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Vitamins and Minerals

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Vitamins and minerals are nutrients that humans use in very small quantities for metabolic processes. They are grouped together as micronutrients due to being needed in far smaller amounts than the macronutrients (proteins, carbohydrates and fats).1

Vitamins are organic compounds sourced from plants and animals. In contrast, minerals are inorganic andΒ sourced from soil and water.1

In general, vitamins and minerals support the processes that allow for normal growth, development, metabolism and overall functioning of the human body.


Unlike macronutrients, vitamins do not provide energy. Instead, they have specific biochemical roles in metabolism. Importantly, the body is unable to synthesise vitamins in adequate amounts, and they must be consumed in adequate amounts through diet.

There are thirteen different vitamins:1

  • Eight β€œB” group vitamins and vitamin C (water-soluble)
  • Vitamins A, D, E and K (fat-soluble)

Water-soluble vitamins

Table 1. An overview of water-soluble vitamins.1,2

Vitamin Function Sources Deficiency
B1: Thiamine Co-enzyme for dehydrogenase reactions in carbohydrate and amino acid metabolism Wholegrain, cereals, pork and legumes
  • Wernicke syndrome
  • Korsakoff syndrome
  • Beriberi
B2: Riboflavin Co-enzyme in redox reactions (e.g. Krebs cycle) Meat, fish, eggs, milk, green vegetables
  • Cheilosis
  • Angular stomatitis
  • Hyperaemia
B3: Niacin Co-enzyme in redox reactions (e.g. Krebs cycle) Meat, liver, cereals, seeds, legumes
  • Glossitis
  • Pellagra
B5: Pantothenic Acid Co-enzyme A co-factor for acyl transfer reactions (e.g. fatty acid synthesis) Organ meats, egg yolks, milk and broccoli
  • Dermatitis
  • Enteritis
  • Alopecia
B6: Pyridoxine Co-factor for decarboxylation reactions, glycogen phosphorylation and transamination Meats, nuts, whole grains and vegetables
  • Convulsions
  • Sideroblastic anaemia
  • Peripheral neuropathy
B7: Biotin Co-factor for carboxylase reactions Eggs, meat, fish, nuts and seeds Rare

  • Dermatitis
  • Conjunctivitis
  • Alopecia
  • Enteritis
  • Myalgia
B9: Folate Co-enzyme for 1-carbon transfer methylation reactions
Nitrogen-base synthesis for RNA and DNA
Green leafy vegetables, legumes
  • Adults: macrocytic megaloblastic anaemia, glossitis, (no neurological symptoms)
  • Foetus: neural tube defects
B12: Cobalamin Co-factor for methylmalonyl-Co-A, methionine synthesis and DNA synthesis Meat and dairy products
  • Macrocytic megaloblastic anaemia
  • Neurological symptoms (e.g. paraesthesias)
C: Ascorbic Acid Hydrophilic antioxidant Fruits and vegetables (uncooked) Scurvy

Fat-soluble vitamins

Table 2. An overview of fat-soluble vitamins.1,2

Vitamin Function Sources Deficiency
A: Retinol Vision, antioxidant, cell differentiation and specialisation Organ meats, butter, egg yolks, green leafy vegetables
  • Night blindness
  • Xerosis cutis
  • Keratomalacia
D: Calciferol Calcium and phosphate homeostasis Cholecalciferol: exposure to sunlight, fish, milk and plants
Ergocalciferol: plants, fungi, fortified foods
  • Osteomalacia
  • Rickets
E: Tocopherol Antioxidant Meat, eggs, oil, leafy vegetables
  • Muscle weakness
  • Demyelination of spinal column tracts
  • Acanthocytosis
  • Haemolytic anaemia
K: Phytomendione Coagulation co-factor for clotting factor II, VII, IX and X, protein C and S Green vegetables
Synthesis via intestinal flora
  • Coagulopathy
  • Vitamin K deficiency of the newborn
Vitamin D deficiency3

Vitamin D deficiency is one of the most common vitamin deficiencies. There are several causes, including lack of sunlight exposure, malnutrition (often from substance abuse), malabsorption disorders and chronic kidney disease.

Clinically, untreated vitamin D deficiency manifests as osteomalacia in adults and rickets in children. Other complications include hypocalcaemia and hypophosphataemia.

Supplementation of vitamin D is common, particularly in countries with low levels of sunlight, or where sun protection is important.Β 

People most at risk of vitamin D deficiency are those living in residential/care homes or who are hospitalised, those with poor mobility, those with poor sun exposure and people with gastrointestinal diseases affecting absorption.


Like vitamins, minerals do not provide energy to the body. Minerals are unable to be synthesised and must be consumed.

Minerals are classed into two groups

  • Major minerals: large amounts are needed
  • Trace minerals: small amounts are needed

Mineral deficiencies range from being very common (e.g. iron deficiency) to very rare.

Major minerals

Table 3. An overview of the major minerals.4

Mineral Function Sources Deficiency Toxicity
Calcium Bone and teeth mineralisation, muscle contraction, blood clotting, blood pressure Dairy products, canned fish with bones Stunted growth, bone loss Constipation, increased kidney stone risk
Potassium Fluid and electrolyte balance, cellular integrity, muscle contraction and nerve impulses All whole foods particularly bananas, avocado and tomato Irregular heartbeat, muscular weakness, glucose intolerance Muscle weakness, vomiting (hyperkalaemia)
Sodium Fluid and electrolyte balance, muscle contraction, nerve impulse transmission Table salt, processed foods, bread, meats Muscle cramps, mental apathy, loss of appetite Oedema, acute hypertension
Chloride Fluid and electrolyte balance, stomach acid Table salt, soy sauce, meats, milk, eggs, bread Do not occur under normal physiology Vomiting
Phosphorus Bone and teeth mineralisation, cells, genetic material, blood clotting and blood pressure All animal products Muscular and bone weakness/pain Calcification of tissues (kidneys)
Magnesium Bone mineralisation, protein building, muscle contraction, immunity Nuts, legumes, whole grains, dark green vegetables Weakness, confusion, dysphagia *From non-food sources only diarrhoea, alkalosis, dehydration

Trace minerals

Table 4. An overview of trace minerals.5

Mineral Function Sources Deficiency Toxicity
Iron Co-factor for cytochrome P450 reaction
Haemoglobin and myoglobin
Red meat, legumes, green leafy vegetables Iron deficiency anaemia Haemochromatosis
Iron toxicity
Copper Co-factor in many reactions and part of some enzymes Organ meats, shellfish, fish, nuts, whole grains, chocolate Menkes disease
Sideroblastic anaemia
Abnormal hair growth
Muscle weakness
Neurologic manifestations
Delayed wound healing
Wilson’s disease
Zinc Protein structure
Co-factor in many reactions
Meat, seafood and poultry Immune dysfunction
Male hypogonadism
Nausea, vomiting, diarrhoea
Abdominal pain
Iodine Thyroid hormone Seaweed, fish, shellfish, iodised table salt, dairy, eggs Hypothyroidism
Selenium Co-factor in peroxidase reactions Brazil Nuts Heart failure
Skeletal dysfunction
Poor immune response
Nail changes
Nausea, vomiting, diarrhoea
Peripheral neuropathy
Sulphur Key part of amino acids: methionine and cysteine Cruciferous vegetables
Animal proteins
Brittle nails, hair loss, arthritis, nausea, vomiting, diarrhoea, skin rashes, cognitive impairment Nausea, vomiting, diarrhoea
Chromium Component of glucose tolerance factors Meat, grains, fruits, vegetables Impairment in glucose tolerance and insulin sensitivity Contact dermatitis
Allergic asthma
Haemorrhagic Gastroenteritis
Fluoride Induction of bone formation
Prevents tooth enamel demineralisation
Added to water Dental caries
Dental fluorosis
Skeletal fluorosis
Iron deficiency6

Iron deficiency is the most common nutritional disorder, affecting both industrialised and non-industrialised populations. It is estimated that over 2 billion people (30% of the world’s population), have iron deficiency anaemia. The causes of iron deficiency differ between age groups:

  • Infants and children: high milk diets have no iron, yet also have high iron needs to support growth
  • Women of childbearing age: menstruation and childbirth (increased blood loss)
  • People over fifty: bowel cancer
  • All age groups: diet

Symptoms of iron deficiency include fatigue, pallor, apathy, weakness and temperature intolerance.

Iron deficiency anaemia is the severe depletion of iron resulting in low haemoglobin and is rarer than iron deficiency.

Iron deficiency is correctable by addressing the cause, though supplements are often used to boost iron stores. An iron infusion can be used.Β 


Dr Chris Jefferies


  1. Whitney E, Rolfes SR, Crowe T. Understanding Nutrition. 5th ed: Cengage Learning Australia; 2022.
  2. Pazirandeh S. Overview of water-soluble vitamins. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Available from: [LINK]
  3. Drezner MK. Patient education: Vitamin D deficiency (Beyond the Basics). In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Available from: [LINK]
  4. Med Libretexts (2020) 8.6: Major minerals, Medicine LibreTexts. Libretexts. Available from: [LINK]
  5. Pazirandeh S, Burns DL,Griffin IJ. Overview of dietary trace elements. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Available from: [LINK]
  6. Auerbach M. Causes and diagnosis of iron deficiency and iron deficiency anemia in adults. In:Β Post TW, ed. UpToDate. Waltham, MA: UpToDate. Available from: [LINK]


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