Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FATTY ACIDS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed1980

Biosynthetic control of the natural abundance of carbon 13 at specific positions within fatty acids in Escherichia coli. Evidence regarding the coupling of fatty acid and phospholipid synthesis.

Stable carbon isotope ratios (13C/12C) at natural abundance levels have been determined for individual carbon atoms in each of the major phospholipid fatty acids of Escherichia coli grown on glucose as the sole carbon source. Two models were constructed for the isotope effects and carbon flow pathways which must be responsible for the observed isotopic fractionations. Both models incorporate a branch in the carbon flow at which fatty acyl-acyl carrier protein (acyl-ACP) is utilized either for complex lipid synthesis or for elongation by fatty acid synthetase. Depletion of carbon 13 in the carboxyl groups of myristic and palmitoleic acids (relative to carbonyl groups in precursor acyl-ACP's) was observed to occur at this branching site. Only one of the models was consistent both with this observation and with the observation (Silbert, D. F., Ruch, F., and Vagelos, P. R. (1968) J. Bacteriol. 95, 1658-1665) that exogenous fatty acids are incorporated into phospholipids but are not elongated. The successful model has free fatty acid as the intermediate product coupling fatty acid biosynthesis to phospholipid synthesis. Essential to this pathway are those reactions catalyzed by thioesterases I and II as well as acyl-ACP synthetase, enzymes whose roles have previously been unknown in vivo.

Acyl Carrier Protein↗
PubMed1975

Substitution of cellular fatty acids in yeast cells by the antibiotic cerulenin and exogenous fatty acids.

Cell growth of Saccharomyces cerevisiae ATCC 12341 inhibited by the antibiotic cerulenin, a specific inhibitor of fatty acid and sterol syntheses, was reversed by various exogenous fatty acids. Myristic acid (14 : 0), pentadecanoic acid (15 : 0), palmitic acid (16 : 0), and oleic acid (18 : 1) reversed effectively the growth inhibition by cerulenin. When these cells were reversed by adding pentadecanoic acid, over 90% of native even-numbered fatty acids was substituted by odd-numbered fatty acids. Those in the cells reversed by adding oleic acid were almost all unsaturated fatty acids. Cerulenin did not inhibit either elongation or desaturation systems in S. cerevisiae.

Antifungal Agents↗
PubMed1992

A microsomal fatty acid synthetase from the integument of Blattella germanica synthesizes methyl-branched fatty acids, precursors to hydrocarbon and contact sex pheromone.

Methyl-branched fatty acids present in the integument of the German cockroach, Blattella germanica, were identified by gas chromatography-mass spectrometry of their methyl esters and reduction products (alkanes) as n-3-, n-4-, n-5-, n-7-, n-8-, and n-9-monomethyl fatty acids and as n-5,9-, n-3,9-, and n-3,11-dimethyl fatty acids with 16 to 20 total carbons. These fatty acids have the same branching patterns as do the major hydrocarbons of this insect, including 3,11-dimethylnonacosane, the precursor to the major contact sex pheromone, and are presumed to be intermediates in hydrocarbon formation. A novel microsomal fatty acid synthetase (FAS) located in the integument of this insect incorporated [methyl-14C]methylmalonyl-CoA into methyl-branched fatty acids as demonstrated by radio-high-performance liquid chromatography. A cytosolic FAS is also present in the integument. Both the microsomal and the soluble FAS incorporated [methyl-14C]methylmalonyl-CoA into fatty acids, but only the microsomal FAS was able to efficiently use methylmalonyl-CoA as the sole elongating agent. This is the first report of the characterization of methyl-branched fatty acids from the integument of an insect and of an integumental microsomal FAS that incorporates methylmalonyl-CoA into branched fatty acids.

Acyl Coenzyme A↗
PubMed2000

Natural and azido fatty acids inhibit phosphate transport and activate fatty acid anion uniport mediated by the mitochondrial phosphate carrier.

The electroneutral P(i) uptake via the phosphate carrier (PIC) in rat liver and heart mitochondria is inhibited by fatty acids (FAs), by 12-(4-azido-2-nitrophenylamino)dodecanoic acid (AzDA) and heptylbenzoic acid ( approximately 1 microm doses) and by lauric, palmitic, or 12-azidododecanoic acids ( approximately 0.1 mm doses). In turn, reconstituted E. coli-expressed yeast PIC mediated anionic FA uniport with a similar pattern leading to FA cycling and H(+) uniport. The kinetics of P(i)/P(i) exchange on recombinant PIC in the presence of AzDA better corresponded to a competitive inhibition mechanism. Methanephosphonate was identified as a new PIC substrate. Decanephosphonate, butanephosphonate, 4-nitrophenylphosphate, and other P(i) analogs were not translocated and did not inhibit P(i) transport. However, methylenediphosphonate and iminodi(methylenephosphonate) inhibited both electroneutral P(i) uptake and FA cycling via PIC. AzDA analog 16-(4-azido-2-nitrophenylamino)-[(3)H(4)]-hexadecanoic acid ((3)H-AzHA) bound upon photoactivation to several mitochondrial proteins, including the 30- and 34-kDa bands. The latter was ascribed to PIC due to its specific elution pattern on Blue Sepharose and Affi-Gel. (3)H-AzHA photolabeling of recombinant PIC was prevented by methanephosphonate and diphosphonates and after premodification with 4-azido-2-nitrophenylphosphate. Hence, the demonstrated PIC interaction with monovalent long-chain FA anions, but with divalent phosphonates of short chain only, indicates a pattern distinct from that valid for the mitochondrial uncoupling protein-1.

Affinity Labels↗
PubMed1996

Changes in the breast milk fatty acids and plasma lipids of nursing mothers following consumption of n-3 polyunsaturated fatty acid enriched eggs.

The effect of chicken eggs enriched with n-3 fatty acids on breast milk and plasma fatty acids was determined in eight nursing women. The n-3 polyunsaturated fatty acid (PUFA) enriched eggs (n-3 eggs) contained 690 mg of n-3 fatty acid with 165 mg composed of longer chain n-3 fatty acid (C20:5 n-3, C22:5 n-3, and C22:6 n-3). Consuming two n-3 eggs as a part of their normal daily meal for 6 wk resulted in a significant (p < 0.05) deposition of total n-3 fatty acids at 3.6% compared with 1.9% for the pretest milk and a reduction in n-6:n-3 ratio (6.7 vs. 3.0). The C20 and C22 n-3 PUFA comprised 1.2% compared with 0.4% in the pretest milk (p < 0.05). Consuming n-3 eggs did not (p > 0.05) alter the C20:4 n-6 or the total n-6 fatty acid content of breast milk. Mean plasma total cholesterol and triglycerides were unchanged at the end of the 6-wk trial. Analysis of the breast milk lipids revealed increased (p < 0.05) predominance of n-6 and n-3 PUFA in the milk phospholipids over triglycerides. Positional distribution of phospholipid fatty acids indicated 20:4 n-6 and 20:5 n-3 in the sn-2 position, whereas the sn-1 position had increased levels of C16:0 and C18:0 (p < 0.05). The present study demonstrates that breast milk n-3 PUFA content can be increased without altering the plasma cholesterol or triglycerides when the n-3 PUFA eggs were consumed by nursing women.

Cholesterol↗
PubMed1999

Specific modifications of phosphatidylinositol and nonesterified fatty acid fractions in cultured porcine cardiomyocytes supplemented with n-3 polyunsaturated fatty acids.

Mechanisms for the antiarrhythmic effect of n-3 polyunsaturated fatty acids (PUFA) are currently being investigated using isolated cardiac myocytes. It is still not known whether the incorporation of n-3 PUFA into membrane phospholipids is a prerequisite for its protective action or if n-3 PUFA exert antiarrhythmic effects in their nonesterified form as demonstrated by recent studies. Adult porcine cardiomyocytes were grown in media supplemented with arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). After 24 h, analysis of total lipids showed that the myocytes were enriched with the respective fatty acids compared to control cells. Large proportions of all three fatty acids supplemented (69% AA, 72% DHA, and 66% EPA) remained unesterified. Fatty acid analyses of total phospholipids (PL) revealed that the incorporation of EPA and DHA, though small, was significantly different (P<0.05) from that of the control cells. The PL fraction was further separated into phosphatidylinositol (PI), phosphatidylethanolamine, phosphatidylcholine, and phosphatidylserine to study the pattern of incorporation of the fatty acids in these fractions. It became apparent that EPA and DHA were selectively incorporated into the PI fraction. This study demonstrates that in adult porcine cardiomyocytes, the n-3 PUFA supplementation selectively modulates two important lipid fractions, nonesterified fatty acid and PI, which were implicated in the mechanisms of prevention of cardiac arrhythmias.

Animals↗
PubMed1976

Effects of essential fatty acid deficiency and carbon tetrachloride-induced liver cirrhosis on lipid and fatty acid compositions of oral palatal epithelium in rats.

Lipid pattern and fatty acid composition of oral palatal epithelium were investigated in three groups of Sprague-Dawley rats: essential fatty acid (EFA)-deficient rats, which were fed diets containing 0.07 calorie% EFA for more than two generations; liver cirrhotic rats repeatedly injected with carbon tetrachloride; control rats fed standard pellets. The fatty acid pattern was studied in choline phosphoglycerides, ethanolamine phosphoglycerides, total phosphoglycerides, triglycerides and free fatty acids. Disturbances in the farry acid composition were seen chiefly in the EFA-deficient group, where marked reductions of the polyunsaturated fatty acids 18:2 and 20:4 (n-6) of the linolecic acid series were observed. At the same time, a compensatory increase was registered in the amount of 18:1 and 20:3 (n-9) of the oleic acid series. Corresponding findings were also found for the liver cirrhotic rats, except for the reduction of 18:2, but the changes of the fatty acid pattern in this group were not as marked as was observed for the EFA-deficient rats. In the lipid pattern no differences were seen between the three experimental groups, except for a somewhat higher content of lipid phosphorus and cholesterol in the EFA-deficient rats and a higher amount of free fatty acids in the liver cirrhotic group compared with the control rats. Changed physiological condition of the oral mucosa was suggested to be a result of the observed disturbances in the fatty acid composition of the oral epithelium.

Animals↗
PubMed2003

Liver fatty acid binding protein is required for high rates of hepatic fatty acid oxidation but not for the action of PPARalpha in fasting mice.

Liver fatty acid binding protein (L-FABP) has been proposed to limit the availability of long-chain fatty acids (LCFA) for oxidation and for peroxisome proliferator-activated receptor alpha (PPAR-alpha), a fatty acid binding transcription factor that determines the capacity of hepatic fatty acid oxidation. Here, we used L-FABP null mice to test this hypothesis. Under fasting conditions, this mutation reduced beta-hydroxybutyrate (BHB) plasma levels as well as BHB release and palmitic acid oxidation by isolated hepatocytes. However, the capacity for ketogenesis was not reduced: BHB plasma levels were restored by octanoate injection; BHB production and palmitic acid oxidation were normal in liver homogenates; and hepatic expression of key PPAR-alpha target (MCAD, mitochondrial HMG CoA synthase, ACO, CYP4A3) and other (CPT1, LCAD) genes of mitochondrial and extramitochondrial LCFA oxidation and ketogenesis remained at wild-type levels. During standard diet, mitochondrial HMG CoA synthase mRNA was selectively reduced in L-FABP null liver. These results suggest that under fasting conditions, hepatic L-FABP contributes to hepatic LCFA oxidation and ketogenesis by a nontranscriptional mechanism, whereas L-FABP can activate ketogenic gene expression in fed mice. Thus, the mechanisms whereby L-FABP affects fatty acid oxidation may vary with physiological condition.

3-Hydroxybutyric Acid↗
PubMed1976

Specific inhibition of hepatic fatty acid synthesis exerted by dietary linoleate and linolenate in essential fatty acid adequate rats.

Dietary linoleate and linolenate were investigated for their ability to specifically inhibit liver and adipose tissue lipogenesis in meal-fed (access to food 900-1,200 hr), essential fatty acid (EFA) adequate rats. Supplementing a high carbohydrate diet containing 2.5% safflower oil with 3% palmitate 16:0, oleate 18:1, or linoleate 18:2 did not affect in vivo liver or adipose tissue fatty acid synthesis. However, 18:2 addition to the basal diet did result in a significant (P less than 0.05) decline of liver fatty acid synthetase (FAS) and glucose-6-phosphate dehydrogenase (G6PD) activities. When the safflower oil content of the basal diet was reduced to 1%, the addition of 3% 18:2 or linolenate 18:3 significantly (P less than 0.05) depressed hepatic FAS, G6PD, and in vivo fatty acid synthesis by 50%. Addition of 18:1 caused no depression in hepatic FAS activity but did result in a significant (P less than 0.05) decline in liver G6PD activity and fatty acid synthesis which was intermediate between basal and basal +18:2- or +18:3-fed animals. Adipose tissue rates of lipogenesis were completely unaffected by dietary fatty acid supplementation. Similarly, the addition of 3 or 5% 18:3 to a basal diet for only one meal resulted in no change in lipogenesis relative to that in animals fed the basal diet. The data indicate that, like rats fed EFA-deficient diets, dietary 18:2 and 18:3 exert a specific capacity to depress rat liver FAS and G6PD activities and rate of fatty acid synthesis.

Adipose Tissue↗
PubMed1991

Lack of dose response by dietary n-3 fatty acids at a constant ratio of n-3 to n-6 fatty acids in suppressing eicosanoid biosynthesis from arachidonic acid.

This study evaluated whether it is the ratio of n-3 to n-6 fatty acids or the absolute amount of n-3 fatty acids in diets that determines the degree of inhibition of eicosanoid biosynthesis from arachidonic acid (AA). Rats were fed diets containing different doses of linolenic acid or menhaden oil for 3 mo. Constant ratios of n-3 to n-6 fatty acids were maintained by concomitant increases in safflower oil as the n-6 fatty acid source. Results showed that AA concentrations in liver, platelet, and lung phospholipids and concentrations of eicosanoids synthesized in tissues were significantly (P less than 0.05) suppressed both by linolenic acid and menhaden oil; however, there was a lack of a dose response within groups fed different amounts of the same dietary fat. These results indicate that the ratio of n-3 to n-6 fatty acids in the diets, rather than the absolute amount of n-3 fatty acids, is the determining factor in inhibiting eicosanoid biosynthesis from AA.

Animals↗
PubMed1992

Fatty acid radical formation in rats administered oxidized fatty acids: in vivo spin trapping investigation.

We report in vivo evidence for fatty acid-derived free radical metabolite formation in bile of rats dosed with spin traps and oxidized polyunsaturated fatty acids (PUFA). When rats were dosed with the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and oxidized PUFA, the DMPO thiyl radical adduct was formed due to a reaction between oxidized PUFA and/or its metabolites with biliary glutathione. In vitro experiments were performed to determine the conditions necessary for the elimination of radical adduct formation by ex vivo reactions. Fatty acid-derived radical adducts of alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) were detected in vivo in bile samples collected into a mixture of iodoacetamide, desferrioxamine, and glutathione peroxidase. Upon the administration of oxidized 13C-algal fatty acids and 4-POBN, the EPR spectrum of the radical adducts present in the bile exhibited hyperfine couplings due to 13C. Our data demonstrate that the carbon-centered radical adducts observed in in vivo experiments are unequivocally derived from oxidized PUFA. This in vivo evidence for PUFA-derived free radical formation supports the proposal that processes involving free radicals may be the molecular basis for the previously described cytotoxicity of dietary oxidized PUFA.

Animals↗
PubMedDate not supplied

Where to find omega-3 fatty acids and how feeding animals with diet enriched in omega-3 fatty acids to increase nutritional value of derived products for human: what is actually useful ?

Omega-3 polyunsaturated fatty acids have two major field of interest. The first lies in their quantitative abundance and their role in the development and maintenance of the brain. The second is their role in the prevention of different pathologies, mainly the cardiovascular diseases, and more lately some psychiatric disorders, from stress to depression and dementia. Thus, dietary omega-3 fatty acids are very important to ensure brain structure and function, more specifically during development and aging. However, concerning essential alpha-linolenic acid (ALA), most occidental diets contain about 50 % of the recommended dietary allowances. The problem is to know which foods are naturally rich in this fatty acid, and to determine the true impact of the formulations (enriched in omega-3 fatty acids, either ALA or EPA and DHA) in chows used on farms and breeding centres on the nutritional value of the products (meat, butter, milk and dairy products, cheese, and eggs, etc), and thus their effect on the health of consumers, especially to ensure adequate quantities in the diet of the aging people. The consequences (qualitative and quantitative) of modifications in the composition of animal foods on the value of derived products consumed by humans are more marked when single-stomach animals are concerned than multi-stomach animals. Because, for example, hydrogenating intestinal bacteria of the latter group transform a large proportion of polyunsaturated fatty acids in their food into saturated fatty acids, among others, thus depriving them of any biological interest. Under the best conditions, by feeding animals with extracts of linseed and rapeseed grains for example, the level of ALA acid is increased approximately two-fold in beef and six-fold in pork, ten-fold in chicken, and forty-fold in eggs. By feeding animals with fish extracts or algae (oils) the level of DHA is increased about 2-fold in beef, 7-fold in chicken, 6-fold in eggs, and 20-fold in fish (salmon). To obtain such results, it is sufficient to respect only the physiological needs of the animal, which was generally the case with traditional methods. It is important to stress the role of fish, whose nutritional value for humans in terms of lipids (determined by omega-3 fatty acid levels) can vary considerably according to the type of fats the animals have been fed. The aim of preventing some aspects of cardiovascular disease (and other pathologies) can be achieved, or on the contrary frustrated, depending on the nature of fatty acids present in fish flesh, the direct consequence of the nature of fats with which they have been fed. It is the same for eggs, "omega- 3 eggs" being in fact similar to natural eggs, were used in the formulation of certain formula milks for infants, whose composition was closest to that of breast milk. In fact, the additional cost on the price paid by the consumer is modest compared to the considerable gain in nutritional value in terms of omega-3 fatty acids content. Interestingly, in aged people, ALA recommendations in France are increased (0.8% daily energy intake in adult, 0.9 % in aged) and DHA is multiplied by 2 (0.05 % daily energy intake in adult, 0.1 % in aged; as well as in pregnant and lactating women).

Aged↗
PubMed1994

Effect of maternal dietary arachidonic or linoleic acid on rat pup fatty acid profiles.

Rapidly growing neonatal mammals accrete relatively large quantities of long chain (> or = C20) polyunsaturated fatty acids (LCP) in membrane phospholipids. We have examined accumulation of omega 6 LCP in suckling neonatal rat pups during the first 14 d of life when their dams received essential fatty acids in the form of triglycerides containing linoleic acid or arachidonic acid. Dietary levels of these fatty acids were either 1 or 5% of total dietary fatty acids. The fatty acid profile of pup stomach contents (composed solely of the dams' milk) and plasma lipids, as well as liver and brain phospholipids, were determined. Stomach linoleic and arachidonic acid levels reflected the diet of the dams. Pup plasma and liver arachidonic acid levels increased progressively from the group receiving 1% linoleic acid to 5% linoleic acid and from 1% arachidonic acid to 5% arachidonic acid. Interestingly, brain phosphatidylethanolamine and phosphatidylcholine arachidonic acid levels were more stable than plasma or liver levels. These results suggest that the brain may be capable of either selective transport of omega 6 LCP or chain elongation/desaturation of linoleic acid. These data indicate that care must be exercised when adding LCP to infant formula since widely divergent accretion rates of arachidonic acid may occur in various tissues.

Animals↗
PubMed2001

[Prevention of gestational hypertension with calcium, linoleic acid, mono and polyunsaturated fatty acid supplements].

BACKGROUND: The aim of this study was to evaluate the benefits of calcium, linoleic acid and mono- and polyunsaturated fatty acids in the prevention of gestational hypertension. METHODS: Between January 1999 and June 2000, 65 primagravidas with a risk of gestational hypertension between the 20th and 24th week of pregnancy were recruited using Doppler velocimetry of the uterine arteries and Holter 24-h pressure monitoring. Patients with diabetes, hypertensive gestosis and previous renal pathologies were excluded. The patients were divided into 2 unequal groups: Group A (40 patients) was treated with calcium, linoleic acid, and mono and polyunsaturated fatty acid supplements; Group B (25 patients) received no treatment. The patients in both groups underwent Doppler velocimetry of the uterine arteries and Holter pressure monitoring at 28-30-32-35 weeks of gestation. RESULTS: Calcium linoleic acid and mono and polyunsaturated fatty acid supplements were effective in significantly reducing the incidence of gestational hypertension (p>0.05); in fact 90% of patients in Group A underwent a physiological evolution of pregnancy compared to only 10% affected by gestational hypertension. In the control group the incidence of this pathology was much higher (32%). CONCLUSIONS: The authors conclude that calcium linoleic acid and mono and polyunsaturated fatty acid supplements are useful and effective in the prevention of gestational hypertension in women at risk for this pathology.

Adult↗
PubMed1986

Fatty-acid biosynthesis in man, a pathway of minor importance. Purification, optimal assay conditions, and organ distribution of fatty-acid synthase.

Fatty-acid synthase has been purified to homogeneity from human liver by a 3-step procedure including protamine sulfate/ammonium sulfate fractionation, affinity chromatography on 2',5'-ADP-Sepharose 4B and gel filtration on Sephacryl S-300. Both the human and rat fatty-acid synthase had similar characteristics regarding molecular mass, subunit structure, amino-acid composition, and substrate affinities. In order to measure the fatty-acid synthase activities in small tissue samples it was necessary to improve the sensitivity of an isotopic assay using [14C]malonyl-CoA as tracer. Special attention was paid to the dual role of free CoASH as an activator and inhibitor of the enzyme. Considerable differences existed between the specific activities of the fatty-acid synthase complex measured in human and rat lipogenic organs. Only negligible values of about 1 mU/mg protein were found in human liver and adipose tissue, while the corresponding activities were 10- to 50-fold higher in young lean rats. Less pronounced but still remarkable differences were determined for the activity of the acetyltransferase which catalyses the initial primer reaction of the fatty-acid synthase complex. In some selected cases under long-term fat-free diet (alcoholism, parenteral nutrition) elevated values of fatty-acid synthase activities were detected in human tissues. Under usual diet, with a relatively high fat content of up to 40 percent, and even after a carbohydrate-rich diet for three days, fatty-acid synthase activity remained low. It is concluded that under the dietary conditions, common for the industrialized world, de novo lipogenesis in man is negligible.

Adipose Tissue↗
PubMed2002

The fatty acid profile of buccal cheek cell phospholipids is a noninvasive marker of long-chain polyunsaturated Fatty Acid status in piglets.

The fatty acid pattern of cheek cell phospholipids has been proposed as a noninvasive marker of long-chain polyunsaturated fatty acid (PUFA) status. However, the cheek cell phospholipid fatty acid pattern has been compared only with that of plasma and erythrocytes. The objective of this study was to assess the extent to which the fatty acid profile of cheek cell phospholipids reflects that of tissue phospholipids. Piglets (n = 31; 6 d old) were fed five formula diets differing in total fat and fatty acid composition. After 14 d of consuming the assigned diets, cheek cell plasma, erythrocyte, liver, muscle, adipose tissue, retina and brain samples were collected for determination of the phospholipid fatty acid patterns. There were significant correlations between the cheek cell phospholipid content of most PUFA and the content of these fatty acids in tissue phospholipids (r = 0.509-0.951, P < 0.01). The cheek cell phospholipid content of most of the PUFA, except 20:4(n-6), reflected that of other tissue phospholipids as well as, or nearly as well as the contents of plasma and/or erythrocyte phospholipids. The correlations between the 22:6(n-3) contents of cheek cell, plasma, or erythrocyte phospholipids and those of brain and retina phospholipids were relatively poor (r = 0.596-0.737, P < 0.001). We conclude that the fatty acid pattern of cheek cell phospholipid can be used as a noninvasive marker of PUFA status, but it is not a better index than the pattern of plasma or erythrocyte phospholipids, particularly for assessing the fatty acid pattern of organs with slow fatty acid incorporation and/or turnover rates.

Adipose Tissue↗
PubMed2003

Effect of tartaric acid and dietary fibre from sun-dried raisins on colonic function and on bile acid and volatile fatty acid excretion in healthy adults.

Sun-dried raisins are a source of dietary fibre and tartaric acid. The effects of tartaric acid on colon function have not been the focus of extensive research. The purpose of the present study was to evaluate the effects of dietary fibre and tartaric acid from sun-dried raisins on colon function and on faecal bile acid and short-chain fatty acid (SCFA) excretion in healthy adults. Thirteen healthy subjects were fed 120 g sun-dried raisins/d or 5 g cream of tartar (equivalent to the tartaric acid in 120 g sun-dried raisins)/d for 9 weeks, divided into 3-week cycles. The experimental diets were fed in a crossover design after an initial control period. Faeces were collected for the last 4 d of each cycle for analysis of SCFA and bile acids. Intestinal transit time decreased from 42 h on the baseline diet to 31 h on cream of tartar (P<0.1) and to 28 h on sun-dried raisins (P<0.05). Faeces were softer on both sun-dried raisins and cream of tartar, but sun-dried raisins increased faecal wet weight (P<0.05), while cream of tartar did not. Sun-dried raisins caused significant reductions from baseline values in total bile acid concentration (from 1.42 (SD 1.03) to 1.09 (SD 0.76) mg/g, P<0.05), whereas cream of tartar did not (1.40 (SD 1.06) mg/g). Sun-dried raisins also significantly reduced the lithocholic (LC):deoxylithocholic acid (DC) ratio (from 1.63 (SD 0.85) to 1.09 (SD 0.50), P<0.02), whereas cream of tartar reduced the ratio, but to a lesser extent (1.29 (SD 0.79), NS). Both faecal bile acids and the LC:DC ratio are indicators of reduced risk for colon cancer. Sun-dried raisins increased total SCFA excretion (from 5.6 (SD 3.4) to 7.6 (SD 3.0) g/4 d, P<0.05), which remained unchanged with cream of tartar (5.6 (SD 3.0) g/4 d). Both sun-dried raisins and cream of tartar appear to be good stool softeners and to shorten intestinal transit time, although the fibre in sun-dried raisins has the added benefit of increasing faecal weight. Both sun-dried raisins and cream of tartar modulate the composition of faecal bile acids and SCFA in a way that has potential health benefits.

Adult↗