In short:
- Vitamins and minerals are essential micronutrients that the body mostly cannot synthesize in sufficient amounts on its own.
- The most common deficiencies in Europe are vitamin D, magnesium and iron.
- A varied diet covers most needs, but pregnant women, older adults and vegans often need supplements.
- An excess of fat-soluble vitamins (A, D, E, K) can accumulate and harm your health — do not exceed the recommended daily amounts.
Vitamins and minerals are essential micronutrients that the body mostly cannot synthesize on its own. Unlike the macronutrients — protein, fat and carbohydrates — the body needs them only in small amounts, but serious health problems arise when they are lacking.
What are vitamins and minerals, and why are they important for health?
Vitamins and minerals belong to the group of micronutrients and take part in hundreds of enzymatic reactions — from energy production to supporting the immune system and DNA synthesis. Vitamins are organic compounds divided into fat-soluble (A, D, E, K) and water-soluble (the B group and vitamin C). Minerals are inorganic elements such as calcium, magnesium, iron and zinc.
Globally, micronutrient deficiency affects more than two billion people (Bailey et al., 2015). In Estonia, vitamin D deficiency is especially common in autumn and winter, when the intensity of sunlight does not allow sufficient vitamin synthesis in the skin.
You can find more detailed information on the properties and mechanisms of action of individual vitamins in the Vitamins overview.
Which vitamins does the body need every day?
The body needs 13 different vitamins, each with its own metabolic and physiological role.
Fat-soluble vitamins (stored in body fat and the liver):
– Vitamin A — vision, immune system, cell differentiation
– Vitamin D — calcium absorption, bone strength, immune defense
– Vitamin E — an antioxidant that protects cell membranes against oxidative stress (Traber and Stevens, 2011)
– Vitamin K — blood clotting and bone metabolism
Water-soluble vitamins (do not accumulate, need to be replenished daily through food):
– Vitamin C — collagen synthesis, antioxidant protection, immune system
– B1, B2, B3, B5 — energy metabolism in cells
– B6 — amino acid metabolism, support for hormone synthesis
– B9 (folic acid) — cell division and DNA synthesis, especially important during pregnancy
– B12 — maintaining the myelin sheath of nerve fibers, red blood cell production
– B7 (biotin) — fatty acid and glucose metabolism
You can find more about how water-soluble vitamins work in the Vitamins article.
Which minerals are the most important for the human body?
Minerals are divided into macrominerals (needed at more than 100 mg per day) and microminerals, also known as trace elements (needed at less than 100 mg per day).
Macrominerals:
– Calcium — the structure of bones and teeth, muscle contraction, nerve conduction
– Magnesium — a cofactor in more than 300 enzymatic reactions (DiNicolantonio et al., 2018)
– Potassium — blood pressure regulation, heart rhythm, muscle function
– Phosphorus — bone structure and energy metabolism (part of ATP synthesis)
Microminerals (trace elements):
– Iron — a component of hemoglobin, oxygen transport in the blood
– Zinc — immune function, wound healing, DNA synthesis
– Iodine — synthesis of thyroid gland hormones
– Selenium — antioxidant protection, thyroid gland function
What do vitamin and mineral deficiencies look like?
The symptoms of a deficiency depend on the specific micronutrient. The most common deficiencies and their signs:
- Vitamin D deficiency: fatigue, muscle weakness, bone pain, more frequent infections. In Europe, vitamin D deficiency affects more than 40% of the population (Cashman et al., 2016).
- Iron deficiency: pallor, chronic fatigue, shortness of breath on exertion, poorer concentration
- Magnesium deficiency: night-time muscle cramps, sleep disturbances, irritability, heart rhythm disorders
- Vitamin B12 deficiency: numbness and tingling in the limbs, fatigue, memory problems — often seen in vegans and older adults
- Iodine deficiency: an enlarged thyroid gland (goiter), fatigue, changes in body weight
If you suspect a deficiency, see your family doctor — a blood test will show exactly which micronutrients you are short of. The Estonian Health Board recommends paying particular attention to vitamin and mineral status in pregnant and breastfeeding women, older adults and people on restricted diets.
Are vitamin and mineral supplements necessary?
A healthy adult who eats a varied, balanced diet covers most of their needs through food. Supplements are justified in the following cases:
- Vitamin D in winter: in Estonia’s climate, vitamin D synthesis is practically nonexistent from October to April — EFSA recommends that adults take 15 μg (600 IU) per day (EFSA, 2016)
- Folic acid during pregnancy: 400 μg per day to reduce the risk of neural tube defects (EFSA, 2014)
- B12 on a plant-based diet: vegans lack the main source of B12, as it is found mainly in animal-based foods
- Iron: only on a doctor’s advice, when iron deficiency has been confirmed
The combined effect of micronutrients on the immune system has been studied extensively — vitamins C, D and E, together with zinc and selenium, work synergistically to strengthen the body’s defenses against infections (Gombart et al., 2020).
Active people who follow the recommendations in Building a training program: the complete guide should keep in mind that intensive training can increase the daily requirement for magnesium, B vitamins and iron.
References
- Bailey RL, West KP Jr, Black RE. (2015). The Epidemiology of Global Micronutrient Deficiencies. Ann Nutr Metab. PMID: 26045325
- Traber MG, Stevens JF. (2011). Vitamins C and E: beneficial effects from a mechanistic perspective. Free Radic Biol Med. PMID: 21664268
- Cashman KD, Dowling KG, Škrabáková Z et al. (2016). Vitamin D deficiency in Europe: pandemic? Am J Clin Nutr. PMID: 26864360
- DiNicolantonio JJ, O’Keefe JH, Wilson W. (2018). Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis. Open Heart. PMID: 29387426
- Gombart AF, Pierre A, Maggini S. (2020). A Review of Micronutrients and the Immune System–Working in Harmony to Reduce the Risk of Infection. Nutrients. PMID: 32010907
- EFSA NDA Panel. (2016). Dietary reference values for vitamin D. EFSA Journal. doi:10.2903/j.efsa.2016.4547
- EFSA NDA Panel. (2014). Scientific Opinion on Dietary Reference Values for folate. EFSA Journal. doi:10.2903/j.efsa.2014.3893
Frequently asked questions
Does a multivitamin cover all your vitamin and mineral needs?
A multivitamin is no substitute for a varied diet, but it can be a useful addition if your diet is restricted. Most multivitamins contain the recommended daily amounts, but the doses are often conservative and may not cover increased needs — for example during intensive training, pregnancy or illness.
When is the best time to take vitamins and minerals?
Fat-soluble vitamins (A, D, E, K) are absorbed better with food that contains fat. Iron is absorbed most efficiently on an empty stomach, but it can cause stomach irritation — to ease this, eat a small snack with it. Magnesium is often recommended in the evening before bed, as it supports muscle relaxation.
Is it dangerous to take too many vitamins and minerals?
Yes. An excess of the fat-soluble vitamins A and D in particular is dangerous, as they accumulate in the body and can cause toxicity. Water-soluble vitamins are excreted in the urine, but high doses of vitamin B6 can also damage nerve tissue. It is always worth following the manufacturer’s recommendations and consulting a doctor before starting high-dose supplements.
What are the best food sources of vitamin D?
The best food sources are fatty fish (salmon, mackerel, herring), cod liver oil and foods fortified with vitamin D, such as some dairy products and eggs. Because the amount you get from food is often insufficient, and in Estonia’s climate the winter sun is too weak to trigger synthesis in the skin, most adults are advised to take a vitamin D supplement from October to April.
How can you improve iron absorption from food?
Eat iron-rich foods — meat, legumes, dark green vegetables — together with sources of vitamin C such as citrus fruits and bell pepper, which significantly improve iron absorption. Avoid drinking tea and coffee right before an iron-rich meal, as tannins inhibit absorption. People on a plant-based diet should check their iron status regularly.
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