Minerals: what they do and where to find them

MINERALS

 

Calcium

EU RDA (1)
800 mg

BEST SOURCES
Milk and milk products, dark green vegetables, small canned fish (with bones), dried pulses.

FUNCTIONS
Bone and tooth formation, blood clotting, nerve transmission.

DEFICIENCY SYMPTONS
Stunted growth, rickets, osteoporosis, convulsions.

TOXIC? (2)
Accumulation is virtually unknown.

TIPS
Ensure a good daily intake with dairy products, cows milk, and canned fish.

DID YOU KNOW?
The most spectacular role of calcium is that it helps the heart to contract. Vitamin D is essential for calcium absorption.

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Chloride

EU RDA (1)
800 mg

BEST SOURCES
Salt and salty foods.

FUNCTIONS
Formation of gastric juice, helps maintain acid-base balance.

DEFICIENCY SYMPTONS
Dietary deficiency is virtually unknown.

TOXIC? (2)
Excessive intake can lead to vomiting.

TIPS
Dietary chloride comes almost entirely from salt.

DID YOU KNOW?
Our bodies lose chloride during persistent heavy sweating or diarrhoea.

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Magnesium

EU RDA (1)
375 mg

BEST SOURCES
Whole cereals, nuts and green vegetables.

FUNCTIONS
Aids metabolism, muscle contraction, bone development. Activates enzymes. Involved in protein and DNA synthesis.

DEFICIENCY SYMPTONS
Neuromuscular dysfunction conditions, reduced blood pressure, weakness.

TOXIC? (2)
High intake may cause nausea, vomiting and hypertension. Raised blood levels almost impossible to achieve by diet alone.

TIPS
Use whole grain products instead of refined grain products.

DID YOU KNOW?
Magnesium can help relieve migraine headaches and reduce blood pressure.

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Phosphorus

EU RDA (1)
700 mg

BEST SOURCES
Meat, poultry, fish, dairy products, whole-cereal products and dried fruit.

FUNCTIONS
Helps bone and tooth formation and body's acid-base balance. Aids metabolic energy control.

DEFICIENCY SYMPTONS
Weakness, demineralisation of bone and loss of calcium.

TOXIC? (2)
High intake lowers calcium levels in the blood.

TIPS
Roast or grill lamb, beef, pork and poultry.

DID YOU KNOW?
Many processed foods, and meats have high phosphorus content.

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Potassium

EU RDA (1)
2000 mg

BEST SOURCES
Dried fruits, cocoa and chocolate, wheat bran, tomato concentrate, nuts, pulses, potatoes, vegetables.

FUNCTIONS
Acid-base and body water balance. Helps maintain proper nerve function and muscle contraction.

DEFICIENCY SYMPTONS
Muscular fatigue, nausea, anorexia, cardiac arrhythmia.

TOXIC? (2)
Excess can lead to delirium, hallucinations, numbness and cardiac arrest.

TIPS
To increase potassium intake, eat plenty of vegetables.

DID YOU KNOW?
A diet high in potassium and low in sodium may help manage blood pressure.

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Chromium

EU RDA (1)
40 µg 

BEST SOURCES
Spices, wheat, raw sugar, yeast, vegetables oils, fats, meats and peanuts.

FUNCTIONS
Important for glucose and energy metabolism. A co-factor for insulin.

DEFICIENCY SYMPTONS
Impaired ability to metabolise glucose (rare).

TOXIC? (2)
Too much could lead to liver and kidney damage.

TIPS
Yeast is a very high chromium food source.

DID YOU KNOW?
Chromium levels in human tissue decline with age, except for the lungs, where it accumulates.

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Cobalt

EU RDA (1)
No values for this mineral.

BEST SOURCES
Meats, seafood and milk products.

FUNCTIONS
Constituent of vitamin B12.

DEFICIENCY SYMPTONS
Not reported in humans.

TOXIC? (2)
Large safety margin between normal and toxic quantities.

TIPS
Roast or grill meat and fish.

DID YOU KNOW?
Small quantities of B12 can be formed by our intestinal bacteria.

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Copper

EU RDA (1)
1 mg

BEST SOURCES
Meats, shellfish, dried vegetables, drinking water and cocoa.

FUNCTIONS
Involved in iron absorption, metabolism and formation of elastic and connective tissue. Enzyme function.

DEFICIENCY SYMPTONS
Rare. Metabolic and muscle problems, less resistance to infection.

TOXIC? (2)
Minimal dietary risk, but precautions are needed when copper salts are used to control microbial growth.

TIPS
Cook food in minimum amount of water for shortest possible time.

DID YOU KNOW?
Copper is used as a growth promoter in some farm animals.

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Fluoride

EU RDA (1)
3.5 mg 

BEST SOURCES
Seafood (bony fish), drinking water, tea.

FUNCTIONS
Helps prevent dental caries and may have a role in the maintenance of normal adult skeleton.

DEFICIENCY SYMPTONS
Higher frequency of tooth decay.

TOXIC? (2)
Tooth mottling, skeletal changes when fluoride supplements are taken with fluoridated drinking water.

TIPS
Use of fluoridated water can double fluoride intake.

DID YOU KNOW?
Fluoridation of water can have a major impact on the prevention of tooth decay.

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Iodine

EU RDA (1)
150 µg

BEST SOURCES
Sea fish, shellfish, cod liver oil and milk.

FUNCTIONS
Necessary for normal function of thyroid gland and, hence, metabolic rate.

DEFICIENCY SYMPTONS
Goitre (enlarged thyroid).

TOXIC? (2)
High intake can cause toxic modular goitre and hyperthyroidism.

TIPS
Iodised salt is an ideal help in preventing deficiency.

DID YOU KNOW?
Worldwide, about 0.5 billion are iodine deficient.

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Iron

EU RDA (1)
14 mg

BEST SOURCES
Lean meat, dried fruit, cereals, green vegetables (when accompanied by vitamin C).

FUNCTIONS
A component of haemoglobin and needed by bone marrow to make new blood cells.

DEFICIENCY SYMPTONS
Pallor, weakness, breathlessness, less resistance to infections, apathy, inattentiveness.

TOXIC? (2)
Too high a dose of iron supplements can lead to cirrhosis of the liver.

TIPS
Eat food rich in vitamin C along with iron-rich food to maximise absorption.

DID YOU KNOW?
Most white breads are enriched by iron in the U.K..

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Manganese

EU RDA (1)
2 mg

BEST SOURCES
Tea, but widely distributed in various foods.

FUNCTIONS
Growth of bones and tendons and synthesis of complex carbohydrates and proteins.

DEFICIENCY SYMPTONS
Very rare. Depression, weakness, tremors, irrational behaviour, leg cramps.

TOXIC? (2)
Unlikely to consume toxic dietary amounts.

TIPS
A daily cup of tea proves a good portion of manganese intake.

DID YOU KNOW?
Toxicity only seen in those exposed to certain dusts.

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Molybdenum

EU RDA (1)
50 µg 

BEST SOURCES
Milk, dried legumes, liver, kidney, and cereals.

FUNCTIONS
Constituent of several enzymes.

DEFICIENCY SYMPTONS
Very rare. Only two cases reported.

TOXIC? (2)
Gout-like symptoms.

TIPS
Most diets provide sufficient molybdenum.

DID YOU KNOW?
80% of molybdenum is absorbed in the stomach and small intestine.

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Selenium

EU RDA (1)
55 µg

BEST SOURCES
Protein-rich animal products (meat, eggs, etc.), seafood, certain mushrooms and cereals.

FUNCTIONS
Protects cells against oxidative damage. Stimulates the immune system.

DEFICIENCY SYMPTONS
Low levels linked with muscular weakness, cardiomyopathy.

TOXIC? (2)
Excess may cause gastro-intestinal problems, nerve disorders, nail and hair changes.

TIPS
Eat seafood and cereal foods.

DID YOU KNOW?
When used with vitamin E may increase the well-being (e.g. mental alertness, anxiety, fatigue) of elderly people.

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Zinc

EU RDA (1)
10 mg

BEST SOURCES
Seafood, meats, whole cereals, eggs, pulses.

FUNCTIONS
Extremely important in the immune system and for its role with enzyme activity.

DEFICIENCY SYMPTONS
Growth failure, skin lesions, mental lethargy, impaired immunity.

TOXIC? (2)
High doses may lead to fever, nausea, vomiting, diarrhoea and blood disorders.

TIPS
Fermented grain products (e.g. bread) are better than whole cereals.

DID YOU KNOW?
Zinc availability may be limited by phytate in cereals and certain vegetables.

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Definitions
EU RDA - European Union Recommended Daily Allowance as published in COMMISSION DIRECTIVE 2008/100/EC
of 28 October 2008 amending Council Directive 90/496/EEC on nutrition labelling for foodstuffs as regards
recommended daily allowances, energy conversion factors and definitions (available at: http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:285:0009:0012:EN:PDF).

Note: it must be remembered that age, sex and environment all influence the need for minerals. Eating less food to reduce weight or eating too many refined foods can lead to temporary deficiencies.

Sources used for this chart
Reports of the Scientific Committee for Food (31st Series), Nutrient and Energy Intakes for the European Community, Directorate-General Industrial Affairs, Office des publications officielles des Communautes Europeennes, Luxembourg, 1993.
Recommended Dietary Allowances, 10th Edition, National Research Council, National Academy Press, Washington D.C., 1989. Metal Contamination of Food, C. Reilly, Elsevier, London, 1991

(1) EU RDA - European Union Recommended Daily Allowance.

(2) Toxicity of Minerals: The column "Toxic?" refers strictly to the intake of minerals usually present in foodstuffs. Intakes in excess of the dietary recommendations can be dangerous. Always keep to the recommended dosage as advised by your doctor or medical advisor.