Vitamins and Minerals

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Introduction

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 and 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.

Vitamins

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 “B” 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.

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.

Minerals

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 Dysgeusia Anosmia Alopecia Male hypogonadism	Nausea, vomiting, diarrhoea Abdominal pain
Iodine	Thyroid hormone	Seaweed, fish, shellfish, iodised table salt, dairy, eggs	Hypothyroidism Goitre	Hyperthyroidism
Selenium	Co-factor in peroxidase reactions	Brazil Nuts	Heart failure Skeletal dysfunction Poor immune response Macrocytosis	Nail changes Nausea, vomiting, diarrhoea Peripheral neuropathy Fatigue
Sulphur	Key part of amino acids: methionine and cysteine	Cruciferous vegetables Animal proteins Legumes Dairy	Brittle nails, hair loss, arthritis, nausea, vomiting, diarrhoea, skin rashes, cognitive impairment	Nausea, vomiting, diarrhoea Headaches
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 Osteoporosis	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.

Editor

Dr Chris Jefferies

References

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