Circulating Carotenoid Concentrations, Disease Risk, and Genetics
Scientific interest in antioxidants seems to be waning – for no apparent reason. If anything, limited consumption of vegetables (and fruit) should be driving consumer and researcher interest. Why? Because previous studies have found maintaining high concentrations of serum carotenoids may protect against heart attacks, stroke, and Alzheimer’s disease mortality.
Using a genome wide association study (GWAS) from 441 Old Order Amish adults, D’Adamo and colleagues find genetics may determine serum carotenoid concentrations, in this case lycopene concentrations. The study benefitted from a controlled diet over a 6 day period in a population which was homogeneous in terms of genetics, environmental exposures, and lifestyle habits. The mean serum lycopene concentration was 39.2 µg/dL, ranging from 19.3 to 59.1 (0.75; 0.37-1.14 µmol/L). These serum lycopene concentrations are consistent with nationally representative data for the US population over 6 years of age (39.4 µg/dL, 0.76 µmol/L).
Low serum carotenoid concentrations predict mortality in US adults. Tomato products, usually catsup, are the primary source of lycopene in the US diet. Karppi and colleagues measured differences in acute myocardial infarction in men with serum lyocopene concentrations of 0.11 vs 0.16 µmol/L (5.2 vs 8.3 µg/dL).
It appears from this GWES findings that genetic differences in absorption and metabolism may explain non-linear, sometimes statistically insignificant relationships between carotenoid status, eg. lycopene, and outcome as much as dietary intake.
These studies provide further evidence of the importance of having objective measures of nutrient status.
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Institute of Medicine (US) Panel on Dietary Antioxidants and Related Compounds, Dietary Reference Intakes for Vitamin C, vitamin E, Selenium and Carotenoids. National Academies Press. 2000 Table 8.1, Concentrations of Selected Carotenoids in Human Serum and Tissues