The Effects of Vitamin A on the Human Body

What Is Vitamin A?

Vitamin A is an unsaturated monoalcohol of the aliphatic ring. Vitamin A is a retinoid that crystalizes at 63-64 degrees celsius, forming yellow prismatic crystals. It is insoluble in water and glycerin but soluble in methanol, ether, chloroform, fats, and oils.

The importance of vitamin A

When most people talk about Vitamin A, they are referring to Vitamin A1 (retinol). Vitamin A1 is the preformed type and can be found in animal products, including the livers of mammals and saltwater fish. Vitamin A2 (beta carotene), must be converted into retinol before your body can use it. Vitamin A2 is used less often and can be found in the livers of freshwater fish, as well as plants.

What’s the Function of Vitamin A On the Body?

Promoting Healthy Skin

healthy skin

Vitamin A regulates and normalizes your cells, which is necessary for the normal regeneration of your skin’s bottom cells. It promotes collagen production and has antioxidant effects. Vitamin A also thickens your skin’s epidermis, the outer layer that protects the underlying layers from the environment. Vitamin A makes skin smoother and works to keep it soft and plump. It is also believed to prevent skin cancer.

Protecting Skin

protecting your skin

Vitamin A fosters glycoprotein synthesis while enhancing the immune function of the skin and the mucous membrane. This protects your body against bacterial infections, reduces dandruff and supports human development. Vitamin A also reduces skin damage caused by air pollutants by improving the stability of the cell wall.

Reducing Acnes And Wrinkles

Reducing Acnes And Wrinkles

Retinol propionate and retinol acetate are common ingredients found in cosmetics, moisturizers, conditioners and anti-aging products because it is clinically proven to reduce acnes and wrinkles.

Protecting Eyes

Protecting The Eyes

Lack of Vitamin A can make you prone to conditions that lead to vision loss and/or night blindness such as corneal softening, corneal ulcers, and dry eyes.

What Changes Will Happen to the Human Body If Vitamin A Is Insufficient ?

Just as consuming the right amount of Vitamin A plays an important role in maintaining a healthy, well-proportioned body, bright eyes and smooth skin, not getting enough of this amazing nutrient can cause some problems.

Your Skin Turns to Become Dry

Lack of Vitamin A can accelerate the division of the skin’s cells, cause cell death, and shedding of subcutaneous tissue. This results in rough, dry and flaky skin, especially on your elbows, knees, and buttocks.

There Appears Acne on Your Face

There Appears Acne on Your Face

If your body remains Vitamin A deficient for a long time, your pores will become enlarged and blocked by all of the dead cells on the top layer of your skin. When this happens, it results in excessive grease secretion and simultaneously prevents the grease from reaching the skin’s surface. The trapped grease can lead to whiteheads, blackheads, severe acne, eczema, and other skin conditions.

Accompany with Vision Loss to Some Extent

Accompany with Vision Loss to Some Extent

Symptomatic clinical Vitamin A deficiency is first manifested in the eyes, causing night blindness or inability to see clearly in dark light. Dry eye symptoms may also appear after a few weeks.

What Is the Impact of Vitamin A Deficiency Around the World?

vitamin A deficiency

Vitamin A is a large family, and vitamin A is undoubtedly the leader in the family. Vitamin A deficiency is the most common public health problem in the world, and iron and iodine are listed as the three major micronutrient deficiencies in the world. Vitamin A deficiency is one of the most important nutritional factors affecting severe infection and death among children in developing countries. In 2002, the vitamin A deficiency rate was 9.3%, and the vitamin A marginal deficiency rate was 45.1%. The incidence of in China is between ≥ 2% and < 10%, which is a moderate epidemic area.

So How to Get Enough Vitamin A?

How to get enough vitamin A

Thankfully, you can easily make sure your body has enough Vitamin A by consuming foods that are rich in this important nutrient. As stated above, Vitamin A1 (retinol) is mainly found in animal products such as animal liver, dairy products, and eggs. Foods rich in Vitamin A2 (beta-carotene) include leafy greens such as spinach, yellow fruits and vegetables, alfalfa, pea seedlings, sweet potatoes, carrots, green peppers, and pumpkins. Cantalope, carrots and butternut squash all get their bright color from Vitamin A2. Vegetables that have lost their original color or never turn green are Vitamin A deficient.

Here is a more complete list of foods you can eat to increase your intake of both types of Vitamin A:

Liver Oil

Animal livers are very rich in Vitamin A and are usually safe to eat. Polar bear livers, however, are so high in Vitamin A that they can easily be toxic to humans. In the 1990s, Arctic explorers reportedly suffered from headaches, vomiting, and lethargy a few hours after eating polar bear livers.

The amount of Vitamin A in the animal’s liver depends on diet and age. For example, Halibut liver oil contains more Vitamin A than Cod liver oil, which is easier to find. This is because Cod liver oil is harvested and sold when the fish are still young. Halibut usually spend more years feeding on green seaweed, a good source of Vitamin A. Similarly, the livers of adult cattle and sheep contain much higher levels of Vitamin A than that of calves and lambs.


Pears, apples, loquats, cherries, bananas, longans, apricots, litchi, watermelon, and melon are also great sources of Vitamin A. With the exception of apricots, most yellow fruits contain less than 400 units of Vitamin A per serving.


Chinese cabbage, shepherd’s purse, tomato, eggplant, pumpkin, cucumber, green pepper, spinach, alfalfa, pea seedling, sweet potato, carrot, etc. are all good sources of Vitamin A. According to the food analysis table, the vegetables that have the most abundant amount of Vitamin A (about 12,000 units) per serving (100g) are kale, spinach, and other green vegetables.

Even one serving of string beans, broccoli, carrots, yellow squash, apricots, sweet potatoes or yams provides 5,000 units of vitamin A, which is the recommended daily serving size for adults. An average serving of tomatoes, peas, celery, lettuce, and asparagus also contains nearly 2,000 units.


Mung beans, rice, and walnuts also contain Vitamin A.

Meat, Fish and Dairy Products

Meat, fish and dairy products

Pork, chicken, eggs, turtle, crab, and snail all contain Vitamin A1. Animal kidneys and chop suey are very high too. Vitamin A can also be found in milk and dairy products, including unskimmed milk and poultry eggs. The amount of Vitamin A found in eggs and cream depends on the animal’s diet. The amount of Vitamin A in whole milk varies from 500 to 7,000 units per liter, but the average is about 2,000 units. Researchers have yet to find a way to stop the oxygen in milk from destroying most of the Vitamin A during the homogenization process. Vitamin A found in homogenized milk is added after the process is complete.

Cows that eat hay produce winter butter, which is very popular among professional chefs. Unfortunately, winter butter only contains approximately 2,000 units of Vitamin A per pound. Summer butter contains an average of 12,000 units per pound. The amount of vitamin A added in every pound of butter substitute is usually about 12,000 units.

Which Foods Have the Highest Amount of Vitamin A?

In order to know for sure how much Vitamin A your favorite foods contain, you’ll need to do some research. Don’t forget that the amount of Vitamin A doesn’t just vary based on the type of food you eat; It also varies with serving size. To make things a little easier for you, we’ve compiled the following list of Vitamin A rich foods, along with the approximate amount of Vitamin A per serving:

What Should Be Noted When Taking Supplements?

As with all nutrients, it is best to obtain your daily dose of Vitamin A from the foods you eat, rather than taking a supplement. Still, taking Vitamin A supplements every day can be beneficial to your health but studies have shown that supplements are not suitable for everyone. It is always best to check with your doctor before you begin taking supplements, especially if you suffer from any of the following:

What Should Be Noted When Taking Supplements?


The conventional psoriasis drug retinol, a derivative of Vitamin A, is stored in the liver when it enters the body. Consuming more than 0.7 mg per day for men or more than 0.6 mg per day for women can result in an overdose which will produce toxins in the body. These toxins can lead to conjunctivitis, hair loss, and further skin problems.


People with osteoporosis or those at risk should not take Vitamin A supplements at all. Vitamin A supplements can increase your risk of developing osteoporosis or aggravate your condition if you have already been diagnosed. High doses of Vitamin A can raise the level of phosphorus in the blood, which can reduce bone mineral density and lead to bone loss.

Gastric Ulcers, Prostate Cancer and Kidney Disease

Studies have found that when patients with gastric ulcers take drugs to treat gastric ulcers, Vitamin A supplementation can seriously weaken the latter’s efficacy. Additionally, kidney disease and prostate cancer patients are advised not to take Vitamin A supplements.

What’s The Typical Case For Vitamin A Overdose?

vitamin A overdose

The 2011 World Health Organization guidelines do not recommend Vitamin A supplementation for newborns and infants between 1-5 months of age unless recommended and monitored by a physician.

Because Vitamin A is a fat-soluble micronutrient that can exist in the adipose tissue of the human body, high doses of Vitamin A may be harmful. Studies in recent years have found infants who receive high doses of Vitamin A supplements can suffer serious side effects such as increased tension of anterior fontanelle, vomiting and so on.

Due to the abuse of Vitamin A concentrate in China, poisoning symptoms are increasing. In China, it is often thought that it is best for the body to consume as much Vitamin A as possible. Because of this, many parents and medical staff assume that it is not important to monitor Vitamin A levels, but this is not the case. Excessive intake of Vitamin A can quickly become toxic. There are two types of vitamin A poisoning:


Due to individual differences in the storage of Vitamin A in the liver, toxic doses may vary greatly in children. General Vitamin A injections of 300,000 IU, can produce toxic symptoms in infants and children within a few days. The manifestations were anorexia, restlessness or drowsiness, vomiting, swelling of the anterior fontanel, enlargement of the head circumference, cranial suspicion cracking, papillary edema, and so on. An increase of intracranial pressure is common in the acute type, which seems to be caused by the increase of cerebrospinal fluid volume or absorption disorder. If children do not have an infection of the nervous system prior to taking Vitamin A and suddenly develop intracranial hypertension symptoms, those symptoms disappear rapidly after the withdrawal of vitamin A.


The dosage of chronic Vitamin A poisoning reaches tens of thousands of units a day. In the early stage of chronic Vitamin A poisoning, people may experience irritability, loss of appetite, low fever, hyperhidrosis, alopecia, later typical symptoms of bone pain, metastasis pain, soft tissue swelling, and tenderness. Some patients face intracranial hypertension, headaches, vomiting, a wide and bulging anterior fontanel, a separation of skull seams, esotropia, nystagmus, and amblyopia. The following symptoms are rare but include skin itching, desquamation, rash, chapped lips, dry hair, hepatosplenomegaly, abdominal pain, myalgia, bleeding, kidney lesions, and regenerated low anemia with leukopenia. These symptoms can lead to more serious health problems or even death.

Kana Z

Kana Z

I am a writer focussing on beauty, cosmetics, skincare, haircare and body care. I have a special interest in establishing solutions for problem skin. I have being working and studing with some of the world’s top skincare experts, hairstylists, makeup artists, perfume creators, photographers and models. I also currently write for websites of the skincare brand. My Specialties: beauty, journalism, skincare, haircare, cosmetics and problem skin.

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