Infections and heart disease

Part 2: Low cholesterol compromises the immune system

There is, however, another reason for a poorly-functioning immune system: Low blood cholesterol, particularly low LDL

There is substantial epidemiologic evidence indicates that relative hypocholesterolemia (low blood cholesterol) in apparently healthy individuals is associated with increased subsequent mortality from cancer and other nonatherosclerotic causes of death, including diseases caused by infectious agents. In a study from 1997, a group at the Center for Clinical Pharmacology, University of Pittsburgh, Pennsylvania, found that the immune systems of the men whose cholesterol averaged 3.9 mmol/L (151 mg/dL) were significantly less effective than those of men with an average cholesterol of 6.8 mmol/L (261 mg/dL).

The researchers write: "Relative to the high cholesterol group, hypocholesterolemic men had significantly fewer circulating lymphocytes, fewer total T cells, and fewer CD8+ cells (P's < 0.05). Trends toward fewer CD4+ cells and less IL-2 release in response to PHA were also noted in the low, compared to the high, cholesterol group."

The best protection from coronary heart disease could well be a strong immune system. In this respect, lowering your cholesterol level doesn't look like a good idea.

References
1. Muldoon MF, Marsland A, Flory JD, et al. Immune system differences in men with hypo- or hypercholesterolemia. Clin Immunol Immunopathol 1997; 84: 145-9.