feature among impoverished communities in developing countries – suffer from anemia or low numbers of healthy red blood cells and night blindness. Their susceptibility to VAD is higher in the third trimester of pregnancy when fetal growth and the mother’s own blood volume increases.
Anemia can have serious consequences if left untreated:
- Risk of membrane rupture in the uterus
- Premature delivery
- Death of the mother
As a result of anemia from vitamin A deficiency during pregnancy, a baby is also seriously impacted in several ways:
- Risk of death in the baby’s first year of life
- Low birth weight/small size
- Low levels of hemoglobin
Vitamin A supplements taken during pregnancy under medical supervision can help decrease the frequency of anemia.24 Other studies claim that vitamin A supplements prescribed as late as the second and third trimester do not hold out the promise of improving the mother’s health or that of her baby. A balanced diet with sufficient nutrients is the best way to avoid anemia during pregnancy.25
4. Poor Hair Health
A healthy head of hair signals overall wellness. Along with other vitamins, minerals, proteins, and fats, vitamin A regulates several factors in hair and scalp health. Specifically, vitamin A (a good source is dark green vegetables) is necessary for the production of sebum, the natural oil secreted from glands in hair follicles to nourish and moisturize the scalp. Also, beta-carotene, a compound found in brightly colored fruits and vegetables such as carrots, sweet peppers, squash, papaya, and mango, is converted into vitamin A by the body to maintain hair and scalp health.26
5. Skin Disorders
Vitamin A is converted in the skin to a compound named retinoic acid which regulates the functioning of skin cells to keep them smooth, soft, and healthy. When there is a deficiency of vitamin A, certain changes may be observed:
- Skin appears thick, hard, and flat due to a process called keratinization.
- If the deficiency worsens, skin develops hard bumps, commonly called “gooseflesh.”
- The skin’s natural color becomes ashen and sallow as the epithelium, the skin’s membranous inner lining, loses its transparency and the blood vessels which give the skin its normal tone cannot be seen.
- The epithelia or inner linings of sweat and oil glands dry out and atrophy.
- The nails too become dull, dry, and brittle with lengthwise ridges.
Patients with some types of skin cancer seem to have low levels of beta-carotene and vitamin A (retinol). Can increasing intake help? Science is not sure yet.27
Treatment for these conditions involves large doses of vitamin A, and progress is slow. Keratinization can also affect the inner surfaces of the respiratory tract, gastrointestinal tract, and the urinary tract.28 29
The bottom line? Get your vitamin A from a wide variety of food sources. If, for any reason, you suspect a vitamin A deficiency in your child, consult a doctor to find out more about appropriate vitamin A supplementation. Don’t self-medicate as 80–90% of vitamin A is stored in the liver and excessive doses of supplements can lead to toxicity and other complications.
References [ + ]
|1, 16.||↑||Micronutrient Deficiencies. WHO.|
|2.||↑||The Nutrition Source. Harvard T.H. Chan School of Medical Health.|
|3.||↑||Underwood, Barbara A. “Prevention of vitamin A deficiency.” Institute of Medicine. Prevention of Micronutrient Deficiencies: Tools for Policymakers and Public Health Workers (1998): 103-166.|
|4.||↑||Vitamin A deficiency. DermNet NZ.|
|5, 19, 27.||↑||Vitamin A (Retinol). PennState Hershey.|
|6, 7, 12.||↑||World Health Organization. “Xerophthalmia and night blindness for the assessment of clinical vitamin A deficiency in individuals and populations.” (2014).|
|8.||↑||[McLaren, Donald Stewart and Kraemer, Klaus. Manual on Vitamin A Deficiency Disorders (VADD). Karger Medical and Scientific Publishers, 2012|
|9, 11, 14.||↑||Gilbert, Clare. “The eye signs of vitamin A deficiency.” Community eye health 26, no. 84 (2013): 66.|
|10.||↑||McLaren, Donald Stewart and Kraemer, Klaus. Manual on Vitamin A Deficiency Disorders (VADD). Karger Medical and Scientific Publishers, 2012|
|13, 17.||↑||McLaren, Donald Stewart and Kraemer, Klaus. Manual on Vitamin A Deficiency Disorders (VADD). Karger Medical and Scientific Publishers, 2012.|
|15.||↑||Institute of Medicine (US), Committee on Military Nutrition Research. Military Strategies for Sustainment of Nutrition and Immune Function in the Field. Washington (DC): National Academies Press (US); 1999. 12, Vitamin A and Immune Function.|
|18.||↑||Yang, Hui Ming, Meng Mao, and Chaomin Wan. “Vitamin A for treating measles in children.” The Cochrane Library (2005).|
|20.||↑||Measles. Kids Health.|
|21.||↑||[Gilbert, Clare. “Vitamin A deficiency disorders in children”. International Centre for Eye Health.|
|22.||↑||Sommer, Alfred and West, Keith P. Vitamin A Deficiency: Health, Survival, and Vision. Oxford University Press, 1996.|
|23.||↑||Institute of Medicine, Committee on Nutritional Status During Pregnancy and Lactation. Nutrition During Pregnancy: Part I: Weight Gain, Part II: Nutrient Supplements. National Academies Press. Jan 1990.|
|24.||↑||Hamdy, A. M., M. M. Abdel Aleem, and A. A. El-Shazly3. “Maternal Vitamin A Deficiency during Pregnancy and Its Relation with Maternal and Neonatal Hemoglobin Concentrations among Poor Egyptian Families”. Volume 2013 (2013), Article ID 652148.|
|25.||↑||Vitamin A supplementation during pregnancy. WHO.|
|26.||↑||NUTRITION AND HAIR HEALTH. The Trichological Society.|
|28.||↑||Vitamin A. Merck Manual.|
|29.||↑||Urbach, Erich. Skin Diseases Nutrition and Metabolism. Butterworth-Heinemann, 2015.|
Disclaimer: The content is purely informative and educational in nature and should not be construed as medical advice. Please use the content only in consultation with an appropriate certified medical or healthcare professional.