Vitamins A & D (Vitamins Part III)

There are several vitamins that are fat-soluble (cannot dissolve in water). They include vitamins A, D, E & K, this post will discuss A & D whereas the following post will cover E & K.

Quick facts:

  • Do not break down I water, so they stick around longer
  • Because of this, they can build up in toxic levels if you get too much.
  • Are sturdy; can withstand various forms of cooking, freezing and different storage methods. Except vitamin E, it is fairly vulnerable to elemental changes.

Vitamin A

There are two forms of vitamin A preformed vitamin A and pro-vitamin A carotenoids.

Provitamin A carotenoids include beta carotene (most common one), alpha carotene, and beta-cryptoxanthin which are converted by your body into vitamin A. You can find these in fruit, plant based foods and veggies.

Preformed vitamin A is found in fruits, fish, poultry and dairy products. Both very important for vison function but is also important for your immune system, lungs and other organs to work right.

Studies have been done to learn the health effects of vitamin A. It has been noted that people that eat a LOT of foods containing beta-carotene have a lower chance of developing certain types of cancer but it doesn’t seem to apply to the supplements so you have to eat the food instead.


There is also notes that consuming beta carotene rich foods slow down the rate of vision loss in people that are aging, called age-related macular degeneration. It’s also shown that children that are deficient in vitamin A can get the measles more severely than once that consume proper amounts.

Daily intake: 700-900 mcg (microgram) for adults

Sources: Dark green & vibrant yellow or orange fruits and veggies. Fish, eggs, liver, dairy products. More sources include salmon, fortified cereals, cantaloupe, apricots, mangoes, squash, and carrots.

People usually think of these when they hear vitamin A. Source!
People usually think of these when they hear vitamin A. Source!

Deficiency: is rare as people usually consume enough from their daily food choices. Although the deficiencies are rare in developed countries, it can cause xerophthalmia which is the inability to see in low light (night time) and can lead to blindness if left untreated.


Vitamin D

This controls the intestinal absorption of our calcium and calcium reabsorption by our kidneys. It works as a hormone in our body.
Our bodies can produce this pretty well by being exposed to sunlight. After that, your body begins to convert the UV lights into a cholesterol based compound that turns into vitamin D3.

Daily amount: 600 IU per day. Although if you end up getting up to 4000 IU per day there hasn’t been any evidence of it doing any harm.

Sources: There’s not many foods have vitamin B in it naturally so food sources are usually fortified with it and come in a form of vitamin supplements. However, you can get vitamin D by being outside for at least 15 minutes a day. The problem with that is, if you have darker skin, your body’s not going to absorb as much vitamin D as a person with lighter skin or if you have applied sunscreen correctly. So it seems the best way to get it is to take a supplement although the levels in the supplements are usually pretty low.

The synthesis of vitamin D. Source.
The synthesis of vitamin D. Source.

Vitamin D has been shown to decrease your risk of developing fractures as an older adult and may even help increase your muscular strength. There’s also been studies that show it can decrease your chances of developing heart disease if you get the right amount of vitamin D. it may help ward off some cancers although, studies are still being conducted on that area.

There is news that getting the right levels may help ward off the flu and the common cold by strengthening your immune system.

New studies and reports are being conducted daily about vitamin a and vitamin D. It’s interesting to find out just how getting the proper amount of vitamins can affect our health and wellbeing.

Vitamin D sources. Photo credit.
Vitamin D sources. Photo credit.

Deficiency: This like vitamin A, is rare if you live in developed countries although it can cause rickets in children. This keeps the long bones in their legs from developing properly and leads to bowed legs. In adults, deficiency can cause osteomalacia which is when the bones in your body lose their mineral content and makes them more susceptible to breaks.

Vitamins play a huge role into how our bodies function on a day to day basis. I hope these posts are helping you understand them better!


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