Alternative methods for determining the nutritional effects of foods on the body Aliyah Saifuddin, Balazs Bajka, Andrew Surman King’s College London, UK Accurate assessment of nutrient bioavailability and absorption are important for Nutritional Scientists to assess the metabolic effects of different foods. Current standard analytical techniques used depend on the analyte – gas chromatography with mass spectrometry or flame ionisation detection (GC-MS/FID) for free fatty acid (FFA) analysis 1 or high-performance liquid chromatography with mass spectrometry (HPLC-MS) 2 or ion exchange chromatography (IEX) 3 for amino acid (AA) analysis. These highly powerful techniques are also specialist and the instruments are delicate and expensive to maintain. This research aims to design easier, more affordable analytical methods for both AA and FFA analysis which conveniently both use HPLC with diode array detection (DAD) or fluorescence detection (FLD). These studies utilise food subjected to in vitro digestion protocols (each phase mirrors the conditions of physiological digestion) 4 and sampled at various time points, or blood is collected by venepencture at time points following meal consumption and the samples are analysed. The methods compromise on analytical sensitivity compared to the standards, but this is overcome with the use of precolumn analytical derivatization 5,6 (which is already done by default for FFA analysis using GC) 7 to tag analytes to enhance separation and/or detection. Additionally, blood collection is not trivial. Collection by venepuncture requires a phlebotomist and the participant must stay in the clinical facility for the full duration of the study. This can limit sample sizes, is expensive, inconvenient for both the phlebotomist and participant and painful for the participant. This research also explores the use of dried blood spot (DBS) sampling as a more affordable, easier, and more convenient alternative. Using DBS means that sampling does not have to be done in situ (samples can be collected elsewhere and posted) so the possibility to sample more remote populations and represent the currently unrepresented increases. This could even stretch to exploring fields like animal nutrition which previously may have been deemed impossible. In summary, using HPLC-DAD/FLD for DBS analysis in nutritional studies is a cheaper alternative that hopefully more research facilities will be able to adopt in comparison to the current standards. Consequently, the barrier to robust analysis would be lowered with fewer costs and geographical obstacles involved and accessibility would be increased. References 1. M. L. Grundy et al., J Funct Foods , 2017, 38 , 378–388. 2. Giordano et al., Methods in Molecular Biology , Humana Press Inc., 2019, vol. 2030,153–172.
3. M. Abdulrazzaq et al., Clin Biochem , 2001, 34 , 399–406. 4. A. Brodkorb et al., Nat Protoc , 2019, 14 , 991–1014. 5. P. Frank et al., 2008, 1–6. 6. R. Wood et al., J Chromatogr A , 1983, 254 , 237–246. 7. F. Marangoni et al., Anal Biochem , 2004, 326 , 267–272.
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