Towards nutrition with precision: unlocking biomarkers as dietary assessment tools.

Precision nutrition requires precise tools to monitor dietary habits. Yet current dietary assessment instruments are subjective, limiting our understanding of the causal relationships between diet and health. Biomarkers of food intake (BFIs) hold promise to increase the objectivity and accuracy of dietary assessment, enabling adjustment for compliance and misreporting. Here, we update current concepts and provide a comprehensive overview of BFIs measured in urine and blood. We rank BFIs based on a four-level utility scale to guide selection and identify combinations of BFIs that specifically reflect complex food intakes, making them applicable as dietary instruments. We discuss the main challenges in biomarker development and illustrate key solutions for the application of BFIs in human studies, highlighting different strategies for selecting and combining BFIs to support specific study designs. Finally, we present a roadmap for BFI development and implementation to leverage current knowledge and enable precision in nutrition research.

Occurrence of sulfate-reducing bacteria in well water: identification of anaerobic sulfidogenic bacterial enrichment cultures.

Bacteriological studies of well water mainly focus on aerobic and facultative aerobic coliform bacteria. However, the presence of obligate anaerobic bacteria in well water, especially sulfate-reducing bacteria (SRB), possible causative agents of some diseases, is often ignored. In this study, the presence of SRB and coexisting anaerobic bacteria with SRB in sulfate-reducing enrichment cultures obtained from 10 well water samples in Istanbul was investigated. A nested polymerase chain reaction-denaturing gradient gel electrophoresis strategy was performed to characterize the bacterial community structure of the enrichments. The most probable number method was used to determine SRB number. Out of 10, SRB growth was observed in only one (10%) enrichment culture and the SRB number was low (<10 cells/mL). Community members were identified as Desulfolutivibrio sulfodismutans and Anaerosinus sp. The results show that SRB coexist with Anaerosinus sp., and this may indicate poor water quality, posing a risk to public health. Furthermore, Anaerosinus sp., found in the human intestinal tract, may be used as an alternative anaerobic fecal indicator. It is worth noting that the detection of bacteria using molecular analyzes following enrichment culture techniques can bring new perspectives to determine the possible origin and presence of alternative microbial indicators in aquatic environments.

Mediterranean meal favorably effects postprandial oxidative stress response compared with a Western meal in healthy women.

Oxidative stress and inflammation are underlying factors in the pathogenesis of chronic diseases. The postprandial state is characterized by low-grade oxidative and inflammatory responses, but the impact of different dietary patterns on these responses is unclear. The objective of this study was to investigate postprandial oxidative and inflammatory responses to Mediterranean diet (MED) and Western diet (WD) meals. In a randomised crossover design, eleven healthy women, aged between 19-45 years with a body mass index of 20.0-24.9 kg/m2, consumed two different isocaloric meals: MED and WD. Blood samples were collected at fasting and 2, 3, 4 h postprandially and analyzed for oxidative [total antioxidant status (TAS), total oxidant status (TOS), total thiol, native thiol, malondialdehyde (MDA)] and inflammatory [high sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, IL-17, IL-23, tumor necrosis factor alpha (TNF-α) and nuclear factor kappa B (NF-κB)] markers. MED meal intake resulted in increases in TAS (0.05±0.02 mmol/L; p=0.017), total thiol (23.00±7.69 µmol/L; p=0.013) and native thiol (12.82±4.94 µmol/L; p=0.027), while a decrease in MDA (-0.17±0.06 nmol/L; p=0.022) at 2 h. On the other hand, TAS reduced significantly overall (p=0.005) after WD meal intake. There was a significant increase after WD meal intake for IL-6 (1.39±0.49 pg/mL; p=0.017), IL-17 (4.30±1.50 pg/mL; p=0.017), IL-23 (8.38±3.51 pg/mL; p=0.038) at 4 h. However, serum hs-CRP, TNF-α and NF-κB levels were not changed significantly by meal intake. The results indicate that MED meal induces favorable effects on oxidative stress, while WD meal partially increases inflammation in daily life.

Determining the factors affecting energy metabolism and energy requirement in cancer patients.

Cancer is the second most common cause of death worldwide. It is a generic name for a large group of diseases that can affect any part of the body. Cancer affects both energy intake through the diet and the total energy expenditure (TEE) through the changes in energy metabolism, resulting in negative or positive energy balance. Determining daily energy requirement is very important in the regulation of the nutrition therapy in a cancer patients. Due to the difficulty in directly measuring the TEE, resting energy expenditure, which is the largest component of the TEE, is often used in the determination of the energy requirement. In this study, the effects of disease-specific factors such as tumor burden, inflammation, weight loss and cachexia on energy metabolism in cancer patients were investigated.

Coexistence of sulfate reducers with the other oil bacterial groups in Diyarbakir oil fields.

The existence of sulfate-reducing bacteria (SRB) is a major concern in oil industry due to the detrimental effects of SRB in oil technology. SRB are co-habited with diverse microbial populations in oil fields. The presence of other bacterial groups in oil fields may alter SRB activity in different ways. Therefore, understanding this coexistence may provide insights into problems induced by SRB activity and possible solutions to these problems. To investigate this aspect, not only the presence and abundance of SRB but also bacterial population that coexists with SRB in sulfate-reducing enrichment cultures obtained from the Diyarbakir oil fields in southeast of Turkey was determined by using cultivation- and molecular-based approaches. The most probable number technique (MPN) was used to determine the number of sulfidogenic bacteria in the enrichments. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction-amplified 16S rRNA gene fragments was performed to examine the bacterial diversity of the enrichments. The results demonstrated that the number of sulfidogenic bacteria in the enrichments was low (<103 cells/mL). The DGGE analysis indicated that community members belonging to the Firmicutes were more abundant than those of other phyla. Members belonging to SRB mainly consisted of the genera Desulfosporosinus, Desulfovibrio, Thermodesulfovibrio, and Desulfotomaculum. Fermentative bacteria, acetogens, nitrate reducers, and sulfur reducers were also detected in the enrichments. The results of this study not only provide information regarding the diversity of the cultivable portion of the bacterial community that coexists with cultivable SRB, but they also offer insights into the interactions of bacteria in complex microbial communities that inhabit natural environments.