Habitual Nut Exposure, Assessed by Dietary and Multiple Urinary Metabolomic Markers, and Cognitive Decline in Older Adults: The InCHIANTI Study.

SCOPE: The association between self-reported dietary intake and urinary metabolomic markers of habitual nut exposure with cognitive decline over a 3-year follow-up in an older Italian population is prospectively evaluated. METHODS AND RESULTS: A total of 119 older participants are selected, based on self-referred nut intake: the non-nut consumer (n = 72) and the regular consumer (≥2.9 g d-1 , n = 47). Nut exposure is measured at baseline either with the use of a validated food frequency questionnaire or with an HPLC-Q-ToF-MS metabolomic approach. Three years after, 28 from the nonconsumers and 10 from the consumers experienced cognitive decline. Dietary nut exposure is characterized by urinary metabolites of polyphenols and fatty acids pathways. Nut consumption estimated either by the dietary marker or by the urinary marker model is in both cases associated with less cognitive decline (OR: 0.78, 95% CI: 0.61,0.99; p = 0.043 and OR: 0.995, 95% CI: 0.991,0.999; p = 0.016, respectively) with AUCs 73.2 (95% CI: 62.9, 83.6) and 73.1 (62.5, 83.7), respectively. CONCLUSIONS: A high intake of nuts may protect older adults from cognitive decline. Metabolomics provides accurate and complementary information of the nut exposure and reinforces the results obtained using dietary information.

Urine metabolomics shows an induction of fatty acids metabolism in healthy adult volunteers after supplementation with green coffee (Coffea robusta L.) bean extract.

BACKGROUND AND OBJECTIVE: Green coffee bean extract is used as herbal medicine or supplement for weight reduction and obesity. The active constituents are considered caffeine and chlorogenic acid (CGA) derivatives. The mode of action of CGA is still unclear and can be related to peroxisome proliferator-activated receptor α (PPAR-α) and liver X receptor Rα (LXR-α). Metabolomics may be an innovative tool for the description and discovery of the multiple target nature of such phytocomplex. METHODS: 24 h urine samples were collected once a week from ten healthy adult volunteers consuming daily 400 mg of dry Green coffee bean extract (GCBE, 4.9% of chlorogenic acid) each day for 30 days (5 harvesting days, considering also the first day of supplementation). Urine samples were analyzed by LC-QTOF using both untargeted and targeted approaches. The latter was used to monitor two urinary markers of oxidative stress (allantoin, 8-OHdG). RESULTS: Metabolomics analysis (PLS-DA) revealed changes in urine composition before and during the treatment with GCBE. Markers related to treatment were metabolites related to polyphenol administration as hippuric acid, benzoic acid derivatives, dihydroferulic and dihydrosinapic acid sulphate, but also carnitine derivatives and dicarboxylic acids. On the other hand, no changes in the levels of allantoin and 8-OHdG were observed. CONCLUSION: This preliminary study showed the possible usefulness of metabolomics approach in the evaluation of GCBE consumption in healthy subjects. The observed changes in urinary composition can be related to the catabolism of GCBE constituents and to induced fatty acid metabolism, mainly related to carnitine derivatives. This latter result could be considered, at least in part, as a further proof of the mode of action of green coffee extract.

Whole Milk Increases Intestinal ANGPTL4 Expression and Excretion of Fatty Acids through Feces and Urine.

The angiopoietin-like 4 (ANGPLT4) protein is involved in lipid metabolism and is known to inhibit lipoprotein lipase in the bloodstream. We investigated the effect of milk on intestinal ANGPTL4 and the metabolic profile of growing pigs and the effect of free fatty acids (FFAs) on ANGPTL4 in ex vivo and in vitro assays. Feeding pigs whole milk increased intestinal ANGPTL4 mRNA and increased fecal excretion of long-chain FFA compared to the control group fed soybean oil (n = 9). Furthermore, FFAs (C4-C8) induced ANGPTL4 gene expression in porcine intestinal tissue mounted in Ussing chambers and ANGPTL4 protein secretion to both the apical and basolateral sides of intestinal Caco-2 cells on permeable membranes. Altogether, these results support an ANGPTL4-induced secretion of fecal FFAs. Urinary levels of FFAs (C4-C12), 3-hydroxyadipic acid, and suberic acid were also increased by milk consumption, indicating higher energy expenditure compared to the control group.

Cyclic fatty acids found in frying oils are detoxified via classical drug metabolic pathway but also by ß-oxidation and eliminated as conjugates in rats.

Cyclic fatty acid monomers (CFAM) are mainly formed during heat treatments, such as frying, of edible oils. These fatty acids are mixtures of disubstituted five- or six-carbon-membered ring structures. Some earlier studies have suggested that some of these molecules could be metabolized and detoxified, but so far, neither the detoxification mechanisms nor the metabolite identifications have been elucidated. The objective of the present study was to identify the metabolites resulting from the metabolism and detoxification of CFAM. A deuterium-labeled CFAM, [9-(2)H]-10-(6-propyl-2-cyclohexenyl)-dodecenoic acid, was synthesized and fed to rats for 3 days, along with a standard chow diet while the control group was fed the same chow diet which did not contain any CFAM. Biological fluids (urine, blood) were collected for both groups of rats and analyzed using an untargeted metabolomic approach by ultra-performance liquid chromatography coupled with mass spectrometry. Two discriminant metabolites and 18 molecules derived from CFAM were identified or tentatively identified in plasma and urine samples, respectively. The structures of the metabolites suggest that CFAM having a six-carbon-membered ring could be detoxified by the classical drug metabolic pathway (phase I and phase II reactions), but our study also indicates that these are substrates for the ß-oxidation pathway and eliminated as glucuronide, sulphate, and/or nitrate conjugates. Urine metabolomics investigations without diet effects have indicated a higher excretion of medium-chain acylcarnitines in the D-CFAM diet group, which may indicate an incomplete ß-oxidation.

Liquid chromatography-mass spectrometry methods for urinary biomarker detection in metabonomic studies with application to nutritional studies.

The effects of sample preparation and chromatographic method differences on the classification and recovery of metabolic biomarkers from UPLC-MS measurements on urine samples of humans exposed to different dietary interventions have been investigated. Eight volunteers consumed three high-fat meals (rich in saturated, monounsaturated and polyunsaturated fatty acids, respectively) in randomized order with a washout period in between. For each participant, urine samples were obtained prior to and at three timed intervals after each meal. Samples were processed either by dilution (1 : 4) or by liquid-liquid extraction and then run under two different gradient conditions. For each analysis method, a total of 96 observations (eight participants, four time points, three diets) were measured. The total ion count chromatograms were analyzed using partial-least-squares discriminant analysis. All three dietary classes could be discriminated irrespective of sample preparation and chromatographic method. However, the main discriminating metabolites varied according to sample preparation, indicating that sample treatment and chromatographic conditions influence the ability to extract biomolecular information. Diluted samples showed higher m/z compounds (ca 400 u) while liquid-liquid extraction samples showed low m/z at the same retention time span. Optimized methods for metabolite identification (e.g. organic acids) were statistically inferior to global screening for mixed compound identification, confirming that multiple compound class-based metabolic profiles are likely to give superior metabonomic (diagnostic) classification, although great care has to be taken in the interpretation in relation to matrix effects.

Effect of Hibiscus sabdariffa L. dried calyx ethanol extract on fat absorption-excretion, and body weight implication in rats.

The effect of Hibiscus sabdariffa L. (Hs) calyx extract on fat absorption-excretion and body weight in rats, was investigated. Rats were fed with either a basal diet (SDC = Control diet) or the same diet supplemented with Hs extracts at 5%, 10% and 15% (SD(5), SD(10) and SD(15)). Only SD(5) did not show significant increases in weight, food consumption and efficiency compared to SD(C). The opposite occurred in SD(15) group which showed a significant decrease for these three parameters. The SD(10) responses were similar to SD(15), with the exception of food consumption. In both SD(C) and SD(5) groups, no body weight loss was observed; however, only in the latter group was there a significantly greater amount of fatty acids found in feces. A collateral effect emerging from the study is that components of Hs extract at the intermediate and greater concentrations used in this experiment could be considered possible antiobesity agents.

Metabolic and endocrine aspects of the ketogenic diet.

The ketogenic diet (KD) is designed to simulate the biochemical effects of fasting by maintaining a state of ketosis. The complex interplay of endocrine and metabolic factors requires that a continuous ingestion of a diet high in lipid calories is necessary to achieve such a state and yet maintain body weight. The resulting condition provides for much of the cerebral energy requirements in the form of ketone bodies. We review energy metabolism with special emphasis on fatty acid oxidation to provide the readers with a foundation that facilitates identification of patients who will especially benefit from this diet, as well as to assist clinicians in screening candidates who may experience a catastrophic outcome if fasted and placed on this diet. The review includes a discussion of the role of carnitine in mitochondrial fatty acid metabolism, and the criteria for carnitine supplementation. Only limited information is available regarding the interaction of the diet with the commonly used antiepileptic drugs.

Disposition of ingested olestra in weanling mini-pigs.

The disposition of ingested olestra in Hanford mini-pigs was examined by following a single oral gavage dose of radiolabelled (U-14C-sucrose) olestra Eight dosed animal (four/sex) and one undosed animal were killed 1, 3 and 7 days after dosing, and tissues were collected and counted. Urine and faeces were collected continuously and counted. Tissue lipids were extracted and analysed for intact radiolabelled olestra by size exclusion chromatography. Sucrose will be excreted in urine if olestra is absorbed and metabolized. Mean recovery of radiolabel was 96.6% of the administered dose. Of the recovered radiolabel, more than 99.4%, on average, was not absorbed and found in faeces, or cage and animal wash solutions. The absorbed radiolabel (0.6%), was distributed across the carcass, all tissues and blood, or excreted in urine. This radiolabel primarily came from the metabolism of glucose and fructose resulting from the hydrolysis of the trace levels of penta- and lower sucrose esters present in the test material. No radiolabel was found in the olestra-containing fraction of liver lipids, the primary measure of absorbed and non-metabolized olestra, at a detection limit of 0.0002% of dose. A conservative estimate of the amount of 14C-sucrose excreted in the urine was 0.0012%. The total absorption of intact olestra was thus less than 0.0014% of the dose, the sum of the two measures. These results indicate that intact olestra is essentially not absorbed by the weanling mini-pig, an animal with a young developing gastrointestinal tract similar to that of young children (2-5 yr).

Fish oil n-3 fatty acids selectively limit the hypertrophy of abdominal fat depots in growing rats fed high-fat diets.

Because dietary n-3 polyunsaturated fatty acids (n-3 PUFA) from fish oils have profound effects on lipid metabolism, we examined whether they influence the growth of adipose tissue at different locations in growing rats. Rats were fed for 4 wk on high-fat (HF) diets (20% fat) containing very low (L), medium (M), and high (H) amounts of n-3 PUFA but similar amounts of saturated fatty acids and n-6 PUFA. A fourth group was fed a standard laboratory diet (control group) to estimate changes in adipose tissue mass related to growth. At the end of the dietary treatment, the lipid mass (LM) of the four major adipose depots (subcutaneous, SC; mesenteric, MES; retroperitoneal, RP; epididymal, EPI) and total adiposity were significantly higher in each of the three HF groups than in the control group. The lipid gain in EPI was due to fat cell hypertrophy alone, whereas RP showed both hypertrophy and hyperplasia. Energy intake, fatty acid excretion, and body mass were the same in the three groups fed HF diets. Similarly, there was no difference in the LM or in lipid gains specifically caused by HF feeding of SC and MES between the HF groups. In contrast, the LM of RP was significantly lower in the H than in the L and M groups (50 and 30%, respectively). The LM of EPI was also 30% lower in the H than in the L group.(ABSTRACT TRUNCATED AT 250 WORDS)

Preparation of fatty acid methyl esters by direct transesterification of lipids with aluminium chloride-methanol.

A new and simple procedure has been developed that allows the direct transesterification of lipids, using aluminium chloride as a catalyst and methanol as the esterifying alcohol. The concentration of the salt and reaction conditions have been investigated for the different lipid classes. Comparative studies, performed with boron trifluoride-methanol, indicate that the same values are obtained when using either reagent. In addition, the method has been adapted for transesterification in the presence of silica gel and other adsorbents, thus allowing the preparation of fatty acid methyl or ethyl esters directly from samples previously fractionated by thin-layer chromatography. This new reagent is very stable and easy to handle, the fatty acids being generated in the same tube without further purification steps.

Long term 'marine diet' in Eskimos is not associated with altered urinary excretion of total tetranor prostaglandin metabolites.

The total urinary excretion of tetranor prostaglandin metabolites, measured as tetranorprostanedioic acid (TPD), was quantified in traditionally living Greenland Eskimos (E) and compared with that in Caucasian Danes (D). TPD excretion (microgram/24h) was not significantly different between both groups, neither for males (331 +/- 62.4 (E) vs. 331 +/- 25.7 (D), mean +/- SEM, n = 9 and 10) nor for females (190 +/- 31.7 (E) vs. 264 +/- 27.4 (D), n = 11 and 10, P2 greater than 0.05). Since urinary prostaglandin metabolites are thought to reflect the total prostaglandin turnover in vivo, these results suggest that a long-term intake of relatively large amounts of polyunsaturated fatty acids of the (n-3) family does not alter total prostaglandin turnover in vivo. This is in contrast to stimulated prostanoid formation in vitro, and thus suggests a different regulatory role of dietary and tissue fatty acids for 'stimulated' and 'basal' prostaglandin production.