7 Health Benefits of Vitamin A (Evidence-Based)

Health Benefits of Vitamin A

Vitamin A is one of the essential micronutrients and plays a significant role in maintaining optimal health. Do you know what are the ‘Health Benefits Of Vitamin A’? They are really amazing and you will be amazed to know them. Let’s see what they are! 

Brief About Vitamin A

Vitamin A, also known as ‘Retinol’ plays a vital role in maintaining healthy vision, immune function, embryo development, reproduction, cell differentiation and proliferation. Vitamin A is obtained through 2 dietary forms: (i) Preformed Vitamin A and (ii) Provitamin A. 

• Preformed Vitamin A is the active form of vitamin A which is derived from animal sources such as meat, dairy products, fish, etc and it is used directly by the body. It includes retinal, retinol and retinoic acid.
• Provitamin A is the inactive form of vitamin A which means it is firstly converted to active form within the body. It is derived from colourful plants, fruits and vegetables and includes beta-carotene, beta-cryptoxanthin and alpha-carotene. 

7 Evidence Based Health Benefits of Vitamin A

(1) Benefits of Vitamin A for Skin and Hair

Vitamin A performs an important regulatory role for skin and hair health. A research published in the journal, Molecules showed that retinol is critical for UV-induced melanin synthesis. Also, some studies have shown that vitamin A reduces the chances of developing acne and other skin issues.

Moreover, it regulates the HFSCs (Hair Follicle Stem Cells), anagen (Growing phase of hair follicles), catagen (Shrinking of hair follicles) and the anagen and catagen transition. 10 Amazing Benefits of Aloe Vera

(2) Benefits of Vitamin A for Eyes

Vitamin A is one of the most essential vitamins to maintain optimal eye health and plays an important role in phototransduction. Some observational studies and clinical trials have found that people taking vitamin A supplements had 25% lower risk of developing advanced AMD (Age-related Macular Degeneration).

A study published in the journal, Clinical Ophthalmology investigated the effects of short term oral vitamin A supplementation on the ocular tear film in 30 male patients with dry eye of age range 18-38 years. And the findings indicated that vitamin A massively improved the quality of tears and tear osmolarity value and decreased the TF (Tear Film) Grade, but the quantity of tears were not affected. Eye Flu: Causes, Symptoms, Prevention And Home Remedies

(3) Benefits of Vitamin A for Brain

Scientific evidences has provided an indication that vitamin A regulates the brain physiology, functioning, behavior and learning ability in post-embryonic and adult life.

A study published in the journal, Molecular Nutrition and Food Research showed that a balance of retinol attenuated the behavioral plasticity, which directly impacts the storage and recovery of memory. Moreover, it showed a relation of vitamin A and neurogenesis, neuronal survival and synaptic plasticity. Top 5 Incredible Benefits of Ashwagandha

(4) Strengthens Bone

The benefits of vitamin A also extend to one’s bone health and strength.

• The Korea National Health And Nutrition Examination Survey (KNHANES) examined the dietary intake of vitamin A on bone health of 2907 men and 3547 women of age 50 years or more than that. And it was positively correlated with BMD (Bone Mineral Density) at the total hip and femoral neck in men and at the lumbar spine in women.
• The Rancho Bernardo Heart and Chronic Disease reported an inverse U-shaped relationship between vitamin A intake and BMD in elderly men and postmenopausal women aged 55 years old and above. The BMD initially increased with increased vitamin A intake and reached peak at 2,000-2,800 IU of vitamin A supplementation and then dropped even after increased dosage.
• On the other hand, a study published in the Journal of Family Medicine and Primary Care reviewed a total of 13 studies which included 5 cross-sectional studies and 8 cohort studies and found that 3 out of 5 cross-sectional studies showed an increment in BMD while the rest 2 showed a decrement. And 4 out of 8 cohort studies showed an increase in BMD while 2 showed no association and 1 reported an inverse U-shaped association. Sunlight: The Powerhouse of Vitamin D

(5) Boosts Immunity

Vitamin A plays a vital role in strengthening the immune system and hence, protecting the body from various diseases. A research published in the Journal of Clinical Medicine reported that retinol performs promoting and regulatory roles in both the innate and adaptive immune system. 

Furthermore, it stated that vitamin A depicted a significant therapeutic effect on various diseases like tuberculosis, infectious diseases in children like pneumonia, measles, etc and showed a strong correlation between vitamin A deficiency and occurrence of the above mentioned diseases.

(6) Promotes Reproductive Health

The vitamin A also benefits the reproductive system and plays a crucial role in its development. A study published in the journal, Nutrients showed that vitamin A is extremely essential for reproduction in both the male and female.

Furthermore, it is also responsible for the development of embryos and vitamin A is also essential for the maintenance of the male genital tract and spermatogenesis.

(7) Cancer Prevention

Epidemiological studies have found an inverse correlation between cancer development and dietary consumption of vitamin A. Retinol inhibits the growth of different types of cancer and tumour including skin, oral cavity, lung, breast, etc due to its anti-tumour and anti-metastatic properties. However, more evidence is still required to establish the effect of retinol on cancer.

Deficiency of Vitamin A

Deficiency of vitamin A, also known as ‘Hypovitaminosis A’ is extremely rare, especially in developed countries. Following are some of the symptoms which one may notice due to deficiency of vitamin A:

• Night blindness
• Xerophthalmia
• Complete blindness
• Immune impairment
• Dermatological issues
• Opthalmological problems

Vitamin A Dosage per day

The vitamin A intake depends on various factors like the age of an individual, gender, etc but the Recommended Daily Allowance (RDA) of vitamin A is 700-900 mcg (microgram) daily in teenagers and adults. Kids should have around 300-600 mcg of vitamin A per day. This much amount is safe and sufficient to avail all the health benefits of vitamin A without any worry.

How much Vitamin A is too much?

The Tolerable Upper Intake Level of Vitamin A is 10,000 IU (3,000 mcg), exceeding this limit creates health complications and vitamin A toxicity. However, one should not go even closer to this or any higher vitamin A intake limit redundantly, so as to prevent vitamin A toxicity.

Vitamin A Side Effects (Vitamin A Toxicity)

There are no side effects of vitamin A unless it is consumed in massive chronic dosages on a long-term basis. Consuming more than 10,000-15,000 IU daily for long-term leads to vitamin A toxicity or ‘Hypervitaminosis A’. Following are the side effects which one can experience due to vitamin A toxicity:

• Dry skin
• Nausea
• Bone pain
• Headaches
• Cerebral edema
• Anorexia
• Blurred vision
• Liver toxicity

Who should not take vitamin a? 

Though there are numerous health benefits of vitamin A, there are still some contraindications. Pregnant and Breastfeeding women should not consume vitamin A and should definitely consult a doctor before consuming it. 

Takeaway

Vitamin A is one of the essential micronutrients and adequate vitamin A consumption is really vital for eye health, reproductive system and immunity. Its excess and inadequate consumption, both can lead to health complications. The above mentioned “7 Evidence Based Health Benefits of Vitamin A” explicitly proves its importance to the human body.