Absorption Of Saturated Fatty Acids Research Articles

Impurity contribution to ultraviolet absorption of saturated fatty acids.

Saturated fatty acids are abundant organic compounds in oceans and sea sprays. Their photochemical reactions induced by solar radiation have recently been found as an abiotic source of volatile organic compounds, which serve as precursors of secondary organic aerosols. However, photoabsorption of wavelengths longer than 250 nanometers in liquid saturated fatty acids remains unexplained, despite being first reported in 1931. Here, we demonstrate that the previously reported absorption of wavelengths longer than 250 nanometers by liquid nonanoic acid [CH3(CH2)7COOH)] originates from traces of impurities (0.1% at most) intrinsically contained in nonanoic acid reagents. Absorption cross sections of nonanoic acid newly obtained here indicate that the upper limit of its photolysis rate is three to five orders of magnitude smaller than those for atmospherically relevant carbonyl compounds.

Dietary intake of n-3 PUFAs modifies the absorption, distribution and bioavailability of fatty acids in the mouse gastrointestinal tract

BackgroundDietary polyunsaturated fatty acids (PUFAs), especially n-3 PUFAs, are important for human health. The intestinal tract, a location that is heavily colonized by microorganisms, is the main organ for absorbing fatty acids.MethodsThe purpose of this study was to analyze the effects of dietary n-3 and n-6 PUFAs on the distribution of different types of fatty acids and their bioavailability along the gut. Mice were fed for a week with experimental diets containing high n-3 or high n-6 fatty acid levels. Blood was collected at different time points, and after 7 days the mice were euthanized and their digestive tract was divided into 17 segments for fatty acids analyses.ResultsWe found that supplementing n-3 fatty acids significantly changed the ratio of n-6/n-3 PUFAs, increased the bioavailability of n-3 PUFAs, and altered fatty acid distribution. In addition, in the n-3 diet group, the absorption of saturated fatty acids (SFAs) along the gut was found to be inhibited, which was confirmed by feeding the mice with a diet containing deuterium-labeled palmitic acid and stearic acid.ConclusionThese results show that a diet rich in n-3 PUFAs can significantly modify the distribution and bioavailability of fatty acids, and particularly, may block the absorption of SFAs in the mouse gastrointestinal (GI) tract.

Use of re-esterified palm oils, differing in their acylglycerol structure, in weaning-piglet diets

Re-esterified oils are new fat sources obtained from chemical esterification of acid oils with glycerol (both economically interesting by-products from oil refining and biodiesel industries, respectively). The different fatty acid (FA) positional distribution and acylglycerol composition of re-esterified oils may enhance the apparent absorption of saturated fatty acids (SFA) and, thus, their overall nutritive value. The aim of the present study was to investigate the potential use of re-esterified palm oils, in comparison with their corresponding acid and native oils, and also with an unsaturated fat source in weaning-piglet diets. The parameters assessed were: FA apparent absorption, acylglycerol and free fatty acid (FFA) composition of feces, and growth performance. One-hundred and twenty weaning piglets (average weight of 8.50±1.778 kg) were blocked by initial BW (six blocks) and randomly assigned to five dietary treatments, resulting in four piglets per pen and six replicates per treatment. Dietary treatments were a basal diet supplemented with 10% (as-fed basis) of native soybean oil (SN), native palm oil (PN), acid palm oil (PA), re-esterified palm oil low in mono- (MAG) and diacylglycerols (DAG) (PEL), or re-esterified palm oil high in MAG and DAG (PEH). Results from the digestibility balance showed that SN reached the greatest total FA apparent absorption, and statistically different from PN, PA and PEL (P<0.05). There were no statistical differences among palm-oil sources (P>0.05), but PEH achieved the greatest total FA apparent absorption. Animals fed PEL, despite the fact that PEL oil contained more sn-2 SFA, did not show an improved absorption of SFA (P>0.05). Animals fed PA and PN showed similar apparent absorption coefficients (P>0.05), despite the high FFA content of PA oil. The acylglycerol and FFA composition of feces was mainly composed of FFA. There were no significant differences in growth performance (P>0.05). Results of the present study suggest that, despite the different acylglycerol structure of re-esterified oils, there were no significant differences in digestibility or performance with respect to their corresponding PN and PA oils in weaning-piglet diets.

Use of re-esterified palm oils, differing in their acylglycerol structure, in fattening pig diets

Re-esterified oils are new fat sources obtained from the chemical esterification of acid oils with glycerol (both economically interesting by-products from oil refining and biodiesel industries, respectively). The different fatty acid (FA) positional distribution and acylglycerol composition of re-esterified oils may enhance the apparent absorption of saturated fatty acids (SFA) and, therefore, their overall nutritive value, which might lead to an increased deposition of SFA. The aim of the present study was to investigate the potential use of re-esterified palm oils, in comparison with their corresponding acid and native oils in fattening pig diets, studying their effects on fatty acid apparent absorption, acylglycerol and free fatty acid (FFA) composition of feces, growth performance, carcass-fat depots and fatty acid composition of backfat. Seventy-two crossbred boars and gilts (average weight of 24.7±2.55 kg) were blocked by initial BW (nine blocks of BW for each gender), housed in adjacent individual boxes, and fed one of the four dietary treatments, which were the result of a basal diet supplemented with 4% (as-fed basis) of native palm oil (PN), acid palm oil (PA), re-esterified palm oil low in mono- and diacylglycerols (PEL), or re-esterified palm oil high in mono- and diacylglycerols (PEH). Regarding results from the digestibility balance, PA and PN showed similar apparent absorption coefficients (P>0.05), despite the high, FFA content of the former. However, re-esterified palm oils (both PEL and PEH) showed a higher apparent absorption of total FA than did their corresponding native and acid oils (P<0.001), mainly due to the increased apparent absorption of SFA (P<0.001). This resulted in a greater feed efficiency and an increased deposition of SFA in backfat of pigs fed PEH, when compared with those fed PA (P<0.05), although no differences were found for carcass-fat depots (P>0.05). We conclude that re-esterified oils are interesting fat sources to be considered in fattening pigs.

Physiological role of hepatic NPC1L1 in human cholesterol and lipoprotein metabolism: New perspectives and open questions

The importance of the cholesterol transporter Niemann-Pick C1 like protein 1 (NPC1L1)in the small intestine for efficient absorption of cholesterol is well documented and its physiological importance is clear (1). Similarly, the drug ezetimibe (Zetia™), which blocks function of this transporter, reduces plasma cholesterol, primarily LDL, by dramatically reducing intestinal absorption of dietary and biliary cholesterol (2). There are controversies about the exact mechanism by which NPC1L1 functions: whether the protein is on the apical cell membrane or intracellular vesicles or both (3–5), and whether ezetimibe directly blocks NPC1L1 or interrupts its association with other proteins in the sterol absorption and transport pathway (6–8). Nevertheless, it is now accepted that this protein is the key player in sterol absorption, although other transporters may play ancillary roles (9, 10).

Modulation of lipid metabolism with the overexpression of NPC1L1 in mouse liver

Niemann-Pick C1-like 1 protein (NPC1L1), a transporter crucial in intestinal cholesterol absorption, is expressed in human liver but not in murine liver. To elucidate the role of hepatic NPC1L1 on lipid metabolism, we overexpressed NPC1L1 in murine liver utilizing adenovirus-mediated gene transfer. C57BL/6 mice, fed on normal chow with or without ezetimibe, were injected with NPC1L1 adenovirus (L1-mice) or control virus (Null-mice), and lipid analyses were performed five days after the injection. The plasma cholesterol levels increased in L1-mice, and FPLC analyses revealed increased cholesterol contents in large HDL lipoprotein fractions. These fractions, which showed α-mobility on agarose electrophoresis, were rich in apoE and free cholesterol. These lipoprotein changes were partially inhibited by ezetimibe treatment and were not observed in apoE-deficient mice. In addition, plasma and VLDL triglyceride (TG) levels decreased in L1-mice. The expression of microsomal triglyceride transfer protein (MTP) was markedly decreased in L1-mice, accompanied by the reduced protein levels of forkhead box protein O1 (FoxO1). These changes were not observed in mice with increased hepatic de novo cholesterol synthesis. These data demonstrate that cholesterol absorbed through NPC1L1 plays a distinct role in cellular and plasma lipid metabolism, such as the appearance of apoE-rich lipoproteins and the diminished VLDL-TG secretion.

Dietary cholesterol reverses resistance to diet-induced weight gain in mice lacking Niemann-Pick C1-Like 1

Niemann-Pick C1-Like 1 (NPC1L1) mediates intestinal cholesterol absorption. NPC1L1 knockout (L1-KO) mice were recently shown to be resistant to high-fat diet (HFD)-induced obesity in one study, which was contrary to several other studies. Careful comparison of dietary compositions in these studies implies a potential role of dietary cholesterol in regulating weight gain. To examine this potential, wild-type (WT) and L1-KO mice were fed one of three sets of diets for various durations: (1) a HFD without added cholesterol for 5 weeks; (2) a high-carbohydrate diet with or without added cholesterol for 5 weeks; or (3) a synthetic HFD with or without added cholesterol for 18 weeks. We found that L1-KO mice were protected against diet-induced weight gain only on a diet without added cholesterol but not on a diet containing 0.16% or 0.2% (w/w) cholesterol, an amount similar to a typical Western diet, regardless of the major energy source of the diet. Food intake and intestinal fat absorption were similar between the two genotypes. Intestinal cholesterol absorption was blocked, and fecal cholesterol excretion increased in L1-KO mice. Under all diets, L1-KO mice were protected from hepatosteatosis. In conclusion, increasing dietary cholesterol restores diet-induced weight gain in mice deficient in NPC1L1-dependent cholesterol absorption.

Reduced absorption of saturated fatty acids and resistance to diet-induced obesity and diabetes by ezetimibe-treated andNpc1l1−/−mice

The impact of NPC1L1 and ezetimibe on cholesterol absorption are well documented. However, their potential consequences relative to absorption and metabolism of other nutrients have been only minimally investigated. Thus studies were undertaken to investigate the possible effects of this protein and drug on fat absorption, weight gain, and glucose metabolism by using Npc1l1(-/-) and ezetimibe-treated mice fed control and high-fat, high-sucrose diets. Results show that lack of NPC1L1 or treatment with ezetimibe reduces weight gain when animals are fed a diabetogenic diet. This resistance to diet-induced obesity results, at least in part, from significantly reduced absorption of dietary saturated fatty acids, particularly stearate and palmitate, since food intake did not differ between groups. Expression analysis showed less fatty acid transport protein 4 (FATP4) in intestinal scrapings of Npc1l1(-/-) and ezetimibe-treated mice, suggesting an important role for FATP4 in intestinal absorption of long-chain fatty acids. Concomitant with resistance to weight gain, lack of NPC1L1 or treatment with ezetimibe also conferred protection against diet-induced hyperglycemia and insulin resistance. These unexpected beneficial results may be clinically important, given the focus on NPC1L1 as a target for the treatment of hypercholesterolemia.

ABSORPTION AND LYMPHATIC TRANSPORT OF INTERESTERIFIED OR MIXED FATS RICH IN SATURATED FATTY ACIDS AND THEIR EFFECT ON TISSUE LIPIDS IN RATS

Interesterification of fully hydrogenated plant oils with liquid oils has been used as an alternative to partial hydrogenation to produce a zero-trans solid fat due to recent reports of unfavorable effects of dietary trans fatty acids on serum cholesterol levels. Present study was carried out to examine absorption of saturated fatty acids derived from mixed and interesterified fats and their effects on concentration of serum cholesterol. Dietary fats consisted of tripalmitin or tristearin: high oleic safflower oil: safflower oil ratios of 44.4:35.3:20.3 or their interesterified products; a melting point of the interesterified fat was lower than that of the corresponding mixed fats. When rats were fed these-fat containing diets for three wks, absorption rate estimated by excretion of fatty acids into feces was higher in interesterified fat-fed rats than in the corresponding mixed fat-fed rats. This improved absorption was accompanied by an increased concentration of liver triacylglycerols and an increased proportion of stearic acid in the adipose tissue and an increased proportion of oleic acid in serum and liver. Dietary fats exerted no significant effect on the liver or serum cholesterol concentration or the excretion of neutral or acidic steroids into feces. In contrast to dietary fat absorption, administration of the mixed and interesterified fats, emulsified with taurocholate and albumin, into stomach of rats cannulated with thoracic lymph duct resulted in lymphatic triacylglycerols with a comparable transport rate and with a similar fatty acid composition at each position of triacylglycerols. These results demonstrate that interesterification improves absorption of dietary fats, possibly by facilitating emulsification of saturated fats, but seems not to exert any adverse effects on the concentration of serum and liver cholesterol. © 1997 Elsevier Science Inc.

The influence of specific phospholipids as absorption enhancer in animal nutrition

AbstractThe ability of Lysoforte, a specific phospholipid, to act as absorption enhancer in animal nutrition, has been studied. The addition of Lysoforte in feed supplements a natural surfactant, which assists and promotes the absorption of nutrients. Tests With live baby hamster kidney cells demonstrated the influence on the absorption of saturated fatty acids. Animal trials with broilers, sows, piglets and pigs were set up to investigate the improvement of the technical performance as well as the influence on the carcass quality in pigs. The synergistic effect of Lysoforte on other additives, such as enzymes, has been examined in broiler trials as well.Der Einfluß eines speziellen Phospholipids als Absorptionsverstärker in der Tierernährung. Es wurde die Eigenschaft von Lysoforte, einem speziellen Phospholipid, als Absorptionsverstärker in der Tierernährung untersucht. Der Zusatz von Lysoforte ins Mischfutter liefert einen natürlichen Emulgator, der die Aufnahme von Nährstoffen stimuliert. Versuche mit Nierenzellen von Hamsterjungen zeigten einen Einfluß auf die Absorption von gesättigten Fettsäuren. Tierversuche mit Mastküken, Säuen, Ferkeln und Schweinen wurden angelegt, um sowohl die Wirkung auf die Leistung der Tiere als auch den Einfluß auf die Schlachtkörperqualität festzustellen. Ein synergistischer Effekt von Lysoforte mit anderen Zusatzstoffen, wie zum Beispiel Enzymen, wurde in Versuchen ebenfalls untersucht.

Absorption of isomeric, palmitic acid‐containing triacylglycerols resembling human milk fat in the adult rat

The effect of the positional distribution of palmitic acid (16:0) in triacylglycerols (TAG) on 16:0 apparent absorption in adult rats was investigated. The rats were fed two diets which contained 30 energy % as fat with identical total fatty acid compositions, both containing 30% 16:0. The Betapol diet contained TAG with 73% of total 16:0 in the sn-2 position, the control diet contained TAG with 6% of total 16:0 in the sn-2 position. After six weeks on these diets, the rats were killed two or six hours after the last meal, and the small intestine was removed, cut into 10-cm segments, and the fatty acid composition of the segment's contents was determined. At both time points the amount of 16:0 in the intestinal segments starting at 40 cm from the stomach was much lower in the animals fed Betapol than in the animals fed the control diet. Overall absorption of 16:0 and stearic acid was significantly greater in the Betapol group. Absorption of oleic and linoleic acid from the small intestine was similar in both groups, although the overall absorption was significantly greater in the animals fed Betapol. Total fat absorption was significantly higher in the Betapol-fed rats than in the control-fed rats. No effect on calcium and nitrogen absorption, on plasma total cholesterol and TAG levels, and on bodyweights (growth) was seen. The data demonstrate that the positional distribution of the fatty acids in the TAG molecule affects the site of absorption in the small intestine and particularly the net absorption of saturated fatty acids.

Metabolism of polyglycerol and polyglycerol esters

Metabolism of tri-(G 3) and polyglycerol (G 10) and G 3 and G 10 esters was studied in vivo in the rat, and in vitro with pancreatic enzymes. Fatty acid-labeled (oleic acid and eicosanoic acid), G 10 ∗-labeled esters and 14C-labeled tri-(G 3 ∗) and polyglycerol ( G 10 ∗ ) were used so that the metabolic fate of the fatty acids and of the G 3 and G 10 moieties could be independently determined. Our data showed that the ester bonds were hydrolyzed to a large extent prior to absorption. The free fatty acids were absorbed via the thoracic duct pathway. Eicosanoic acid was not as readily absorbed as was oleic acid. The free or partially esterified polyglycerols were not as well absorbed as the fatty acids; absorption was by a pathway other than the thoracic duct, presumably by the portal venous blood. Distribution of radioactivity among respiratory CO 2, urine, feces and carcass was determined. CO 2 was the major end product of fatty acid catabolism. G 3 ∗ and G 10 ∗ moieties were not catabolized or stored in the carcass, but were excreted unchanged in the urine. Hydrolysis experiments in vitro confirmed that the oleic acid ester bond in the G 3 and G 10 esters was readily cleaved, as is the same bond in triglycerides. The eicosanoate bond was cleaved more slowly than the oleate bond. The slower rate of hydrolysis of the eicosanoate ester linkage coupled with a slower rate of absorption of saturated fatty acids would explain why more of the label from this compound than from oleate was detected in the feces and gastrointestinal contents.