Effect Of Dietary Lactose Research Articles

Changes in gut microbiota and lactose intolerance symptoms before and after daily lactose supplementation in individuals with the lactase nonpersistent genotype

BackgroundApproximately 70%–100% of the Asian adult population is lactase nonpersistent (LNP). The literature shows that many individuals with the LNP-genotype can consume ≤12 g of lactose without experiencing gastrointestinal discomfort. Repetitive consumption of lactose may reduce intolerance symptoms via adaptation of the gut microbiota. ObjectiveThis study aimed to assess the effects of daily consumption of incremental lactose doses on microbiota composition and function, and intolerance symptoms. MethodsTwenty-five healthy adults of Asian origin, carrying the LNP-genotype were included in this 12-wk before and after intervention trial. Participants consumed gradually increasing lactose doses from 3 to 6 g to 12 g twice daily, each daily dose of 6 g, 12 g, or 24 g being provided for 4 consecutive weeks. Participants handed-in repeated stool samples and underwent a 25 g lactose challenge hydrogen breath test (HBT) before and after the 12-wk intervention. Daily gastrointestinal symptoms and total symptom scores (TSSs) during the lactose challenge were recorded. ResultsA significant increase from 5.5% ± 7.6% to 10.4% ± 9.6% was observed in Bifidobacterium relative abundance after the intervention (P = 0.009), accompanied by a 2-fold increase (570 ± 269 U/g; P < 0.001) in fecal β-galactosidase activity compared with baseline (272 ± 158 U/g). A 1.5-fold decrease (incremental area under the curve; P = 0.01) in expired hydrogen was observed during the second HBT (38 ± 35 ppm·min), compared with the baseline HBT (57 ± 38 ppm·min). There was a nonsignificant decrease in TSS (10.6 ± 8.3 before compared with 8.1 ± 7.2 after intervention; P = 0.09). Daily consumption of lactose was well tolerated, with mild to no gastrointestinal complaints reported during the intervention. ConclusionsIncreased levels of Bifidobacterium indicate an adaptation of the gut microbiota upon repetitive consumption of incremental doses of lactose, which was well tolerated as demonstrated by reduced expired hydrogen concentrations during the second 25-g lactose HBT. Bifidobacteria metabolize lactose without gas production thereby potentially reducing intestinal gas formation in the gut of individuals with the LNP-genotype. This increased lactose tolerance possibly lifts the necessity to remove nutrient-rich dairy foods completely from the diet.The trial is registered at the International Clinical Trials Registry Platform: NL9516. The effect of dietary lactose in lactase nonpersistent individuals on gut microbiota.

A Study on the Effects of Dietary Lactose on Ovarian Function and Body Weight in Normal and Obese Female Albino Rats

A Study on the Effects of Dietary Lactose on Ovarian Function and Body Weight in Normal and Obese Female Albino Rats

Effects of Dietary Lactose on Long‐term High‐fat‐diet‐induced Obesity in Rats

In this study, we examined the effects of lactose on long-term high-fat-diet-induced obesity in rats. A total of 112 Sprague-Dawley strain female rats (6 weeks old) were divided into four groups: a basic control diet group (Cont), 10% lactose diet group (Lac), high-fat diet group (Fat), and high-fat with 10% lactose diet group (Fat+Lac). After 0, 7, 14, and 84 days from starting the experimental diet, the animals were fasted overnight and killed by bleeding from the abdominal aorta under anesthesia (n = 8 or 9/group). After 84 days, the addition of lactose to the high-fat diet decreased the final body weight, body weight gain, fat accumulation, and the levels of serum leptin, serum triglycerides, and serum glucose significantly (p < 0.05). Although there was no significant difference in the levels of serum calcium and phosphorus between the Fat and Fat+Lac groups, lumbar vertebral bone mineral density was significantly higher in the Fat+Lac group than in the Cont group on Day 82. Interestingly, the level of serum 1alpha, 25-dihydroxyvitamin D(3) in the Fat+Lac group on Day 84 was reduced by 74% compared with the Fat group (p < 0.01), while there was no significant difference in serum parathyroid hormone levels between the Fat and Fat+Lac groups. This is the first study to suggest that the addition of lactose to a long-term high-fat diet may regulate not only calcium metabolism but also fat deposition. Further studies on the mechanism of dietary lactose in the regulation of adiposity would provide valuable data for the prevention of long-term high-fat-diet-induced obesity.

Effect of Dietary Lactose on the Productive Performance of Young Turkeys

Studies were conducted to assess the performance of turkeys fed diets containing lactose. Study 1 consisted of 96, mixed-sex turkey poults that were housed in battery cages and fed diets containing 0 (8% cornstarch), 0.5, 1, 2, 4, or 8% lactose from 0 to 6 wk. Study 2 used 360, mixed-sex turkey poults that were raised in floor pens and fed a commercial diet and diets containing 0 (4% starch), 0.5, 1, 2, or 4% lactose from 0 to 6 wk. Diets and water were offered ad libitum throughout both trials. The objectives were 1) to determine the effect of lactose on turkey performance and 2) to establish the optimum level for lactose inclusion in diets. In Study 1, feed intake, BW, fecal ammonia and nitrogen, and feed efficiency were determined. Diet composition, BW, feed intake, total body and carcass composition, cecal pH, volatile fatty acids (VFA) and lactic acid were measured in Study 2. Turkeys consuming the 4% lactose diet gained the most weight (P < 0.01) compared with other treatments in Study 1, and lactose improved feed efficiency. In Study 2, all lactose diets resulted in heavier BW (P < 0.05) compared with the commercial diet. Turkeys consuming diets with 0.5, 1, 2 or 4% lactose had less total body fat compared with turkeys consuming a commercial or 0% lactose diet (P < 0.05).

Effect of Lactose and Lactobacillus acidophilus on the Colonization of Salmonella enteritidis in Chicks Concurrently Infected with Eimeria tenella

The effect of dietary lactose and Lactobacillus acidophilus on the colonization of Salmonella enteritidis (phage type 4) in newly hatched leghorn chicks concurrently infected with Eimeria tenella was studied. There were six groups of birds in each of two replicate trials: uninfected controls, birds infected with S. enteritidis, birds infected with S. enteritidis and E. tenella, birds infected with S. enteritidis and E. tenella that were fed with dietary lactose (5%), birds infected with S. enteritidis and E. tenella that were provided with L. acidophilus, and birds infected with S. enteritidis and E. tenella that were fed both L. acidophilus and dietary lactose (5%). Chickens were necropsied at 2, 5, and 8 days after S. enteritidis inoculation for bacteriological examination. The cecal population of S. enteritidis was significantly increased by infection with E. tenella. Lactose alone and the combination of lactose and L. acidophilus significantly reduced the population of S. enteritidis in the ceca of birds infected with E. tenella (P < 0.05), but the combination was more effective than lactose alone (P < 0.05). Adding anaerobic culture of L. acidophilus alone did not significantly decrease the population of S. enteritidis in the ceca. No significant reduction of colonization of S. enteritidis in the liver and spleen of birds with coccidiosis was observed.

The Effects of Dietary Lactose and Rye on Cecal Colonization of Clostridium perfringens in Chicks

Five experiments were conducted to determine the effects of dietary lactose and rye on cecal colonization of Clostridium perfringens in white leghorn chickens. Six days after oral inoculation of the organism, the numbers of C. perfringens organisms in the cecal contents were significantly lower in chickens on 2% and 10% lactose-supplemented feed than in chickens on unsupplemented feed. When C. perfringens was given in drinking water, 10% lactose supplementation was needed to significantly reduce the counts of C. perfringens 4, 6, and 8 days after feeding began. Effect of rye-ration on cecal colonization of C. perfringens was also examined. Counts of C. perfringens in cecal contents of chickens fed a diet containing 50% rye were significantly higher than control values 4, 6, and 8 days after feeding began. When chicks were fed a diet containing both 10% lactose and 50% rye, C. perfringens counts in cecal contents were lower than in chickens fed 50% rye only at 6 days after feeding began. Results led to the conclusion that dietary lactose is effective in reducing the cecal colonization of C. perfringens.

Effect of Dietary Lactose and Cell Concentration on the Ability of a Continuous-Flow-Derived Bacterial Culture to Control Salmonella Cecal Colonization in Broiler Chickens

The effect of dietary lactose and of cell concentration of a continuous-flow (CF) derived bacterial culture on Salmonella typhimurium cecal colonization in 10-d-old broiler chickens was examined. One-day-old chicks were provided 1) no CF culture and the control diet; 2) no culture and a 2% lactose diet; 3) CF culture (108 or 1011 anaerobic cfu) and control diet; or 4) CF culture (108 or 1011 anaerobic cfu) and 2 to 4% lactose diet. All groups were challenged orally with 104S. typhimurium at 3 d of age. Salmonella typhimurium growth in cecal contents was significantly decreased (P < .05) at 10 d of age when 2% lactose was used in combination with CF culture containing 108 or 1011 anaerobic cfu. The protection factor (log10Salmonella control diet divided by log10Salmonella treatment group) for these treatment groups was 2.49 and 9.26, respectively. Results indicate that birds treated with CF culture and maintained on 2% dietary lactose are protected against S. typhimurium colonization. Additionally, inoculating birds with CF culture containing a higher concentration of anaerobic colony-forming units resulted in a substantially higher protection factor.

Effect of Dietary Lactose on Cecal Morphology, pH, Organic Acids, and Salmonella enteritidis Organ Invasion in Leghorn Chicks

The effect of 14 or 19 days of 10% dietary lactose administration on Salmonella enteritidis (SE) colonization and histological, morphometric, and organic acid changes of the ceca were investigated. At Day 13 or 18, chicks were challenged with 108 cfu of SE. Chicks were killed and cultured 24 h later. A reduction in the total number of positive SE organ invasions was observed following 14 days (P < .001) or 19 days (P < .005) of treatment in chicks fed with lactose. Histological examination revealed a marked reduction in lamina propria thickness of ceca, as well as subjective epithelial cell proliferation from chicks following either 14 or 19 days of lactose administration. Using morphometric analysis, a reduction in the mean lamina propria thickness in chickens fed with lactose during 14 or 19 days was observed as compared with controls (P < .05). Yet, an increase (P < .05) in the mean epithelial cell length in both lactose-treated groups was observed as compared with controls. Lactose decreased luminal pH (P < .05) and increased the concentration of acetic, propionic, butyric, and lactic acid (P < .05). These data indicate that lactose-induced resistance to SE organ invasion is associated not only with an increase in organic acid concentration but also with measurable morphological changes of the cecal mucosa.

Effects of Dietary Lactose on Incidence and Levels of Salmonellae on Carcasses of Broiler Chickens Grown to Market Age

Two trials were conducted to evaluate the effects of lactose in the diet of broilers grown to market weights on incidence and levels of salmonellae on the carcass. Lactose was substituted for sand in otherwise nutritionally complete diets at levels of 0, 2.5, 5, and 7.5% and fed from day-old to 49 days of age. Birds were reared on used (Trial 1) or new (Trial 2) litter and inoculated via the drinking water on Days 2, 7, and 14 with 108 cfu/mL Salmonella typhimurium (ATCC 14028). At 50 days, 12 (Trial 1) or 24 (Trial 2) birds per treatment were processed and prechill carcasses were evaluated for salmonellae incidence and level by the most probable number (MPN) method. Body weight of male broilers was significantly reduced by feeding diets containing up to 7.5% lactose. Feed intake of broilers fed diets containing lactose was significantly reduced and feed utilization improved, suggesting that lactose provided some metabolizable energy. The degree of litter caking was significantly increased, and cecal pH was significantly decreased as dietary lactose increased. Prechill carcasses of broilers fed diets with 7.5% lactose had significantly higher levels of salmonellae than did prechill carcasses of broilers fed 0% lactose. The results of the present study suggest that supplementing poultry diets with lactose is not a viable means in itself of reducing or eliminating salmonellae incidence or levels on processed broiler carcasses.

Effect of dietary lactose on salt-mediated changes in mineral metabolism and bone composition in the rat

The effects of salt (sodium chloride) supplementation of rat diets (80 g/kg diet), with or without lactose (150 g/kg), were studied in weanling rats over 14 d. Dietary salt increased water intake and reduced weight gain and food conversion efficiency, but these variables were unaffected by lactose. Salt-supplemented rats exhibited a three- to fivefold increase in urinary calcium excretion and a small increase in urinary magnesium and phosphorus excretion, irrespective of dietary lactose content. In addition, salt supplementation reduced plasma alkaline phosphatase (EC 3.1.3.1) activity. Lactose increased urinary Ca and Mg excretion and plasma Ca and P concentrations. Salt reduced tibia mass but not tibia mass expressed relative to body-weight, but neither variable was affected by lactose. Both tibia Mg content and concentration were reduced by salt but unaffected by lactose, and neither tibia P content nor concentration was affected by salt or lactose. Tibia Ca content was reduced by salt but this was prevented by lactose. Tibia Ca concentration was unaffected by salt or lactose, although there was a reduction (not significant) in tibia Ca concentration in animals fed on the lactose-free diet. These results show that lactose had no independent effect on bone and that reduced accretion of bone mass and mineral content in rats fed on the high-salt diets was due, at least in part, to reduced growth. Failure to offset sodium-induced hypercalciuria by a compensatory increase in net Ca absorption may have contributed to reduced bone Ca accretion. The protective effect of lactose against reduced bone Ca accretion may be due to increased Ca absorption.

Effect of Dietary Lactose on Salmonella Colonization of Market-Age Broiler Chickens

The effect of providing lactose in feed and inoculation with volatile fatty acid-producing anaerobic cultures (AC) of cecal flora on Salmonella typhimurium colonization was evaluated in broilers. One-day-old chicks were divided into four groups and provided 1) no lactose, no AC; 2) AC, no lactose; 3) AC and lactose on days 1-10; or 4) AC and lactose on days 1-40. All groups were challenged per os with 10(6) Salmonella on day 3 and with 10(8) Salmonella on day 33. Salmonella growth in the cecal contents was significantly decreased (P less than 0.01) on day 10 in the chicks provided lactose from day 1-10. However, after the removal of lactose from the diet, the chicks were susceptible to Salmonella colonization. The number of Salmonella in the ceca was significantly reduced (P less than 0.05) in the chicks provided lactose throughout the 40-day growing period. Dietary lactose decreased the pH of the cecal contents and was accompanied by marked increases in the concentrations of undissociated bacteriostatic volatile fatty acids in the cecal contents.

Effect of Dietary Lactose on Cecal pH, Bacteriostatic Volatile Fatty Acids, and Salmonella typhimurium Colonization of Broiler Chicks

One-day-old broiler chicks were inoculated with volatile fatty acid producing cecal flora from adult chickens. The chicks were divided into four groups and provided 1) no lactose, 2) 2.5% lactose in water, 3) 5% lactose in feed, or 4) 10% lactose in feed, until 10 days of age. All groups were challenged at 3 days of age with 10(6) or 10(8) S. typhimurium. At 10 days, the number of Salmonella in the ceca of the chicks challenged with 10(6) Salmonella was significantly decreased (P less than 0.01) in the groups provided lactose as compared with the controls. A significant decrease (P less than 0.01) in Salmonella numbers occurred in the chicks challenged with 10(8) Salmonella and provided 10% lactose. Providing 2.5% lactose or 5% lactose failed to inhibit Salmonella growth in chicks challenged with 10(8) Salmonella. The pH of the ceca of the groups provided lactose decreased significantly (P less than 0.05) and was accompanied by significant increases (P less than 0.01) in the concentrations of bacteriostatic acetic and propionic acids. Results showed that providing dietary lactose to broiler chicks and inoculation with normal cecal flora decreased cecal pH, increased the concentrations of bacteriostatic volatile fatty acids, and inhibited Salmonella colonization.

Biological Control of Salmonella typhimurium in Young Chickens

The effect of dietary lactose and anaerobic cultures of cecal microflora of mature chickens on the colonization of young broiler chickens by Salmonella typhimurium was evaluated. Newly hatched chicks were given either no treatment (controls), anaerobic cecal cultures, lactose (2.5%) in the drinking water, or both anaerobic cultures and lactose. Chicks were challenged per os at 3 days of age with either 10(6) or 10(8) S. typhimurium resistant to nalidixic acid and novobiocin. On day 10, the cecal contents of the chicks were examined for S. typhimurium, pH, short-chained volatile fatty acids (VFAs), undissociated VFAs, and lactic acid. Chicks given either lactose alone or cecal anaerobes alone had significantly (P less than 0.05) fewer S. typhimurium recovered from their ceca than the controls. Chicks given the combination of dietary lactose and cecal anaerobes had significantly fewer S. typhimurium recovered from their ceca than the chicks given dietary lactose or cecal anaerobes alone. Chicks given lactose had significant (P less than 0.05) increases in the lactic acid concentration of their cecal contents. Increased lactic acid concentrations were directly correlated to decreased cecal pH values and caused a reduction in the total concentration of VFAs but a significant (P less than 0.05) increase in the undissociated form of some VFAs.

Effects of dietary lactose and purified diet on intestinal microflora of rats.

In the rats fed on lactose-containing purified diet (PDL), bifidobacteria remarkably increased in number in both the jejunum and cecum as compared with those fed on control diet (PD) or conventional diet (NMF). Besides, lactobacilli, streptococci, staphylococci, and Escherichia coli increased in number in the jejuna and/or ceca of rats fed on PDL as compared with those fed on PD. The incidence and numbers of Lactobacillus species were remarkably different between the rats fed on PDL and those on any of the other diets. Indole-producing Bacteroides spp. were rarely isolated from the PDL-fed rats. The cecum was markedly enlarged in the PDL rats and reduced in the PD rats as compared with that in the NMF animals.

The effect of dietary lactose on the early recovery from protein-energy malnutrition. I. Clinical and anthropometric indices

To assess the advisability of using lactose-containing formulas in the rehabilitation of severely malnourished children, indices of clinical recovery, growth and restoration of body proteins and gastrointestinal function were measured longitudinally during the initial 45 days of hospitalization in 20 male, preschool children with kwashiorkor and marasmic-kwashiorkor. All patients received a diet based on cows' milk, but half were allocated to a formula pretreated with β-galactosidase to hydrolyze the lactose, while the others received the untreated, intact milk. The groups were identical with respect to clinical criteria on admission. For the final 37 days of the protocol, the subjects received 4 g of protein and 150 kcal of energy per kg per day. More diarrhea was experienced by the intact lactose group during early hospitalization. Overall, recovery was satisfactory in both cohorts, and there were no differences in rates of growth, body protein repletion, restoration of energy reserves nor intestinal functions. In conclusion, the routine reduction of lactose content from a milk-based diet for severe protein-energy malnutrition offers no advantages.

The effect of dietary lactose on the early recovery from protein-energy malnutrition. II. Indices of nutrient absorption

Absorption of dietary energy, nitrogen, carbohydrates and calcium, and retention of nitrogen and calcium were studied in 20 children with protein-energy malnutrition of the edematous type, using metabolic balance techniques and breath H2 analysis, to assess the advisability of using lactose-containing formulas in the rehabilitation of severely malnourished children. Ten patients received for 45 days a diet formula based on cows' milk (intact milk) and 10 similar children received the same formula pretreated with β-galactosidase to hydrolyze the lactose (hydrolyzed milk). Dietary intakes were gradually increased to reach, on the 8th day, 4 g of protein and 150 kcal/kg. There were no differences between groups with respect to absorption or retention of the index nutrients. Postprandial carbohydrate malabsorption was occasionally observed in two patients with servings of the intact milk formula, and in one with the hydrolyzed milk diet. When the nutritional quality of a diet is assessed, the amount of nutrients that are absorbed and utilized are more important than the small, incompletely absorbed fractions that do not have significant metabolic or clinical implications. Therefore, the use of milk as the protein source for recovery diets is not contraindicated in the routine treatment of PEM.

Effect of dietary lactose on gain, feed conversion, blood, bone and intestinal parameters in postweaning rats and swine.

Two trials were conducted to determine the effect of lactose on performance, bone integrity and certain blood constituents in postweaning rats and swine. The effect of lactose on calcium and phosphorus and percentage ash content of the small intestine was also determined. In both trials, average daily gains were not influenced by the feeding of diets containing 30% lactose. Feed conversion was depressed in both rats and pigs when 30% lactose was fed. Transitory diarrhea was observed in rats fed 30% lactose, but not in swine. In the rat trial, no significant differences due to treatment were observed for serum Ca of P, but a linear increase (P < .01) in alkaline phosphatase was observed as lactose increased in the diet. Analysis of blood constituents from multiple bleedings during the pig trial showed that in the first 2 weeks, alkaline phosphatase was increased (P < .01) in pigs fed lactose and slightly decreased in those not fed lactose. Lactose affected the change in serum Ca for 0 to 10 weeks (P < .05) as indicated by a marked reduction in serum Ca of pigs not fed lactose and a slight increase for those fed lactoss. Serum calcium decreased in the absence of lactose but increased in the presence of lactose (P < .05) in pigs fed .4% Ca diets. In both trials, breaking strength parameters (peak force and stress) were not affected by dietary lactose. Bones from pigs fed no lactose had a higher stress to strain ratio (P < .05) than those from pigs fed lactose. In the rat trial, stress to strain ratio was variable across all treatments. Percentage of bone ash increased (P < .01) as lactose increased in the diet. Dietary treatments did not affect the mineral content of specific gut segments.

Effect of Dietary Lactose at Levels Comparable to Human Consumption on Cholesterol and Bile Acid Metabolism of Conventional and Germfree Rats

In recent years, the use of milk products and the concomitant intake of lactose have been tentatively linked to the etiology of cardiovascular disease. An effect of lactose on the microbial modification of acid and neutral sterols has been suggested. In the present study lactose intake, ranging up to 30% of total diet increased beta-muricholic (beta-MC) but not cholic acid concentrations in conventional (CV) rat small intestine to the extent that at the 20% and 30% intake level, the intestinal cholic: beta-MC ratio approached that in germ-free (GF) rats. Total intestinal bile acid (BA) content increased by approximately 1/3, but remained at less than half the value found in GF rats. At lactose intake levels within a range corresponding to the consumption of dairy products often recommended for adult man (5% to 10%) only moderate changes in intestinal, and little change in fecal BA were found during and after the 3 months experimental period. Intestinal beta-MC was increased in the presence and in the absence of an intestinal microflora. Experiments with GF rats fed 10% lactose or 10% maltose indicated that this increase is evoked similarly by both carbohydrates. The slight increase in serum cholesterol levels seen with disaccharide feeding, which became evident only in the GF rats, was again not specific for lactose. No influence was found of lactose feeding on liver cholesterol values. Comparison of CV rats fed nonsterile and radiation-sterilized lactose-containing diets suggested that this mode of sterilization has only a minor influence on the resulting data. When GF experiments are to be incorporated, sterilazation of diet by irradiation with 3.5 to 4.0 X 10(6) Rad is preferable to autoclaving. The present data indicate that no major effect specifically related to a normal dietary intake of lactose on cholesterol and BA metabolism of the adult rat could be demonstrated for the duration of these experiments.

Effects of dietary lactose and vitamin D on intestinal phosphate transport in patients with familial hypophosphatemia

Effects of dietary lactose and vitamin D on intestinal phosphate transport in patients with familial hypophosphatemia

Effects of dietary lactose and lactase preparation on the intestinal absorption of calcium and magnesium in normal infants

Effects of dietary lactose and a lactase preparation on the intestinal absorption of calcium and magnesium were studied in 3 groups under 8 months of age; infants on a proprietary milk, infants on a lactose-free milk, and infants on a proprietary milk to which a lactase preparation was added. The intestinal absorption of both elements was reduced in infants on a lactose-free milk and enhanced in infants who were fed on a proprietary milk and given a lactase preparation.