Lean-seafood intake increases urinary iodine concentrations and plasma selenium levels: a randomized controlled trial with crossover design.

PURPOSE: Iodine deficiency due to insufficient nutritional intake is a public health challenge in several European countries, including Norway. Lean-seafood has a high iodine and arsenic (As) content and is a good source of selenium (Se). Evidence of a direct effect of increased intake of lean-seafood on iodine status is limited. The main aims were to determine the iodine status at baseline and to investigate possible dietary effects on urinary iodine concentration (UIC) after intervention with lean-seafood versus non-seafood. Plasma Se, and plasma and urinary As concentrations were also measured. METHODS: A randomized controlled crossover study comprising two 4 weeks experimental periods with two balanced diets varied in main proteins (60% of total dietary proteins) of lean-seafood and non-seafood, separated by a 5 week washout period. RESULTS: Twenty participants (7 males, 13 females) were included and the mean ± SD age was 50.6 ± 15.3 years for all participants. Fasting UIC was median (25th, 75th percentile) 70 (38, 110) and 79 (49, 94) µg/L in the lean-seafood and non-seafood intervention at baseline, respectively. UIC increased after 4 weeks of the lean-seafood intervention to 135 (110, 278) µg/L, but not after the non-seafood intervention [58 (33, 91) µg/L] (P diet-effect < 0.001). Fasting plasma Se increased in the lean-seafood intervention and decreased in the non-seafood intervention (P diet-effect = 0.001). Fasting urinary and plasma As increased in the lean-seafood intervention and was unchanged in the non-seafood intervention (P diet-effect < 0.001). CONCLUSION: The participant's UIC was below the recommended median (100 µg/L) at baseline, but increased sufficiently after a 4 week intervention with lean-seafood.

The Effect of Lean-Seafood and Non-Seafood Diets on Fecal Metabolites and Gut Microbiome: Results from a Randomized Crossover Intervention Study.

SCOPE: The impact of dietary protein types on the gut microbiome is scarcely studied. The aim of the present study is therefore to examine the effects of lean-seafood and non-seafood proteins on the gut microbiome composition and activity and elucidate potential associations to cardiovascular disease (CVD) risk factors. METHODS: A crossover intervention study in which 20 healthy subjects consumed two diets that varied in protein source was conducted. 1 H NMR spectroscopy and 16S rDNA sequencing analyses were applied to characterize fecal metabolites and gut microbiota composition, respectively. RESULTS: A twofold increase in fecal trimethylamine excretion was observed after the lean-seafood diet period. Circulating TAG and the total to high-density lipoprotein (HDL) cholesterol ratio as well as circulating TMAO levels were each associated with specific gut bacteria. Following the non-seafood diet period, a decreased relative abundance of Clostridium cluster IV and a tendency toward an increased Firmicutes/Bacteroidetes ratio were found. CONCLUSIONS: Lean-seafood and non-seafood diets differentially modulate the gut microbiome composition and activity. Furthermore, the gut microbiota composition seems to affect circulating TMAO levels and CVD risk factors.

Suboptimal Iodine Status and Low Iodine Knowledge in Young Norwegian Women.

Previous studies have documented mild to moderate iodine deficiency in pregnant and lactating women in Norway. This study focused on non-pregnant young women because their future children may be susceptible to the adverse effects of iodine deficiency. We assessed urinary iodine concentration (UIC), iodine intake from food and supplements, and iodine knowledge in 403 non-pregnant women, mainly students, aged 18⁻30 years. Iodine concentration was measured in spot urine samples analyzed by inductively coupled plasma mass spectrometry and iodine intake was calculated from a self-reported food frequency questionnaire. Knowledge about iodine was collected through the self-administered, paper-based questionnaire. Median (p25⁻p75) UIC was 75 (42⁻130) µg/L and 31% had UIC < 50 µg/L. Habitual iodine intake was 100 (69⁻136) µg/day. In multiple regression models, supplemental iodine, use of thyroid medication, and iodine intake from food were positively associated with UIC, while vegetarian practice was negatively associated, explaining 16% of the variance. Approximately 40% of the young women had low iodine knowledge score and no differences were found between women in different study programs. Young women in Norway are mild to moderately iodine-deficient, and public health strategies are needed to improve and secure adequate iodine status.

The Effect of Lean-Seafood and Non-Seafood Diets on Fasting and Postprandial Serum Metabolites and Lipid Species: Results from a Randomized Crossover Intervention Study in Healthy Adults.

The metabolic effects associated with intake of different dietary protein sources are not well characterized. We aimed to elucidate how two diets that varied in main protein sources affected the fasting and postprandial serum metabolites and lipid species. In a randomized controlled trial with crossover design, healthy adults (n = 20) underwent a 4-week intervention with two balanced diets that varied mainly in protein source (lean-seafood versus non-seafood proteins). Nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry analyses were applied to examine the effects of the two diets on serum metabolites. In the fasting state, the lean-seafood diet period, as opposed to the non-seafood diet period, significantly decreased the serum levels of isoleucine and valine, and during the postprandial state, a decreased level of lactate and increased levels of citrate and trimethylamine N-oxide were observed. The non-seafood diet significantly increased the fasting level of 26 lipid species including ceramides 18:1/14:0 and 18:1/23:0 and lysophosphatidylcholines 20:4 and 22:5, as compared to the lean-seafood diet. Thus, the lean-seafood diet decreased circulating isoleucine and valine levels, whereas the non-seafood diet elevated the levels of certain ceramides, metabolites that are associated with insulin-resistance.

Lean-seafood intake decreases urinary markers of mitochondrial lipid and energy metabolism in healthy subjects: Metabolomics results from a randomized crossover intervention study.

SCOPE: Proteins constitute an important part of the human diet, but understanding of the effects of different dietary protein sources on human metabolism is sparse. We aimed to elucidate diet-induced metabolic changes through untargeted urinary metabolomics after four weeks of intervention with lean-seafood or nonseafood diets. It is shown that lean-seafood intake reduces urinary excretion of metabolites involved in mitochondrial lipid and energy metabolism possibly facilitating a higher lipid catabolism in healthy subjects. METHODS: In a randomized controlled trial with crossover design, 20 healthy subjects consumed two balanced diets that varied in main protein sources for 4 weeks. Morning spot urine samples were collected before and after each intervention period. Untargeted metabolomics based on (1) H NMR spectroscopy and LC-MS analyses were applied to characterize the urinary metabolic response to the interventions. RESULTS: The lean-seafood diet period reduced the urinary level of l-carnitine, 2,6-dimethylheptanoylcarnitine, and N-methyl-2-pyridone-5-carboxamide, relative to the nonseafood period. The dietary analysis revealed that the higher urinary level of trimethylamine-N-oxide after the lean-seafood diet period and guanidinoacetate and 3-methylhistidine after the nonseafood diet period was related to the endogenous content of these compounds in the diets. CONCLUSIONS: Our data reveal that 4 weeks of lean-seafood intake reduces urinary excretion of metabolites involved in mitochondrial lipid and energy metabolism possibly facilitating a higher lipid catabolism in healthy subjects after the lean-seafood intake.

Lean-seafood intake reduces cardiovascular lipid risk factors in healthy subjects: results from a randomized controlled trial with a crossover design.

BACKGROUND: Observational studies have strongly indicated an association between fish consumption and reduced risk of cardiovascular disease, but data from randomized controlled trials have been inconclusive. OBJECTIVE: Our primary outcome in this study was to elucidate the potentials of the 2 main dietary protein sources lean seafood and nonseafood to modulate fasting and postprandial lipids in healthy subjects. We hypothesized that lean-seafood intake would reduce cardiovascular lipid risk factors in healthy subjects more than would the intake of nonseafood protein sources. DESIGN: This study was a randomized controlled trial with a crossover design. After 3-wk run-in periods and separated by a 5-wk washout period, 20 healthy subjects (7 men and 13 women) consumed 2 balanced diets that varied in main protein sources (60% of total dietary proteins from lean-seafood or nonseafood sources for 4 wk). At days 1 and 28 of each intervention, fasting and postprandial blood samples were collected before and after consumption, respectively, of test meals with cod or lean beef. RESULTS: Relative to the nonseafood intervention, the lean-seafood intervention reduced fasting (relative difference by diets: 0.31 mmol/L; P = 0.03) and postprandial (P = 0.01) serum triacylglycerol concentrations. The lower serum triacylglycerol concentration was associated with reduced fasting triacylglycerol in chylomicrons and very-low-density lipoproteins (VLDLs) (P = 0.004), reduced fasting VLDL particle size (P = 0.04), and a reduced postprandial concentration of medium-sized VLDL particles (P = 0.02). The lean-seafood intervention prevented the elevated ratio of total cholesterol to HDL cholesterol in the fasted serum (P = 0.03) and postprandial serum (P = 0.01) that was observed after the nonseafood intervention. CONCLUSION: The dietary protein source determines fasting and postprandial lipids in healthy individuals in a manner that may have an effect on the long-term development of cardiovascular disease. This study was registered at clinicaltrials.gov as NCT01708681.