Normally, it is quite difficult to consume all the vitamins that our body needs on a daily basis only through food. This is why nutritionists advise taking multivitamin dietary supplements.

Everyone knows that vitamins are fundamental to stay healthy, however, most of us are unaware of the specific role that each vitamin plays in the organism.
In this article, we provide detailed information about the most important nutrients and vitamins and their sources. After reading this, you will notice the effects that vitamins, minerals and essential trace elements on your physical state, appearance and wellness.
Vitamins: the best health insurance
The most recent research has shown that a vitamin deficiency entails serious consequences for the organism, even worse than what was previously thought.

That is why most nutritionists advise taking a multivitamin/mineral tablet as the best “health insurance” to prevent any nutritional deficiency.
Do not leave your health to chance. The additional intake of vitamin and mineral supplements ensures that your body has all the nutrients it needs. That is why millions of people take them daily.
How long does it take to notice the effects of a multivitamin complex?
The time it takes to notice the effects of dietary vitamin supplements depends on the degree of their deficiency in the body. If you have a serious vitamin deficiency, it means that your body will have an increased demand and it will take longer to notice the effects.
In general, and depending on each case, the effects of vitamins can be experienced after 3 to 12 weeks.
Is it better to take individual supplements of each vitamin or a multivitamin complex?
The most advisable approach is to take a multivitamin complex since it will provide all the nutrients and vital substances that our body needs on a daily basis.
Moreover, depending on the individual needs, we may also take a specific vitamin apart from the multivitamin complex. If you are a smoker, for example, you should take an extra dose of vitamin C.
If you happen to have high cholesterol, you can add an Omega 3 capsule. If you want to keep your skin young and smooth for longer, taking OPC or amino acid capsules would be ideal.
However, you should always take a basic multivitamin and mineral complex to obtain the essential nutrients.
Classification of vitamins
We can classify vitamins as water-soluble and fat-soluble. The fact that they are soluble either in water or fats and oils will determine their absorption, storage in the body and excretion.
Water-soluble Vitamins (group B and C), Characteristics:
- They are those that dissolve in water. Their storage is minimal, which is why we must consume them on a daily basis.
- Absorption by passive diffusion.
- Urinary excretion: if there is an excess of water-soluble vitamins, they are excreted through the urine, which is why they do not entail a high level of toxicity.
Fat-soluble Vitamins (A, D, E, and K), Characteristics:
- They are those that dissolve in fats and oils. They are stored in the liver and fatty deposits.
- Absorption mediated by bile salts.
- Excretion through the feces.
Vitamin A, essential for our sight
Vitamin A is fat-soluble. Apart from its beneficial properties for the sight, vitamin A is also crucial for:
- A healthy and strong skin tissue and hair
- Strong defenses
- Healthy cells
- The maintenance of the blood
- A high libido
- Strong bones and teeth
- Healthy nails
- A good state of the mucosa
- An improved fertility
- As we have previously said, a good sight

Natural sources of vitamin A, foods that contain vitamin A:
Vitamin A can be found in the following foods: liver, red and orange fruits and vegetables, like carrots (beta-carotene), spinach, cheese, salmon, apricot (such as beta-carotene), papaya (beta-carotene), kale (beta-carotene) and egg yolk. Check which foods are rich in vitamins
Tip: If you work in front of a computer for a long period of time or you watch TV for hours, you should take a proper supply of vitamin A. The eyes have to regulate the stimuli received from light and darkness 10000 times. These light stimuli produce retinol rhodopsin, which requires a lot of vitamin A.
Vitamin B1, the energy vitamin
The group B vitamins are water soluble. Vitamin B1 is essential for:
- Improving the memory
- Having a greater mental acuity
- A quick healing of wounds
- Calming the nerves
- Metabolizing carbohydrates
- Encouraging a good digestion
- Keeping the heart healthy and strong
- Having more energy
Natural sources of vitamin B1, foods that contain vitamin B1:
Wheat germ, brewer's yeast, spirulina, whole grains, sunflower seeds, nuts, egg yolk, liver and buckwheat.
Tip: If you smoke, drink a lot of coffee or tea, suffer stress, or take the pill, you will need additional vitamin B1.
Vitamin B2, the spark of cells
Vitamin B2 is important for:
- Cell energy and breathing
- A healthy skin and hair
- The metabolism of fats, carbohydrates and proteins
- Improving the fertility
- A good sight
- The proper functioning of the thyroid gland
- Strong nails

Natural sources of vitamin B2, foods that contain vitamin B2:
Spirulina, almond, salmon, liver, egg yolk, cheese, milk, whole grains, and green leaf vegetables
Tip: If you undergo a lot of stress, you need a proper supply of vitamin B2. Most of the people undergo a lot of pressure, due to their work, certain personal situations, or specific problems. The vitamin B2 reserves are spent more quickly with the presence of stress hormones.
Vitamin B3 (niacin) to have nerves of steel
Vitamin B3 or niacin is important for:
- The production of sex hormones
- A proper condition of the nervous system
- A good digestion
- A healthy dermis
- A lower cholesterol
- A positive mental state
- A good oxygenation of the blood
Natural sources of vitamin B3, foods that contain vitamin B3:
Brewer’s yeast, peanuts, spirulina, salmon, tuna, chicken, and lamb.
Tip: The greatest enemy of vitamin B3 is sugar. If you eat sweets, chocolate, candies, gums, Coca-Cola and other sugary drinks regularly, you may have a vitamin B3 deficiency.
Vitamin B5 (pantothenic acid), helps to prevent grey hairs
Vitamin B5 is important for:
- Gaining energy and vitality
- Metabolizing fats, proteins and carbohydrates
- Producing hair pigments (to avoid grey hairs)
- Maintaining a healthy cartilage and connective tissue
- Healthy nerves
- Enhancing the ability to focus
Natural sources of vitamin B5, foods that contain vitamin B5:
Kidney, yeast, mushrooms, egg, avocado, salmon, broccoli and mung beans.
Tip: If you wake up and notice that your arms and legs are stiff, you are aching and you have difficulty to move, you could be suffering from a vitamin B5 deficiency.
Vitamin B6, the vitamin for athletes
Vitamin B6 is important for:
- The metabolism of proteins
- Coping with stress
- Maintaining stable sugar levels in the blood
- Encouraging vitality and wellness
- Improving the defenses
- Women during pregnancy and menopause
- The optimal functioning of the brain
Natural sources of vitamin B6, foods that contain vitamin B6:
Liver, salmon, sardines, bananas, avocados, dates, figs, walnuts, and soybeans.
Tip: The concentration of vitamin B6 in the body drops by 20%, just three hours after taking the contraceptive pill. This poses a serious risk for women who take the pill, since it could cause mental disorders. Vitamin B6 is also specially important during the menopause, since its use counteracts the loss of bone mass associated with menopause.

Vitamin B12, essential for muscle power
Vitamin B12 is important for:
- The bones
- Optimal levels of fat
- The brain and nervous system
- The formation of red cells
- Mental acuity
- Strength and muscle energy
- Cell division and the formation of DNA and RNA
- Coping with stress
- Having a positive mental state
Natural sources of vitamin B12, foods that contain vitamin B12:
Oysters, spirulina, herring, yolk of egg, dairy products, cabbage, meat and fish.
Tip: Vitamin B12 is found mainly in meat, and therefore its consumption can be a problem for vegetarians. Specially for vegetarians who do not eat milk or eggs. In these cases the intake of vitamin B12 dietary supplements is essential to provide adequate levels of vitamin B12 in the body.
Folic acid, the vitamin of well-being
Folic acid is important for:
- The formation of red cells
- Cell division and a healthy growth of the fetus
- Endorphins, the hormones of happiness
- Serotonin and norepinephrine
- People with stress
- A healthy and strong hair
- The gastrointestinal activity
Natural sources of folic acid, foods that contain folic acid:
Liver, wheat germ, brewer’s yeast, egg yolk, nuts, beets, asparagus, and vegetables.
Tip: It is advisable to take an additional amount of folic acid when we are planning to become pregnant, since it is necessary for the healthy development of the fetus, and it also helps to prevent premature birth, spontaneous abortion, and any deformity in the baby.
Biotin, the beauty vitamin
Biotin is important for:
- The skin
- Maintaining stable sugar levels
- A balanced metabolism of fats
- Making hair and nails grow healthily
- Healthy muscles
- Energy for the brain and nerve cells
Natural sources of biotin, foods that contain biotin:
Liver, spirulina, soybean, egg yolk, nuts, whole grains, brewer’s yeast, salmon, and brown rice.
Tip: Biotin is required for a silky and luminous dermis and to keep a strong and bright hair. Biotin has a stronger effect than many expensive cosmetic products. Biotin is also produced by intestinal bacteria. When the intestinal flora is damaged by nicotine, alcohol, or unhealthy foods, a biotin deficiency can occur in the body.
Vitamin C, the best cell protection
Vitamin C is water soluble and it is important for:
- Maintaining the body’s defenses
- Protecting us against the free radicals
- Tissue regeneration
- A firm and smooth skin
- The metabolism of calcium in the body
- Healthy gums
- Optimism and happiness
- Mental focus
- The elasticity of the blood vessels

Natural sources of vitamin C, foods that contain vitamin C
Fruits such as cherry, kiwi, lemons, oranges, grapefruit, raspberries. Also spinach, cabbage and peppers.
Tip: Taking vitamin C is specially important for people who smoke. We should take more vitamin C in order to counteract significant increase of the free radicals that comes with smoking. A vitamin C deficiency can cause premature wrinkles. Taking vitamin C can prevent and counteract these symptoms.
Vitamin D, the sunshine vitamin
Vitamin D is fat-soluble and it is important for:
- Keeping the bones strong
- Healthy and strong teeth
- Wellness and joy
- Strengthening the immune system
- Preventing osteoporosis
- Preventing colon and breast cancer
- When you have low levels of vitamin A
Discover how Vitamin D Affects the Sport Performance.
Natural sources of vitamin D, foods that contain vitamin D
Liver, cod liver oil, egg yolk, milk, dairy products, butter, yeast, vegetables, tuna, herring, sardines, and margarine. This vitamin is not found in fruits nor vegetables.
Tip: Sunbathing for half an hour is enough for the demands of the body. However, if we live in areas where there is little sunlight, we should take vitamin D supplements to avoid this deficiency.
Vitamin E, the vitamin that gives energy to the cells
Vitamin E is a fat-soluble vitamin and it is important for:
- Protecting the cells against the harmful effects of the free radicals
- The prevention of degenerative diseases
- A proper production of sperm
- Having a good blood flow
- A faster wound healing
- Helping to treat scarring problems
- People undergoing a lot of physical stress
- A healthy cardiovascular system

Natural sources of vitamin E, foods that contain vitamin E
Wheat germ oil, sunflower seeds, soy, almonds, spirulina, dried fruit, pepper, salmon, and flax seeds.
Tip: Athletes and sportspeople need more vitamin E. Vitamin E helps to transport enough oxygen to the muscles, which helps to increase the strength and physical performance. Oxygen is very important for the muscles, since it helps to prevent the harmful effects of the free radicals.
Scheme of the vitamins
The term vitamin was coined by doctor Funk, and it means “amines of life”; even though they do not have an amine function, there is no life without vitamins. The main characteristic that separates vitamins from minerals is their organic nature when compared to the inorganic nature of the minerals. The function of vitamins consists on regulating many of the chemical processes that take place in the organism, which means that each vitamin performs a specific task. The organism cannot produce most of the vitamins, which is why it is so important to follow a balanced diet so that we do not trigger any deficiency, even though the needs of vitamins are minimal, a lack can have catastrophical consequences for the body.

Vitamins are mainly divided in to groups:
- Water soluble
- Fat soluble
The water soluble ones are the 8 vitamins from the B group and vitamin C. They must be consumed daily, since the organism has a very reduced ability to store them, so that the excess is eliminated through the urine.
The fat soluble vitamins (A, D, E, and K) are soluble in a fatty substance and they are stored in the organism, specially in the liver, so that we can have some kind of reserve in otder to face a deficiency; however, you should not consume more than what you need, since an excess (10 times the recommended amount) or hypervitaminosis can trigger serious health problems.
Water-soluble Vitamins
Vitamin C (ascorbic acid)
Functions
Antioxidant, O2 and H2 transporter, coenzyme in the synthesis of collagen, coenzyme in the synthesis of noradrenaline, iron (Fe) absorption. It is also involved in the metabolism of lipids and certain amino acids.
Deficiency
Scurvy: Inflammation of the gums, possible weakening and fall of teeth, dry mouth and eyes, joint pain, hair loss, and even death.
Excess
It does not produce toxic effects if the dose does not exceed 1g/day. It can trigger diarrhea, kidney stones and an iron overdose if it is higher.
Sources
Kiwi, guayaba, red pepper, black currant, parsley, Brussels sprouts, lemon, cauliflower, potatos, spinach, strawberries, oranges…
RDA
90mg / 75mg
Vitamin B1 (thiamine)
Functions
Transferring aldehyde groups through oxidative decarboxylation, it stimulates the CH metabolism and the nervous function of the CNS.
Deficiency
Loss of appetite, apathy, depression, numbness in legs and arms, beriberi…
Excess
It does not have toxic effects.
Sources
Whole grain products, whole eggs, nuts, beef or pork meat, lentils, guts, garlics…
RDA
1.2mg / 1.1mg
Vitamin B2 (riboflavin)
Functions
It forms coenzymes with FAD and FMA, stimulates the oxidation of fats and CH, the health of the skin, nails, and hair.
Deficiency
Lack of energy, nervousness, depression, eye, mouth, and skin disorders…
Excess
It does not have toxic effects.
Sources
Meat, fish, protein-rich foods in general; nuts, whole cereals and legumes.
RDA
1.3mg / 1.1mg
Vitamin B3 (niacin)
Functions
It forms coenzymes with NAD and NADP, stimulates the anaerobic glycolisis, encourages the oxidation of fats and CH, the lipolisis and the health of the skin, nails, and hair.
Deficiency
“Pellagra” or the 3 Ds syndrome (dementia, dermatitis and diarrhea).
Excess
Headache, nausea, irritated skin, hepatic damage, inhibition of the lipolisis…
Sources
Meat, guts, fish, whole cereals, cheese, eggs and foods rich in tryptophan.
RDA
16mg / 14mg
Vitamin B5 (pantothenic)
Functions
It is an essential component of the CoA in the transfer of acyl groups (CH and fats oxidation; lipolisis).
Deficiency
Nausea, fatigue, depression and loss of appetite.
Excess
It does not have toxic effects.
Sources
Guts, meat, dairy products, eggs, whole cereals, legumes, vegetables…
RDA
5mg
Vitamin B6 (pyridoxine)
Functions
It forms coenzymes with pyridoxal phosphate, stimulates the protein metabolism, the formation of hemoglobin and red cells, the glycogenolysis and glyconeogensis.
Deficiency
Irritability, convulsions, anemia, dermatitis, injuries in the oral mucosa…
Excess
Loss of nervous sensitivity and abnormal walking.
Sources
Whole cereals, walnuts, nuts, bananas, egg yolk, potatos, vegetables, meat and fish.
RDA
1.3µg
Vitamin B8 (biotin)
Functions
It forms coenzymes to transfer C02 and stimulates the metabolism of carbs, fats and proteins.
Deficiency
Nausea, fatigue, and scratches on the skin.
Excess
It does not have toxic effects.
Sources
Meat, milk, egg yolk, whole cereals, legumes, vegetables…
RDA
30 µg
Vitamin B10 (Para-aminobenzoic acid)
Functions
It forms coenzymes with DNA and RNA and it is involved in the formation of hemoglobin, red and white cells, and in the synthesis of purines and amino acids.
Deficiency
Anemia, fatigue, diarrhea, digestive disorders, infections, fetal problems during pregnancy…
Excess
It does not have toxic effects.
Sources
Green vegetables, brewer’s yeast, whole cereals, nuts, meats and potatos.
RDA
400µg
Vitamin B12 (cobalamin)
Functions
It forms coenzymes with DNA and RNA, and it is involved in the formation of red and white cells and in the regeneration of the tissues.
Deficiency
Anemia, fatigue, nerve damage, paralysis and infections.
Excess
It does not have toxic effects.
Sources
Meat, fish, guts, eggs, dairy products, seafood, cereals…
RDA
2.4 µg
Fat-soluble Vitamins
Vitamin A (retinol)
Functions
Eye pigmentation, it keeps the epithelial cells hydrated, antioxidant effect, provides stability to the cell membranes.
Deficiency
Night blindness, dryness of the skin and eyes. It can delay growth in children.
Excess
Nausea, headaches, fatigue, hepatic damage, joint pain, dryness of the skin, alterations of the fetus during pregnancy…
Sources
Animal guts, carrots, spinach, parsley, butter, sweet potatos, soy oil, tuna, cheese, eggs, vegetables…
RDA
0.9mg / 0.7mg
Vitamin D (calciferol)
Functions
It regulates the phospho-calcium metabolism: it works together with calcitonin (opposite to PTH) and improves the absorption of Ca and P in the intestines.
Deficiency
Decalcification of the bones, dental caries and even rickets.
Excess
Nausea, loss of appetite, irritability, joint pain, calcification of the soft tissues (kidneys).
Sources
Liver, fish, eggs, oils, margarine, milk, yogurt, and sunbathing.
RDA
5 µg
Vitamin E (tocopherol)
Functions
Antioxidant effect, it protects the cell membranes and improves the synthesis of the “hemo” group.
Deficiency
Muscle alterations, damage to the retina and inhibiting growth in children.
Excess
Headache, fatigue, diarrhea.
Sources
Vegetable and seed oils, liver, eggs, soy, wheat germ, nuts, coconut…
RDA
15 mg
Vitamin K (menadione)
Functions
Anti-coagulant effect.
Deficiency
Hemorraghes and bleeding.
Excess
Thrombosis and vomits.
Sources
Liver, eggs, green leaf vegetables, cheese, butter…
RDA
120µg / 90 µg
Excess of Vitamins
We are used to hear how bad a lack of vitamins can be for our health. Nobody would dare to deny the importance of these nutrients for the proper functioning of the organism. In fact, vitamins are catalysts in all our physiological processes, and their deficit – clinically known as avitaminosis or hypovitaminosis – can increase the chances of suffering a disease.
Due to this, many people use vitamin complexes without any medical prescription, ignoring that an excessive accumulation of a vitamin – or hypervitaminosis – can be as harmful as its lack. An excess of certain nutrients in our system is capable of triggering an organic intoxication with different consequences for our health.
But not all vitamins have harmful effects when there is an excess. Many of them (like vitamin C), are easily excreted through the urine without any issue. Others, like vitamin A and D, can be accumulated an produce an organic imbalance with different consequences.
Excess of vitamin A
While consuming vitamin A in reasonable amounts is fundamental for the proper functioning of the sight and tissues, an excess increases the risk of suffering osteoporosis, blurry sight, loss of weight, and lack of appetite. The symptoms of an intoxication due to an excess of this nutrient can be:
- Cephalea
- Vomits
- Bone pain
- Blurry sight
- Irritability
- Intense tiredness
- Somnolence
- Hair loss
Vitamin A is naturally found in many foods, both in those of vegetable origin (like carrots, kale, sweet potato, spinach, broccoli, cabbage, pumpkin) as well as foods of animal origin (like eggs or milk). It is advisable to increase the consumption of these foods if there is a lack of this vitamin, even though it is quite hard to do so just through foods.
Excess of vitamin D
While vitamin D is involved in the absorption of calcium, an excess produces just the same effects of an excess of calcium:
- Muscle weakness
- Tiredness
- Cephalea
- Nausea
- Constipation
- Loss of appetite (anorexia)
- Dehydration
- Fatigue
- Irritability
Before using supplements to treat a lack of vitamin D you can try and consume products that are rich in this nutrient. A boiled egg, cow liver, sun-dried mushrooms, or some fish oils have good quantities of vitamin D. There are many products that are also enhanced with vitamin D like dairy products, cereals, or bread. Regardless, the best source of vitamin D is the Sun. Sunbathing for around 30 minutes daily is enough for our body to produce this vitamin.

Adjust the consumption of vitamins
Most of the time, the treatment for this type of disorders just involves giving up the nutrient that is producing the imbalance. It is necessary to point out that developing a hypervitaminosis solely from consuming foods is extremely hard.
Normally, it happens as a result of an excessive consumption of synthetic supplements without professional supervision. In this sense, information is essential to prevent this. A varied diet that includes at least five portions of fruit and vegetables daily should be enough to meet the nutritional requirements of most people. So, the use of vitamin supplements is reserved to those who, for some reason, cannot fix the deficiency through a proper diet.
However, you should consult your doctor if you suspect that your organism lacks vitamins even if you follow a healthy diet. Only a professional is capable of determining when certain nutrient values are lower than they should. In this case, they will advise supplements according to the personal circumstances of the patients, their state of health, and the nutritional needs to guarantee a proper physiological functioning.