Vitamin A is an essential vitamin but the body needs only trace amounts of it. It is acquired from two sources – animal sources that contain retinoids and plant sources that contain carotenoids. Deficiency and overdose can cause severe health problems.
Causes of Vitamin A Deficiency
Vitamin A deficiency is uncommon in developed countries like the US. It is more prevalent in developing countries where lower income group people cannot afford to eat animal products that have preformed vitamin A or beta-carotene-rich foods. According to the WHO, women and young children are most at risk. Based on this, some high risk groups who suffer from vitamin A deficiency have been identified.
Premature babies: Babies who suffer from malabsorption disorders at birth are susceptible to vitamin A deficiency especially in developing countries. Preterm babies often do not have enough vitamin A stores in the liver and throughout the first year of their lives and they have low retinol concentrations in the plasma. This deficiency in preterm babies makes them vulnerable to chronic lung, eye and gastrointestinal diseases.
Babies in developing countries do not get sufficient vitamin A from mothers’ milk that is vital to meet their dietary requirements from birth to 6 months. This is because poor mothers suffer from vitamin A deficiency and their breast milk has suboptimal concentrations of vitamin A, which is not adequate to meet the needs of babies solely fed on breast milk. As the baby grows, he or she continues to display signs of vitamin A deficiency, even after breast milk has been stopped. The most common sign of this deficiency is xerophthalmia (dry eyes), which is a symptom whereby the eyes fail to produce tears.
Pregnant and breastfeeding women in developing countries lack sufficient intake of vitamin A – again due to poverty or unawareness. Vitamin A is vital for pregnant women to enable proper fetal tissue maintenance and growth and to support the mother’s own metabolism. These pregnant women also suffer from xerophthalmia (around 9.8 million worldwide according to WHO statistics). Such a deficiency can lead to increased death rates among pregnant women and babies, higher rates of anemia and slower growth and development of the infants.
Cystic Fibrosis: People who suffer from this disease can suffer from vitamin A deficiency since they have pancreatic insufficiency. Better pancreatic replacement treatment combined with caloric supplements and improved nutrition can help overcome this deficiency in cystic fibrosis patients. Oral vitamin A supplements correct low levels of serum beta-carotene according to certain studies.
Asthma patients also have low serum levels of vitamin A. it has not been established if this is due to inflammation associated with asthma or whether it is one cause of asthma. The more severe the symptoms of asthma the greater are the deficiency symptoms of vitamin A. It is also more elevated in children than in adults.
Symptoms of vitamin A deficiency
Some of the distinct signs of a vitamin A deficiency include:
- Night blindness
- Keratinization of skin
- Itching and burning sensation in eyes
- Xeropthalmia or dry eye syndrome
- Inflammation of eyelids
- Brittle nails
- Precancerous signs in body tissues
- Sexual disorders
Excess Vitamin A : Hypervitaminosis
Excess vitamin A can cause birth defects. Babies and small children are especially prone to vitamin A toxicity even if they take small doses. This toxicity need not necessarily come from vitamin A supplements or foods but also from topical creams that contain retinol.
Hypervitaminosis refers to excess of vitamin A in the body. There are two types:
- Acute when the patient consumes an excess of vitamin A over a short term
- Chronic when the patient overdoses over a long period
Symptoms of hypervitaminosis
The following are some of the symptoms of hypervitaminosis:
- Abnormally soft craniotabes in new born babies
- Reduced appetite
- Double vision in small children
- Skin itching, peeling, yellow discoloration, high sun-sensitivity
- Hair loss, hair seborrhea
- Vision changes
- Liver damage
- Greater intracranial pressure
- Infants with bulging fontanelle
- Pain and inflammation of bone and joints
Diagnostic tests such as x-rays, blood calcium, cholesterol, liver function tests and tests to detect vitamin A levels will be done on patients who exhibit the above symptoms. Treatment involves immediate stoppage of vitamin A.
Vitamin A supplements
The daily requirement of vitamin A for men is 0.7mg and women 0.6mg. Most of the vitamin A requirements are got from a wide variety of fruits, grains, fortified dairy products and vegetables.
Vitamin A supplements are available as retinyl palmitate or retinol as capsules or tablets. 10,000 I.U is the safe upper limit of this vitamin. Unlike retinol, beta-carotene does not usually build up in the body. In rare cases when there is an excess, it is revealed by the skin turning yellow or orange. If you reduce beta-carotene intake, the skin color returns to normal.
For better absorption, it is recommended that vitamin A supplements be taken with food.
Precautions while taking Vitamin A supplements
Pregnant women should be cautious for all prenatal vitamins contain vitamin A. if vitamin A supplement is taken separately by pregnant women, it can result in serious birth defects in their fetus. Pregnant women must also be careful not tot take synthetic vitamin A. Alcoholics and smokers must avoid beta-carotene supplements. Diabetics must consult their doctor prior to taking vitamin A supplements.
Vitamin A is also available as part of many health and fitness, cold, skin, eye and immune system formulas. Do not take multiple formulas for then you may be at risk of suffering from excess vitamin A. Depending on vitamin A intake, avoid carob for this can increase the amount of this vitamin in the body.
Care must be taken to ensure that you have sufficient levels of vitamin A in the body so that you do not suffer from a deficiency or excess – both of which have serious consequences.