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Posts Tagged ‘carotenoids’


Reporter and Curator: Dr. Sudipta Saha, Ph.D.

Antioxidant micronutrients, such as vitamins and carotenoids, exist in abundance in fruit and vegetables and have been known to contribute to the body’s defence against reactive oxygen species. Numerous epidemiological studies have demonstrated that a high dietary consumption of fruit and vegetables rich in carotenoids or with high serum carotenoid concentrations results in lower risks of certain cancers, diabetes and cardiovascular disease. These epidemiological studies have suggested that antioxidant carotenoids may have a protective effect against diabetes or cardiovascular disease. However, the consumption of carotenoids in pharmaceutical forms for the treatment or prevention of these chronic diseases cannot be recommended, because some large randomized controlled trials did not reveal any reduction in cardiovascular events or type 2 diabetes with b-carotene. High doses of carotenoids used in the supplementation studies could have a pro-oxidant effect. Therefore, it is favourable to intake carotenoids from foods through the combination of other nutrients such as vitamins, minerals or phytochemicals, not by supplements.

The metabolic syndrome is a clustering of metabolic abnormalities that increase the risk for diabetes and cardiovascular disease. Typically, it includes excess weight, hyperglycaemia, evaluated blood pressure, low concentration of HDL-cholesterol, and hypertriacylglycerolaemia. This syndrome is emerging as one of the major medical and public health problems in Japan, and persons with this syndrome have an increased risk of morbidity and mortality due to cardiovascular disease and diabetes. Recently, many studies have examined the associations of dietary patterns with the metabolic syndrome and shown that diets rich in fruit and vegetables have been inversely associated with the metabolic syndrome. These previous reports suggest that a high intake of fruit and vegetables may reduce the risk of the metabolic syndrome through the beneficial combination of antioxidants, fibre, minerals, and other phytochemicals. Some recent cross-sectional and case–control studies have shown the associations of serum antioxidant status with the metabolic syndrome. Ford et al. reported that low intake and/or low serum concentrations of vitamins and carotenoids were associated with the risk of the metabolic syndrome. Although very few data are available about the associations of antioxidant carotenoids with the metabolic syndrome, people who have the metabolic syndrome are more likely to have increased oxidative stress than people who do not have this syndrome.

In some recent studies, it has been reported that oxidative stress, which is an imbalance between pro-oxidants and antioxidants, occurs more frequently in metabolic syndrome subjects than in non-metabolic syndrome subjects. Oxidative stress may play a key role in the pathophysiology of diabetes and cardiovascular disease. On the other hand, smoking is a potent oxidative stress in man. This increment of oxidative stress induced by smoking may develop insulin resistance, and increased insulin resistance may result in the clustering of the metabolic abnormality. Therefore, antioxidants could have a beneficial effect on reducing the risk of these conditions in smokers. However, there is limited information about the interaction of serum antioxidant carotenoids and the metabolic syndrome with smoking habit. This study was aimed to investigate the interaction of serum carotenoid concentrations and the metabolic syndrome with smoking. The association of the concentrations of six serum carotenoids, i.e. lutein, lycopene, a-carotene, b-carotene, b-cryptoxanthin and zeaxanthin, with metabolic syndrome status stratified by smoking status was evaluated crosssectionally.

In this study, the associations of the serum carotenoids with the metabolic syndrome stratified by smoking habit were evaluated cross-sectionally. A total of 1073 subjects (357 male and 716 female) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Inverse associations of serum carotenoids with the metabolic syndrome were more evident among current smokers than non-smokers. These results support that antioxidant carotenoids may have a protective effect against development of the metabolic syndrome, especially in current smokers who are exposed to a potent oxidative stress.

Source References:

http://www.ncbi.nlm.nih.gov/pubmed/18445303

http://www.ncbi.nlm.nih.gov/pubmed/19450371

http://www.ncbi.nlm.nih.gov/pubmed/21216053

http://www.ncbi.nlm.nih.gov/pubmed/19631019

http://www.ncbi.nlm.nih.gov/pubmed/12324189

http://www.ncbi.nlm.nih.gov/pubmed/18689373

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