Minerals and Nutrition; Functions, Daily Requirements and Food Sources

Although minerals occur in small amounts in foods, they are vital for health. The body cannot produce them, so they must be obtained from food.

Minerals have different roles and functions in the body, and their deficiencies can cause a wide range of disorders and diseases. It is therefore useful to examine each mineral separately.

1. Calcium (Ca)

There is 1.2–1.5 kg of calcium in the body of a healthy adult individual. While almost all of this amount is found in the structure of bones and teeth, 12–15 grams are found in other tissues. Approximately 200–400 mg of calcium is removed from the body daily.

An adult’s average daily calcium requirement is 800 mg. During growth and youth, from ages 11 to 24, it is about 1.2 grams. Women need 1.3–1.5 grams a day during pregnancy, breastfeeding and menopause. The daily requirement for people over 65 is also approximately 1.3–1.5 grams.

The richest source of calcium is milk and dairy products. The calcium absorption in milk and dairy products is also higher than in other foods. The richest dairy product in terms of calcium is cheese. Although it varies depending on the type of cheese, 100 grams of cheese generally contains between 1,000 mg and 500 mg of calcium. Among dairy products, the food with the highest calcium absorption is yogurt. There is approximately 250 mg of calcium in 100 mL of milk.

Other rich calcium sources include sesame, hazelnuts, almonds, molasses, tahini, seafood, green leafy vegetables, legumes and dried fruits. Meat, cereal products and fresh fruits are low in calcium.

Functions of calcium in the body

1. The essential function is to ensure the development and health of bones and teeth.

2. Takes part in nerve conduction in the nervous system,

3. Effective in regular and healthy functioning of the muscles,

4. Has a role in blood coagulation,

5. Necessary for the activation of hydrolytic enzymes,

6. Effective on blood pressure,

7. Effective in maintaining electrolyte balance,

8. Has a beneficial effect in relation to colon cancer risk.

Calcium deficiency

The calcium level in the blood is 8.8–10.8 mg/dL. Cramps, muscle contractions and tremors can be observed when the blood level falls below these values. Symptoms can disappear immediately after calcium intake.

An inadequate diet can cause calcium deficiency. Calcium deficiency can be also caused by insufficient vitamin D intake. In case of insufficient vitamin D intake, even if enough calcium is taken, the calcium taken cannot be absorbed sufficiently from the intestines.

As a result, deficient vitamin D intake leads to the inability to meet the calcium requirement. On the other hand, high protein, salt and caffeine intake also causes excessive calcium to be excreted from the body.

Calcium deficiency makes bones and teeth brittle and unhealthy. Bone disease appears as rickets in children and as osteomalacia or osteoporosis in older adults. Deficiency can also cause abnormal muscle function, cramps and contractions.

A high intake of calcium in the diet can cause constipation, kidney stone formation and disorders in bone development. On the other hand, heavy calcium intake can also reduce the absorption of minerals such as iron, zinc, magnesium and phosphorus. The daily intake of calcium should not be over 2.5 grams.

2. Phosphorus (P)

There are approximately 700 grams of phosphorus in the body of an adult individual and 85% of this amount is in the structure of bones and teeth.

Functions of phosphorus in the body

1. Vital for bone and tooth development and health,

2. Involved in the structure of cell membranes and protective sheaths of nerve cells,

3. Is essential for energy metabolism as a component of ATP (adenosine triphosphate),

4. Provides activation of some enzymes.

The daily phosphorus requirement of the body is 0.8–1.2 grams. Since it is found in almost all foods, its deficiency is rare. Generally, foods high in protein are also high in phosphorus. The primary sources of phosphorus are; meat and meat products, eggs, legumes, nuts, milk and dairy products and oilseeds. Phosphorus found in animal foods is superior to phosphorus found in plant foods in terms of bioavailability.

Phosphorus deficiency can be seen in premature infants who are breastfed for a long time and in patients who take aluminum hydroxide for a long time. Phosphorus deficiency can cause bone loss, weakness, anorexia, kidney failure and intestinal problems.

On the other hand, excessive phosphorus intake increases the amount of urinary excretion of calcium, magnesium and potassium. As a result, excessive phosphorus consumption can cause osteoporosis and secondary hyperparathyroidism.

3. Sodium (Na)

There are about 100 grams of sodium in the body of an adult individual. Sodium is usually found in extracellular fluids.

A sodium intake of at least 500 mg per day is required. However, since it is found in almost all foods, its deficiency is uncommon. Animal foods contain more sodium than plant foods.

Table salt (NaCl), pickled olives, cheese, water and liquid foods are the richest sources. Since salt use is high in our society, excess intake rather than sodium deficiency poses a risk to health. Daily salt consumption should not exceed 6 grams.

Functions of sodium in the body

1. Regulates osmotic pressure in the body,

2. Provides activation of some enzymes,

3. Effective on the absorption of nutrients from the membrane,

4. Necessary for the health of the nervous system and muscle tissue.

The kidneys take over the control of the sodium amount in the body. Sodium deficiency can be seen in cases of intense vomiting and diarrhea and excessive sweating. As a result of deficiency, disorders such as vomiting, mental confusion, cramps, weakness and coma may occur.

If sodium is taken in excess, it causes an increase in blood pressure and edema formation. In this case, especially salt consumption should be reduced.

4. Chloride (Cl)

An adult’s body contains approximately 80 grams of chloride. In extracellular fluid it is associated with sodium, and in intracellular fluid with potassium.

It is recommended to take chloride at a level of at least 750 mg per day. However, its deficiency is uncommon. Salt consumption easily meets the daily chloride need. On the other hand, it is present in more or less almost all foods.

This way, approximately 5-12 grams of chloride intake per day is obtained. The removal of chloride from the body is also very rapid.

Functions of chloride in the body

1. Plays a vital role in maintaining the body’s water balance,

2. Effective in regulating the osmotic pressure balance of the body,

3. Acts as a buffer in the creation of acid-base balance,

4. Necessary to produce hydrochloric acid (HCl), which is stomach acid; Therefore, it is extremely important in maintaining stomach acidity.

5. It helps to transport carbon dioxide in blood cells.

Conditions such as intense sweating, constant diarrhea and vomiting can cause chloride deficiency. As a result, conditions such as loss of appetite, weakness and fatigue may occur.

5. Potassium (K)

There are approximately 150 grams of potassium in the body of an adult individual. Almost all foods contain more or less potassium. Therefore, its deficiency is not very common. Although the daily need is 1.6-2.0 grams, 2-6 grams of potassium is taken into the body daily in a standard diet.

The richest sources are dried fruits and vegetables, tomatoes, juices, coffee, tea, green leafy vegetables, meat and meat products, milk and dairy products, cereals and nuts.

Functions of potassium in the body

1. Regulates intracellular osmotic pressure,

2. Helps maintain cell integrity,

3. Takes part in glycogen metabolism; necessary for the production of glycogen,

4. It is vitally important for the continuous functioning of the heart,

5. Takes a role in the regulation of blood pressure,

6. Helps regulate muscle movements.

Potassium deficiency is called hypokalemia. Vomiting, diarrhea, strenuous activity, kidney disorders and the use of certain diuretic drugs can cause potassium deficiency.

In potassium deficiency;

1. Anorexia, nausea and vomiting,

2. Cramps, problems in the nervous system and fatigue,

3. Disorders such as heart rhythm disorder and palpitations can be seen.

Excess potassium is called hyperkalemia. It can cause heart disorders and kidney failure, with potentially fatal consequences.

6. Magnesium (Mg)

There are about 25 grams of magnesium in the body of an adult individual. It is found in almost all foods, especially plants with chlorophyll. Therefore, its deficiency is rare. The daily magnesium requirement is an average of 300 mg.

The magnesium requirement of the body increases in cases of high calcium and vitamin D intake and intense stress. The richest sources are coffee, tea, cocoa and nuts.

Functions of magnesium in the body

1. Provides the activation of more than 300 enzymes involved in the digestion of foods and synthesis reactions,

2. Has an important role in cell growth and regeneration,

3. Has an active role in muscle work,

4. Helps nerve conduction,

5. Plays a role in maintaining osmotic pressure and acid-base balance in the body.

Magnesium deficiency is not encountered under normal conditions. However, magnesium deficiency can be seen in alcoholic individuals and individuals with kidney and intestinal disorders.

In magnesium deficiency;

1. Nausea, vomiting and loss of appetite,

2. Growth retardation,

3. Involuntary muscle movements and tremors,

4. Problems in the nervous system,

5. Decreased calcium absorption,

6. Coma can be seen.

7. Zinc (Zn)

There are approximately 2 -4 grams of zinc in the body of an adult individual. While the daily requirement is 10 mg in children aged 1 to 10 years, it is 15 mg in individuals over 10.

Zinc needs increase in older adults, pregnant women, people following restrictive diets and vegetarians. Deficiency can cause serious health problems, while high doses can be toxic.

Rich food sources of zinc include seafood, meat and offal, eggs, milk and dairy products, oilseeds and legumes. Zinc from animal foods is absorbed more readily than zinc from plant foods.

Phytates in cereal bran prevent the body from making full use of zinc. This effect is largely eliminated in whole-wheat sourdough bread. (For more detailed information on the mineral content of different breads and sourdough fermentation, see World Bread Atlas; Varieties, Nutrition and Culture.)

Functions of zinc in the body

1. Activates more than 100 enzymes in the body,

2. Takes part in nucleic acid synthesis,

3. Has a role in protein and carbohydrate metabolism,

4. Effective in making the immune system strong,

5. Has important roles in growth and reproduction.

Zinc deficiency can occur with malnutrition and in individuals with intestinal absorption problems and in vegetarians.

In zinc deficiency;

1. Weakness in the sense of taste and smell,

2. Delay in the healing of wounds,

3. Weakening of the immune system,

4. Forgetfulness and difficulty in movement, problems in the nervous system,

5. Growth retardation, dwarfism,

6. Underdevelopment of the sex organs,

7. Liver and spleen enlargement,

8. Dermatitis,

9. In advanced insufficiency, anemia, heart failure, tumor formation, kidney disorders and jaundice can be seen.

Taking more than 2 grams of zinc per day can have a toxic effect. Toxic effects can be seen as metallic taste, diarrhea, hair loss, nail breakage, nausea and vomiting.

8. Iron (Fe)

There are 4-5 grams of iron in the body of an adult individual and about 60% in the structure of hemoglobin in the blood. Most of the remaining amount is stored in the liver.

The most critical function of iron in the body is oxygen transport. Iron participates in the structure of hemoglobin in the blood and provides oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs. However, iron also participates in the structure of many enzymes. Iron is also a vital mineral for the immune system and mental activities.

The body generally loses about 0.9 mg of iron each day, which must be replaced through the diet. However, only 5–35% of ingested iron is absorbed, so dietary intake must be considerably greater than the 0.9 mg lost.

The recommended amount is 10 mg for adult men and 15 mg for adult women. Daily needs increase during strenuous physical activity, pregnancy and growth.

Almost all foods contain more or less iron. The rate of absorption of iron found in animal foods is higher than that of iron found in plant foods. While 35% of the iron in meat can be absorbed in the intestines, this rate is between 5-10% in plant foods. Phytic acid in the structure of plants reduces the absorption of iron in plant foods.

Meat is important both because its iron is readily absorbed and because it increases the absorption of iron from other foods eaten with it. The best sources in terms of iron content and absorption include liver and other offal, meat, eggs, molasses, tahini, green leafy vegetables, dried fruits, legumes, hazelnuts, peanuts and sesame.

On average, 100 grams of liver contains 9 mg; 100 grams of meat 2.5 mg; one egg contains 1.4 mg; 25 grams of tahini contains 2.2 mg of iron.

Dietary vitamin C, citric acid and lactic acid increase iron absorption. Eating citrus fruits such as oranges with meat can therefore improve the absorption of dietary iron. Tea and coffee reduce its bioavailability.

Iron deficiency is common in our society, especially among women. Foods such as liver, offal, eggs, molasses and hazelnuts may be recommended for people with iron deficiency. Including oranges and tangerines with meals and avoiding tea and coffee may also help address the deficiency.

The most important consequence of iron deficiency is anemia. Symptoms can include dizziness, weakness, loss of appetite, easy fatigue, disturbed sleep, shortness of breath, palpitations, hair loss and brittle nails.

Excessive iron intake, especially from high-dose supplements, can be toxic. Excessive consumption can cause health problems such as vomiting, stomach cramps and liver cirrhosis.

9. Copper (Cu)

There are approximately 50–120 mg of copper in the body of an adult individual. Deficiency is rare because it is found in many foods. However, taking too much has a toxic effect.

The recommended daily intake is 1.5–3.0 mg. The richest sources are liver, offal, seafood, sesame, hazelnut, peanut, legumes and meat. Only 5% of the copper taken with food can be absorbed by the body.

Copper has essential functions in the body

1. Takes part in the activation of many enzymes,

2. Takes part in the production of collagen, which is connective tissue,

3. Effective on the skin, hair and eye color,

4. Takes part in cholesterol metabolism,

5. Takes place in the structure of hemoglobin in the blood,

6. Effective on immunity.

As a result of copper deficiency, conditions such as anemia, edema formation and deterioration of bone health can be seen.

Toxic effects occur in the individual due to excessive dietary intake of copper or consuming highly acidic foods prepared in materials such as copper pots. Stomach pain, nausea, vomiting and diarrhea can be seen as toxic effects.

10. Manganese (Mn)

There are about 10–40 mg of manganese in the body of an adult individual. Deficiency is rare. Its primary sources are tea, green leafy vegetables, grains, nuts and walnuts. The recommended daily intake is 2–5 mg. The daily requirement is met with a regular diet.

Manganese acts as a catalyst in some reactions in metabolism. In its deficiency, development and growth problems can be seen in the skeleton.

Excess manganese exposure is generally an occupational problem in workers exposed to manganese salts and fumes. It can cause neurological disorders resembling schizophrenia.

11. Selenium (Se)

There are about 15 mg of selenium in the body of a healthy individual. The most important function of selenium for the body is its antioxidant effect in close relationship with vitamin E. It protects cells against cancer. In cases where there is enough vitamin E in the body, selenium affects growth positively.

The richest sources of selenium are seafood and meat. During the preparation of food, some selenium is lost by evaporation. The recommended daily intake of selenium is 0.05–0.1 mg.

Selenium deficiency is rare. Lack is generally seen in local people whose soil is poor in selenium. In selenium deficiency, extreme weakness occurs in the muscles. There may be a decrease in the elasticity of the heart and vessels.

Daily intake of selenium of more than 1 mg may cause nausea, vomiting, hair loss and skin lesions.

12. Cobalt (Co)

An adult’s body contains about 1 mg of cobalt. It occurs in almost all foods, although often in small amounts. Its richest sources are meat and dairy products.

Since it is in the structure of vitamin B₁₂ (cobalamin), there is no deficiency in cobalt when enough vitamin B₁₂ is taken. It is known that cobalt is involved in the metabolism of sulfur-containing amino acids (cysteine and methionine) in the body.

Cobalt also affects iron utilization, thyroid hormone synthesis and hypertension. Excess intake is toxic and can be fatal in workers with high occupational exposure, patients receiving regular dialysis, and people who drink cobalt-contaminated beer.

13. Iodine (I)

An adult individual has 10 to 20 mg of iodine in his body and about 70% is in the thyroid glands. Iodine participates in the structure of T3 (triiodothyronine) and T4 (thyroxine) hormones secreted by the thyroid gland. For the thyroid gland to work correctly, there must be enough iodine in the body continuously.

The daily iodine requirement of the individual is directly proportional to the body weight and in general, two µg iodine intake per kilogram is recommended. For example, the daily iodine requirement of an individual weighing 80 kg is approximately 160 µg.

The body’s need for iodine increases in young people of developmental age, pregnant women, lactating women and in menopause. The richest sources of iodine are iodized salt, seafood, milk and eggs. One hundred grams of fish is about 30 µg; 1 gram of iodized salt contains between 7 and 70 µg of iodine.

Iodine is not naturally found in “iodized” salt. Since there is not enough iodine in the soil and waters of some regions, potassium iodide (KI) is added to the produced salts as an iodine additive.

Salt consumption is necessary for iodine intake; however, it is extremely important not to exceed 6 grams per day. Adding salt to the food from the beginning during cooking causes a significant part of the iodine contained in the salt to be lost by evaporation during cooking.

Therefore, adding salt after the food is cooked and ready may be advisable. Thus, the loss of iodine in the salt can be prevented.

Goiter occurs in iodine deficiency. Goiter is the enlargement of the thyroid glands, causing swelling in the front of the neck. Generally, an iodine intake of fewer than 50 µg per day can result in goiter.

Adequate iodine intake is very important for regulating and healthy functioning of basal metabolism. However, iodine is also necessary for healthy growth and nervous system development.

Iodine deficiency can also cause the condition historically called cretinism, characterized by intellectual disability and abnormalities in physical appearance. It is particularly seen in children born to mothers who were iodine deficient during pregnancy.

Daily intake of more than 2 mg of iodine can have a toxic effect.

14. Fluoride (F)

There are approximately 2.5 grams of fluoride in the body of an adult individual. Fluoride intake is extremely important, especially during childhood and developmental periods. The fluoride taken at these ages ensures that the teeth are protected against caries throughout life.

Adequate fluoride intake in the body also protects against osteoporosis in the elderly. However, fluoride intake cannot cure the disease after osteoporosis occurs. Therefore, the regular presence of fluoride in a healthy individual’s diet is necessary for dental and bone health.

A fluoride intake of 1.5–4 mg per day is recommended. The richest source of fluoride is water, tea and seafood. There is approximately 0.7–1.2 mg of fluoride in one liter of water.

If there is less than 0.7 mg/L fluoride in the drinking water of a region, the complaints of tooth decay are seen intensely in the local people. On the other hand, if there is more than 2 mg of fluoride per liter in drinking water, local people experience yellowness and brown spots (fluorosis) on the teeth.

Taking more than 20 mg of fluoride per day has a toxic effect.

15. Chromium (Cr)

There are approximately 6–12 mg of chromium in the body of an adult individual. The most critical task of chromium in the body is to increase the effectiveness of insulin and help carbohydrate and fat metabolism.

The recommended daily intake of chromium for adults and individuals of developmental age is 50–200 µg. The richest sources are liver, offal, whole grains, honey, cultivated mushrooms and nuts. In chromium deficiency weight loss, nervous system disorders and problems in sugar metabolism can be seen.

No side effects have been reported due to excessive dietary intake of chromium. However, diseases such as allergic dermatitis, skin ulcers and lung cancer can be seen in individuals exposed to industrial air waste and in workers who are heavily exposed to chromium-containing dust.

16. Nickel (Ni)

Nickel is present in the body at the nanogram level. The tissues with the highest concentration are hair, bone, heart, kidney and liver. Nickel increases the effectiveness of insulin. However, it is thought to affect blood formation, cell membranes and RNA synthesis.

The recommended daily intake for nickel is 100–300 µg. It is found in much higher amounts in plant foods than in animal foods. The richest sources are nuts, grains, legumes and chocolate.

Note: This article is intended solely for general informational purposes. It does not constitute medical advice or personalized nutritional guidance. Nutritional needs may vary from person to person. Always consult a healthcare professional or a registered dietitian before making any dietary changes.

References

Raymond, J. L., & Morrow, K. (2023). Krause ve Mahan Besin ve Beslenme Bakım Süreci (16. baskı; G. Akbulut, Çev. Ed.). Nobel Tıp Kitabevleri.

Aksoy, M. (Ed.). (2022). Beslenme Biyokimyası (7. baskı). Ankara Nobel Tıp Kitabevleri.

Sencer, E., & Orhan, Y. (2005). Beslenme. İstanbul Medikal Yayıncılık.

Gökalp, H. Y., Nas, S., & Certel, M. (2002). Biyokimya-I: Temel Yapılar ve Kavramlar. Pamukkale Üniversitesi Mühendislik Fakültesi.

World Health Organization & Food and Agriculture Organization of the United Nations. (2004). Vitamin and mineral requirements in human nutrition (2nd ed.). World Health Organization.

National Institutes of Health, Office of Dietary Supplements. (2026). Calcium: Fact Sheet for Health Professionals.

National Institutes of Health, Office of Dietary Supplements. (2026). Magnesium: Fact Sheet for Health Professionals.

National Institutes of Health, Office of Dietary Supplements. (2026). Zinc: Fact Sheet for Health Professionals.

National Institutes of Health, Office of Dietary Supplements. (2025). Iron: Fact Sheet for Health Professionals.

National Institutes of Health, Office of Dietary Supplements. (2022). Copper: Fact Sheet for Health Professionals.

National Institutes of Health, Office of Dietary Supplements. (2024). Iodine: Fact Sheet for Health Professionals.

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