Iodine is needed for the normal function of the thyroid gland and hence our metabolic rate.
Sources
Sea fish, shellfish and milk.
The recommended daily amount of iodine is 150 micrograms for adults and children over the age of 5. Iodine deficiency is rare in the UK due to the level of iodine in milk and the availability of sea fish. Low intakes may be seen in vegans, for whom edible seaweeds can be a useful source of iodine. Excessive intakes of iodine can have toxic effects on the thyroid gland.
The body of a healthy adult will contain about 3-4g of iron. Over half of this is in the form of haemoglobin, the red pigment in blood. Iron is also found in muscles and in the liver where it can be stored for a limited period of time.
Iron is needed for healthy blood, as it forms a key part of red blood cells which are needed for effective transportation of oxygen in the body.
Sources
Red meat, dried fruit, fortified breakfast cereals, green vegetables, bread and flour products. By law, iron must be added to most flour (except wholemeal).
Whilst the iron in meat is absorbed fairly well, the iron in cereals and vegetables - non-haem iron - is less readily absorbed from food into the body. Absorption of non-haem iron can be improved when accompanied by vitamin C.
The recommended daily amount is 14 micrograms for adults and children over the age of 5. Teenage girls and young women are at most risk of inadequate intakes due to increased requirements for iron to replace blood lost during menstruation. Vegetarians and vegans may also need to pay careful attention to their diets to ensure adequate intakes of iron in the diet.
Iron deficiency can lead to a form of anaemia which is characterised by a lack of energy, pallor (pale condition) and inattentiveness.
Potassium is needed for normal nerve function and muscle contraction, and for the regulation of blood pressure.
Sources
Fruit and vegetables are good sources of potassium, and aiming for the recommended (at least) five portions of fruit and vegetables a day will help increase potassium intakes. Meat also provides potassium.
There is no recommended daily amount for potassium. UK recommended intakes which would be sufficient for most of the population are 3,500mg per day for adult men.
In the UK there is a general need to increase potassium intakes and decrease sodium intakes to achieve a better balance of the two minerals. Eating at least five portions of fruit and vegetables a day will help increase potassium intakes, whilst serving them with no added salt during cooking or at the table will help reduce sodium intakes.
