Millions of Americans suffer from high blood cholesterol. It is a risk factor for heart disease, the largest cause of death in the country, so it is rarely recognized that the opposite can also occur and your body can suffer from a cholesterol deficiency. A low level of cholesterol in the blood is specifically known as hypocholesterolemia; when the body finds itself unable to perform many of the functions previously carried out by cholesterol, the deficiency can manifest as a myriad of conditions with different symptoms and treatments. Cholesterol deficiency is much rarer than elevated cholesterol levels but just as potentially dangerous.
Cholesterol
Cholesterol is a type of lipid needed as a structural component in cell membranes and a precursor to hormones. It is packaged in molecules known as lipoproteins for transport within the blood. Therefore, measuring the amount of lipoproteins within the blood will tell you the amount of cholesterol in your body. A blood cholesterol level below 160 mg/dL---milligrams per deciliter---is considered too low. By comparison, levels between 160 and 200 mg/dL are desirable.
Deficiency
Dietary cholesterol does not necessarily translate into blood cholesterol. Most cholesterol is actually synthesized in the cells from fatty acids. Malnutrition and malabsorption may cause a cholesterol deficiency, because our diets contain the building blocks that construct cholesterol. However, it might also be caused by disruptions in the biosynthesis pathway. Smith-Lemli-Opitz syndrome, for example, is a genetic disorder that causes a deficiency in an enzyme --- a protein that facilitates chemical reactions --- that converts the intermediate molecule 7-dehydrocholesterol to cholesterol.
Considerations
According to an article by William E. Connor in the January 1995 issue of "The Journal of Clinical Investigation," the brain has the highest cholesterol concentration of any organ in the body. It is needed for the permeability and fluidity of nerve cells. Because of the blood brain barrier, which is the separation of circulating blood and cerebrospinal fluid in the nervous system, the brain synthesizes its cholesterol independently from the rest of the body.
Effects
The use of cholesterol as a structural component in nerve cells means that a deficiency will manifest itself both in the mental landscape and the physical constructs of the brain. William E. Connor reported in his paper that cholesterol deficiency during human growth and development has been known to cause mental impairment, hyper tonicity, which is low osmotic pressure in the cells, and microcephaly, which impairs the growth of the brain's physical size.
Theories/Speculation
A 1994 study by C. J. Glueck and colleagues in "The American Journal of the Medical Sciences" examined the relationship between low blood cholesterol and individuals with affective disorders such as depression, bipolar disorder and schizoaffective disorder. It found that low blood cholesterol concentrations were more common in patients with affective disorders than in urban supermarket screenees --- 20 percent vs. just 4 percent --- but the researchers found no evidence that low blood cholesterol could cause or worsen affective disorders. The relationship between cholesterol and affective disorders still remains controversial, and the role that a cholesterol deficiency plays in the brain continues to be investigated. In 2009 a medley of researchers led by D. De Berardis, publishing in the "Journal of Biological Regulators and Homeostatic Agents," did state that the majority of literature shows a consistent relationship between cholesterol levels and both mood disorders and suicidal behavior.
Diagnosis and Treatment
Unless the cholesterol deficiency is a product of malnutrition or a nutritional deficiency existing in the diet, or even a corrective medical condition, it is very difficult or impossible to reverse its effects. This is especially true of genetic disorders. Because the cause may be so varied, however, the potential treatment will depend upon the diagnosis of the disease.
References
- University of Cincinnati-Clermont College: Lipids
- "The Journal of Clinical Investigation"; A Cholesterol Deficiency Syndrome in Humans; W. E. Connor; January 1995
- "The American Journal of the Medical Sciences"; Hypocholesterolemia and Affective Disorders; C. J. Glueck; October 1994
- "Journal of Biological Regulators and Homeostatic Agents"; The Role of Cholesterol Levels in Mood Disorders and Suicide; D. De Berardis, et al.; July 2009
