"Anaemia is the general term for having either fewer red blood cells than normal or having an abnormally low amount of haemoglobin in each red blood cell," it explains.
The NHS warns: "Some of these problems can also happen if you have a deficiency in vitamin B12 or folate but do not have anaemia.
These vitamins are crucial for daily functioning, but a deficiency can lead to symptoms such as tingling sensations (pins and needles), low energy and fatigue.
Anaemia caused by a lack of Vitamin B12 or B9 (folate) occurs when the body is deficient in these vital vitamins.
The NHS clarifies that red blood cells carry oxygen around the body using haemoglobin.
