Nutrient Status, Healthy Livers, and Metabolic Syndrome
Nutrition science developed from a desire to understand the components of a healthy diet. The goal of nutrition guidance (nutrition policy) is to guide human behavior, including food choices, to favor health and longevity. By helping people understand the 5 food groups in the context of a healthy plate, government agencies hope to influence nutritional value of our diet and ultimately, human health.
Liu and colleagues examined the association between serum carotenoid concentrations and metabolic syndrome. They conducted a community-based cross-sectional study of 2,148 adults (50-75y) living in Guangzhou, China. Individuals with metabolic syndrome had elevated body mass index (BMI), waist circumference, blood pressure, serum triglycerides, and fasting blood glucose (vs those without metabolic syndrome). They also had significantly lower serum carotenoid concentrations. Interestingly, this population had serum α-tocopherol concentrations >30 µmol/L, a level of low mortality risk; and much higher than most young Americans. The two groups, those with metabolic syndrome and without, differed by age, education but not household income, smoking status, and alcohol consumption. Unfortunately, nothing was presented about their dietary intake or physical activity patterns.
Previously, Rock and colleagues reported that serum carotenoids (and α-tocopherol) directly reflect intake of these compounds. Variations in concentration could be quantified by dietary intake, demographics, BMI, circulating lipid concentrations, smoking and alcohol consumption.
It is difficult to dissect the health effects of individual nutrients from lifestyle behaviors, i.e. dietary choices, physical activity and lifestyle choices (e.g. smoking) . Why? Because lifestyle behaviors are often correlated and not independent. Smoking, physical activity, and nutrition have the greatest impact on mortality with fewer than 20% of adults engaging in multiple healthy behaviors.
Unhealthy behaviors also affect the health of children. Children with non-alcoholic fatty livers (NAFL) under consume omega-3 fatty acids found in fish, vitamin E and dietary. They consume more meat, saturated fat, cholesterol and foods and beverages containing fructose. Weight loss combined with dietary changes and behavior modification for 48 weeks helps maintain normal liver enzyme patterns.
Scientists discovered deficiency diseases by removing micronutrients from the diet of animals and sometimes humans. Based on detailed investigative studies, nutrient recommendations were derived to prevent deficiency. Yet in 2014, the exact role of micronutrients in maintaining the structure and function of the body and its organs remains uncertain.
By measuring serum concentrations, scientists will continue to acquire evidence on the optimal nutrient concentrations needed to maintain health and prevent disease.
Liu J, Shi W, Cao Y, He L, Guan K, Ling W, Chen Y. Higher serum carotenoid concentrations associated with a lower prevalence of the metabolic syndrome in middle-aged and elderly Chinese adults. 2014 Br J Nutr doi: 10.1017/S000711451400316X
Yang M, Gong S, Ye SQ, Lyman B, Geng L, Chen P, Li D-Y. Non-alcoholic fatty liver disease in children: Focus on nutritional interventions. 2014 Nutr doi: 10.3390/nu6114691
Wright ME, Lawson KA, Weinstein SJ, Pietinen P, Taylor PR, Virtamo J, Albanes D. Higher baseline serum concentrations of vitamin E are associated with lower total and cause-specific mortality in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. 2006 Am J Clin Nutr 84(5):1200-1207
Rock CL, Thornquist MD, Kristal AR, Patterson RE, Cooper DA, Neuhouser ML, Neumark-Sztainer D, Cheskin LJ. Demographic, dietary and lifestyle factors differentially explain variability in serum carotenoids and fat-soluble vitamins. Baseline results from the sentinel site of the olestra post-marketing surveillance study. 1999 J Nutr 129:855-864
Ford ES, Bergmann MM, Boeing H, Li C, Capewell S. Healthy lifestyle behaviors and all-cause mortality among adults in the United States. 2012 Prev Med doi: 10.1016/j.ypmed.2012.04.016