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Description Iodine is an essential trace element – only small amounts are needed to maintain good health.
Function/ Used for Iodine is used to form thyroid hormones (thyroxine and tri- iodothyronine), which regulate metabolic rate.
Intake Recommended intake

EU NRV: 150µg

 

UK average daily intake

Requirements vary depending on age and gender. The UK National Diet and Nutrition Survey lists up-to-date intake requirements and average intakes1

As a supplement Available as a single supplement. Also commonly available as part of a multivitamin and mineral formula.

Different multivitamin and minerals products will vary in the percentage NRVs they include. People should always check the label for information about a specific product.

Found in (dietary sources) Good sources include saltwater fish and shellfish, kelp, seaweed, sea salt, iodised salt, and dairy products.
Deficiency Deficiency may lead to hypothyroidism. Symptoms include tiredness, muscle weakness, breast pain and tenderness, sudden or unexplained weight gain. A classic deficiency sign is goitre (enlargement of the thyroid gland in the neck in order to compensate for low levels of iodine intake).

Infants born to severely deficient mothers are likely to suffer from cretinism (stunted physical and mental growth).

Precautions and contraindications Supplements usually only necessary on medical advice.

Safe Upper Level: 500µg /day2

Use in pregnancy and breastfeeding Doses exceeding the NRV should not be used during pregnancy or breastfeeding (they may result in abnormal thyroid function in the infant)3.
Interactions e.g. with other medications Iodine may interact with thyroid medication3.
Adverse effects High iodine intake may induce hyperthyroidism (particularly in those over the age of 40 years) or hypothyroidism in autoimmune thyroid disease.

Toxicity is rare with intakes below 5000µg daily and extremely rare at intakes below 1000µg daily.

Hypersensitivity reactions including headache, rashes, symptoms of head cold, swelling of lips, throat and tongue, and joint pain have been reported.3

References 1.     https://www.gov.uk/government/collections/national-diet-and-nutrition-survey

2.     Expert Group on Vitamins and Minerals, 2003.

3.     Mason, P. Dietary Supplements. Pharmaceutical Press, London, 2001.

 

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Description Iron is an essential trace mineral.
Function/ Used for Iron is essential for the formation of haemoglobin which is present in red blood cells. Haemoglobin is being formed in the body all the time and is the substance in red blood cells that transports oxygen around the body.
Intake Recommended intake

EU NRV: 14mg

 

UK average daily intake

Requirements vary depending on age and gender. The UK National Diet and Nutrition Survey lists up-to-date intake requirements and average intakes1.

As a supplement Available as a single supplement. Also commonly available as part of a multivitamin and mineral formula.

Different multivitamin and minerals products will vary in the percentage NRVs they include. People should always check the label for information about a specific product.

Found in (dietary sources) Good sources include liver, kidney, heart, red meat, beef, pork, canned pilchards/sardines, fish, shellfish, wholegrain cereals, eggs, spinach, chicken, leafy green vegetables and fortified breakfast cereals.

Iron is most easily absorbed from animal sources.

Vitamin C improves the absorption of iron from plant sources.

Deficiency Symptoms include anaemia, concave and brittle nails, sore tongue, cracking in the corners of the mouth, increased susceptibility to infection. Also, tiredness, muscle fatigue, skin itching, dizziness, headache, insomnia, brittle hair and hair loss.
Precautions and contraindications Iron supplements should be avoided in conditions associated with iron overload (e.g. haemochromatosis, haemosiderosis, thalassaemia), and gastrointestinal disease, particularly inflammatory bowel disease, diverticulitis and peptic ulcer1.

Overdose of iron is dangerous, particularly in young children.

 

Safe Upper Level: 17mg2

Use in pregnancy and breastfeeding Iron supplementation is not generally required in pregnancy, but iron status should be monitored.
Interactions e.g. with other medications Antacids, tetracyclines (antibiotics), warfarin (anti-coagulant), calcium carbonate or calcium phosphate, and zinc may reduce the absorption of iron – they should be given two hours apart.

Aspirin and NSAIDs such as ibuprofen may cause stomach irritation, bleeding and iron loss which may lead to deficiency. To avoid irritation take with food.

Large doses of iron may increase the requirement for vitamin E.3,4

Adverse effects Iron supplements may cause gastrointestinal irritation, nausea and constipation, which may lead to faecal impaction (where dried, hard stools collect in the rectum and anus), particularly in the elderly.

Patients with inflammatory bowel disease may suffer  worsening of diarrhoea.

Liquid iron preparations may stain the teeth.3

References 1.     https://www.gov.uk/government/collections/national-diet-and-nutrition-survey

2.     Expert Group on Vitamins and Minerals, 2003.

3.     Mason, P. Dietary Supplements. Pharmaceutical Press, London, 2001.

4.     Gaby, A. R. A-Z Guide to Drug-Herb-Vitamin Interactions. HealthNotes 2006.

 

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