Vitamin A Guide: Benefits, Deficiency Symptoms, Overdose & more

Vitamins and Minerals belong to a group of Nutrients called Micronutrients. The word “micro” means that they don’t account for a large proportion of your food. This, however, doesn’t mean they are any less important as so called Macronutrients.

Vitamins play very important role in many biological and chemical processes in living organisms. In this article I am going to have a closer look at Vitamin A and the role it plays in our bodies.

I will be trying to cover the topic as comprehensive as possible. Here is a list of topics that will be discussed:

  • What is Vitamin A?
  • What Does Vitamin A Do?
  • Vitamin A Benefits
  • Vitamin A Deficiency Symptoms
  • Rich Foods Sources of Vitamin A
  • Vitamin A Supplements
  • Vitamin A Recommended Doses
  • Vitamin A Overdose and Side Effects
  • Vitamin A Toxicity
  • Vitamin A for Acne
  • Vitamin A Creams
  • Useful Tools to Take Care of Your Vitamin A Needs

What is Vitamin A?

Vitamin A belongs to a group of fat soluble vitamins. It means that the body can store it in its fat tissues. Unlike water soluble vitamins there is slight risk of overdose; therefore supplementation should be exercised with care.

Vitamin A exists is several forms. The active form in the human body is retinol. Consumption of mostly animal based food will also supply you with retinol. On the other hand, plant based diet will provide carotenes which are then converted to retinol by the body.

What Does Vitamin A Do?

Vitamin A is needed for many metabolic processes. Probably its most important function of is a good eye health.

In produces pigment called retinal in the eye’s retina. Retinal is a substance absorbing sun light and is very important for low-light vision.

Vitamin A affects also other body functions, like healthy teeth and bones grow. It plays a role in the soft tissue development and creation of many proteins throughout your body as well.

It is also essential for pregnant and lactating women. Retinoic acid (one of Vitamin A metabolites) aids in growth hormone production in the developing foetus. The growth hormone plays important role in formation of heart, eyes, limbs and ears.

Vitamin A Benefits

Adequate levels of Vitamin A present many health benefits. It is essential to maintain strong immune system. It also benefits healthy growth of tissue so is important especially for children.

Vitamin A keeps strong many frontline barriers against infections. Those barriers include nose, throat, lungs, skin, eyes, digestive and urinary tract.

Here is the list of all its main benefits:

  • Promotes healthy skins and fights acne
  • Reducing appearance of wrinkles
  • Derivative etretinate found effective against psoriasis
  • Eases symptoms of measles
  • Prevents developing cataracts, macular degeneration (AMD) and glaucoma
  • Keeps mucous membranes healthy
  • Increases resistance to cancer
  • Effective for treatment of pneumonia
  • Inhibits production of DNA in cancerous cells
  • Topical application may even treat some skin cancers
  • Slowing down tumor growth and leukemia
  • Fights viral diseases (respiratory viruses, even HIV)
  • Showing anti-infection powers
  • Preventing stroke and heart attacks

Vitamin A Deficiency Symptoms

Vitamin A deficiency is quite wide spread these days. This is especially true for in developing countries, but numerous cases are recorded every year in developed countries as well.

Statistics show that there are approximately 250 million children world-wide who suffer Vitamin A deficiency. For children it can have serious consequences. One of the worst is a loss of eyesight.

Recognizing Vitamin A deficiency early is important. Here are some warning signs:

  • Compromised or reduced vision at night or dim light
  • Dry eyes (can lead to xeropthalmia – loss of goblet cells that produce tears)
  • Eye inflammation
  • Epithelial changes and degeneration (eye, nose, sinuses, middle ear, mouth, respiratory tract, lungs)
  • Skin changes (xeroderma – dry and itchy skin, hyperkeratosis – skin thickening or phrynoderma – toad skin )
  • Changes in respiratory tract (frequent bacterial infection)
  • Digestive tracts (compromised secretion of digestive juices)
  • Diarrhoea
  • Changes in the reproductive tract (vaginitis)
  • Skeletal degeneration (brain and spinal cord injuries)
  • Insufficient resistance to bacterial infections (due to mucus membranes degeneration)

Rich Foods Sources of Vitamin A

There is difference when it comes to sources of Vitamin A. Animal sources contain mostly retinol, the active form of Vitamin A. Whereas vegetable and fruit contain carotenes which are also called pre-vitamins.  It means that they are converted by the body to active forms of vitamins.

The highest levels of Vitamin A in animal based foods can be found in livers. That includes for example chicken, beef, turkey, duck or lamb liver. Other good sources of animal based retinol are eggs, caviar, tuna fish, cod fish, oysters and some types of cheese like parmesan or Edam.

If you prefer vegetarian sources of Vitamin A in form of carotenoids then look for carrots, kale, chives, butternut squash, spinach, dandelion, lettuce or parsley.

As mentioned earlier, animal sources contain retinol, which is the active form of Vitamin A. Too much of retinol can be harmful. On the other hand, consumption of carotenes from vegetables is much safer.

There are no known causes of beta-carotene causing an overdose.

Conversion of carotenes (like beta-carotene in carrots) into Vitamin A is influenced by its present level in the body. If there is enough of it then the conversion rate is decreased. This mechanism protects your body from Vitamin A overdose.

For more detailed information about foods rich in Vitamin D, please see our comprehensive list here: Top 120 Foods High in Vitamin A

Vitamin A Supplements

The best way to consume enough of Vitamin A is through foods. There are plenty of foods, both animal and plant based that contain plenty of it. However, if for some reasons you or your child is suffering Vitamin A deficiency then supplementing is an option.

Vitamin A is usually part of most standard multivitamins.

You can also buy many over-the-counter supplements specifically for Vitamin A. For maximum absorption and efficiency it’s recommended to use supplements that contain combination carotenes alpha, beta and gamma.

Some sources recommend combination of Vitamin A and E. These are often sold as emulsion in form of drops or soft gels. Use of carotene based supplements is safe and does not pose a risk of overdose.

If you use supplements containing retinol then make sure following recommended doses to avoid eating too much of it.

Vitamin A Recommended Doses

When it comes to recommended doses of Vitamin A, it is not so straightforward as with some other Vitamins. Recent best practise to measure Vitamin A is in “Retinol activity equivalent” or “mcg REA”. That’s because there is different biological activity between retinol and carotenoids.

So, let’s first have a look at few facts and conversion factors.

  • 1 IU of retinol = 0.3 mcg REA
  • 1 IU of beta-carotene from supplements =  0.15 mcg REA
  • 1 IU of beta-carotene from food = 0.05 mcg REA
  • 1 IU of alpha-carotene or beta-cryptoxantin = 0.025 mcg REA

As you can see, conversion of mcg (micrograms) to IU (international units) cannot be done without knowing dietary sources of Vitamin A.

Recommended doses of most Vitamins and Minerals depend an age and other circumstances (like pregnancy or breastfeeding). Here are general guidelines for daily recommended doses of Vitamin A:

  • 0-6 months: 400 mcg REA
  • 7-12 months:  500 mcg REA
  • 1-3 years: 300 mcg REA
  • 4-8 years: 400 mcg REA
  • 9-13 years: 600 mcg REA
  • 14-18 years: 900 mcg REA
  • 19-50 years: 900 mcg REA
  • 51 years and over: 900 mcg REA

For more details about recommended doses of Vitamin A as well as other 58 important Vitamins, Minerals and other Nutrients check our detailed guide here: Recommended Daily Allowances of Nutrients.

Vitamin A Overdose Risks and Side Effects

As mentioned earlier, Vitamin A is a fat soluble vitamin and high doses, particularly retinol, can lead to overdose symptoms.

These are typical Overdose Risk & Side Effects:

  • Increased risk of osteoporosis and fractures (especially in older people)
  • Fatigue
  • Irritability
  • Mental issues
  • Decreased appetite
  • Anorexia
  • Stomach discomfort
  • Nausea
  • Vomiting
  • Headaches
  • Mild fever
  • Excessive sweating
  • Increased risk of cancer in smokers
  • Birth defects (primarily if overdose occurs in the first 3 months of pregnancy)
  • Dry or cracking lips and skin
  • Hair loss

One surprising effect of excessive Vitamin A levels in smokers is increased risk of developing cancer. It is not known exactly why this is happening. In any case, smokers should be cautious about their Vitamin A intake.

Better way to decrease your chance of cancer if you smoke is to increase your intake of Vitamin C instead. Off course, if you quit smoking, that works even better.

Vitamin A Toxicity

Too high doses of Vitamin A intake or their persistence over prolonged period of time significantly increase risk of Vitamin A toxicity.

Toxicity can manifest itself as aggravated overdose symptoms or it can also lead to more serious conditions like:

  • Dizziness
  • Malaise
  • Blurred vision
  • Joint and Bone pain
  • Swelling
  • Skin turning yellow
  • Slow growth
  • Intracranial pressure
  • Intense itching
  • Eye and liver damage
  • High calcium bool levels
  • Bulge in the fontalle (usually in infants)

Toxicity symptoms may develop also in case of single extra-large dose. It is generally believed that doses under 10000 IU are regarded as safe. Higher doses may be warranted for treatment of some medical condition.

They should be prescribed by a medical practitioner and thoroughly monitored. The risk of Vitamin A Toxicity can also be increased with use of some drugs. If you develop any of the symptoms mentioned above, talk to your doctor immediately.

Vitamin A for Acne

Vitamin A has been hailed by many as a miracle vitamin for problems with acne. Traditional recommended doses of Vitamins are usually sufficient for maintaining a good health. But to treat a medical problem higher doses are often required.

A safe daily dose of Vitamin A is at 10000 IU (international units) for men and 8000 IU for women.  To treat acne the effective doses are at levels around 20000 to 30000 IU. As you can see it exceeds the safe doses two to three fold.

Can such high doses cause any health problems?

Well, not if you are taking it for a limited time, usually few weeks. People who tried this approach reported that their acne significantly improved after 2 or 3 weeks. Once you notice improvement, try decrease the dose under the safe level of about 8000 IU for girls and about 10000 IU for boys.

Another way to tackle the overdose issue is supplementing carotenoids instead of retinol. As you may know, carotenoids are safe even in high doses and it’s very unlikely that you develop overdose or toxicity symptoms.

The downside of carotenoids is that carotenoids may not be as effective as retinol. That’s because with the high doses your body will decrease the conversion rate. This means that your retinol levels may not reach the levels required for effective acne disappearance.

Some people report that even doses at the maximum safe level (8000 to 10000 IU) have been effective against their acne. The best way would be to start at these safe levels. I would then consider moving to higher doses only if these safe levels show as insufficient.

There is one more important thing to be aware of. High doses of Vitamin A can cause birth defects. Therefore, never practise this type of treatment while pregnant. Also make sure that you use proper contraception during this treatment to avoid becoming pregnant.

To be on a safe side continue with contraception for few months after discontinuing it. That gives your body time to normalise your Vitamin A levels.

If you are male then this off course doesn’t need to concern you. But you still should be cautious about few other symptoms. Especially for your people the high doses of Vitamin A may lead to liver damage and raising your cholesterol levels.

The good news is that after stopping the treatment these side effects should go away.

Vitamin A Creams

The question here is: What is more effective in treating skin condition – Vitamin A ingested and supplied to the tissues through blood or creams.

The answer is pretty simple. Vitamin A as well as all other nutrients is much better utilised by your body when supplied through the “normal” channels designed to deliver nutrition.

Human body evolved to receive nutrients through the blood. The evolution never intended for the nutrients to be supplied by artificial means like skin creams.

But can the creams be effective?

Yes they can. Modern technology developed substances that can penetrate your skin’s natural barriers and deliver its content deep into the tissue.

But there is a problem.

Most creams and cosmetics products contain many additives like preservatives and stabilisers. They make creams consistent, give them nice smell or make them last on shop shelves for years. If you apply any cream to your skin, all of the creams content is then absorbed into your skin.

And here is their main problem. Apart from delivering nutrients they also deliver other chemicals which can be harmful. You may have heard of women who used all sorts of anti-aging products.

These products worked for some time suppressing or masking the wrinkles. But at the same time they were causing damage. After years of their use the skin suddenly accelerates its aging. That’s just one thing you should be aware of.

So, when deciding whether to use Vitamin A as a supplement or as a cream then use these rules:

  • Avoid using cheap commercial creams
  • Prefer more expensive quality organic products which contain no chemical preservatives
  • Beware of some expensive brands which still may be full of additives (read the labels, not the front cover)
  • Creams are good only as a short term solution
  • For long term results look at the nutrition
  • Even after skin improvement continue high vitamin diet or regular supplementation of Vitamin A within recommended doses

I hope that this few rules will help you to make the right decision while combating acne or other skin related conditions.

Useful Tools to Take Care of Your Vitamin A Needs

I have developed for you some handy tools. They should help you to take better care of your health and wellbeing. These tools will guide you and make sure that you are getting the right amount of Vitamin A as well as other nutrients in your Diet.

Tool #1: Nutrition Calculator

First tool is Nutrition Calculator for Microsoft Excel. With this calculator you now will be able to analyse your Diet and find out nutritional values of 59 different Nutrients.

This calculator will help you uncover which vitamins, minerals or other essential nutrients might be at insufficient levels. You can then make simple adjustments to your Diet to rectify it.

To find more information about this Nutrition Calculator in Excel click here.

Tool #2: eBook Discover Nutrient Rich Foods

This eBook contains extensive lists with 250 food items for every of the 59 essential Nutrients. They are the same Nutrients as those included in the Nutrition Calculator mentioned previously.

To evaluate your Diet do these steps:

  1. Use the Nutrition Calculator first to discover missing Nutrients.
  2. Your next job is to find out which foods contain those missing Nutrients.
  3. Here is where the eBook comes. In this eBook you will be able to find these foods.

How to find Nutrient rich foods?

Simply look at the Top 250 List for a specific Nutrient and find out instantly which foods contain it in high amounts. Pick the foods you like and include them into your Diets.

And that’s all, job’s done!

Now you should rest knowing that your food covers all essential Nutrients in adequate amounts.

To find out more information about this eBook click here.

In this article I tried to cover the topic as thoroughly as I could. If you find my information useful then I am happy. However, if you would like to add something more or share your thoughts then please do so in the comments below. I will love to hear your feedback!

One Handy Tip

To make sure your Diet is nutritionally balanced use our FREE Nutrition Calculator in Excel. It includes:

  • Massive database with 1923 Food items
  • For each Food item content of 60 Nutrients (Vitamins, Minerals, Macronutrients and Amino Acids)

To download a Sample of our Nutrition Calculator, click the button below:

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