Many biological and dietary factors affect your cholesterol level, including saturated fat intake, liver function and hormone production. Early scientific studies such as the one published in the 1916 issue of "The Journal of Biological Chemistry" reveal a relationship between anemia and cholesterol content. Although doctors still do not understand the mechanism of why anemia causes a low cholesterol level, various studies continue to support the existence of the relationship.
Anemia
Anemia is a general term used to describe a condition characterized by a low level of functioning red blood cells in your blood. Several types of anemia exist, classified by the cause. Iron-deficiency anemia occurs due to a lack of the mineral iron, which your body needs to produce the oxygen-carrying protein in red blood cells known as hemoglobin. Aplastic anemia occurs when your bone marrow fails to produce enough new red blood cells. Sickle cell anemia is a genetic disease that occurs when your body produces defective hemoglobin, making your red blood cells irregularly shaped. Patients with anemia often have low blood cholesterol levels. Since high blood cholesterol -- levels of more than 240 mg/dl -- contribute to the onset of heart disease, learning more about this relationship may help reveal ways to prevent high cholesterol.
Theories
Cholesterol, a fat-like substance, travels through the blood to reach cells that use it to produce hormones, make vitamin D and provide structure to cell membranes. Although cholesterol and red blood cells do not directly interact, research published in the 2010 issue of "Journal of Research in Medical Science" proposes theories to explain why anemic patients have lower blood cholesterol levels than patients with normal levels of red blood cells. In conditions of anemia, your body may increase the rate of red blood cell production, a process known as erythropoiesis, which may lead to increased cholesterol uptake by certain types of white blood cells. A decrease in red blood cells affects the fluid portion of the blood known as plasma, causing plasma dilution. Since cholesterol travels through the plasma, this may affect cholesterol concentrations. A low level of red blood cells may leave an increased amount of unused iron which can cause defective liver function. Since liver cells produce the majority of cholesterol in your body, this can result in a decreased cholesterol production. Anemia may cause hormonal disturbances, and an increase in hormone production may use more cholesterol, leaving a reduced blood cholesterol level.
Evidence
Even in the absence of an explanation, various research study results confirm the link between anemia and low cholesterol. A study published in the November 2007 issue of the "American Journal of Medical Science" investigated the link between iron deficiency anemia and blood lipid levels. In this study, doctors compared the cholesterol levels in premenopausal women with iron deficiency anemia against non-anemic control patients. The study concluded that a low level of iron provides a protective effect against high cholesterol, which can cause atherosclerosis and lead to heart disease. A study published in the March 2008 issue of the "British Journal of Hematology" supports the theory of plasma dilution, stating that the changes in cholesterol levels caused by anemia occur due to a redistribution of the cholesterol. A study conducted in an anemic mouse model and published in the 1986 issue of the "International Journal of Biochemistry, Biophysics and Molecular Biology" determined that the low cholesterol level occurs as a result of a decreased cholesterol production in the liver.
Healthy Suggestions
Although doctors urge you to maintain low blood cholesterol levels, under 200 mg/dl, anemia is not a healthy way to obtain this result. Anemia causes a variety of symptoms, including fatigue, irregular heartbeat, shortness of breath, chest pain, dizziness and headache. To prevent anemia, get the daily recommended intake of iron, listed by the Institute of Medicine as 8 mg per day for men and post-menopausal women and 18 mg per day for premenopausal women. A vitamin B-12 deficiency or folate deficiency can also lead to anemia, so eat plenty of green leafy vegetables and lean meat, fish and poultry. To keep low blood cholesterol levels, exercise regularly, quit smoking, maintain a healthy weight and limit your intake of saturated and trans fats, as suggested by the National Heart, Lung and Blood Institute.
References
- "The Journal of Biological Chemistry"; Cholesterol in Human Blood Under Pathological Conditions; Denis, W.; 1916
- "American Journal of Medical Science"; The Relationship Between Iron Deficiency Anemia and Lipid Metabolism in Pre-Menopausal Women; Ozdemir, A. et al.; November 2007
- "International Journal of Biochemistry, Biophysics and Molecular Biology"; Relationship Between Anemia and Cholesterol Metabolism in Sex-linked Anemic Mouse; Au, S. and Schilling, R.; September 1986
- "British Journal of Hematology"; Hypocholesterolaemia and Anaemia; Westerman, M.; March 2008
- "Journal of Research in Medical Sciences"; Serum Lipid Profiles in Patients with Beta-Thalassemia Majory and Intermediate; Haghpanah, S. et al.; May-June 2010
- National Heart, Lung and Blood Institute; High Blood Cholesterol; September 2008
