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Associations of Diet and Plasma BCAA Concentrations in Healthy Men and Women – Results from the KarMeN Study
- Benedikt Merz, Manuela Rist, Achim Bub, Bernhard Watzl
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E589
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Diet is the only source of the essential branched-chain amino acids (BCAA) isoleucine, leucine and valine. High plasma concentrations of these amino acids are discussed as risk factors for the onset of several diseases such as type 2 diabetes mellitus (T2D) or cardiovascular diseases (CVD). Information about the contribution of the overall diet to plasma levels of these amino acids is controversial. Our objective was to investigate which dietary pattern is associated with plasma BCAA concentrations in a healthy population and which other additional nutrients besides isoleucine, leucine and valine, such as other amino acids, may contribute to the diseases risk.
The Karlsruhe Metabolomics and Nutrition (KarMeN) study is a cross-sectional study aiming to determine the impact of a number of factors on the human metabolome in healthy men and women aged 18 and 80 years. In our study, fasting plasma amino acid concentrations as well as current and habitual dietary intake were assessed in 298 apparently healthy individuals, 171 men (57.4%) and 127 women (42.6%) with a mean age of 44.5 and 51.6 years, respectively. All reported foods were summarized into 35 food groups. Dietary patterns were derived that explain as much variation as possible in plasma BCAA concentrations using reduced rank regression. The first derived current dietary pattern covering the diet of the past 24 hours, showed 19.2% of explained variance for BCAA plasma concentrations, whereas the first habitual dietary pattern, covering a period of more than 4 weeks, explained 32.5%. For further analysis, we focused on the first derived habitual dietary pattern. This pattern was high in meat, sausages, sauces, eggs, and ice cream but low in nuts, cereals, mushrooms, and pulses. The age, sex, and energy intake adjusted dietary pattern score was associated with an increase in animal-based protein and at the same a decrease in plant-based protein, dietary fibre and an unfavorable fatty acid composition. Amino acids alanine, lysine and the aromatic amino acids phenylalanine, tyrosine, and tryptophan were positively associated with the dietary pattern score as well. All of these factors were reported to be associated with risk of T2D and CVD.
Our data suggest that rather than the dietary intake of BCAA, the overall dietary pattern contributing to high BCAA plasma concentrations may modulate the chronic diseases risk.
Body composition of New Zealand European and Pacific women is associated with lower dietary fibre intake and gut microbiota diversity
- Nikki Renall, Benedikt Merz, Blair Lawley, Gerald W. Tannock, Marine Corbin, Jeroen Douwes, Rozanne Kruger, Bernhard H. Breier
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E685
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Diet is considered one of the key drivers of the world-wide obesity epidemic, and the gut microbiota may play a role in this multifaceted disease due to their mutualistic relationship. This study investigated relationships between habitual dietary intake of New Zealand European and Pacific women and their gut microbiota and body fat content. Pacific (44%) and NZ European (NZE; 56%) women (n = 287) aged 18–45 years were recruited based on body mass index (normal versus obese) and stratified as low (< 35%) or high (≥ 35%) body fat percentage (BF%). Dietary intake was assessed with a 5-day estimated food record and a semi-quantitative food frequency questionnaire, which were used to calculate habitual dietary intake using the National Cancer Institute (NCI) method. BF% was assessed by dual-energy x-ray absorptiometry (DXA). Fasting blood samples were analysed for markers of insulin sensitivity. The DNA from faecal samples was analysed following shotgun sequencing. There were no significant differences in BF% between Pacific and NZE women (p = 0.498). Significant differences in homeostasis model assessment of insulin resistance (HOMA-IR) index were observed between Pacific (3.4 [2.3, 5.9]) and NZE (2.1 [1.5, 3.1], p ≤ 0.001) women, and between; low-BF% (1.9 [1.3, 2.7]) and high-BF% (3.4 [2.5, 5.9], p ≤ 0.001) groups. The highest (27.6g/d [24.9, 30.6]) compared to the lowest tertile (16g/d [13.3, 17.6]) of habitual total dietary fibre (DF) intake was associated with a significantly lower HOMA-IR (2.1 [1.3, 3.1] versus 3.3 [2.1, 5.3] p ≤ 0.001) respectively. Higher DF intake was also associated with significantly lower BF% (β -0.35, p ≤ 0.001), and this relationship became stronger when considering the intake of other macronutrients (β -0.47, p ≤ 0.001). Alpha diversity; observed taxonomic units (OTU's; rs = -0.15, p = 0.011), Pielou's evenness (rs = -0.20, p = 0.001), and Shannon index (rs = -0.22, p ≤ 0.001), were all negatively correlated with BF%. In contrast BF% was positively correlated with the Firmicutes:Bacteroidetes ratio (rs = 0.26, p ≤ 0.001). HOMA-IR index was significantly higher in Pacific and women in the higher BF% group, indicating an increased metabolic disease risk. Higher habitual DF intake was associated with lower BF% and HOMA-IR, suggesting a potential metabolically protective effect. The positive effects of higher DF intake may be associated with microbiota diversity, as higher BF% was associated with reduced alpha diversity and an increased Firmicutes:Bacteroidetes ratio. Further analysis will explore which foods contributed to the higher DF intake, and associations with body composition, microbiota and biomarkers of metabolic health.