The role of vitamins in the body: what are they for?

Although vitamins do not have energy value, these substances remain essential for the body. They are necessary for various physiological processes: the harmonious functioning of the body depends on the presence of these vitamins. However, almost all vitamins cannot be synthesized by the body. While some may be, this production remains insufficient. Therefore, their intake through food is essential. A look back at the different pathways used by our body to meet needs:

• Our body is not capable of synthesizing them: we find the majority of vitamins, that is to say vitamins A, K1, E, B1, B2, B5, B6, B9 and C. Only food can cover our needs. Their origins are exogenous.

• Our body knows how to synthesize them, but not in sufficient quantity: some vitamins are biosynthesized by the intestinal microbiota such as vitamins K2, B8 and B12. Vitamin B3, on the other hand, is converted from tryptophan (an amino acid). However, these productions are tiny and uncertain. We consider them to be worthless: food must cover our needs. Their origins are mostly exogenous and a minority endogenous.

• Our body knows how to synthesize it: this part only concerns vitamin D since our supply route mainly comes from our own production, food will supplement it. In summary, the synthesis of vitamin D is initiated mainly in the skin: UV-B rays coupled with 7-dehydrocholesterol make it possible to produce pre-vitamin D3 which will give, following hepatic and renal metabolism, the vitamin D active that we know. The fact remains that it is essential to ensure dietary intake of vitamin D because our production depends on many factors (latitudes, place of life, seasons, skin pigmentation, use of cosmetics, etc.). The origin of vitamin D is mainly endogenous and in the minority exogenous.

Also called retinol, Vitamin A is a vitamin found in food in its main form of retinol or in the form of provitamin A, better known as beta-carotene.

The body being a magnificent machine, vitamin A can largely be stored in the liver. Small bonus of beta-carotene, it is also considered an excellent anti-oxidant. It will thus allow the body to fight against oxidative stress.

Plays a role in the body to...

• the mechanism of vision
• the regulation of gene expression at the level of embryonic development, cell growth and tissue renewal
• the antioxidant effect
• regulation of the immune system
• regulation of the insulin signal, repression of adipogenesis

Its main food sources are…

Acai powder, moringa, dried apricots, offal, cold meats, herring, carrots and vegetables in general.

Recommended nutritional intakes (anc)

• 800 µg RE*/day for men
• 600 µg RE*/day for women
• 350 to 800 µg RE*/day for children depending on age and sex

*Total vitamin A intakes were estimated in “retinol equivalent” (RE) according to the following equivalence: 1 RE = 1 µg of retinol = 6 µg of β-carotene. For example, you will find around 10,000 µg of beta-carotene in 100 g of cooked sweet potato or around 1,000 µg in 100 g of raw apricots.

Learn more about: vitamin A and the beta carotene

Vitamin D, or cholecalciferol, plays a major role in bone metabolism! How ? By stimulating the intestinal absorption of the famous calcium while reducing its elimination through the urine.

Besides this, vitamin D is involved in cell differentiation and in the modulation of the immune system.

Note that there are two types of vitamin D, the D2 or ergocalciferol form produced by plants and the D3 or cholecalciferol form which is of animal origin. It can also be produced by the skin under the effect of UVB

 Plays a role in the body to...

• maintaining theframework and muscle functions
• the functioning of the immune system
• increased calcium absorption
• mood regulation
• prevention of certain cancers

 Its main food sources are…

Oily fish, animal livers, egg yolk, cheese, butter or cocoa.

 Recommended nutritional intakes (anc)

• 5 to 10 mcg/day for adults
• 10 to 15 µg/day for the elderly
• 5 to 25 µg/day for children depending on age

So, when the sun is scarce, get your vitamin D from food.

Vitamin E is, like vitamin C, recognized for its antioxidant properties: it neutralizes free radicals. This is also why it is often used as a preservative, whether in cosmetics or in the food industry. It is actually a family of eight forms, including tocopherols and tocotrienols.

Plays a role in the body to...

• the effect antioxidant
• protection of the cardiovascular system

Its main food sources are…

Oils, oilseed products such as walnuts, hazelnuts, almonds. But also seeds like hemp, spices like paprika or oregano and vegetables and fruits, like broccoli or tomatoes.

Recommended nutritional intakes (anc)

• 12 mg/day for men
• 12 mg/day for women
• 4 to 11 mg/day for children depending on age and sex

To easily meet your vitamin E needs, you should know that 100 g of wheat germ oil contains approximately 150 mg of vitamin E, it is the oil richest in vitamin E! You still find it in quantity in avocado, almond or safflower oils at a rate of 30 to 40 mg per 100 g of oil. So don’t hesitate to season your salads by alternating the oils!

Vitamin K is an essential vitamin to ensure proper blood clotting. It also promotes the fixation of calcium, we can say that its action is complementary to that of vitamin E.

It can certainly be provided by food, but it is also synthesized by our intestinal flora: bacteria. It is found in two major forms: phylloquinone or vitamin K1 mainly provided by food and menaquinone or vitamin K2 mainly synthesized by bacteria. It is therefore found in fermented foods such as yogurts for example.

Plays a role in the body to...

• there blood clotting
• bone metabolism

Its main food sources are…

Moringa, aromatic herbs, cabbage, spinach, salads, yogurts, cheeses or soybean oil.

Recommended nutritional intakes (anc)

• 45 to 65 µg/d for adults
• 70 µg/d for people over 75 years old
• 15 to 40 µg/d for children depending on age

For example, 100 g of cooked broccoli provides 110 µg of vitamin K1 and cooked spinach triumphs with almost 500 µg of vitamin K provided for only 100 g.

Vitamin B1, better known by the scientific name thiamine, has a vital role in the body. It participates in the metabolism of glucose, that is to say in its transformation into energy. It is also involved in amino acid metabolism and plays a key role in the transmission of nerve messages.

Plays a role in the body to...

• tHE energy metabolism
• energy production (assimilation of carbohydrates, lipids and proteins)
• the nervous system (transmission of nerve impulses, memory, reasoning and concentration)

Its main food sources are…

Royal jelly, whole grains, meats (especially pork), vegetables, pulses, fruits, brewer's yeast, oysters, seafood.

Recommended nutritional intakes (anc)

• 1.3 mg/day for men
• 1.1 mg/day for women
• 0.2 to 1.3 mg/day for children depending on age and sex

For example, you will find around 11.6 mg of thiamine in 100 g of nutritional yeast, 2.4 mg per 100 g of dried spirulina or even 1.3 mg per 100 g of wheat germ.

Also called riboflavin, vitamin B2 is involved in the synthesis of two coenzymes, FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide). The latter are themselves involved in our energy metabolism and more particularly in the production of energy and the use of nutrients wisely. They also help reduce oxidative stress in our body.

Plays a role in the body to...

• tHE energy metabolism (proteins, lipids, carbohydrates)
• the functioning of our nervous system
• the phenomenon of vision (promotes sight in semi-darkness)
• the health of the skin and mucous membranes

Its main food sources are…

Royal jelly, offal, aromatic herbs, meats, dried vegetables, brewer's yeast, oysters, seafood.

Recommended nutritional intakes (anc)

• 1.3 mg/day for men
• 1.1 mg/day for women
• 0.2 to 1.3 mg/day for children depending on age and sex

For example, you will find around 11.6 mg of thiamine in 100 g of nutritional yeast, 2.4 mg per 100 g of dried spirulina or even 1.3 mg per 100 g of wheat germ.

Vitamin B3 exists in two forms: nicotinic acid, also called niacin, and nicotinamide, also known as vitamin PP. These are elements necessary for the synthesis of two coenzymes, NAD+ and NADP+, involved in particular in the transformation of nutrients into energy. Vitamin B3 also seems involved in the synthesis of neurotransmitters essential for well-being: serotonin and dopamine.

Plays a role in the body to...

• tHE energy metabolism
• the functioning of the nervous system
• the synthesis of sex hormones, insulin and hemoglobin
• keratin synthesis

Its main food sources are…

Brewer's yeast, offal, mushrooms, peanuts, fish...

Recommended nutritional intakes (anc)

• 14 mg/d for men
• 11 mg/day for women
• 3 to 14 mg/day for children depending on age and sex

For example, you will find around 19 mg of vitamin B3 in 100 g of potato chips, 18 mg per 100 g of nutritional yeast or even 14 mg per 100 g of peanut butter (but that does not mean that it must be abused).

Vitamin B5 is also known as pantothenic acid. It is found generally in all living organisms, hence its name which comes from the Greek word “pantos” and which means “everywhere”.
Like other vitamins, it is also involved in the energy metabolism of our cells. Once in the body, vitamin B5 is transformed into coenzyme A which acts on the nervous system and the adrenal glands.

Plays a role in the body to...

• tHE energy metabolism
• oxygen transport
• la synthesis fatty acids, cholesterol, and through this sexual hormones
• intellectual performance

Its main food sources are…

Brewer's yeast, offal, eggs, whole grains, peanuts, mushrooms, soy, cashew nuts, royal jelly, spirulina, cheeses, spices...

Recommended nutritional intakes (anc)

• 5 mg/d for men
• 5 mg/day for women
• 2 to 5 mg/day for children depending on age and sex

For example, you will find around 21.9 mg of vitamin B5 in 100 g of dried shiitake, 7 mg per 100 g of sunflower seeds or even 6 mg per 100 g of animal liver.

Vitamin B6, also called pyridoxine, is particularly involved in the body's general metabolism. Vitamin B6 from animal sources is much more sensitive to preparation methods (freezing, canning or cooking) than vitamin B6 from plant sources.

Plays a role in the body to...

• tHE energy metabolism (proteins and glycogen in particular)
• the functioning of the nervous system (synthesis of chemical messengers)
• hormonal regulation
• reducing fatigue
• red blood cell production

Its main food sources are…

Royal jelly, brewer's yeast, wheat germ, liver, banana, nuts, legumes, eggs, aromatic herbs...

Recommended nutritional intakes (anc)

• 1.8 mg/day for men
• 1.5 mg/day for women
• 0.6 to 1.6 mg/day for children depending on age and sex

You will find around 4 mg of vitamin B6 in 100 g of rice bran, 2.5 mg per 100 g of dried mint or even 1.4 mg per 100 g of roasted pistachios.

Biotin, or vitamin B8, plays an essential role in the production of our energy. Chemically, it can come in eight different forms but only D-biotin, of natural origin, is active. Namely that it is provided both by food, but also by our intestinal flora. It can also be called vitamin H.

Plays a role in the body to...

• tHE energy metabolism
• the health of mucous membranes, hair and skin
• the functioning of the nervous system
• the synthesis of macronutrients (carbohydrates and lipids)

Its main food sources are…

Egg yolks, liver, royal jelly, nuts, mushrooms, brewer's yeast...

Recommended nutritional intakes (anc)

• 50 mcg/day for men
• 50 to 60 µg/day for women
• 6 to 50 µg/day for children depending on age and sex

For example, you will find around 200 µg of vitamin B8 in 100 g of chicken liver, 50 µg per 100 g of almonds or even 16 µg per 100 g of hard-boiled eggs.

Vitamin B9, better known as folic acid or the famous folates, is essential for the synthesis of DNA but also of amino acids. In addition, it plays an important role in the synthesis of chemical mediators involved in brain functioning. This vitamin is essential at the start of pregnancy for the proper development of the fetal nervous system. It also participates in the production of our red and white blood cells, the proper functioning of the immune system and the cellular renewal of the skin and mucous membranes.

Plays a role in the body to...

• there construction of genetic material (DNA and RNA) and the fetal development
• the functioning of the immune and nervous system
• hematopoiesis (formation of blood cells)
• cardiovascular prevention
• amino acid synthesis

Its main food sources are…

Pomegranate and hemp seeds, brewer's yeast, wheat germ, liver, nuts, dried vegetables, fruits and vegetables in general...

Recommended nutritional intakes (anc)

• 330 µg/d for men
• 300 to 400 µg/d for women
• 150 to 250 µg/day for children depending on age and sex

The maximum dose recommended by the EFSA via food is 1 mg/day. Beyond this dose an increased risk of developing certain diseases seems to exist in the long term. For example, you will find more than 2000 µg of vitamin B9 in 100 g of baker's yeast, around 600 µg per 100 g of animal liver or even 200 µg per 100 g of raw spinach.

Vitamin B12 or cobalamin, is involved in the energy metabolism mainly of lipids and amino acids. Just like vitamin B9, it will participate in the development of cells. Its association with vitamins B9 and B6 is very important and beneficial for the body.

Plays a role in the body to...

• energy metabolism
• the functioning of the immune system
• the functioning of the nervous system (synthesis of neurotransmitters)
• reduction of fatigue and depressive states
• tHE cell development

Its main food sources are…

Meats, fish, eggs, seafood, shellfish and offal.

Recommended nutritional intakes (anc)

• 2.4 µg/d for men
• 2.4 to 2.8 µg/day for women
• 0.8 to 2.3 µg/d for children depending on age and sex

For example, you will find around 100 µg of vitamin B12 in 100 g of animal liver, around 30 µg per 100 g of oysters or even 5 µg per 100 g of egg yolks.