Cholesterol is a necessary component of every cell in your body, comprising the delicate membrane that separates each cell from its surrounding environment. Cholesterol also contributes to the formation of hormones and the production of bile. However, health problems caused by excess cholesterol are prevalent in modern societies. A dynamic field of research is dedicated to solving the riddle of cholesterol management, with new insights and potentially useful information continually being revealed and much yet to be learned about this important substance.
Algae and LDL
Algae may offer cholesterol-lowering benefits, say researchers at Kwong Living Trust Food Safety and Analysis Laboratory and Department of Biology, Hong Kong Baptist University. In the six-week laboratory animal study that tested three different extracts of algae, total cholesterol and low-density lipoprotein, the bad form of cholesterol, were decreased significantly in two out of the three groups. The algae lowered cholesterol by inhibiting HMG-CoA reductase, an important enzyme in the manufacture of cholesterol. Intestinal cholesterol receptors were also reduced, resulting in less absorption of cholesterol from food. The study was published in the May 2011 issue of the "Journal of Agricultural and Food Chemistry."
Exercise and Cholesterol Levels
Researchers at the Lipids Laboratory, Faculty of Medical Sciences, University of Sao Paulo, Brazil reported that exercise might lower your cholesterol by increasing a process known as reverse cholesterol transport, whereby cholesterol is brought back to the liver and recycled. In the laboratory animal study, mice that exercised on a treadmill for 30-minute sessions, five times per week, showed higher cholesterol excretion levels, higher levels of cholesterol in cells that carry cholesterol back to the liver and higher levels of cholesterol in the liver. Plasma levels of cholesterol did did not decrease with exercise, but the overall effect of increasing reverse cholesterol transport discourages atherosclerosis and improves cardiovascular health. Human trials are needed to confirm the results of this preliminary study published in the April 2011 issue of the journal "Lipids."
Immune Connection
Your immune system plays an important role in the formation of arterial plaques, say researchers at Sezione di Medicina Interna, Dipartimento di Medicina Clinica e Scienze Immunologiche, Università degli Studi di Siena, Italy, in an article published in the April 2005 issue of the journal "Italian Annals of Internal Medicine." Dysfunction of the endothelium -- the inner lining of blood vessels -- impairs the ability of the endothelium to carry out blood vessel dilating and anti-clotting functions. The endothelium also becomes more permeable to cholesterol, which infiltrates the artery wall, becomes trapped there, and oxidizes. White blood cells called macrophages attempt to remove the oxidized cholesterol and, in the process, attract other white blood cells. If the immune response becomes chronic the inflammation progresses and changes from a protective mechanism to an injurious one. Plaque can then accumulate and may rupture and the inflammatory process escalates. Blood platelets may also be activated and initiate clotting.
Amaranth
Amaranth seed, often eaten as a grain substitute, reversed atherosclerotic plaques in a study on laboratory animals, published in the May 2011 issue of the journal "Lipids in Health and Disease." In the study, a diet supplemented with 150 mg per 1 kg body weight of amaranth extract for 45 days significantly decreased total cholesterol levels, decreased levels of byproducts of lipid oxidation and lower levels of C-reactive protein -- a marker for inflammation. Area of plaque formation was also significantly diminished in the group that consumed amaranth extract.
References
- "Journal of Agricultural and Food Chemistry"; Microalga Decreases Plasma Cholesterol by Down-Regulation of Intestinal Npc1l1, Hepatic LDL Receptor, and HMG-CoA Reductase; J. Chen, et al.; May 2011
- "Lipids"; Aerobic Exercise Improves Reverse Cholesterol Transport in Cholesterol Ester Transfer Protein Transgenic Mice; D. Rocco, et al.; April 2011
- "Italian Annals of Internal Medicine"; Immune Factors in Atherosclerosis; A. Pasqui, et al.; April 2005
- "Lipids in Health and Disease"; Lipid Lowering by Hydroalcoholic Extracts of Amaranthus Caudatus L. Induces Regression of Rabbits Atherosclerotic Lesions; N. Kabiri, et al.; May 2011
