Vitamins D/K

Vitamins A, D and K, along with E which is discussed in detail in the Vitamin E category, are fat soluble vitamins, which dissolve in fat, or lipids, unlike water soluble ones that dissolve in water.

Fat soluble vitamins follow the same absorption and blood transport methods as lipids, and can deposit in certain organs and tissues, particularly in the liver, in muscles and in adipose tissue.

While the quantities of vitamins A and D stored in the body are used as reserves to cover any subsequent demands, vitamin K is generally rapidly metabolised, and its excess is eliminated.

However, only in cases of long-term intake of high dosages, often due to long cycles of pharmacological therapies, these nutrients might be toxic for the body.

Vitamin A (for growth)
Function

Stimulates growth and resistance to infections. Protects skin and mucous tissue. Stimulates the formation of retinal pigments and cellular growth.
Sources
Liver, butter, dairy, egg yolk, cod liver oil.
Alterations caused by its deficiency
Night blindness, low resistance to infections, desquamation of skin, poor growth.

Vitamin D (antirachitic)
Function

Stimulates growth. Favours intestinal absorption of calcium, participates in the formation of bones and teeth.
Sources
Egg yolk, milk, cod liver oil.
Alterations caused by its deficiency
Rachitism and defective bone formation.

Vitamin K (anti-haemorrhagic)
Function

Favours growth. Essential to maintain blood coagulation factors in the liver.
Sources
Vegetables, wheat germ. Produced by intestinal flora.
Alterations caused by its deficiency
Haemorrhagic symptoms.