Lutein (2001, 2011, 2017) & Atherosclerosis
Learn more about atherosclerosis.
Researchers evaluated the effect of high levels of the carotenoid lutein in the circulatory system with respect to incidence of coronary artery disease in lab animals. The researchers measured the thickness of the innermost two layers of artery walls. They found that animals given an extra lutein supplement to their western diet equivalent had 44% smaller sized coronary artery lesions. Their conclusion was that supplementation with lutein and increased lutein content in the daily diet helps to protect against atheroschlerosis.
Researchers: James H. Dwyer, et al, The Los Angeles Atherosclerosis Study
Published: Oxygenated Carotenoid Lutein and Progression of Early Atherosclerosis, Circulation, June, 2001
Researchers again measured the thickness of the two inner walls of the coronary arteries before plaque had formed to determine whether carotenoids could be helpful. They also measured the degree of artery stiffness using carotid ultrasonography and blood levels of carotenoids.
This study involved 125 patients with early atherosclerosis and 107 control subjects who were 45 to 68 years old. The patients with early atherosclerosis had markedly lower levels of lutein in the blood. They found further that lutein levels were tied to inner artery wall thickness and that zeaxanthin and beta-carotene were associated with artery thickness and other measurements. These latter connections need to be further investigated.
Researchers: Z. Zou, X. Hu, Y. Huang, et al.
Published: High serum level of lutein may be protective against early atherosclerosis: the Beijing atherosclerosis study, Atherosclerosis, December, 2011.
A study was done back in 1995 that connected low levels of the carotenoid lutein in the blood with a greater risk of developing hardening of the arteries - atherosclerosis. They had noted that patients in Northern Ireland where vegetable and fruit intake was low had a much higher rate of the condition than subjects in Southern France, where vegetables and fruit make up a large percentage of the diet.
In 1995 researchers thought that the difference was due to the ability of carotenoids to prevent free radical activity causing oxidation of fats to harden into plaque.
However, it is now accepted by most health professionals that coronary artery disease is largely caused by inflammation, and that large cells within areas of plaque damage artery lining tissue which aggrevates such inflammation.
The blood carries precursor proteins which are part of the immune system known as C3 and C3a. These precursor proteins are found in much higher concentrations in patients with atherosclerosis, and the metabolism of these precursors (a normal function of the immune response) in the case of artery walls generates a "membrane attack complex (MAC)" which kills artery wall cells resulting in damage to the artery wall.
What researchers discovered is that when lutein levels are high in the blood then concentrations of C3 and C3a are reduced - indicating that the body is in a more healthy condition. Note that the high levels of C3 and C3a are also present in patients with macular degeneration.
Researchers: A. N. Howard, D. I. Thurnham
Published: Lutein and atherosclerosis: Belfast versus Toulouse revisited, Medical Hypotheses, January 2017.