Dietary reference values for vitamins and minerals

The term vitamin A includes free and esterified retinol found in food, its metabolites produced in the body and responsible for its biological activity (retinal and retinoic acids), and provitamin carotenoids (β-carotene, α-carotene and β-cryptoxanthin).

The essential nature of vitamin A lies in the role of retinoic acids in genome expression regulation, immune system function and differentiation of mucosal epithelia (including the ocular epithelium), as well as the retinal epithelium in twilight vision. Symptoms of vitamin A deficiency include intrauterine and postnatal growth retardation, birth defects, loss of twilight vision and dry eye.

Only animal products (such as fish oil, butter, liver, etc.) contain retinol. Plant products (such as carrots, yellow or orange sweet potatoes, melons, pumpkins, mangoes, green leafy vegetables, etc.) provide provitamin carotenoids.

The main dietary sources of retinol are offal, egg yolk and butter. The main dietary sources of β-carotene are vegetables (carrots, sweet potatoes, green leafy vegetables) and fruits (mangoes, melons).

Updated dietary reference values for vitamin A (μg RE/d)

Vitamin B1, sometimes also called thiamine, is mainly involved in carbohydrate metabolism. The vitamin B1 requirement therefore depends on carbohydrate intake and for this reason it is preferable to express dietary reference values in milligrams per megajoule (mg/MJ) of energy consumed, rather than in mg/d.

A vitamin B1 deficiency is usually expressed through various symptoms such as damage to one or more nerves or symptoms of heart failure. It can lead to the development of beriberi, with neurological and cardiac manifestations. A clinical vitamin B1 deficiency is not always due to inadequate dietary intake; it can also be associated with alcoholism or intestinal malabsorption.

The main dietary sources of vitamin B1 are wholegrain cereal products, meat – especially pork – and oilseeds.

Updated dietary reference values for vitamin B1 (mg/MJ of energy consumed)

Vitamin B2 (or riboflavin) is a water-soluble vitamin that is heat-stable but sensitive to light. Vitamin B2 plays a part in energy metabolism.

Cases of deficiency are rare and the symptoms are aspecific. These may include mucocutaneous (e.g. seborrhoeic dermatitis, cheileitis, etc.) or ocular signs (e.g. dryness).

The main dietary sources of vitamin B2 are liver, dairy products (cheese, milk and yoghurt) and eggs.

Updated dietary reference values for vitamin B2 (mg/d)

Vitamin B3, sometimes also known as niacin, is a water-soluble vitamin involved as a redox cofactor in the metabolism of glucose, amino acids and fatty acids.

Because of the role of vitamin B3 in energy metabolism, the requirements and recommendations are frequently expressed in milligrams of niacin equivalent per megajoule (NE/MJ).

Long-term vitamin B3 deficiency can lead to the development of pellagra, whose most common symptoms are photosensitive dermatitis, skin lesions, vomiting, diarrhoea, depression and dementia.

The main dietary sources of vitamin B3 are liver, meat, fish, seafood and wholegrain cereals.

Updated dietary reference values for vitamin B3 (mg NE/MJ)

Vitamin B5 (or pantothenic acid) plays an essential structural role in the synthesis of coenzyme A. It is also required for the synthesis of acyl carrier proteins and several synthases. It is therefore essential for the synthesis and metabolism of carbohydrates, amino acids and fatty acids.

Vitamin B5 deficiency is rare. Signs of deficiency observed in subjects on diets lacking pantothenic acid include mood changes, sleep disturbances and neurological, cardiac and gastrointestinal disorders.

Pantothenic acid is ubiquitous in food. The main dietary sources of vitamin B5 are meat, bread, milk and dairy products.

Updated dietary reference values for vitamin B5 (mg/d)

Vitamin B6

Vitamin B6 plays a part in the metabolism of amino acids and in neurotransmitter synthesis.

Vitamin B6 deficiency leads to microcytic hypochromic anaemia, convulsions due to a deficit in gamma-isobutyric acid synthesis and skin symptoms (eczema, seborrhoeic dermatitis).

The main dietary sources of vitamin B6 are foods of plant (all forms of cereals, starchy vegetables, soy products, fruits other than citrus) and animal origin (cow, calf, pig and poultry liver, fish).

Updated dietary reference values for vitamin B6 (mg/d)

Vitamin B8, sometimes called biotin, is a cofactor of several carboxylases involved in fatty acid synthesis, gluconeogenesis and branched-chain amino acid catabolism.

Humans cannot synthesise biotin. On the other hand, the intestinal microbiota produces large quantities of it, although it is not known whether this synthesis can help meet vitamin B8 requirements.

Vitamin B8 deficiency is rare and is characterised by dermatitis, hair loss, conjunctivitis, ataxia and delayed development in children.

The Ciqual food composition table does not list the vitamin B8 content of foods. However, the main dietary sources reported by EFSA are liver, cooked eggs, mushrooms and some cheeses, while smaller amounts are found in lean meat, fruits, cereals and bread.

Updated dietary reference values for vitamin B8 (µg/d)

Vitamin B9 is a general term covering folates, which are naturally found in the diet, and folic acid, which is the synthetic form found in fortified foods and supplements. Folic acid is more stable than folates and has better bioavailability. To account for this difference in bioavailability, the concept of dietary folate equivalent (DFE) is used.

Vitamin B9 plays a part in amino acid metabolism and cell division. Folate deficiency is therefore first seen in rapidly renewed tissues such as blood cells. As a result, the initial consequence of vitamin B9 deficiency is megaloblastic anaemia, i.e. the production of abnormally large red blood cells with poorly differentiated nuclei.

Vitamin B9 is also involved in the prevention of neural tube closure defects. These are a group of birth defects that result from incomplete closure of the neural tube during the early stages of embryogenesis. Although women affected by these embryonic anomalies usually have normal vitamin B9 intakes, their serum and red blood cell vitamin B9 concentrations are low. Folic acid supplementation during the preconception period has a well-established protective role and has led to numerous recommendations.

The main dietary sources of vitamin B9 are pulses, leafy vegetables and liver. Brewer's yeast and wheat germ are also sources of folate.

Updated dietary reference values for vitamin B9 (µg DFE/d)

*Value possibly overestimated for the 2nd and 3rd trimesters of pregnancy but below the UL

Vitamin B12, also known as cobalamin, refers to a group of water-soluble cobalt-based compounds involved in the metabolism of propionate and vitamin B9. As a result, there is an interaction between the metabolism of vitamin B9 and that of vitamin B12.

As with vitamin B9, a clinical vitamin B12 deficiency is most often expressed as megaloblastic anaemia. It is accompanied by symptoms due to impaired oxygen transport, such as fatigue or dyspnoea. A vitamin B12 deficiency can also lead to neurological damage with progressive demyelination in the brain and spinal cord, accompanied by motor and sensory disorders. This damage can also be associated with neuronal dysfunctions that cause certain mental disorders: irritability, memory and mood disorders. The neurological manifestations regress in response to vitamin B12 intake but sequelae persist in most cases.

Vitamin B12 is synthesised by micro-organisms, mainly bacteria and archaea, especially those present in the rumen. The main dietary sources of vitamin B12 are offal (especially liver), fish, eggs, meat, milk and other dairy products. Vitamin B12 deficiency is therefore particularly common in vegans.

Updated dietary reference values for vitamin B12 (µg/d)

Vitamin C (or ascorbic acid) acts as a coenzyme in the functioning of a limited number of enzymes of the oxygenase family, involved mainly in the synthesis of carnitine and catecholamine, and in the hydroxylation of proline in collagen. This latter role explains the symptoms affecting the connective tissue observed with a clinical deficiency leading to the development of scurvy. In addition, vitamin C is a reducing agent involved in antioxidant defences as a scavenger of reactive oxygen and nitrogen species. Vitamin C is also known to promote the absorption of non-haem iron.

The main dietary sources of vitamin C are fruits (such as blackcurrants and citrus) and vegetables (especially parsley and red pepper).

Updated dietary reference values for vitamin C (mg/d)

Vitamin D is a fat-soluble vitamin. It plays a part in maintaining calcium and phosphorus homeostasis, and in the mineralisation of mineralised tissues (bone, cartilage and teeth) during and after growth.

Symptoms of clinical vitamin D deficiency include rickets in children and osteomalacia (bone decalcification) in adults, caused by impaired bone mineralisation due to reduced absorption of dietary calcium and phosphorus. A vitamin D deficiency leads to a reduction in bone mineral density and predisposes elderly subjects – especially postmenopausal women – to osteoporosis, which can increase the risk of fractures.

In humans, vitamin D is also synthesised endogenously from cholesterol by cells in the deep layers of the epidermis under the direct action of ultraviolet radiation (UV-B). This synthesis depends on many factors, including the latitude where a person lives, season, age, skin pigmentation, clothing worn and use of sun cream.

The main dietary sources of vitamin D are oily fish, cod liver oil (which has particularly high concentrations of vitamin D) and egg yolk.

Updated dietary reference values for vitamin D (µg/d)

Vitamin E is the common term for four tocopherols (alpha, beta, delta and gamma) and four tocotrienols (alpha, beta, delta and gamma), which have different antioxidant activities. Its main property is its antioxidant function; it inhibits lipid peroxidation due to its lipophilicity. Its antioxidant power depends on synergistic and complementary effects with other endogenous and exogenous antioxidants such as vitamin C and carotenoids.

A clinical vitamin E deficiency causes neurological symptoms including ataxia. It can be observed in patients with cholestatic liver disease, severe undernutrition, lipid absorption disorders and cystic fibrosis.

The main dietary sources of vitamin E are certain vegetable oils, cod liver oil and certain nuts.

Updated dietary reference values for vitamin E (mg/d)

Vitamin K encompasses phylloquinone (vitamin K1), menaquinones (vitamin K2) and synthetic menadione (vitamin K3). Phylloquinone and menaquinones are fat-soluble compounds. Vitamin K is involved in the activation of proteins that play a role in blood clotting (vitamin K1) and bone metabolism (vitamin K2). As a result, vitamin K1 deficiency leads to coagulation disorders due to a decrease in the activity of procoagulant proteins and an increase in prothrombin time (induced blood clotting time). In bone, vitamin K2 deficiency results in the secretion of incompletely carboxylated osteocalcin species.

A dietary deficiency is rare but can lead to lipid absorption disorders. In addition, high intakes of α-tocopherol in individuals with low vitamin K status may cause clotting disorders.

According to the data in Ciqual, vitamin K1 is mainly found in dark green leafy vegetables (herbs, kale, spinach, salads and cruciferous vegetables) and certain vegetable oils. Menaquinones (vitamin K2) are synthesised by bacteria and are mainly found in animal products (liver, beef and poultry, egg yolk and fermented dairy products) and fermented products. However, little is known about the types and content of menaquinones in food, or their intestinal absorption.

Updated dietary reference values for vitamin K1 (µg/d)

Choline plays a part in metabolism, lipid and cholesterol transport, and neurotransmitter synthesis. It is a constituent of certain phospholipids that play an important role in the structure and function of cell membranes.

Choline can be synthesised by the body, but this is insufficient, which makes choline intake via food essential.

Inadequate choline intake can lead to liver and muscle damage. 

The Ciqual table does not provide information on choline content. The main known dietary sources are eggs, meat and fish.

Updated dietary reference values for choline (mg/d)

Calcium is the most abundant mineral in the body – accounting for 1-2% of body weight – and is found mainly in the skeleton, which contains 99% of body calcium. Calcium plays a key role in the mineralisation and structure of the skeleton. It is required for many biological functions such as neuromuscular excitability, blood clotting, membrane permeability, hormone release, enzyme activation and cell signalling. Blood calcium levels are finely regulated in relation to bone reserves. Regulation of calcium metabolism is characterised by control of intestinal absorption and urinary excretion, as well as bone matrix resorption and formation. Calcium absorption is positively influenced by vitamin D status.

Reduced bone mass due to inadequate intake or malabsorption of calcium leads to skeletal damage such as osteoporosis or osteomalacia, and increases the risk of fractures.

The main dietary sources of calcium are dairy products, pulses, nuts, cereal products, some leafy vegetables (cabbage, chard, spinach, etc.), seafood and some hard water with a high calcium and magnesium content.

Updated dietary reference values for calcium (mg/d)

Chlorine in the body is present as the chloride ion (Cl^-). It contributes to many functions such as maintaining osmotic and acid-base balance, and muscular and nervous activity.

Chloride deficiency due to inadequate intake is rare. It has been observed in infants receiving chloride-deficient breast milk or breast milk substitutes, or in patients receiving chloride-deficient liquid nutritional products. In infants and children, hypochloraemia can manifest itself as growth defects, lethargy, irritability, anorexia, gastrointestinal symptoms and general body weakness.

The main dietary sources of chloride are foods to which sodium chloride has been added during processing, for preservation or for other purposes. These include cured meats, cheeses and salted smoked fish.

Updated dietary reference values for chloride (mg/d)

Trivalent chromium is a trace element initially described as necessary for the regulation of carbohydrate, lipid and protein metabolism by insulin. However, the molecular mechanisms involved in its effects have not been clearly demonstrated in humans or animals. Questions are currently being asked about whether nutrient intake is in fact essential in healthy individuals.

Chromium is ubiquitous in food. The Ciqual food composition table does not provide information on the chromium content of foods. The main dietary sources reported by EFSA are meat, fats, bread and cereals, fish, pulses and spices.

In the absence of additional data justifying the essential nature of nutrient intake in healthy individuals, ANSES has not established a dietary reference value for chromium.

Copper is an essential trace element subject to homeostatic regulation. It is a component of many metalloenzymes involved in redox reactions. Copper plays a role in cartilage quality and connective tissue integrity, bone mineralisation, neurotransmitter regulation, heart function, immune function and iron metabolism. Lastly, copper plays an ambivalent role in oxidative stress.

The symptoms of clinical copper deficiency are diverse and include hypochromic anaemia, hypercholesterolaemia, neutropaenia, leukopaenia and myeloneuropathy.

The main dietary sources of copper are offal, molluscs and crustaceans, and oilseeds.

Updated dietary reference values for copper (mg/d)

Iron is necessary for oxygen transport and use, and for various redox reactions.

Iron status is regulated by complex mechanisms that help maintain intracellular and circulating iron concentrations. These mechanisms allow the body to function properly and protect against the harmful consequences of iron overload (iron is a pro-oxidant transition metal).

Although iron losses are not regulated, they are limited by efficient recycling of iron from red blood cells. Iron is regulated by intestinal absorption and reserves, which ensures that losses and intakes are balanced and increased needs are met in certain physiological situations such as pregnancy or growth.

Two forms of iron are found in food: haem and non-haem:

• haem iron is found exclusively in animal flesh (meat and meat products, offal, fish and seafood), where it constitutes 15 to 80% of the iron present, depending on the species and cuts;
• non-haem iron (or metallic iron) is found in most foods, regardless of whether they are of animal or plant origin. The absorption rate of haem iron is higher than that of metallic iron. It is also less variable according to the level of iron reserves than that of metallic iron. The rate of absorption of dietary iron therefore depends on the level of body reserves, but also on the proportion of haem iron in the diet and on the presence of dietary compounds that affect the absorption of metallic iron.

Iron deficiency can lead to iron-deficiency anaemia. Populations most at risk are those with high iron requirements due to growth (infants, children, pregnant women), heavy losses (women with heavy menstrual bleeding, conditions associated with bleeding) or poor absorption (for example, due to inflammation or infection).

The main dietary sources of iron are liver, meat (of all types), fish and seafood, pulses, nuts, cereals, egg yolk and green leafy vegetables.

Updated dietary reference values for iron (mg/d)

Fluoride has no known essential role in growth and development, and no signs of fluoride deficiency have been identified. However, it does play a role in preventing tooth decay. Fluoride also binds to bone but there is currently no evidence of any link between fluoride intake and bone strength.

In adults, about 40% of absorbed fluoride is associated with calcified tissue (bones and teeth) and 1% with soft tissue, the remainder being excreted, mainly by the kidneys and to a lesser extent by sweat and faeces. There is no homeostatic regulation of fluoride and reserves are directly dependent on the level of intake.

The Ciqual food composition table does not provide information on the fluoride content of foods. The main dietary sources of fluoride are water, beverages and foods reconstituted from fluoridated water (such as infant formula), tea, marine fish and fluoridated salt. Intestinal absorption of fluoride is high: on average 80-90%. Dental hygiene products are also a source of fluoride.

Updated dietary reference values for fluoride (mg/d)

Iodine is essential for the synthesis of thyroid hormones, which play a key role in cell growth and maturation processes, thermogenesis, carbohydrate and lipid homeostasis, and the transcriptional modulation of protein synthesis. Iodine also plays a fundamental role in foetal brain development in the first few months of pregnancy.

Iodine deficiency is associated with thyroid hypertrophy and development of a goitre. Severe forms of clinical deficiency can lead to hypothyroidism.

The main dietary sources of iodine are seaweed, iodised salt, marine fish, molluscs and crustaceans, as well as egg yolk and milk depending on the animal's diet.

Updated dietary reference values for iodine (µg/d)

In adulthood, the human body contains about 25 g of magnesium, of which about 50-60% is in the bones and 25% in the muscles. Extracellular magnesium accounts for only 1% of body magnesium. This mineral is involved in over three hundred enzyme systems. It plays a part in many metabolic pathways and physiological functions such as:

• energy production and reactions involving adenosine triphosphate (ATP), mainly in the intermediate metabolism of carbohydrates, lipids, nucleic acids and proteins;
• maintaining cell membrane potential, ion transport, regulation of potassium flow;
• calcium metabolism.

Inadequate intake can have numerous pathological consequences such as gastrointestinal and kidney disorders. Deficiency can lead to hypocalcaemia and hypokalaemia with cardiac and neurological symptoms.

The main dietary sources of magnesium are oilseeds, chocolate, coffee and wholegrain cereals, as well as molluscs and crustaceans and some mineral water.

Updated dietary reference values for magnesium (mg/d)

The UL applies to dissociable magnesium and magnesium oxide consumed as dietary supplements or added to food and drink. It does not include the magnesium naturally present in foods.

Molybdenum is an essential compound in certain enzymes that catalyse redox reactions, and therefore plays a part in the metabolism of certain amino acids.

With the exception of a single case observed in a man receiving prolonged parenteral nutrition without molybdenum, no clinical signs of molybdenum deficiency have been observed in healthy humans.

The Ciqual food composition table does not provide information on the molybdenum content of foods. Other composition tables indicate that molybdenum is found in trace amounts in almost all foods. Foods containing high amounts are pulses, cereals and cereal products, offal (liver, kidney) and nuts.

Updated dietary reference values for molybdenum (µg/d)

Phosphorus is found in the body in the form of phosphates, particularly of calcium and potassium. In adults, around 85% of phosphorus is found in the bones and teeth.

Phosphorus is involved in many physiological processes such as energy storage and transport, regulation of the body's acid-base balance and cell signalling, and bone and tooth mineralisation. It is also an essential component of biological membranes.

A clinical phosphorus deficiency is rarely due to inadequate intake but rather to metabolic disorders, sepsis, chronic alcoholism or major trauma. The clinical signs of deficiency are highly variable. They can include anorexia, anaemia, muscle weakness, bone pain, rickets in children and osteomalacia in adults.

The main dietary sources of phosphorus are cow's milk and dairy products, eggs, oilseeds, fish, offal (mainly liver) and meat.

Updated dietary reference values for phosphorus (mg/d)

Potassium plays a fundamental role in nerve transmission, muscle contraction and heart function. It is also involved in insulin secretion, carbohydrate and protein metabolism and the acid-base balance.

The main symptoms of a clinical potassium deficiency (hypokalaemia) are heart rhythm disturbances, cramps, fatigue and polyuria. It is usually caused by increased potassium losses (e.g. due to diarrhoea or vomiting) or inadequate dietary intake (most often due to very low calorie diets or malnutrition).

The main dietary sources of potassium are chocolate, bananas, vegetables and dairy products. 

Updated dietary reference values for potassium (mg/d)

Selenium is a trace element with physico-chemical properties similar to those of sulphur. It plays a part in thyroid hormone metabolism and in antioxidant defences.

Selenium deficiency may be observed in subjects receiving parenteral nutrition without selenium, and symptoms include muscle weakness.

The main dietary sources of selenium are certain fish and seafood, meat, eggs and oilseeds (particularly Brazil nuts).

Updated dietary reference values for selenium (µg/d)

Sodium is usually found as sodium chloride (NaCl). Sodium plays a key role in regulating osmotic pressure and therefore the volume of extracellular fluid, for nerve transmissions and muscle contractions. It also plays an important role in the intestinal absorption of chloride, amino acids, glucose and water and their reabsorption in the kidney. Sodium is mainly eliminated through urine and sweat.

Severe clinical sodium deficiency is accompanied by the development of cerebral oedema, with malaise, nausea, loss of consciousness and convulsions.

The main dietary sources of sodium are table salt, condiments and sauces, as well as delicatessen meats and cheese.

Updated dietary reference values (AI and UL) for sodium (mg/d)

Zinc is an essential trace element involved in many cellular functions. It plays a part in the activity of nearly 300 enzymes and more than 2500 transcription factors.

Zinc bioavailability is highly dependent on numerous dietary factors that can interfere with this element, such as phytates (found in cereals and pulses), which reduce its absorption.

A clinical zinc deficiency leads to slower height and weight gain and a decrease in the functions of the immune system.

The main dietary sources of zinc are meat, offal, cheese, pulses, fish and seafood.

Updated dietary reference values for zinc (mg/d)