All about Vitamins “ADEK”

Christelle Awkar
Registered Dietitian
USJ and Hotel Dieu Hospital
Awareness Program Coordinator At Dialeb
Clinics At Antelias Medical Center And Abyad Medical Center, Tripoli
Speaker In The Critical Care
King Fahd Military Medical Complex

A vitamin is an organic compound and a vital nutrient that an organism requires in limited amounts. There are fat-soluble and water-soluble vitamins.

Fat-soluble vitamins are the  vitamins A, D, E and K. They are stored in the fat tissues of our bodies, as well as the liver and absorbed with the help of fats.

Water-soluble vitamins are  vitamin  C and all the B vitamins. They are not stored in the body and are expelled through urine.

Let us take a look at the different types of fat soluble vitamins ADEK!



Chemical names: Retinol-Retinal-Retinoic acid - four carotenoids including beta carotene.

Function: It helps form and maintain healthy teeth, skeletal and soft tissue, mucus membranes, and skin. It promotes good vision, especially in low light. Adding to this, carotenoids, dark-colored pigments found in plant foods that can turn into a form of vitamin A, are antioxidants.

Sources: Vitamin A comes from animal sources, such as eggs, meat, fortified skim milk, cheese, butter and liver.

Carotenoids (provitamin A) come from vegetable sources especially  orange and yellow ones (carrot, apricot, melon, sweet potato), most dark green leafy vegetables and broccoli.


·         Adult men: 3000 IU/Day

·         Adult women: 2300 IU /Day

Deficiency: It may cause night-blindness and keratomalacia (eye disorder that results in a dry cornea)

Stability: Partially stable when exposed to light and air but stable in the heat


Chemical names: Ergocalciferol-Cholecalciferol

Function:  It is important for the regulation of Calcium and Phosphorus absorption, maintenance of healthy bones and teeth. Also, it  may be protective against cancer, type 1 diabetes and multiple sclerosis.


·         Adult (1-70 yeas): 600UI

·         Adult (> 70 years): 800 IU


Deficiency: It is common, especially in the elderly, infants, people with dark skin and people living at higher latitudes or who get little sun exposure.

It may cause rickets and osteomalacia.


Sources:  Sunlight exposure is the primary source of vitamin D. A sensible sun exposure on bare skin for 10 minutes allows the body to produce sufficient vitamin D. People who have dark skin need to be exposed more.

Food sources: fatty fish, eggs, fortified skim milk, liver and mushrooms.

Stability:  Stable in the air, light and heat



Chemical names:  Tocopherols- Tocotrienol

Function: It is an antioxidant protecting body tissue from damage caused by substances called free radicals, which can harm cells, tissues and organs. Thus, it plays a role in slowing aging process.


Adults (>14 years):  22.5 IU


Deficiency:  It is very rare. It can cause mild hemolytic anemia in newborns

Sources: Kiwi, avocado, egg, milk, nuts, leafy green vegetables, unheated vegetable oils and whole grains.

Stability: Stable in the air and light but susceptible to the heat



Chemical names:

§  Phylloquinone or vitamin K1(found in plants)

§  Menaquinone or Vitamin K2 (formed  by bacteria in the large intestine).

§  Vitamins K3,K4,K5 (synthetic forms)

Function: It plays a major role in blood clotting, bone metabolism and the regulation of blood calcium levels.


·         Adults men  122 mcg

·         Adults women :  138 mcg

Deficiency: It is rare. It includes prolonged clotting time and excessive bleeding.

Sources:  Leafy green vegetables like kale and swiss chard, parsley, avocado, kiwi.

Stability: Stable in the air and heat but susceptible to light

Bear in mind that vitamins are available in supplements but it is best to obtain any vitamin or mineral through food first. It is not the individual vitamin or mineral alone that makes certain foods an important part of our diet but the synergy of nutrients working together.


*The recommended dietary allowance RDA is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people

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