Breath Hydrogen Response Research Articles

Digestibility, Fermentability, and Energy Value of Highly Cross‐Linked Phosphate Tapioca Starch in Men

The objective of this study was to determine glycemic and breath hydrogen responses in 10 healthy men in response to highly cross-linked starch phosphate (HXLS), made of tapioca starch (TS). Plasma glucose concentration was analyzed at baseline and at 30, 60, 90, 120, 150, and 180 min postprandially. In addition, breath hydrogen excretion was measured at baseline and at hourly intervals, over 10 h, after test substance challenge. When compared with unmodified TS easily digested, the area under the curve of plasma glucose of HXLS was 64% smaller, and was almost the same as that of microcrystalline cellulose. When compared with fructo-oligosaccharide rapidly fermented by the microbial bacteria, the area under the excretion curve of breath hydrogen gas of HXLS was 93% smaller, and was almost the same as that of water only. These results show that HXLS is harder to digest and ferment than unmodified TS in men.

Benefits of breath hydrogen testing after lactulose administration in analysing carbohydrate malabsorption

Breath hydrogen testing after lactulose administration may yield findings of clinical value, but whether it should be a routine part of breath testing has not been evaluated. We examined the contribution of breath testing after lactulose administration to the conduct and interpretation of breath hydrogen responses after fructose and lactose administration. Two hundred consecutive patients were given lactulose, fructose or lactose on separate days (at least 2 days apart); breath hydrogen was monitored every 15 min after the administration of each sugar. Peak breath hydrogen levels after lactulose administration correlated with those after fructose (r = 0.26; P = 0.03) and lactose (r = 0.44; P = 0.004). Of the patients with a reduced response to lactulose, 51% had definite or borderline evidence of fructose malabsorption (FM); similarly, 23% of patients had definite or borderline lactose malabsorption. After lactulose administration, an increase in breath hydrogen levels occurred after the same amount of time or longer than after the administration of fructose or lactose (>120 min). The earlier the first rise in breath hydrogen levels after lactulose administration, the more frequently FM occurred, indicating an association between FM and rapid transit and/or small intestinal bacterial overgrowth. Routine breath hydrogen testing with lactulose administration before other sugars cannot be used to define non-hydrogen producers, but might, by indicating the vigour of hydrogen production in the individual, allow more rational interpretation of results after testing with other sugars. It permits the duration of testing to be judged and provides information on possible mechanisms of FM.

High fructose intake fails to induce symptomatic adaptation but may induce intestinal carriers

Fructose has several interactions in man, including intolerance and promotion of some diseases. However, fructose in fruits and in prebiotics may be associated with benefits. Adaptation to regular fructose ingestion as defined for lactose could support a beneficial rather than a deleterious effect. This study was undertaken to evaluate symptomatic response and potential underlying mechanisms of fecal bacterial change and breath hydrogen response to short term regular fructose supplementation. Forty-five participants were recruited for a 3 day recall diet questionnaire and a 50 g fructose challenge. Breath hydrogen was measured for 4.5 hrs and symptoms were recorded. Thirty-eight subjects provided stool samples for analysis by selective culture of 4 groups of bacteria, including bifidobacteria and lactobacilli. Intolerant subjects returned a second time 15 days later. Ten of these served as controls and 16 received 30 g fructose twice a day. Ten of the latter returned 27 days later, after stopping fructose for a third challenge test. Student’s paired, unpaired t-tests and Pearson correlations were used. Significance was accepted at P

Fructose-sorbitol ingestion provokes gastrointestinalsymptoms in patients with eating disorders

To evaluate gastrointestinal (GI) symptoms and breath hydrogen responses to oral fructose-sorbitol (F-S) and glucose challenges in eating disorder (ED) patients. GI symptoms and hydrogen breath concentration were monitored in 26 female ED inpatients for 3 h, following ingestion of 50 g glucose on one day, and 25 g fructose/5 g sorbitol on the next day, after an overnight fast on each occasion. Responses to F-S were compared to those of 20 asymptomatic healthy females. F-S provoked GI symptoms in 15 ED patients and one healthy control (P<0.05 ED vs control). Only one ED patient displayed symptom provocation to glucose (P<0.01 vs F-S response). A greater symptom response was observed in ED patients with a body mass index (BMI)<or=17.5 kg/m2 compared to those with a BMI>17.5 kg/m2 (P<0.01). There were no differences in psychological scores, prevalence of functional GI disorders or breath hydrogen responses between patients with and without an F-S response. F-S, but not glucose, provokes GI symptoms in ED patients, predominantly those with low BMI. These findings are important in the dietary management of ED patients.

Pilot study on the effect of reducing dietary FODMAP intake on bowel function in patients without a colon

Poorly absorbed short-chain carbohydrates (FODMAPs) in the diet should, by virtue of their osmotic effects, increase fecal output following colectomy and ileal pouch formation or ileorectal anastomosis (IRA). The aim was to perform a proof-of-concept evaluation of this hypothesis. Fifteen patients (13 pouch, 2 IRA) had dietary and symptomatic evaluation before and during a low FODMAP diet. Carbohydrate malabsorption was evaluated by breath tests. Pouchitis was assessed clinically/endoscopically or by fecal lactoferrin. Of 8 patients with a breath hydrogen response to lactulose, 7 had fructose malabsorption, 3 with lactose malabsorption, and 1 had lactose malabsorption alone. Five of 7 studied retrospectively improved stool frequency (from median 8 to 4 per day; P = 0.02), this being sustained over 0.5-3 years of follow-up. Five of 8 patients completed a prospective arm of the study. One patient had sustained improvement in stool frequency and 1 had reduced wind production. Overall, none of 8 patients who had pouchitis improved. In contrast, median daily stool frequency fell from 8 to 4 (P = 0.001) in the 7 without pouchitis. The degree of change in FODMAP intake also predicted response. There was a tendency for pouchitis to be associated with low baseline FODMAP intake. There is a high prevalence of carbohydrate malabsorption in these patients. Reduction of the intake of FODMAPs may be efficacious in reducing stool frequency in patients without pouchitis, depending on dietary adherence and baseline diet.

Effects of sucromalt on postprandial responses in human subjects

To compare postprandial responses elicited by sucromalt, a nutritive sweetener produced by treating a blend of sucrose and corn syrup with an enzyme from Leuconostoc mesenteroides, with those after 42% of high-fructose corn syrup (HFCS), and to see if the reduced responses after sucromalt could be accounted for by carbohydrate malabsorption. Three experiments were performed in separate groups of normal subjects studied after overnight fasts using double-blind, randomized, cross-over designs. HFCS was used as the control because it contained a similar amount of fructose as sucromalt. Experiment 1 (n = 10): plasma glucose and insulin were measured after 50 g sucromalt and 50 g HFCS. Experiment 2 (n = 10): metabolic profiles were measured after 80 g HFCS, 80 g sucromalt or 56 g fructose/glucose blend plus 24 g inulin. Experiment 3 (n = 20): the glycaemic indices of sucromalt and HFCS were determined. Mean glucose and insulin responses after sucromalt were 66 and 62%, respectively, of those after HFCS (P < 0.05). The inulin treatment, used to mimic the effects of carbohydrate malabsorption, elicited higher breath hydrogen (H2), lower glucose and insulin responses, and a significantly earlier rise in serum free fatty acids (FFA) than those of HFCS (all P < 0.05). Sucromalt elicited no rise in breath H2, and delayed falls in glucose and insulin, and a delayed rebound of FFA compared to HFCS (all P < 0.05). The reduced glucose and insulin responses elicited by sucromalt are not explained by malabsorption and are more likely related to differences in either rate of digestion and absorption or postabsorptive handling by body.

Influence of Mulberry Leaf Extract on the Blood Glucose and Breath Hydrogen Response to Ingestion of 75 g Sucrose by Type 2 Diabetic and Control Subjects

In Asia, type 2 diabetes is treated with mulberry leaf. Studies supporting this usage include the demonstration that mulberry leaf 1 ) reduced blood glucose in normal rats (1) and rats with diabetes induced by streptozotocin (2) or alloxan (3), 2 ) reduced fasting blood glucose and A1C concentrations in 12 subjects with type 2 diabetes (4), and 3 ) relative to glybenclamide therapy, reduced fasting blood glucose, serum lipids, and lipid peroxidation indicators in subjects with type 2 diabetes (5). In the present study, we determined whether co-ingestion of mulberry extract with 75 g sucrose influenced the blood glucose response and sucrose absorption of type 2 diabetic and control subjects. Participants included 10 healthy control subjects (aged 24–61 years) and 10 type 2 diabetic subjects without complications who were receiving oral hypoglycemic agents (aged 59–75 years; glycohemoglobin 7.1 ± 0.9% [normal <6.2%]). The study was approved by the Minneapolis VA Medical Center Human Studies Committee. Mulberry leaf extract was provided by NatureGen (San Diego, CA). Placebo (red dye #40 and caramel) was similar in color and taste to the mulberry. At 8 a.m., subjects randomly ingested mulberry extract (1 g) or placebo plus 75 g sucrose in 500 ml hot water. The test was repeated in 1 week with the opposite …

Why do African Americans get more colon cancer than Native Africans?

The incidence of colorectal cancer (CRC) is dramatically higher in African Americans (AAs) than in Native Africans (NAs) (60:100,000 vs. <1:100,000) and slightly higher than in Caucasian Americans (CAs). To explore whether the difference could be explained by interactions between diet and colonic bacterial flora, we compared randomly selected samples of healthy 50- to 65-y-old AAs (n = 17) with NAs (n = 18) and CAs (n = 17). Diet was measured by 3-d recall, and colonic metabolism by breath hydrogen and methane responses to oral lactulose. Fecal samples were cultured for 7-alpha dehydroxylating bacteria and Lactobacillus plantarum. Colonoscopic mucosal biopsies were taken to measure proliferation rates. In comparison with NAs, AAs consumed more (P < 0.01) protein (94 +/- 9.3 vs. 58 +/- 4.1 g/d) and fat (114 +/- 11.2 vs. 38 +/- 3.0 g/d), meat, saturated fat, and cholesterol. However, they also consumed more (P < 0.05) calcium, vitamin A, and vitamin C, and fiber intake was the same. Breath hydrogen was higher (P < 0.0001) and methane lower in AAs, and fecal colony counts of 7-alpha dehydroxylating bacteria were higher and of Lactobacilli were lower. Colonic crypt cell proliferation rates were dramatically higher in AAs (21.8 +/- 1.1% vs. 3.2 +/- 0.8% labeling, P < 0.0001). In conclusion, the higher CRC risk and mucosal proliferation rates in AAs than in NAs were associated with higher dietary intakes of animal products and higher colonic populations of potentially toxic hydrogen and secondary bile-salt-producing bacteria. This supports our hypothesis that CRC risk is determined by interactions between the external (dietary) and internal (bacterial) environments.

Glycemic, insulinemic, and breath hydrogen responses to pullulan in healthy humans

The objective of this study was to evaluate the glycemic, insulinemic, and breath hydrogen responses of healthy adult humans to low–molecular weight pullulan (molecular weight = 6300). Subjects (n = 34) consumed 50 g of maltodextrin or low–molecular weight pullulan in a randomized, double-masked, crossover design. Plasma glucose and serum insulin responses were determined over 180 minutes, and breath hydrogen response was determined for 8 hours. Low–molecular weight pullulan did not improve glucose response, but a reduction ( P < .05) in serum insulin at 30, 60, and 90 minutes was noted. Peak insulin and area under the curve were reduced ( P < .05) by 23% and 20%, respectively. Breath hydrogen increased ( P < .05) at 4, 5, 6, 7, and 8 hours. Although low–molecular weight pullulan does not impact glycemia per se, it may reduce insulin response, resulting in decreased insulin concentrations in healthy adult humans.

Fructose Intake at Current Levels in the United States May Cause Gastrointestinal Distress in Normal Adults

Objective Fructose intake has increased considerably in the United States, primarily as a result of increased consumption of high-fructose corn syrup, fruits and juices, and crystalline fructose. The purpose was to determine how often fructose, in amounts commonly consumed, would result in malabsorption and/or symptoms in healthy persons. Design Fructose absorption was measured using 3-hour breath hydrogen tests and symptom scores were used to rate subjective responses for gas, borborygmus, abdominal pain, and loose stools. Subjects/Setting The study included 15 normal, free-living volunteers from a medical center community and was performed in a gastrointestinal specialty clinic. Intervention Subjects consumed 25- and 50-g doses of crystalline fructose with water after an overnight fast on separate test days. Main Outcome Measures Mean peak breath hydrogen, time of peak, area under the curve (AUC) for breath hydrogen and gastrointestinal symptoms were measured during a 3-hour period after subjects consumed both 25- and 50-g doses of fructose. Statistical Analyses Differences in mean breath hydrogen, AUC, and symptom scores between doses were analyzed using paired t tests. Correlations among peak breath hydrogen, AUC, and symptoms were also evaluated. Results More than half of the 15 adults tested showed evidence of fructose malabsorption after 25 g fructose and greater than two thirds showed malabsorption after 50 g fructose. AUC, representing overall breath hydrogen response, was significantly greater after the 50-g dose. Overall symptom scores were significantly greater than baseline after each dose, but scores were only marginally greater after 50 g than 25 g. Peak hydrogen levels and AUC were highly correlated, but neither was significantly related to symptoms. Conclusions Fructose, in amounts commonly consumed, may result in mild gastrointestinal distress in normal people. Additional study is warranted to evaluate the response to fructose-glucose mixtures (as in high-fructose corn syrup) and fructose taken with food in both normal people and those with gastrointestinal dysfunction. Because breath hydrogen peaks occurred at 90 to 114 minutes and were highly correlated with 180-minute breath hydrogen AUC, the use of peak hydrogen measures may be considered to shorten the duration of the exam.

Effects of a nutritional supplement containing Salacia oblonga extract and insulinogenic amino acids on postprandial glycemia, insulinemia, and breath hydrogen responses in healthy adults

Objective This study evaluated the postprandial glycemic, insulinemic, and breath hydrogen responses to a liquid nutritional product containing Salacia oblonga extract, an herbal α-glucosidase inhibitor, and two insulinogenic amino acids. Methods In a randomized, double-masked, crossover design, 43 healthy subjects were fed the following meals on separate days after overnight fasting: control (C; 480 mL of a study beverage containing 82 g of carbohydrate, 20 g of protein, and 14 g of fat), control plus 3.5 g each of phenylalanine and leucine (AA), control plus 1000 mg of S. oblonga extract (S), and control plus S and AA (SAA). Postprandially, fingerstick capillary plasma glucose and venous serum insulin levels were measured for 180 min, and breath hydrogen excretion was measured for 480 min. Results The baseline-adjusted peak glucose response was not different across meals. However, changes in plasma glucose areas under the curve (0 to 120 min and 0 to 180 min, respectively) compared with C were −9% and −11% for AA ( P > 0.05 each), −27% and −24% for S ( P = 0.035 and 0.137), and −27% and −29% for SAA ( P < 0.05 each). Changes in insulin areas under the curve were +5% and +5% for AA ( P > 0.05 each), −35% and −36% for S ( P < 0.001 each), and −6% and −7% for SAA ( P > 0.05 each). Breath hydrogen excretion was 60% greater ( P < 0.001) in the S-containing meals than in the C- and AA-containing meals and was associated with mild flatulence. Conclusions Salacia oblonga extract is a promising nutraceutical ingredient that decreased glycemia in this study. Supplementation with amino acids had no significant additional effect on glycemia.

Effects of a medical food containing an herbal α-glucosidase inhibitor on postprandial glycemia and insulinemia in healthy adults

ObjectiveTo determine the effect of different doses of Salacia oblonga extract, an herbal α-glucosidase inhibitor, on postprandial glycemic, insulinemic, and breath hydrogen responses in healthy adults. DesignDouble-masked, randomized crossover design. InterventionSubjects, after fasting for 12 hours, consumed four test meals consisting of 480 mL of study beverage (14 g fat, 82 g carbohydrate, and 20 g protein) with 0, 500, 700, or 1,000 mg of S oblonga extract on four separate occasions. Capillary finger-prick plasma glucose and venous serum insulin concentrations were measured at baseline and for 2 hours postprandially. Breath hydrogen excretion was measured at baseline and hourly for 8 hours postprandially. Subjects/settingThirty-nine healthy, nondiabetic adults (body mass index=23.7±0.4, age=25.7±0.9 years. Statistical analyses performedRepeated-measures analysis of variance was applied to the raw data or data that had been transformed (log, rank) when necessary due to nonnormality. The Tukey-Kramer post hoc test was used for pairwise comparisons. ResultsCompared with the control, the 1,000-mg S oblonga extract dose reduced the plasma glucose and serum insulin incremental areas under the curve (0 to 120 minutes postprandial) by 23% (P=.32) and 29% (P=.01), respectively. The other doses of S oblonga extract did not impact glycemia or insulinemia. Breath hydrogen excretion increased linearly as the dose of S oblonga extract was advanced. ConclusionsThe presence of S oblonga extract tended to lower postprandial glycemia and significantly reduced the postprandial insulin response. The increase in breath hydrogen excretion suggests a mechanism similar to prescription α-glucosidase inhibitors. Future studies of S oblonga extract in patients with diabetes are needed.

Hydrogen breath test in the diagnosis of lactose malabsorption: Accuracy of new versus conventional criteria

Increased hydrogen excretion in the breath after carbohydrate ingestion, an expression of carbohydrate malabsorption, represents the pathophysiologic basis of the hydrogen breath test, a simple, noninvasive, reproducible test for the diagnosis of this condition. Few data are available concerning the breath hydrogen response that most accurately identifies carbohydrate malabsorption. In this article we report our application for the first time in clinical practice of 2 recently described, more accurate criteria for the diagnosis of lactose malabsorption (ie, breath hydrogen excretion value > 6 parts per million (ppm) 6 hours after carbohydrate load and a sum greater than 15 ppm for the breath hydrogen values obtained 5, 6, and 7 hours after carbohydrate load). On 3 separate days, we subjected 84 consecutive patients with functional or organic gastrointestinal disease to measurement of hydrogen excretion in the breath after the administration of lactose to test for lactose malabsorption; after the administration of lactulose as a means of ruling out false-negative results resulting from hydrogen-nonproducer status; and after the administration of a nonabsorbable electrolyte solution as a means of ruling out false-positive results caused by the mixing of intestinal content and release of preformed hydrogen trapped in the feces. According to the conventional criterion, 51% of the subjects proved to be lactose malabsorbers. Positive results were obtained with the use of the 6th-hour criterion in 76% of patients, and positive results were found in 80% when the sum of the excretion at hours 5, 6, and 7 was used as the criterion (P < .05 for both comparisons). Ten of 21 and 11 of 25, respectively, showed intolerance symptoms. It was therefore possible for us to diagnose lactose malabsorption in 24% and 27% of patients, respectively, who tested negative according to the conventional criterion. The conventional criterion must be abandoned and these new criteria adopted.

The glycemic, insulinemic, and breath hydrogen responses in humans to a food starch esterified by 1-octenyl succinic anhydride

The objectives of this study were to determine the glycemic, insulinemic, and breath hydrogen responses to food starch esterified with 1-octenyl succinic anhydride (OSA) and glucose in 22 healthy nondiabetic adults. Plasma glucose and insulin concentrations were analyzed at baseline and at 15, 30, 45, 60, 90, and 120 minutes postprandially. Breath hydrogen excretion was measured at baseline and at hourly intervals for 8 hours after the carbohydrate challenge. Peak plasma glucose concentration was reduced 8% ( P < 0.03) and peak insulin concentration was decreased 28% ( P < 0.004) after subjects consumed the OSA beverage compared with the glucose beverage. Similarly, OSA reduced ( P < 0.05) the area under the curve (0–120 min) for both plasma glucose and insulin. The increase in the number of positive breath hydrogen tests with the OSA-substituted starch suggests that the lowered glycemic response is at least partially due to malabsorption of OSA by the small intestine.

Pullulan Is a Slowly Digested Carbohydrate in Humans

Pullulan is an extracellular polysaccharide excreted by the fungus Aureobasidium pullulans. To evaluate the glycemic and breath hydrogen responses and gastrointestinal tolerance to pullulan, nondiabetic healthy adult subjects (n = 28) were studied in a randomized, double-masked, crossover design. After an overnight fast, subjects consumed beverages containing 50 g of carbohydrate from either maltodextrin (control) or pullulan. Capillary blood glucose response was determined for 180 min postprandially. Breath hydrogen response was determined for 8 h postprandially. Compared with control, incremental peak blood glucose concentration was reduced (P < 0.01) when subjects consumed pullulan (4.24 +/- 0.35 vs. 1.97 +/- 0.10 mmol/L). In addition, pullulan reduced (P < 0.01) the positive incremental area under the glucose curve by 50%. When subjects consumed pullulan, the incremental blood glucose excursions were reduced (P < 0.01) at 15, 30, 45, 60 and 90 min, but were maintained above basal glucose concentrations at 150 and 180 min. At 180 min, the blood glucose concentration was higher (P < 0.05) when subjects consumed pullulan compared with control, supporting the hypothesis that pullulan is digested slowly. Breath hydrogen concentrations were increased (P < 0.01) at 3, 4, 5, 6, 7 and 8 h postprandially when subjects consumed pullulan. In the first 24-h postprandial period, the frequency and intensity of flatulence was higher (P < 0.05) after subjects consumed pullulan compared with control. In conclusion, pullulan attenuated the postprandial glycemic excursion compared with an equivalent maltodextrin challenge. Pullulan also increased breath hydrogen excretion and the incidence of gastrointestinal intolerance symptoms, indicating that a portion of pullulan was malabsorbed.

Breath Hydrogen and Methane Responses of Men and Women to Breads Made with White Flour or Whole Wheat Flours of Different Particle Sizes

Objective: While it is well known that consumption of whole grain foods results in beneficial health effects, the great majority of Americans prefer bread made with white flour. Consumption of whole grain foods in high fiber menus may cause undesirable intestinal responses. The purpose of this study was to determine whether consumption of bread made with ultra fine ground whole wheat flour retained beneficial effects while reducing undesirable effects.Methods: Twenty-six men and women (31 to 55 years of age) consumed glucose solutions or bread made with white, whole wheat or fine ground whole wheat flour (1 g carbohydrate/kg body weight) in a Latin square design after two days of controlled diet. Breath methane and hydrogen were determined over the 24 hours after consumption of test foods.Results: Hydrogen and methane responses of men and women were similar. There were no significant differences in methane responses to the different treatments, but hydrogen response was increased by all breads (p<0.0001). Although the overall mean response values were similar for all three breads, the patterns of hydrogen response differed (treatment*time, p<0.003). Gastrointestinal symptoms were not associated with fiber content or particle size of bread; however, subjects reporting symptoms tended to have higher methane responses (0.05<p<0.10).Conclusion: Neither fiber content of bread nor particle size of whole wheat flour substantially affected breath hydrogen or methane responses or gastrointestinal symptoms. Fine ground whole wheat breads may provide a more acceptable food choice than standard whole wheat bread without sacrificing the beneficial health effects of higher fiber.

Digestion of human milk oligosaccharides by healthy infants evaluated by the lactulose hydrogen breath test.

We hypothesized that human milk oligosaccharides (HMO) would not be digested and absorbed in the infant small intestine. The purpose of the study was to quantify the extent of digestion by using the lactulose breath hydrogen test. Twenty-four healthy, breast-fed infants were studied in the home setting. Eight infants (mean age 5.2 months) who had a positive breath hydrogen response (rise > 20 ppm) to the unabsorbable sugar lactulose were given an equivalent load of HMO (0.7 to 1.0 gm/kg body weight) the following week. The breath hydrogen response to the HMO load was compared with that after lactulose by using a paired t test. In seven of the eight infants, a large proportion of the HMO load reached the large intestine and was fermented. In these infants, the mean +/- SEM area under the breath hydrogen curve after HMO (5135 +/- 1148 ppm.4h) was not significantly different from that after lactulose (4949 +/- 1278 ppm.4h, p = 0.7s. This study suggests that HMO resist digestion in the small intestine of most breast-fed infants and undergo fermentation in the colon. HMO may therefore be the source of breath hydrogen in breast-fed infants.

Fructose-Sorbitol Malabsorption and Symptom Provocation in Irritable Bowel Syndrome: Relationship to Enteric Hypersensitivity and Dysmotility

Background: Fructose-sorbitol (F-S) mixtures can provoke symptoms in irritable bowel syndrome (IBS) patients, and a proportion of IBS patients also have enteric hypersensitivity to distension. We hypothesized, therefore, that sugar malabsorption and fermentation to produce hydrogen gas may provoke symptoms to a greater extent in IBS patients hypersensitive to distension than in those patients without such hypersensitivity. Our aims were therefore to compare, in IBS patients, symptoms and breath hydrogen responses after F-S, on the basis of jejunal sensitivity and jejunal motor function. Methods

Maldigestion and colonic fermentation of wheat bread in humans and the influence of dietary fat

A fraction of wheat bread is malabsorbed in healthy humans. The malabsorbed fraction is bigger than what can be accounted for by in vitro measurements of dietary fibers and resistant starch. To determine whether it is a specific fraction defined by the structure of the starch molecule or a variable amount--which depends on the individual, the amount ingested, and other components of the meal--we performed a dose-response study on wheat bread in healthy human volunteers. Malabsorption was evaluated by using the breath-hydrogen test. Test meals were as follows: 20 g wheat bran mixed in 100 mL water; bread made from 25, 75, 100, 150, and 200 g white wheat flour (WWF); bread made from 0 g WWF and 20 g wheat bran; and bread made from 100 g WWF served with 11 or 26 g butter, corresponding to 20% or 35% of energy from fat in the meals. Three of seven volunteers malabsorbed a fraction of the bread made from 25 g WWF and five of seven a fraction of the bread made from 75 g WWF. All volunteers malabsorbed a fraction of the 100-g WWF bread, Bread made from 180 g WWF and 20 g wheat bran resulted in a breath-hydrogen response of the same magnitude as that from bread made from 200 g WWF alone. The 100-g WWF bread + 11 g butter resulted in a significantly higher breath-hydrogen response than did the bread alone, whereas the 100-g WWF bread + 26 g butter resulted in an average response of the same magnitude as that from bread alone. We conclude that the malabsorbed fraction of wheat bread was dependent on the amount ingested, the composition of the meal, and individual gastrointestinal handling. Fermentation of wheat bran resulted in a very low breath-hydrogen response compared with lactulose or wheat bread. Addition of 11 g butter to the bread seemed to increase the malabsorbed fraction of the starch, an effect that was abolished when the amount of butter was increased to 26 g.

Improvement of Lactose Digestion in Humans by Ingestion of Unfermented Milk Containing Bifidobacterium longum

Fifteen lactose malabsorbers were studied to evaluate the effects of consumption of milk containing different strains of Bifidobacterium longum on lactose digestion. Influences of different growth substrates, bile sensitivity, and lactose transport on lactose digestion by bifidobacteria were also investigated. Lactose malabsorption was determined by measuring breath hydrogen excretion of subjects fed four different test milks (three of which contained 5 × 108 cfu/ml of B. longum) on 4 different d using a randomized, double-blinded trial. Test milks included 1) 400ml of lowfat milk (control), 2) 400ml of milk containing B. longum B6 that had been grown with lactose, 3) 400ml of milk containing B. longum B6 grown with lactose plus glucose, or 4) 400ml of milk containing B. longum ATCC 15708 grown with lactose. β-Galactosidase activity was highest in milk containing B6 grown with lactose but was extremely low in milk containing B6 grown with lactose and glucose. Consumption of milk containing B6 grown with lactose resulted in significantly less hydrogen production and flatulence than occurring after consumption of control milk or the milk containing B6 grown with both lactose and glucose. Hydrogen production after ingestion of 15708 was also significantly lower than hydrogen production after ingestion of the control milk. We concluded that milks containing B. longum might reduce breath hydrogen response and symptoms from lactose malabsorption when the culture is grown in a medium containing only lactose to induce a higher β-galactosidase level and increase rate of lactose uptake.