Blood haemoglobin level and iron supplementation

On this page you can find information about hemoglobin, ferritin and prevention of iron deficiency in blood donors.

What is haemoglobin (Hb)?

Haemoglobin is a constituent of red blood cells, helping to transport oxygen from the lungs to other parts of the body. The ability of haemoglobin to carry oxygen is based on the iron present in the haemoglobin molecule.

The haemoglobin level in human blood is very individual.

What is iron needed for?

Iron is a basic component of body tissues. In addition to the haemoglobin of red cells, iron has important functions in muscles and in enzymes which regulate bodily processes.

Iron is stored in the bone marrow and liver. There are great individual differences in the size of iron stores, and men have about threefold larger iron stores than women.

What are the consequences of iron deficiency?

Iron deficiency causes anaemia, i.e. a lowering of blood haemoglobin levels. While anaemia may be caused by a variety of factors, iron deficiency is the most common causative factor.

Mild iron deficiency may cause symptoms such as tiredness and impaired performance even before any decrease in haemoglobin levels becomes manifest.

The donor's hemoglobin value is measured before each blood donation with a rapid test.

How to get enough iron?

A healthy person gets enough iron from a varied, balanced diet. Foods containing liver, meat, blood, lentils, soybeans, edible seaweed, rye and oat bran are rich in iron. Iron absorption can be improved by eating vitamin C-containing food products (e.g. citrus fruits or fruit juices).

Blood donors may have an increased need for iron

The iron lost during a blood donation is gradually replaced by iron obtained from the diet over a period of a few months. In frequent blood donors, the body does not always have enough time to replace the lost iron with dietary iron.

The risk of iron deficiency is also known to be highest among women of fertile age, particularly the youngest (aged 18 to 25).

The Blood Service provides iron supplements to donors at risk of iron deficiency each time they donate blood. The iron supplement is intended to prevent any iron deficiency caused by donating blood. Dietary iron and iron from iron supplements are absorbed independently in the body, so blood donors should choose iron-containing foods even when taking iron supplements.

Can you get too much iron?

The iron supplementation offered by the Blood Service is safe for healthy donors. Of importance is however, that iron affects the absorption of many medicinal products. Donors should take into account to keep a 2 hours time interval between taking any medicines and the iron capsules.

Iron supplementation may cause gastrointestinal symptoms.

How to take iron tablets given during a blood donation

Take one (1) iron tablet every day or every two days. Take all the tablets given to you during your donation. The iron in the tablet is best absorbed if taken on an empty stomach, but you can also take the tablet at mealtimes.

Vitamin C enhances the absorption of iron while milk, coffee, and tea products impair it. The iron tablets also contain a small amount of vitamin C.

Is the iron product suitable for vegans?

The iron preparation distributed to blood donors is also suitable for lactose intolerants, celiacs and vegans.

Read about iron supplement

Recommendations for donation intervals

For women aged 18-25, we recommend donating no more than once a year, and for other women no more than 2-3 times a year. For men, we recommend a maximum of 3–4 blood donations per year.

See the minimum permitted intervals