Postprandial Dried Blood Spot-Based Nutritional Metabolomic Analysis Discriminates a High-Fat, High-Protein Meat-Based Diet from a High Carbohydrate Vegan Diet: A Randomized Controlled Crossover Trial.

BACKGROUND: Due to the challenges associated with accurate monitoring of dietary intake in humans, nutritional metabolomics (including food intake biomarkers) analysis as a complementary tool to traditional dietary assessment methods has been explored. Food intake biomarker assessment using postprandial dried blood spot (DBS) collection can be a convenient and accurate means of monitoring dietary intake vs 24-hour urine collection. OBJECTIVE: The objective of this study was to use nutritional metabolomics analysis to differentiate a high-fat, high-protein meat (HFPM) diet from a high-carbohydrate vegan (HCV) diet in postprandial DBS and 24-hour urine. DESIGN: This was a randomized controlled crossover feeding trial. PARTICIPANTS/SETTING: Participants were healthy young adult volunteers (n = 8) in California. The study was completed in August 2019. INTERVENTION: The standardized isocaloric diet interventions included an HFPM and an HCV diet. Participants attended 2 intervention days, separated by a 2-week washout. MAIN OUTCOME MEASURES: During each intervention day, a finger-prick blood sample was collected in the fasting state, 3 hours post breakfast, and 3 hours post lunch. Participants also collected their urine for 24 hours. DBS and urine samples were analyzed by ultra-performance liquid chromatography mass spectrometry to identify potential food intake biomarkers. STATISTICAL ANALYSES PERFORMED: Principal component analysis for discriminatory analysis and univariate analysis using paired t tests were performed. RESULTS: Principal component analysis found no discrimination of baseline DBS samples. In both the postprandial DBS and 24-hour urine, post-HFPM consumption had higher (P < 0.05) levels of acylcarnitines, creatine, and cis-trans hydroxyproline, and the HCV diet was associated with elevated sorbitol (P < 0.05). The HFPM diet had higher concentrations of triacylglycerols with fewer than 54 total carbons in DBS, and 24-hour urine had higher nucleoside mono- and di-phosphates (P < 0.05). CONCLUSIONS: Nutritional metabolomics profiles of postprandial DBS and 24-hour urine collections were capable of differentiating the HFPM and HCV diets. The potential use of postprandial DBS-based metabolomic analysis deserves further investigation for dietary intake monitoring.

Milk protein-based formulas containing different oils affect fatty acids balance in term infants: A randomized blinded crossover clinical trial.

BACKGROUND: Palm olein is used in infant formula fat blends in order to match the fatty acid profile of human milk. While the effects on fatty acid balance have been evaluated, the use of palm olein in combination with palm kernel oil and supplementation with docosahexaenoic acid (DHA) and arachidonic acid (ARA) has not been similarly assessed in infants. This study evaluated the effects of infant formulas containing different fat compositions on the balance of fat, fatty acids, and calcium. METHODS: In this randomized, crossover, double-blinded study, 33 healthy term infants (68-159 ± 3 days of age at enrollment) were fed two formulas for 14 days in a tolerance period, followed by a 4-day metabolic balance period in 17 of the male subjects. The study compared two commercially available milk-based powdered formulas in Brazil; the PALM formula contained palm olein (44%), kernel palm oil (21.7%), and canola oil (18.5%) as the predominant fats, whereas the NoPALM formula contained other fat sources. RESULTS: Fat absorption (%) was greater for NoPALM versus PALM-fed infants (96.55 and 95.50%, respectively; p = 0.023). The absorption percentage of palmitic acid (C16:0) did not differ significantly between formulas (p > 0.05), but this acid was excreted at significantly higher concentrations in the PALM (29.42 mg/kg/day) than in the NoPALM (12.28 mg/kg/day) formula groups. DHA and ARA absorption percentages were also higher in NoPALM-fed infants. Calcium absorption was higher in NoPALM-fed infants (58.00%) compared to those fed PALM (40.90%), but the difference was not significant (p = 0.104) when calcium intake was used as a covariate. However, calcium retention was higher in NoPALM-fed infants compared to that in PALM-fed infants with or without calcium intake as a covariate. Adverse events did not differ between groups (p > 0.05). CONCLUSIONS: The absorption of essential fatty acids was similar for both formulas; however, long-chain polyunsaturated fatty acids (DHA and ARA) were better absorbed from the NoPALM formula. Fat absorption and calcium retention were lower in term infants fed the PALM-based formula. CLINICAL TRIAL REGISTRATION: Clinicaltrial.gov # NCT00941564 .

Comparison of high-temperature conversion and equilibration methods for the determination of d31-palmitic acid oxidation in man using continuous-flow isotope ratio mass spectrometry.

During nutritional interventions, the ingestion of d(31)-palmitic acid and H(2)(18)O allows the assessment of dietary fatty acid oxidation from cumulative (2)H recovery in urine and the estimation of the total body water pool (TBW) from (18)O dilution. Continuous-flow isotope ratio mass spectrometry (CF-IRMS) coupled to either equilibration or high-temperature conversion (HTC) techniques permits (2)H- and (18)O-enrichment measurements in biological fluids. Thus it was of great interest to compare these methods applied to the determination of dietary fatty acid oxidation. The linearity, accuracy and correlation between CF-equilibration and CF-HTC were first checked using (2)H- and (18)O-enriched water and urine samples. Urine samples from 14 subjects were then measured with both methods. The (2)H and (18)O raw data were normalised against calibration lines. The final aim was to study the impact of the normalised raw results on physiological data (i.e. TBW and d(31)-palmitate recovery). No significant difference was observed between the (18)O- and (2)H-enrichment measurements depending on the analytical method used. The TBW volumes calculated from the (18)O enrichments measured either with CF-equilibration or CF-HTC were not significantly different: respectively, 45.1 ± 1.0 L or 45.7 ± 1.0 L (mean ± sem, p = 0.09). The palmitic acid oxidation results obtained from the (2)H-enrichment measurements and the TBW from CF-equilibration vs. CF-HTC were not significantly different (p ≥ 0.26): with δ(2)H values of, respectively, 16.2 ± 1.6% vs. 16.2 ± 1.1% at 8 h, 18.7 ± 2.0% vs. 17.6 ± 1.3% at 12 h and 21.7 ± 1.9% vs. 21.5 ± 1.3% at 3 days post-dose (mean ± sem). Thus, even if CF-HTC was preferred because it was more practical to carry out, both methods allow the study of dietary lipid oxidation in man and generate similar results.

1H-nuclear magnetic resonance spectroscopy-based metabolic assessment in a rat model of obesity induced by a high-fat diet.

Obesity, whose prevalence is increasing rapidly worldwide, is recognized as a risk factor for diabetes, cardiovascular disease, liver disease, and renal disease. To investigate metabolic changes in the urine of a rat model of obesity induced by a high-fat diet (HFD), rats were divided into the following four groups based on the diet type and degree of weight gain: normal-diet (ND) low gainers, ND high gainers, HFD low gainers, and HFD high gainers. Biochemical analyses of visceral fat-pad weight, plasma, and liver tissues were performed. The (1)H-nuclear magnetic resonance ((1)H-NMR) spectra of urine were analyzed using multivariate statistical analysis to identify the separation of the groups. It was observed that the metabolic profile of urine obtained by (1)H-NMR-spectroscopy-based metabolomic analysis differed between ND low gainers and ND high gainers even though these animals consumed the same normal diet. Several key metabolites in urine, such as betaine, taurine, acetone/acetoacetate, phenylacetylglycine, pyruvate, lactate, and citrate contributed to the classification of these two groups. The metabolic profile of urine also differed between ND low gainers and HFD high gainers, which consumed the different diet and showed a different weight gain. This study has identified features of urine metabolites in various groups and demonstrated the reliability of an NMR-based metabolomics approach to investigate the effects of the diet and the physical constitution on obesity.

Diet and biomarkers of oxidative damage in women previously treated for breast cancer.

This study sought to evaluate the relationship between dietary intake of fat, polyunsaturated fat, saturated fat, arachidonic acid, and selected dietary antioxidants and levels of oxidative damage as measured by urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-epi-prostaglandin F2alpha (8-iso-PGF2alpha) in women previously treated for breast cancer. Two hundred two study subjects participating in the Women's Healthy Eating and Living (WHEL) study were included in this ancillary study. Dietary intakes and concentrations of urinary 8-OHdG and 8-iso-PGF2alpha were measured at baseline and 12 mo in the 179 women included in the analytical cohort. Study subjects demonstrated a significant reduction in dietary total, polyunsaturated, and saturated fat intake and a significant increase in vitamins E and C and beta-carotene intake from baseline to 12 mo. Linear mixed-models analysis using baseline and Year 1 data indicated that vitamin E intake was inversely associated with both 8-OHdG and 8-iso-PGF2alpha. 8-Iso-PGF2alpha is increased with increased body mass index (BMI) and polyunsaturated fatty acid (PUFA) intake, indicating an increase in lipid peroxidation with greater BMI and higher PUFA intake. 8-OHdG was inversely related to age but positively related to arachidonic acid, indicating an increase in DNA damage with higher intake of arachidonic acid (meat). The results of this nested case-controlled study provide potential mechanisms by which a high fruit and vegetable, low-fat diet might reduce the recurrence rate of or early-stage breast cancer.

Spontaneous urinary chemiluminescence and diet. An intervention study in humans.

Spontaneous urinary visible chemiluminiscence has been measured in samples from a diet intervention study in humans. For a month, two groups, each of 21 male volunteers, received either a Mediterranean-type diet or an occidental (high-fat) diet. Urinary chemiluminescence levels (in 10(3) cpm) were 8.5 +/- 3.1 and 6.0 +/- 2.0 for the high-fat and Mediterranean-type diets, respectively. The differences obtained were statistically significant. These results reflect differences in the oxidative stress associate to both diets and support the proposal that spontaneous urinary chemiluminiscence constitutes a complementary index of systemic oxidative stress.

Mutagenicity of deep-frying fat, and evaluation of urine mutagenicity after consumption of fried potatoes.

Mutagen formation during deep-frying was evaluated using standard frying conditions. Portions of pre-fried, sliced potatoes were fried in a commercial brand of hydrogenated vegetable frying fat, which was used repeatedly and for a prolonged period of time. Concentrations of polar oxidation and degradation products, and of dimeric and polymeric triglycerides, were found to increase in the frying fat as well as in fried potatoes with prolonged use of the fat. Thiobarbituric acid-reactive substances were detectable neither in the frying fat nor in the fried potatoes. Polar fractions of repeatedly used frying fat significantly increased the number of revertants in Salmonella typhimurium strain TA97 without S-9 mix. In the presence of S-9 mix mutagenic activity was reduced. As a consequence of ongoing formation of polar degradation and oxidation products, the mutagenicity of the fat increased after repeated use. Polar fractions of lipids extracted from commercially obtained pre-fried potatoes, as well as from fried potatoes, marginally increased the number of revertants in strain TA97 without S-9 mix. The mutagenicity of the lipid fractions of fried potatoes was not related to the heating time of the fat. Methanol extracts of fat-free residues of fried potatoes significantly increased numbers of revertants in strain TA97 after metabolic activation, which indicated that a different class of mutagens had been isolated. The mutagenicity of methanol extracts was not increased after either prolonged or repeated use of the fat. Urine samples of six healthy, non-smoking volunteers, collected during the 24 hr following consumption of portions of potatoes fried in repeatedly used fat, showed no increase in mutagenicity compared with control samples. Since the exact identity of mutagens formed during deep-frying, as well as their metabolic fate in man, is unclear at present, evaluation of possible adverse biological effects associated with consumption of fried foods will require strictly controlled metabolic studies.