ABSTRACT
Niacin inhibits fatty acid flux from adipose tissue to liver, reduces hepatic triglyceride synthesis and increases hepatic lipid oxidation. Thus, niacin may have a role in the regulation of liver fat content in humans. We tested if dietary intake of niacin predicts change of liver fat content during a lifestyle intervention. To this end, we estimated the composition of diet from diaries of 202 healthy subjects at risk of type 2 diabetes undergoing lifestyle intervention comprising physical activity and diet counselling. Total-, subcutaneous- and visceral adipose tissue mass were measured by magnetic resonance (MR) tomography and liver fat content by 1H-MR spectroscopy at baseline and after 9 months of follow-up. Among fat compartments, liver fat content showed the largest decrease (-32%, p < 0.0001). High baseline niacin intake predicted a larger decrease of liver fat (p = 0.004). Subjects in the highest quartile of niacin intake at baseline also had the largest decrease of liver fat (1st:-10%; 2nd:-27%; 3rd:-35%; 4th:-37%). Among 58 subjects with nonalcoholic fatty liver disease (NAFLD) at baseline, NAFLD resolved in 23 subjects during the lifestyle intervention. For one standard deviation increase in niacin intake, the odds ratio for resolution of NAFLD was 1.77 (95% CI, 1.00-3.43). High dietary niacin intake may have a favorable effect on the reduction of liver fat during lifestyle intervention.
Subject(s)
Adipose Tissue/metabolism , Dietary Supplements , Eating , Life Style , Liver/metabolism , Liver/pathology , Niacin , Adiposity , Adult , Biomarkers , Female , Humans , Lipid Metabolism , Lipogenesis , Male , Middle Aged , Niacin/metabolismABSTRACT
OBJECTIVE: To evaluate the mental health outcome of a lifestyle intervention for the prevention of type 2 diabetes and to exclude possible harmful psychological effects. BACKGROUND: There is little empirical data on potential harmful effects of prevention programs. However, information, education, diagnostic procedures, phenotyping and risk assessment may cause or intensify psychological distress such as anxiety, depression or somatization in vulnerable individuals. METHODS: The Tuebingen Lifestyle Intervention Program (TULIP) for the prevention of type 2 diabetes has assessed mental health outcome in the participants after 9 months of program participation using the Symptom Checklist-90-R (SCL-90-R). The 24-months lifestyle intervention TULIP comprises regular exercise and changes in nutrition and assesses both, a broad range of somatic parameters as well as psychometric variables. For an interim analysis of psychological outcome, complete data sets of the SCL-90-R assessed at baseline and after 9 months of intervention were available for 195 participants (125 females, 70 males; age: 46.1 +/- 10.6 years). Data on somatization, anxiety, depression and overall psychological distress were compared to baseline levels. RESULTS: SCL-90-R scores of the TULIP-participants did not significantly differ from the German healthy reference population. Compared to baseline, a significant decrease in SCL-90-R scores was found for anxiety, depression and overall psychological distress at re-assessment after 9 months. CONCLUSION: The interim analysis on mental health outcome of a type 2 diabetes prevention program comprising extensive phenotyping and risk assessment rules out adverse psychological effects, suggesting rather beneficial changes concerning symptoms of anxiety, depression and overall psychological distress.
