Fat-soluble vitamins

Vitamins are vital to our bodies and are often referred to as the first building blocks of our health. There are 13 vitamins and they are involved in many physiological processes.

They are divided into two categories according to their chemical nature. The so-called water-soluble vitamins that occur in the bloodstream, with the 8 B vitamins and vitamin C. And the fat-soluble vitamins, vitamins A, D, E and K. Our body is able to store these vitamins in the liver and our fatty tissue.

In this article we will introduce you to the vitamins, focusing on the fat-soluble vitamins A, D, K and E: their benefits, the intakes necessary for our health, the risks of deficiencies or deficiencies and their food sources.

What are vitamins?

Vitamins are organic elements that are essential for the proper functioning of our body. They have the peculiarity that they are necessary in very small quantities to ensure our health.
Overall, we need to get vitamins through food since our body is unable to produce them itself, with the exception of two of them, vitamins D and K.

Vitamins have no energy value, which means they contain no calories. And for each of them there are nutritional reference values ​​that indicate the target daily amount for our health (RNP: Nutritional Reference for the Population or AS: Satisfactory Intakes).

The functions of vitamins in the body

Vitamins are essential for the proper functioning of several physiological mechanisms. We can divide the benefits of vitamins for our body into two categories:

• A structural role : Vitamins are essential for various structural elements of our body, such as the growth and health of our bones, various cellular activities, the formation of our tissues and skin…
• An operational role : In addition to their involvement in the structure of our body, vitamins ensure the functioning of numerous systems such as the nervous system, the muscles, the immune system or even the cardiac system. They are also involved in DNA synthesis, vision, digestion, etc.

Fat-soluble vitamins: Vitamin A

Vitamin A is also popularly called retinol. It has a precursor, provitamin A (pro-retinol), which is found in the large family of carotenoids, of which beta-carotene is the best known.

The functions of vitamin A:
immune system : Vitamin A contributes to the normal functioning of the immune system.
vision : Vitamin A contributes to maintaining normal vision.
Cell activity : Vitamin A plays a role in the process of cell specialization.
Iron metabolism : Vitamin A contributes to normal iron metabolism.
Health of the skin and mucous membranes : Vitamin A contributes to the maintenance of normal skin. Vitamin A contributes to the maintenance of normal mucous membranes.

The risks of vitamin A deficiency:
Intrauterine and postnatal growth retardation, congenital malformations, dry eyes, loss of twilight vision.

Reference intake levels of vitamin A:
Value: RNP (Nutritional Reference for the Population)
Adult male: 580 mcg/day
Adult women: 490 mcg/day
Pregnant women: 540 mcg/day
Breastfeeding woman: 1,020 mcg/day

Sources of Vitamin A:
Foods of animal origin:
Cod liver oil (30,000 μg / 100 g), offal and liver (14,500 to 4,000 μg / 100 g), fish (1,100 to 285 μg / 100 g), butter (800 μg / 100 g), crème fraîche (390 μg / 100 g), cheese (265 to 350 μg / 100 g), eggs (230 to 450 μg / 100 g).

Plant-based foods:
Sweet potato (10,500 μg / 100 g), carrot (7,200 μg / 100 g), pumpkin (6,900 μg / 100 g), salads (5,300 μg / 100 g), spinach (4,000 μg / 100 g), apricot (2,100 μg / 100 g), melon (1,900 μg / 100 g) 100 g), tomato (1,600 μg / 100 g), red pepper (1,500 μg / 100 g), mango (1,200 μg / 100 g).

Fat-soluble vitamins: Vitamin D

Vitamin D is one of the two vitamins that our body can synthesize. It has hormonal activity and comes in two forms: form D2 called ergocalciferol and of plant origin and form D3 called cholecalciferol, mainly of animal origin. Exposure to sunlight (15 to 20 minutes is enough) allows the synthesis of vitamin D3 in the epidermis of our skin.

The functions of vitamin D:
Bone health: Vitamin D contributes to the maintenance of normal bones. Vitamin D contributes to normal blood calcium levels (blood calcium).
Cell activity: Vitamin D plays a role in cell division.
Muscles: Vitamin D contributes to maintaining normal muscle function.
Immune system: Vitamin D contributes to the normal functioning of the immune system.
Pregnancy and children: Vitamin D is necessary for normal growth and bone development in children.

The risks of vitamin D deficiency:
A vitamin D deficiency reduces bone density, weakens our skeleton and can potentially promote osteoporosis. Deficiency leads to a change in the process of bone mineralization, leading to rickets in children and osteomalacia in adults.

Reference intake levels of vitamin D:
Value: AS (Satisfactory Recording)
Adult male: 15 mcg/day
Adult women: 15 mcg/day
Pregnant women: 15 mcg/day
Breastfeeding woman: 15 mcg/day

Sources of Vitamin D:
Foods of animal origin:
Cod liver oil (250 μg/100 g), cod liver oil (54 μg/100 g), fish eggs (cod and salmon – 27 μg/100 g), herring (22 μg/100 g), fish (halibut, tilapia, trout, swordfish – between 21 and 15 μg/100 g).

Plant-based foods:
Fats of vegetable origin such as margarine (7.5 μg / 100 g).

Fat-soluble vitamins: Vitamin E

Vitamin E brings together several compounds with antioxidant properties: tocopherols (alpha, beta, delta and gamma) and tocotrienols (alpha, beta, delta and gamma). Thanks to its antioxidant action, it contributes to the maintenance of the body by limiting aging.

The functions of vitamin E:
Cell activity: Vitamin E helps protect cells from oxidative stress. This makes it interesting for maintaining cognitive functions, but also for maintaining muscle mass and regeneration.

The risks of vitamin E deficiency:
A deficiency of vitamin E can lead to neurological degeneration.

Reference intake levels of vitamin E:
Value: AS (Satisfactory Recording)
Adult male: 10 mg/day
Adult female: 9 mg/day
Pregnant women: 9 mg / day
Breastfeeding woman: 9 mg/day

Sources of Vitamin E:
Plant-based foods:
Wheat germ oil (149 mg/100 g), sunflower oil (57 mg/100 g), avocado oil (45 mg/100 g), fats of vegetable origin such as margarine (23 mg/100 g), olive oil (22 mg/100 g).

Foods of animal origin:
Cod liver oil (30 mg / 100 g).

Fat-soluble vitamins: Vitamin K

In humans, vitamin K includes vitamins K1 (phylloquinone) and K2 (menaquinone).

The different roles and functions of vitamin K:
Cell activity : Vitamin K (K1) contributes to normal blood clotting.
Bone health: Vitamin K (K2) contributes to the maintenance of normal bones.

The risks of vitamin K deficiency:
Diet-related vitamin K deficiency is rare and can lead to poorer absorption of lipids.

Reference intake of vitamin K:
Value: AS (Satisfactory Intake) for vitamin K1 (there is little data on K2 requirements).
Adult male: 79 mcg/day
Adult women: 79 mcg/day
Pregnant women: 79 µg/day
Breastfeeding woman: 79 mcg/day

Sources of Vitamin K:
Vitamin K1 – foods of plant origin:
Dried herbs (basil, sage, thyme, parsley – 1,200 to 1,700 μg/day), kale (820 μg/day), spinach (500 μg/day), soybean oil (360 μg/day), Brussels sprouts (200 μg/day), broccoli (180 μg/day).

Vitamin K2 – foods of animal origin:
Goose liver (360 μg / 100 g), chicken (34 μg / 100 g), raw egg yolk (32 μg / 100 g),
Butter (15 µg / 100 g).

Other vitamins are also important for our health, these are water-soluble vitamins, vitamins of the B group (B1, B2, B3, B5, B6, B8, B9, B12) and vitamin C. They are absorbed in the small intestine and are not stored in our body. Through the blood circulation they reach their places of action, where they are used directly.
A varied diet, rich in fruits and vegetables, with adequate protein and grain intake, helps meet our varying vitamin needs.