Over many generations, the human body became well-adapted to a high level of iron content in the diet. Neolithic
In the Neolithic era, significant changes are thought to have occurred in both the environment and diet. Some communities of foragers migrated north, leading to changes in lifestyle and environment, with a decrease in temperatures and a change in the landscape which the foragers then needed to adapt to. As people began to develop and advance their tools, they learned new ways of producing food, and farming also slowly developed. These changes would have led to serious stress on the body and a decrease in the consumption of iron-rich foods. This transition is a key factor in the mutation of genes, especially those that regulated dietary iron absorption. Iron, which makes up 70% of red blood cell composition, is a critical micronutrient for effective thermoregulation in the body. Iron deficiency will lead to a drop in the core temperature. In the chilly and damp environments of Northern Europe, supplementary iron from food was necessary to keep temperatures regulated, however, without sufficient iron intake the human body would have started to store iron at higher rates than normal. In theory, the pressures caused by migrating north would have selected for a gene mutation that promoted greater absorption and storage of iron. Viking hypothesis
Studies and surveys conducted to determine the frequencies of haemochromatosis help explain how the mutation migrated around the globe. In theory, the disease initially evolved from travelers migrating from the north.
Iron overload or haemochromatosis (also spelled hemochromatosis in American English) indicates increased total accumulation of iron in the body from any cause and resulting organ damage. The most important causes are hereditary haemochromatosis (HH or HHC), a genetic disorder, and transfusional iron overload, which can result from repeated blood transfusions. Signs and symptoms
Organs most commonly affected by haemochromatosis include the liver, heart, and endocrine glands.Haemochromatosis may present with the following clinical syndromes:

liver: chronic liver disease and cirrhosis of the liver. heart: heart failure, cardiac arrhythmia. hormones: diabetes (see below) and hypogonadism (insufficiency of the sex hormone producing glands) which leads to low sex drive and/or loss of fertility in men and loss of menstrual cycle in women. metabolism: diabetes in people with iron overload occurs as a result of selective iron deposition in islet beta cells in the pancreas leading to functional failure and cell death. skeletal: arthritis, from calcium pyrophosphate deposition in joints leading to joint pains. The most commonly affected joints are those of the hands, particularly the knuckles of the second and third fingers. skin: melanoderma (darkening or bronzing of the skin).The skins deep tan color, in concert with insulin insufficiency due to pancreatic damage, is the source of a nickname for this condition: "bronze diabetes" (for more information, see the history of haemochromatosis). Causes
The term haemochromatosis was initially used to refer to what is now more specifically called haemochromatosis type 1 (or HFE-related hereditary haemochromatosis).