Progression of Carotid Intima-Media Thickness and Plasma Antioxidants: The Los Angeles Atherosclerosis Study

Abstract

Objective-Recent epidemiologic and animal model data suggest that oxygenated carotenoids are protective against early atherosclerosis. We assessed the association between atherosclerotic progression, measured by carotid intima-media thickness (IMT), and plasma levels of oxygenated and hydrocarbon carotenoids, tocopherols, retinol, and ascorbic acid. Methods and Results-Participants were from an occupational cohort of 573 middle-aged women and men who were free of symptomatic cardiovascular disease at baseline. Ultrasound examination of the common carotid arteries, lipid level determination, and risk factor assessment were performed at baseline and 18-month follow-up. Plasma levels of antioxidants were determined at baseline only. Change in IMT was related to baseline plasma antioxidant levels in regression models controlling for covariates. In models adjusted for age, sex, and smoking status, 18-month change in IMT was significantly inversely related to the 3 measured oxygenated carotenoids (lutein, ␤-cryptoxanthin, zeaxanthin; PϽ0.02 for all) and one hydrocarbon carotenoid, ␣-carotene (Pϭ0.003). After adjusting for additional cardiac risk factors and potential confounders, including high-sensitivity C-reactive protein, these associations remained significant (PϽ0.05). Conclusions-These findings suggest that higher levels of plasma oxygenated carotenoids (lutein, zeaxanthin, ␤-cryptoxanthin) and ␣-carotene may be protective against early atherosclerosis. Key Words: atherosclerosis Ⅲ antioxidants Ⅲ carotid arteries T he oxidative-modification hypothesis proposes that atherogenesis is initiated by oxidative damage to lowdensity lipoproteins (LDL) in the artery wall. The presence of oxidized LDL in the subendothelium of arteries stimulates monocyte recruitment and differentiation to macrophage, resulting in the formation of foam cells and increased thickness of arterial walls. 1 Antioxidants have been hypothesized to inhibit lipid peroxidation and play a protective role against chronic diseases such as cardiovascular disease. 2 In vitro studies suggest that vitamins C and E and carotenoids inhibit the damaging activities of oxidized LDL cholesterol. [3][4][5] Evidence from population studies, including descriptive, case-control, and cohort studies, has shown that dietary, 6 -11 plasma, or serum level of vitamin E, 12-14 ascorbic acid, 15-17 and carotenoids 18 -22 were inversely associated with cardiovascular mortality rate or early atherosclerosis. However, other epidemiological studies have reported no association between cardiovascular events with plasma 23,24 or serum antioxidants, 25-27 and dominantly negative results have been reported from intervention trials of ␤-carotene or vitamin E. 28 -32 We previously reported that dietary supplementation with lutein reduced atherosclerosis in two strains of susceptible mice. 22 We also found that plasma lutein was inversely associated with progression of atherosclerosis, as measured by carotid intima-media thickness (IMT), in a cohort of middle-aged women and men. ...

The total antioxidant capacity of the diet is an independent predictor of plasma β-carotene

“…Despite the epidemiological observation that intake of fruits and vegetables rich in carotenoids and plasma concentrations of b-carotene are both inversely related to the prevalence of type II diabetes (Coyne et al, 2005) and to the risk of future cardio-and cerebrovascular events (D'Odorico et al, 2000;Hak et al, 2003Hak et al, , 2004Dwyer et al, 254 (149) 269 (163) 273 (109) 310 (148) 0.033 Vegetables-pulses (g/day)…”

“…A similar pattern has been observed for cardiovascular disease (CVD) risk and death for all causes. With few exceptions, cohort studies show a higher incidence of atherosclerosis and CVD among subjects with low concentrations of plasma b-carotene and, to a lesser extent, with low dietary (or supplemental) intake of carotenoids (Kritchevsky et al, 1995;D'Odorico et al, 2000;Hak et al, 2003Hak et al, , 2004Dwyer et al, 2004), but supplementation studies with b-carotene, either alone or in combination with other antioxidants, have demonstrated no effect in primary or secondary CVD prevention (Tornwall et al, 1999;Asplund, 2002;Vivekananthan et al, 2003). Finally, low-plasma b-carotene is associated with higher mortality for all causes, but b-carotene supplementation does not reduce the risk of death significantly (Greenberg et al, 1996).…”

The potential of avocado paste (Persea americana) as fat substitute in non-dairy ice cream

“…It has been reported that people who consumed avocado regularly tended to have a sufficient nutrient supply of dietary fibre, vitamin K, vitamin E, potassium, magnesium, as well as vitamin B complex [14]. These nutrients provide a wide range of potential health benefits such as preventing hypercholesterolemia [15], vascular damage [16], and reduce the risk of atherosclerosis [17]. The consumption of avocado has been investigated to have positive effects on lipid profiles [18] by increasing HDL cholesterol levels, reducing lipid serum peroxidation, and promoting cardiovascular health [19].…”

“…Plant-based fat sources have great potentials to be used as a replacement for dairy-based fat sources in the ice cream formulation. Furthermore, plant-based sources are generally less expensive compared to dairy fat [21] and provide advantages towards health [15], [16], [17], [18], [19]. The objective of this study was to analyze the physicochemical, rheological and sensorial properties of ice cream that have been substituted with different concentrations of avocado paste.…”

Effect of Chlorella and Its Fractions on Blood Pressure, Cerebral Stroke Lesions, and Life-Span in Stroke-Prone Spontaneously Hypertensive Rats

“…The potent preventive effect of the Chlorella lipid fraction may have been caused by synergistic action due to the high content of multiple antioxidants, carotenoids and others. Recently, Iribarren et al (30), and Dwyer et al (31,32) have presented papers in which epidemiological study and mouse model findings support the hypothesis that increased dietary intake of lutein suppresses the progression of intima-media thickness of the common carotid arteries, and is protective against the development of early atherosclerosis. Extensive epidemiological studies also have shown that increased intake of carotenoids, especially lutein, is correlated significantly with decreased risk of cerebral stroke and coronary heart disease (33)(34)(35).…”