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Effect of diet on increases in systolic pressure induced in rats by chronic cadmium feeding.

Long-term exposure to cadmium in drinking water can induce hypertension in rats. We have consistently observed that from 0.1 to 5 ppm cadmium in deionized drinking water fortified with five essential metals induces a significant pressor effect in female Long-Evans rats on a noncommercial, low cadmium, rye-based diet. To test the effect of diet, a commercial stock diet (Purina Rodent Lab Chow), with either fortified or plain deionized water, was begun at weaning in rats that were receiving water containing 0.1 or 1 ppm cadmium. The overall effect of substituting the stock diet for the rye diet was initially to lessen, and later to prevent entirely, the cadmium-induced pressor effect. Whereas control rats on the rye diet have a constant systolic pressure of about 100 mm Hg throughout the experiment; control rats on the stock diet had an increase in systolic pressure of about 1 mm Hg/month, perhaps because of cadmium from food which contained 10 times as much of the metal as the rye diet. (There was also a somewhat lower pressure among the cadmium-fed rats on stock diet than among those on the rye diet). There were other (non-cadmium) differences between the stock and rye diets and between the remainder of our experimental conditions and those used by other investigators, presumably explaining the failure of some others to induce hypertension with cadmium.

Animals↗

Zinc absorption in humans from meals based on rye, barley, oatmeal, triticale and whole wheat.

The absorption of zinc from meals based on 60 g of rye, barley, oatmeal, triticale or whole wheat was studied by use of extrinsic labelling with 65Zn and measurement of the whole-body retention of the radionuclide. The cereals were prepared in the form of bread or porridge and were served with 200 mL of milk. The oatmeal flakes were also served without further preparation. The absorption of zinc was negatively correlated to the phytic acid content of the meal with the highest absorption, 26.8 +/- 7.4%, from the rye bread meal containing 100 mumol of phytic acid and the lowest, 8.4 +/- 1.0%, from oatmeal porridge with a phytic acid content of 600 mumol. It is concluded that food preparation that decreases the phytic acid content improves zinc absorption.

Absorption↗

Iron absorption from bread in humans: inhibiting effects of cereal fiber, phytate and inositol phosphates with different numbers of phosphate groups.

Iron absorption was measured from five kinds of bread made from various types of flour and fermented in different ways in order to obtain a wide variation in the content of fiber, phytate (inositol hexaphosphate) and its degradation products, inorganic phosphate and inositol phosphates with fewer numbers of phosphate groups (inositol pentaphosphate through monophosphate). Each experiment had 9-10 subjects and, in each subject, iron absorption was measured from control rolls made from low extraction wheat flour and one kind of test roll using two different radioiron tracers: 55Fe and 59Fe. The inhibition of iron absorption was closely related to the content of phytate-phosphorous as determined using the AOAC method, and to the sum of the tri- through hexaphosphate groups as determined using the HPLC method. As an example, prolonged fermentation of whole-rye bread reduced total inositol phosphates to the same amount as in the control rolls and increased fractional iron absorption to the same high level, in spite of a fiber content five times as great. The results strongly suggest that the inhibitory effect of bran on iron absorption is due to its content of phytate and other inositol phosphates present after fermentation, rather than to its content of fiber or other constituents. Thus, effective fermentation will increase the bioavailability of iron in whole-meal bread.

Absorption↗

Bile acid metabolism in rats fed two levels of corn oil and brans of oat, rye and barley and sugar beet fiber.

High concentrations of fecal bile acids are associated with a higher incidence of colon cancer. Dietary changes that alter bile acid metabolism are therefore of interest. Here, we report the effect of feeding diets containing four fiber sources and two fat levels for 7 wk on bile acid excretion and small intestinal bile acids (an index of pool size) in rats. The fiber sources were oat bran, rye bran, barley bran and sugar beet fiber. Fiber-containing diets were 8% dietary fiber and contained either 5 or 20% corn oil. All fiber sources caused significantly greater fecal output compared with the fiber-free basal diet. All fiber sources also resulted in significantly (P less than 0.05) lower fecal bile acid concentration compared with the fiber-free basal diet. Only rye bran resulted in significantly (P less than 0.05) higher total fecal bile acid excretion. Oat bran resulted in a slightly but significantly (P less than 0.05) higher quantity of small intestine bile acids compared with the other diets. Dietary fat level had no significant effect on fecal bile acid concentration or excretion or quantity of small intestinal bile acids. We conclude that all four fiber sources tested resulted in lower fecal bile acid concentration, by effectively causing greater fecal mass. Changes in dietary fat level as corn oil had no effect on fecal bile acids.

Animals↗

Reduction of intestinal viscosity through manipulation of dietary rye and pentosanase concentration is effected through changes in the carbohydrate composition of the intestinal aqueous phase and results in improved growth rate and food conversion efficiency of broiler chicks.

The effect of dietary rye (0, 200, 400 and 600 g/kg substituting for wheat) and pentosanase concentration (0, 1, 2, 4, 8, 16 g/kg) on weight gain, molecular weight distribution of soluble carbohydrates in the intestinal lumen and lumenal viscosity in broiler chicks was investigated. A 4 x 6 factorial design was used with four replicates per treatment and six birds per replicate pen. Diets were fed from 1 to 19 d of age, at which time body weight, food intake and intestinal viscosity and molecular weight distribution of carbohydrate complexes in proximal and distal gut sections were determined. Weight gain and food conversion efficiency (FCE) improved with increasing pentosanase and decreasing rye concentration. Intestinal viscosity, which rose as digesta passed from the proximal to distal small intestine, fell with pentosanase addition and decreasing rye concentration. Intestinal viscosity, which correlated positively with reduced weight gain and FCE, was in turn correlated with the lumenal concentration of soluble high-molecular-weight carbohydrates (HMC, greater than 500 kDa), which constituted less than 15% of the total lumenal carbohydrate concentration. The arabinose and xylose content of the HMC increased with increasing rye concentration, suggesting that HMC composition in addition to concentration may determine intestinal viscosity. The results indicate that pentosanase isolated from rye by extraction methods may not be representative of those released by digestion.

Animal Feed↗

Baked rye products modify cholesterol metabolism and crypt cell proliferation rates in rats.

Young adult male rats were made hypercholesterolemic by feeding cholesterol (+ cholic acid). The effect of rye crispbread on hepatic and plasma cholesterol concentrations, hepatic cholesterol synthesis, small intestinal cell turnover and fecal output was investigated. Diets containing 50 and 75% rye crispbread (g dry wt) were compared with positive control diets of similar gross composition, in which the insoluble component of rye was matched with cellulose and the soluble component with guar gum. A negative control diet containing no non-starch polysaccharide was also included. Cholesterol supplementation was maintained in half the rats on each diet. Rye caused a marked increase in fecal output that was greater than that seen in the positive control groups. However, crypt cell proliferation in the small intestine was less than that seen in the high fiber control groups. Rye reduced total plasma cholesterol concentrations only in those rats that continued to receive the high cholesterol diet. However, whether or not cholesterol was fed, the presence of nonstarch polysaccharide caused a decrease in liver cholesterol concentrations. Rye caused a marked increase in hepatic cholesterol synthesis over both the positive controls and the rats fed a fiber-free diet. This implies that rye causes a loss of cholesterol from the body, probably due to malabsorption of bile acids and cholesterol.

Animals↗

Lactobacillus strain GG supplementation decreases colonic hydrolytic and reductive enzyme activities in healthy female adults.

The effects of yogurt containing viable Lactobacillus strain GG (L. GG) and/or fiber supplements on fecal enzyme activities (beta-glucuronidase, nitroreductase, beta-glucosidase, glycocholic acid hydrolase, urease) and on bacterial metabolites in urine (phenol, p-cresol) were studied in 64 females, 20-41 y old. The subjects were randomly divided into three groups: the first group received L. GG yogurt (2 x 150 mL/d, containing 10(11) colony-forming units (cfu)/L of L. GG), the second group received L. GG yogurt and a rye fiber product (30 g/d, equivalent to 9 g fiber/d), and the third group received placebo yogurt (pasteurized) and fiber. The supplementation period lasted 4 wk, with a preceding 2-wk baseline period and a 2-wk follow-up period. The mean fecal count of L. GG was approximately 10(6) cfu/g feces during the supplementation, and L. GG persisted in the fecal samples of 28% of the subjects for 2 wk after supplementation. L. GG yogurt alone or with fiber significantly decreased fecal beta-glucuronidase, nitroreductase and glycocholic acid hydrolase activities. These enzyme activities returned to baseline levels during the follow-up period. beta-Glucosidase and urease activities were not altered significantly during the study. The addition of fiber to L. GG and placebo yogurt had no effect on the enzymic activities. Urinary excretion of p-cresol decreased significantly in groups receiving L. GG. These data demonstrate that L. GG can modify the colonic environment with possible health effects.

Adult↗

Fiber-degrading enzyme increases body weight and total serum cholesterol in broiler chickens fed a rye-based diet.

Broiler chickens were fed diets based on either outer or inner endosperm from rye. These diets were fed with or without a fiber degrading enzyme to study the effects of the dietary fiber fraction on production results, body composition, serum lipid concentrations and apparent ileal digestibility of nutrients. Elimination of the dietary fiber effect by the enzyme generally improved the production results and caused an increase in total serum cholesterol concentrations. On average, at d 21 of the experiment chickens fed the enzyme supplemented outer endosperm diet had body weights and serum total cholesterol concentrations -23% and 37% higher, respectively, than those of birds fed the corresponding unsupplemented diet. The body fat content tended to be higher and the protein content was generally lower in chickens fed enzyme-supplemented diets. Chickens fed the unsupplemented outer endosperm diet had a low apparent ileal crude fat digestibility of only 23%, and birds fed the enzyme-supplemented diet had crude fat digestibility that was 113% higher but still lower than that of birds fed the inner endosperm diet. Birds fed enzyme-supplemented diets generally had higher apparent ileal digestibilities of organic matter, crude protein, starch, crude fat and dietary fiber components.

Animals↗

Digestibilities of energy, protein, fat and nonstarch polysaccharides in a low fiber diet and diets containing coarse or fine whole meal rye are comparable in rats and humans.

The apparent digestibility of energy, protein, fat and nonstarch polysaccharides (NSP) of a low fiber diet and two high fiber diets containing coarse or fine whole meal rye bread was studied in experiments with humans and rats. Human subjects consumed the experimental diets for 3 wk each in a 3 x 3 cross over design. For the rat diets, duplicate portions of the foods consumed by the human subjects were mixed together, freeze dried and ground. There was a good agreement in the digestibility of energy (humans: 94.7 +/- 0.9, 91.2 +/- 1.2 and 91.6 +/- 1.4%; rats: 95.0 +/- 0.8, 92.5 +/- 1.4 and 91.7 +/- 1.8%) and fat (humans: 95.2 +/- 1.5, 94.4 +/- 1.0 and 94.8 +/- 2.5%, rats: 95.4 +/- 0.9, 94.0 +/- 0.4 and 94.0 +/- 0.4%) for the low fiber diet and the diets containing coarse or fine whole meal bread, respectively. Apparent and true digestibility of protein was consistently lower (P < 0.0001) in humans (apparent digestibility: 90.6 +/- 1.5, 86.2 +/- 1.4 and 86.3 +/- 2.3%; true digestibility: 95.1 +/- 1.5, 90.7 +/- 1.4 and 90.8 +/- 2.2%) than in rats (apparent digestibility: 92.3 +/- 1.1, 89.4 +/- 0.9 and 88.9 +/- 1.0%; true digestibility: 98.3 +/- 1.1, 94.9 +/- 0.9 and 94.2 +/- 1.0%) for all three diets. The digestibility of NSP tended to be lower (P < 0.066) in rats than in humans for the diet containing fine whole meal bread (rats: 59.6 +/- 8.0%, humans: 68.0 +/- 5.2%) and the low fiber diet (rats: 72.1 +/- 10.8%; humans: 80.5 +/- 7.1%), whereas it was similar in both species for the diet containing the coarse whole meal bread (rats: 66.1 +/- 6.0%; humans: 65.8 +/- 9.3%). In spite of some differences in digestibility values, our results suggest that the rat is a suitable model for humans to predict digestibility of nutrients in mixed diets containing cereal fiber sources.

Adult↗

Intake of rye bread ileostomists increases ileal excretion of fiber polysaccharide components and organic acids but does not increase plasma or urine lignans and isoflavonoids.

The excretion of starch, enzyme-resistant starch, dietary fiber components and organic acids (short-chain fatty acids plus lactic acid) as well as plasma and urine lignans and isoflavonoids was studied in eight ileostomists consuming mixed diets with wheat bread (low fiber diet) or rye bread (high fiber diet) in a crossover design. Average ileal excretions of enzyme-available starch were 3.5 g/d during the low fiber period and 4.1 g/d during the high fiber period. The excretion of enzyme-resistant starch was approximately the same (2.3 g/d) in both periods. In comparison with intake, similar amounts of total fiber residues were excreted both by subjects receiving the low fiber diet (3.4 g/d) and by those receiving the high fiber diet (2.7 g/d). However, subjects excreted significantly more of certain polysaccharide residues (fucose, galactose, and uronic acids) than they ingested. On average, the excretion of organic acids was 18.6 mmol/d during the low fiber period and 30.2 mmol/d during the high fiber period. No significant differences in plasma lignans were observed between the high fiber and the low fiber dietary periods. The present findings indicate that enzyme-available starch is highly digested and that a microbial breakdown of dietary fibers and probably other carbohydrates occurs in the small intestine. However, the bacterial activity in the ileostomists was not sufficient to cause an increased level in plasma lignans even when subjects consumed the high fiber rye diet.

Adult↗

Rye bread decreases serum total and LDL cholesterol in men with moderately elevated serum cholesterol.

The objective of this study was to determine the hypocholesterolemic effects of whole meal rye and white wheat breads in healthy humans with elevated serum cholesterol concentrations, and the changes in plasma glucose and insulin concentrations during rye and wheat bread periods. The subjects were 18 men and 22 women with baseline serum cholesterol concentration of 6.4+/-0.2 mmol/L. The study design was a 2x4-wk crossover trial during which each subject randomly consumed rye and wheat breads (20% of daily energy) as part of their usual diet for 4 wk. The bread periods were separated by a 4-wk washout period. Blood samples (after fasting) were collected on two consecutive days at the beginning and end of the bread periods. Serum total cholesterol decreased by 8% (P = 0.002) in men but was not significantly altered in women during the rye bread period. The wheat bread period did not affect any of the variables studied. Analysis of the serum lipids in tertiles of rye bread consumption confirmed the reduction in total cholesterol (P = 0.048) in men and revealed the reduction in LDL cholesterol (P = 0.032); both were dependent on the amount of rye bread consumed (-2, -14 and -10% in total cholesterol and 0, -12 and -12% in LDL cholesterol). Neither rye nor wheat bread influenced the concentrations of glucose and insulin. In conclusion, rye bread is effective in reducing serum total and LDL cholesterol concentrations in men with elevated serum cholesterol. Good compliance with consuming a relatively large amount of rye bread in the usual diet indicates that rye bread offers a practical dietary means of reducing serum cholesterol in men.

Adult↗

Replacement of soybean oil with tallow in rye-based diets without xylanase increases protein synthesis in small intestine of broilers.

We examined the effects of dietary fat type (10% of either soybean oil, S, or beef tallow, T)(3) and xylanase supplementation (-, without; +, with 1 g of Avizyme 1300 per kg diet) in rye- based diets (56%) on tissue protein synthesis in male broilers. Birds were injected with a large flooding dose of a phenylalanine solution (150 mmol/L, 38 atom percentage excess [(15) N] phenylalanine) and tissues were obtained after a 10-min incorporation period. [(15) N]-enrichment in tissue free phenylalanine and tissue protein bound phenylalanine were measured by gas-chromatography mass-spectrometry and by gas-chromatography combustion isotope ratio mass-spectrometry, respectively in order to calculate tissue specific fractional rates of protein synthesis (k(s)). The k(s) (%/d) in (S-), (S+), (T-) and (T+)-fed birds were 56, 64, 84 and 61 (SEM = 3.7) in duodenum, 51, 52, 75 and 58 in jejunum (SEM = 3.1), 66, 67, 105 and 68 (SEM =7.0) in jejunal mucosa cells, 53, 56, 68 and 50 (SEM = 3.7) in ileum and 52, 45, 118 and 39 (SEM = 20.2) in pancreas, respectively. Significant fat, enzyme or interaction effects in these tissues were mainly caused by the elevated k(s) in (T-)-fed birds which was closely associated with intestinal viscosity. We conclude that the effect of soluble nonstarch polysaccharides (NSP) and of NSP-hydrolyzing enzymes may be explained partially by modification in tissue protein synthesis of the intestinal tract.

Animals↗

Rye bread improves bowel function and decreases the concentrations of some compounds that are putative colon cancer risk markers in middle-aged women and men.

Cereal fiber may reduce the risk of colorectal cancer by diluting colonic contents due to increased fecal output, by accelerating intestinal transit, by increasing fecal frequency and by altering bacterial metabolism. The effects of whole-meal rye bread on some putative colon cancer risk markers were investigated in 17 healthy Finnish subjects using a randomized crossover trial with two 4-wk bread consumption periods and a 4-wk washout period between the bread periods. White wheat bread was used as a control. Test breads covered a minimum of 20% of the daily energy intake (range, 4330-14, 033 kJ/d). Intestinal transit time, stool weight, fecal bacterial enzyme activities and short-chain fatty acid, ammonia, diacylglycerol (DAG) and bile acid concentrations in feces (expressed per gram wet feces) were measured. Whole-meal rye bread significantly increased fecal output and fecal frequency and shortened mean intestinal transit time compared with wheat bread in both women and men. Activities of beta-glucuronidase and beta-glucosidase (expressed per gram wet feces) were significantly lower in men and urease activity significantly higher in women during the rye bread period (RBP). Fecal butyrate concentration was higher during the RBP in men. Fecal ammonia and DAG concentrations did not differ between bread periods. Fecal total and secondary bile acid concentrations were significantly lower during RBP in both women and men. This study shows that whole-meal rye bread significantly improves bowel function in healthy adults and may decrease the concentration of some compounds that are putative colon cancer risk markers.

Adult↗

Rye bread in the diet of pigs enhances the formation of enterolactone and increases its levels in plasma, urine and feces.

To obtain new insight into the quantitative and qualitative metabolism of rye and wheat lignans, we performed three series of experiments with catheterized pigs. Two diets with similar levels of dietary fiber and macronutrients but with contrasting levels of plant lignans (isolariciresinol, lariciresinol, matairesinol, pinoresinol, secoisolariciresinol and syringaresinol) were prepared from rye (high in lignans) and wheat (low in lignans) soft and crisp breads. In two series of experiments we quantified the uptake from the gut of enterolactone in four pigs fitted with catheters in the portal vein and mesenteric artery and with an ultrasonic flow probe attached to the portal vein to monitor the blood flow. In a third study with six pigs, we quantified the bioavailability of the plant lignans that can be converted to enterolactone (lariciresinol, matairesinol, pinoresinol, secoisolariciresinol and syringaresinol) and the concentration in the peripheral blood. Plant and mammalian lignans in diets and stool were analyzed by isotope dilution gas chromatography-mass spectrometry and enterolactone in plasma and urine determined by time-resolved fluoroimmunoassay. There was a significantly higher formation of enterolactone in pigs fed the rye diet, and higher fecal and urinary excretion and circulating levels of mammalian lignans than in pigs fed the wheat diet. The conversion of mammalian lignan precursors to enterolactone was 48% with the wheat diet and 60% with the rye diet. Mammalian lignans are absorbed by passive diffusion from the large intestine and a substantial fraction of the absorbed mammalian lignans undergoes enterohepatic circulation, resulting in low diurnal variation in plasma levels of enterolactone.

4-Butyrolactone↗

Dietary lignins are precursors of mammalian lignans in rats.

The mammalian lignans enterolactone (ENL) and enterodiol, commonly found in human plasma and urine, are phytoestrogens that may contribute to the prevention of breast cancer and coronary heart disease. They are formed by the conversion of dietary precursors such as secoisolariciresinol and matairesinol lignans by the colonic microflora. The identification of lignins, cell-wall polymers structurally related to lignans, as precursors of mammalian lignans is reported here for the first time. In study 1, rats were fed rye or wheat bran (15% diet) for 5 d. Untreated brans and brans extracted with solvents to remove lignans were compared. ENL was estimated in urine samples collected for 24 h by time-resolved fluoroimmunoassay. ENL urinary excretion was reduced from 18.6 to 5.3 nmol/d (n=8; P<0.001) when lignans were removed from rye bran and from 30.5 to 6.2 nmol/d (P<0.001) when they were removed from wheat bran. These results suggest that lignins, embedded in the cell wall and retained in the bran during solvent extraction, account for 26-32% of the ENL formed from cereal brans. In study 2, rats were fed a deuterated synthetic lignin (0.2% diet) together with wheat bran (15%) for 3 d. The detection of deuterated ENL by LC-tandem MS in urine (20 nmol/d) clearly confirms the conversion of lignin into mammalian lignans. More research is warranted to determine the bioavailability of lignins in the human diet.

4-Butyrolactone↗

Whole-grain rye bread consumption by women correlates with plasma alkylresorcinols and increases their concentration compared with low-fiber wheat bread.

Whole-grain rye and wheat products are rich in lignans, the precursors of enterolactone (ENL) and alkylresorcinols (ARs), which are phenolic lipids. In this crossover trial, we examined the effect of whole-grain rye bread compared with low-fiber wheat bread on plasma AR levels. Women (n = 39) aged 59 +/- 0.94 y (mean +/- SEM) were advised to consume rye (214 +/- 7.1 g/d) or wheat (178 +/- 6.5 g/d) bread (20% of total daily energy intake) in random order for 8 wk. The test periods were separated by an 8-wk washout period. ARs with different homologues and ENL were measured in plasma collected at the beginning (habitual diet) and end of the test bread periods. AR concentrations were higher (P < 0.001) after the rye bread (352 +/- 24.7 nmol/L) and habitual diet (97.7 +/- 12.1 and 88.3 +/- 8.7 nmol/L) periods than after the wheat bread period (36.6 +/- 4.2 nmol/L). Plasma AR concentrations were correlated with intake of rye bread (r = 0.34, P = 0.037), and with insoluble fiber from the whole diet during the rye (r = 0.39, P = 0.013) and wheat (r = 0.32, P = 0.047) bread periods. The plasma AR 17:0/21:0 ratio differed after the rye (0.84 +/- 0.04) and wheat (0.53 +/- 0.08) bread diet periods (P < 0.001). These data strongly suggest that plasma ARs could be used as specific biomarkers for whole-grain rye intake, and their homologue pattern could be used as an indicator of the bread type consumed.

Bread↗

Rye bread enhances the production and plasma concentration of butyrate but not the plasma concentrations of glucose and insulin in pigs.

The present investigation was undertaken to study the gastrointestinal and physiologic properties of diets based on soft and crisp wheat and rye breads similar in dietary fiber (DF; 230-235 g/kg dry matter) but with different proportions of the main DF polymers: in wheat, cellulose, and in rye, arabinoxylans (AX). The 2 diets provided all macronutrients; consequently, they had lower fat and sugar contents and a higher DF content than human mixed diets. The nutritional properties were studied in experiments in which pigs with cannulated ilea and catheterized portal veins and mesenteric arteries served as models for humans. The characteristics studied were degradation of nutrients, flow at the ileum, fecal output, absorption of nutrients deriving from the assimilation of cereal carbohydrates, and the insulin response. Apparent viscosity at the terminal small intestine, the ileal flow of water, flow and digestibility of noncarbohydrate constituents, but not of carbohydrates at the terminal ileum or the plasma concentrations of glucose and insulin, were higher when pigs consumed the rye compared with the wheat diet. The 2 diets provided approximately equal amounts of carbohydrates available for fermentation in the large intestine but because AX from the rye diet was more degradable than cellulose from the wheat diet, the quantitative degradation in the large intestine was more than twice as high when pigs consumed the former compared with the latter diet. The consequences included moister feces and significantly enhanced gut production and plasma concentrations of butyrate when pigs consumed the rye diet compared with the wheat diet.

Animal Feed↗

Human plasma kinetics and relative bioavailability of alkylresorcinols after intake of rye bran.

Alkylresorcinols (ARs) are phenolic lipids present in whole grain and bran of wheat and rye. Chemically, they comprise 1,3- dihydroxy-5-alkylbenzene homologs with odd-numbered, mainly saturated hydrocarbon side chains in the range of 17-25 carbon atoms. ARs are evaluated both for physiological effects and for their potential use as biomarkers of whole-grain wheat and rye intake. In this study, plasma kinetics and relative bioavailability of ARs in humans were investigated after a single intake of rye bran 120 g (190 mg ARs). The shapes of plasma concentration time curves were similar in the subjects (n = 6) with 2 peaks at approximately 2.8 and 6.5 h and maximum concentrations (mean +/- SEM) of 1253 +/- 125 and 3365 +/- 309 nmol/L, respectively. The relative bioavailability of different homologs increased with increasing length of the AR side chain (r = 0.97, P < 0.001), indicating differences in metabolism. The apparent half-lives were rather short, approximately 5 h for all homologs, which suggests that the AR concentration in plasma could be used as a short- to medium-term biomarker of regular intake of whole-grain wheat and rye.

Absorption↗