Vitamin A

It has an important physiological role in visual cycle in the retina of eye. In vit. A deficiency rods are affected more than cones, irreversible structural changes with permanent night blindness occur if the deprivation is long term. Vit. A promotes differentiation and maintains structural integrity of epithelia all over the body. It is also useful for maintenance of spermatogenesis and foetal development.Deficiency symptoms: Xerois (dryness) of eye, ‘Bitot’s spots’, Keratomalacia (softening of cornea), corneal opacities, night blindness (nyctopia). Dry & rough skin, hyperkeratinization, atrophy of sweat glands. Keratinization of bronchopulmonary epithelium. Unhealthy gastrointestinal mucosa, diarrhoea. Sterility. Vitamin A is a fat-soluble vitamin that plays a crucial role in various physiological functions, including vision, immune system support, and skin health. It exists in different forms, including retinol, retinal, and beta-carotene.

Indications

Vit. A deficiency during infancy, pregnancy, lactation, hepatobillary disease, steatorrhea. Skin diseases like acne, psoriasis, ichthyosis. Prevention of cancer. -Vitamin A is essential for maintaining healthy vision, particularly in low-light conditions. -It supports the immune system, promoting resistance to infections. -Vitamin A is crucial for the development and maintenance of epithelial tissues, such as skin and mucous membranes.

Dosage

-Dosage can vary based on the specific form of vitamin A and individual health needs. -Common dosages are typically expressed in international units (IU) and may range from 2,000 to 10,000 IU per day. -Dietary sources include liver, fish liver oil, dairy products, and certain fruits and vegetables.

Contra-Indications

-Excessive intake of vitamin A, especially in the form of supplements, can lead to vitamin A toxicity. -Pregnant individuals should avoid excessive vitamin A intake, as it can harm the developing fetus.

Special Precautions

Regular use of liquid paraffin, long term oal neomycin use induces steatorrhea & interferes with Vit. A absorption. -Vitamin A is fat-soluble, and excessive intake over prolonged periods can lead to toxicity. Follow recommended dosage guidelines. -Individuals with liver conditions or certain medical conditions should consult with a healthcare professional before using vitamin A supplements.

Side Effects

-Excessive vitamin A intake may lead to symptoms of toxicity, including nausea, dizziness, and, in severe cases, more serious health issues. -Dietary sources of vitamin A, such as beta-carotene from fruits and vegetables, do not typically cause toxicity.

Drug Interactions

-Vitamin A supplements may interact with certain medications, including retinoid drugs, and can enhance the risk of vitamin A toxicity. -Consult with a healthcare provider to assess potential interactions with specific medications.