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PubMed2002

Effect of lactose and dried whey supplementation on growth performance and histology of the immune system in broilers.

The objective of this study was to evaluate the effect of lactose and dried whey supplementation as dietary component on growth performance and histology of lymphoid organs and ileum in broilers. A total of 480 day-old chicks were utilised for 42 days. Animals were assigned randomly to one of three treatments: control, lactose (2.5%), and dried whey (3.85%). Body weight was greater for animals supplemented with lactose or dried whey than for those not supplemented. There were no effects of treatments on feed intake and feed efficiency. In general, the effects of lactose or dried whey supplementation on histology of lymphoid organs and ileum were variable. Plasma cell counts were lower for animals supplemented with lactose than for those supplemented with dried whey. However, the length of intestinal villi during the starter period was greater for experimental groups than for control group.

Animal Feed↗
PubMed2000

Wide variations in the testing of lactose tolerance: results of a questionnaire study in Finnish health care centres.

About 70% of the world's adult population is unable to digest lactose, the sugar found naturally only in milk. This disability leads to gastrointestinal symptoms called lactose intolerance. In Finland, many patients visit health care centres because they are suffering from gastrointestinal symptoms. A few of them are diagnosed as being lactose intolerant. However, a far larger number diagnose themselves as suffering from lactose intolerance. Therefore the diagnostic tests used should be carefully validated and standardized in clinical laboratories throughout the country. The aim of this questionnaire study was to clarify the situation centres with adult patients in Finnish health care and to try to standardize procedures for administering lactose tolerance tests.

Adult↗
PubMed2005

Diagnosis, symptoms, and calcium intakes of individuals with self-reported lactose intolerance.

OBJECTIVE: To determine methods of diagnosis, symptoms, and calcium intake from food and supplements for individuals with self-reported lactose intolerance. METHODS/DESIGN: Cross-sectional survey using a mailed questionnaire. SUBJECTS/SETTING: A convenience sample of 189 adults with self-reported lactose intolerance living in the metropolitan area of Vancouver Canada responded to posters or advertisements, and 159 returned completed questionnaires. MEASURES OF OUTCOME: Methods of diagnosis, symptoms experienced and their severity were self-reported. Estimated calcium intake from food and supplements was assessed using a food frequency questionnaire. Data were analyzed using descriptive statistics, chi-square, Pearson correlation analysis, t-tests and Analysis of Variance. RESULTS: Participants were 47 +/- 15 years of age; 72% female and 28% male; 67% Caucasian; and 54% had self-diagnosed their lactose intolerance. Of the 42% diagnosed by a physician, only 10% had been diagnosed by valid tests. Mean estimated food calcium intake was 591 +/- 382 mg/d and did not differ between those who were self- or physician-diagnosed. Only 11.5% of participants met their age-appropriate Adequate Intake (AI) from food calcium sources alone. Calcium supplements were used by 65% and provided an average of 746 +/- 703 mg calcium/day to those who used them; mean intakes of this group met the AI. CONCLUSIONS: Calcium intake from food sources alone is inadequate to meet the AI in individuals with self-reported lactose intolerance. Physicians managing lactose intolerance need current information on how the AI can be met through appropriate food choices and possible supplementation.

Adult↗
PubMed2005

The myth of increased lactose intolerance in African-Americans.

In the United States, approximately three fourths of African-Americans have the potential for symptoms of lactose intolerance because lactose digestion depends on the presence of the enzyme lactase-phlorizin hydrolase which is reduced by up to 90-95% in individuals with lactase nonpersistence. The 'African-American diet' is more likely to be low in a variety of vitamins and minerals, including calcium. African-Americans consume low amounts of dairy foods and do not meet recommended intakes of a variety of vitamins and minerals, including calcium. Low intake of calcium and other nutrients put African-Americans at an increased risk for chronic diseases. The 2005 Dietary Guidelines recommend consuming three servings of dairy foods per day to ensure adequate calcium intake, among other nutrients, and the National Medical Association has recently published a similar recommendation of three to four servings of dairy per day for the African-American population. Research has shown that lactose maldigesters, including African-American maldigesters, can consume at least one cup (8 oz) of milk without experiencing symptoms, and that tolerance can be improved by consuming the milk with a meal, choosing yogurt or hard cheeses, or using products that aid in the digestion of lactose such as lactase supplements or lactose-reduced milks.

Black or African American↗
PubMed2003

Studies on the preparation of chitosan microcarriers cross-linked by oxidized lactose and culture of primary hepatocytes.

Chitosan microcarriers were prepared using oxidized lactose as a cross-linking agent which was oxidized by sodium periodate. The effect of amount of oxidized lactose on the preparation of chitosan microcarriers was studied and optimized. Rat hepatocytes cultivated on chitosan microcarriers cross-linked by oxidized lactose retained the spherical shape as they have in vivo. Liver-specific functions such as albumin secretion and glucose metabolism were stably maintained for seven days. The metabolic activities of hepatocytes cultured on the oxidized lactose cross-linked chitosan microcarriers were higher than those of hepatocytes on chitosan microcarriers cross-linked by glutaraldehyde and on cytodex 3. The results suggest that oxidized lactose could be an interesting cross-linking agent for chitosan thus reducing the toxic side effects caused by using glutaraldehyde.

Albumins↗
PubMed1997

Dairy sensitivity, lactose malabsorption, and elimination diets in inflammatory bowel disease.

The ability of inflammatory bowel disease (IBD) patients to tolerate dairy products and the guidance they receive from physicians and nutritionists on this subject are important considerations in the management of their IBD. Although most affected persons are able to consume a glass of milk daily without discomfort, additional consideration must be given to specific factors that can be relevant to certain individuals. The declaration by patients that they are "dairy sensitive" may be related to lactose intolerance or malabsorption, the long-chain triacylglycerol content of milk, allergy to milk proteins, as well as psychologic factors and the misconception that dairy products can be detrimental to their health. The prevalence of lactose malabsorption is significantly greater in patients with Crohn disease involving the small bowel than it is in patients with Crohn disease involving the colon or ulcerative colitis. In the latter colonic conditions the prevalence of lactose malabsorption is mainly determined by ethnic risk, which is based on genetic factors. In addition, lactose malabsorption in Crohn disease of the small bowel may be determined by factors other than lactase enzyme activity, such as bacterial overgrowth and/or small bowel transit time. Physicians differ widely in the advice they give their patients: some dogmatically advise avoidance of dairy products when the diagnosis is made whereas others discount the possible role of dairy in the management of IBD. IBD patients avoid dairy products more than they would need to based on the prevalence of lactose malabsorption and/or milk intolerance, probably partly because of incorrect patient perceptions and arbitrary advice from physicians and authors of popular diet books. Adequate scientific and clinical information is now available to permit recommendations about the intake of dairy products for each IBD patient.

Humans↗
PubMed1997

Effects of inulin and lactose on fecal microflora, microbial activity, and bowel habit in elderly constipated persons.

Constipation is an ailment encountered often in elderly people. A study was initiated to test the effects of lactose or inulin on the bowel habits of constipated elderly patients and to correlate these effects with several variables measured in feces such as microflora composition, concentration of lactate and short-chain fatty acids (SCFAs), pH, and the activities of beta-glucosidase and beta-glucuronidase, Groups of 15 and 10 patients received lactose and inulin, respectively, for a period of 19 d. The dose, 20 g/d from days 1 to 8, was gradually increased to 40 g/d from days 9 to 11 and was kept at this dose from days 12 to 19. There was considerable interindividual variations with this kind of dietary intervention. Inulin increased bifidobacteria significantly from 7.9 to 9.2 log10/g dry feces, but decreased enterococci in number and enterobacteria in frequency. In individuals consuming lactose, a noticeable increase in fecal counts of enterococci and a decrease in lactobacilli and clostridia was detected. Total bacterial counts remained unchanged. No changes in the concentrations of fecal SCFAs and lactate were observed. SCFAs showed a slight trend toward higher molar ratios of acetate to butyrate in response to the intake of lactose or inulin. The fecal pH and the beta-glucosidase and beta-glucuronidase activities were not influenced by sugar intake. Inulin showed a better laxative effect than lactose and reduced functional constipation with only mild discomfort.

Aged↗
PubMed2006

Incorporation of orally applied (13)C-galactose into milk lactose and oligosaccharides.

Biosynthesis and functions of human milk oligosaccharides (HMO) are not well known. A typical housekeeping enzyme, beta1,4-galactosyltransferase, links galactose to glucose to form lactose which is then used as backbone for the assembly of HMO. We investigated whether milk lactose and HMO may be labeled in vivo by an orally given (13)C-galactose bolus. Eleven exclusively breastfeeding mothers were given a (13)C-galactose bolus at the end of their breakfast. Milk and urine samples from each nursing up to 36 h were analyzed for carbohydrate composition by high-performance thin-layer chromatography, high-pH anion-exchange chromatography, and fast atom bombardment mass spectrometry. (13)C enrichment of milk fractions, urinary carbohydrates, lactose, and oligosaccharides as well as of breath CO(2) was determined by isotope ratio mass spectrometry. Up to 10% of the orally given galactose bolus was directly transported to the mammary gland and incorporated into milk components. Characteristic for most milk samples was the appearance of two (13)C-peaks, the first immediately after the (13)C-bolus was taken and the second on the next morning. The highest (13)C enrichment was found in lactose followed by neutral and acidic oligosaccharides. In breath samples, the (13)C-excretion followed the same pattern as in milk. (13)C nuclear magnetic resonance of isolated lactose revealed (13)C only at C(1)-atom of galactose and C(1)-atom of glucose. This label was without any exception at the same position as the (13)C-label of the orally applied galactose. Neutral and acidic HMO can easily be (13)C-labeled in vivo which facilitates investigations of their metabolic fate in infants.

Administration, Oral↗
PubMed1979

Effect of lactose on duodenal calcium-binding protein and calcium absorption.

Rats were fed a purified diet containing 30% lactose and calcium absorption was measured in duodenal loops in situ following instillation of 1.25 or 10 mM CaCl2 solutions. Lactose feeding caused absorption to be depressed from 88 to 69% (1.25 mM Ca solution) and from 71 to 43% (10 mM Ca solution). The effect of lactose feeding was more pronounced in 5-month old rats than in 2-month old rats. In the lactose-fed rats, calcium-binding protein (CaBP), measured by a competitive binding assay following partial purification, was depressed on the average from 24 to 10 nmoles Ca bound per mg protein. The effect of the lactose ingestion can be likened to the effect expected from continued high calcium intake, i.e., a decrease in the efficiency of calcium absorption and a decrease in CaBP.

Aging↗
PubMed1985

Effect of lactose on phosphate transport into rat intestinal brush border membrane vesicles.

Brush border membrane vesicles (BBMV) were used to evaluate the influence of lactose on phosphate (Pi) transport in the intestine of the rat. BBMV were prepared from duodenum, jejunum and ileum of 3-, 4- and 7-wk-old rats. Na+-dependent active transport of Pi was investigated in the presence of an Na+ gradient; Na+-independent, diffusional transport was investigated by substitution of choline chloride for NaCl. In 3-wk-old rats active Pi transport dominated, whereas in 4-wk-old rats a decrease in active transport and an increase of the diffusional component of total Pi transport were observed. Furthermore, in 7-wk-old rats, Pi was transported by simple diffusion alone. Addition of lactose to the preincubation medium had no effect on Pi transport in duodenal and jejunal BBMV isolated from 3-wk-old rats. In the remaining BBMV preparations, lactose caused a twofold enhancement of diffusional Pi uptake. Glucose and galactose had no effect on diffusional Pi uptake into BBMV. These results indicate that lactose may directly interact with luminal membranes, thus leading to increased diffusional transport. The membranes with a decreased Na+-dependent Pi transport activity are most susceptible to the influence of lactose.

Aging↗
PubMed1989

Lactose protects against estrogen-induced pigment gallstones in hamsters fed nutritionally adequate purified diets.

To evaluate the impact of dietary factors on gallstone induction in hamsters, male Syrian hamsters were fed for 2-8 wk purified diets that varied in type and amount of simple sugar (glucose vs. lactose, 17.5-72%), fat (2-5%), fiber (0-15%) and estrogen (0 or 300 micrograms/kg diet). Plasma and liver cholesterol and plasma triglycerides were measured, daily weight gain was determined, cecal weights were obtained, and gallbladder bile was scored by light microscopy and analyzed chemically for its lithogenicity and gallstone incidence. Lactose reduced plasma lipids, especially triglycerides, and hepatic cholesterol accumulation, and maintained a lower biliary cholesterol concentration. When fed at 30% or more, lactose reduced weight gain, increased cecal volume 2- to 4-fold and prevented gallstone formation. Diarrhea and death from 'wet tail' was associated with gallstones and was frequent in hamsters fed glucose without fiber, but its incidence was essentially eliminated by rice flour plus fiber or lactose. Under these experimental conditions of time and diet, estrogen supplementation was required for the formation of gallstones. These appeared to be pigment stones containing a minimal amount of cholesterol. In summary, pigment gallstones were induced in less than 8 wk in hamsters fed estrogen-supplemented purified diets. Lactose feeding improved lipid metabolism and reduced gallstone formation, apparently through its impact on large bowel metabolism.

Animals↗
PubMed1994

Lactose maldigestion and milk intolerance: a study in rural and urban Mexico using physiological doses of milk.

Lactose digestion capacity after ingestion of physiological doses of milk and its effect on milk intolerance and consumption were studied in rural and urban populations from three regions of Mexico with different milk intakes. All subjects (n = 926) received two treatments: whole milk (240 mL for children and 360 mL for adults) and the same amount of 90% lactose-hydrolyzed milk; 72% of the subjects also received as a third treatment a water solution containing lactulose (8 g for children and 10 g for adults). Lactose maldigestion determined by a hydrogen breath test was detected in 2 to 43% of subjects (depending on age group) and was higher in subjects from central and southern Mexico than in subjects from northern Mexico (P < 0.01). Only the experience of major symptoms of intolerance affected milk consumption, and these symptoms were present in 0 to 11% of children > 4 y old and in 7 to 17% of the 13- to 60-y-old subjects. No significant differences were found in lactose maldigestion or milk intolerance between rural and urban populations, but milk consumption was higher in urban areas (P < 0.01). Milk consumption in our study was affected primarily by factors not related to the capacity to digest or tolerate the lactose in milk.

Adolescent↗
PubMed1998

Insulin-dependent glucose utilization in intensively milk-fed veal calves is modulated by supplemental lactose in an age-dependent manner.

Postprandial insulin resistance with excessive hyperinsulinemia, hyperglycemia and glucosuria develops with increasing age in veal calves intensively fed milk replacers. We tested the age dependency of insulin resistance, modulated by high lactose intake, glucose oxidation and insulin receptor number and affinity after an overnight period without food. Male calves were fed a milk replacer containing 290 or 423 g lactose and 310 and 541 g total sugar/kg from 69-195 kg body weight. At mean body weights of 95 and 170 kg, insulin-dependent glucose metabolism was studied in euglycemic-hyperinsulinemic glucose clamps (EGC), and glucose-dependent insulin responses were tested in hyperglycemic clamps (HGC). EGC were combined with infusions of [13C6]glucose to measure glucose kinetics and glucose oxidation by determination of 13CO2 exhalation. During EGC and HGC, insulin concentrations were similar in both groups, indicating comparable insulin secretion and metabolic clearance rates. On the basis of glucose infusion rates required to maintain eu- or hyperglycemia in EGC and HGC, respectively, insulin-dependent glucose utilization was not age dependent. However, in calves receiving a high lactose intake, insulin-dependent glucose utilization was enhanced in the early phases, but was reduced in the late stages of the growth trial. Insulin-dependent glucose utilization behaved inversely with atom % excess of [13C6]glucose, but changed in a manner similar to that of the rate of glucose appearance. Inhibition of endogenous glucose output, exhalation of 13CO2 and amounts of oxidized glucose exhibited no group differences. More glucose was therefore stored in lactose-supplemented calves. A reduced insulin receptor number in skeletal muscle in calves fed high amounts of lactose likely contributed to low insulin-dependent glucose utilization.

Aging↗
PubMed2003

Transgenic chickens expressing beta-galactosidase hydrolyze lactose in the intestine.

Chickens do not possess the necessary enzymes to efficiently hydrolyze lactose into glucose and galactose. The bacterial enzyme beta-galactosidase can convert lactose into glucose and galactose. Transgenic chickens that carry the E. coli lacZ gene and express beta-galactosidase could potentially utilize lactose as an energy source. The objective of this study was to determine the ability of the transgenic chicken small intestinal mucosa to hydrolyze lactose into glucose and galactose. Lactase activity was examined in the intestinal muscosa from wild-type chickens and two lines of chickens that carry the lacZ gene and express beta-galactosidase. Lactase activity was significantly higher in both transgenic lines compared with wild-type birds (P < 0.05). The presence of the beta-galactosidase enzyme was revealed by X-gal staining in the intestine of transgenic chickens, whereas it was not present in the wild-type chickens. Overall, it appears that inserting the lacZ gene, which encodes beta-galactosidase, has resulted in a chicken that can utilize lactose as an energy source. This study demonstrates that transgenic technology can be used to modify nutrient utilization in domestic poultry.

Animal Nutritional Physiological Phenomena↗
PubMed1995

Lactose and galactose intake and metabolism in relation to the risk of epithelial ovarian cancer.

It has been suggested that aspects of lactose consumption and metabolism favoring a relatively high tissue level of galactose-1-phosphate may predispose women to ovarian cancer. The authors sought to examine this hypothesis in a study of 108 18- to 74-year-old Caucasian residents of a three-county area of western Washington who were diagnosed with stage I ovarian cancer during 1989-1991, and 108 age- and race-matched controls. Lactose and galactose intake, measured using a food frequency questionnaire, had been hypothesized to increase risk, but were somewhat lower among the cases than among the controls (75th percentile of lactose intake vs. 25th: odds ratio (OR) = 0.80, 95% confidence interval (Cl) 0.52-1.2; of galactose intake: OR = 0.71, 95% Cl 0.48-1.1). Intestinal lactase activity, also hypothesized to have a positive relation with ovarian cancer occurrence, was measured with an oral lactose challenge followed by determination of urinary galactose; no evidence that it was related to the disease was found (75th percentile of excreted galactose vs. 25th: OR = 0.87, 95% Cl 0.62-1.2). Galactose-1-phosphate uridyltransferase (transferase), the enzyme responsible for the metabolism of galactose-1-phosphate, was measured in erythrocytes; no deficit in cases was observed (75th percentile of transferase activity vs. 25th: OR = 1.3, 95% Cl 0.80-2.1). There was also no excess of cases carrying low-activity genetic variants of the transferase enzyme (lower-activity variants vs. higher-activity variants: OR = 0.61, 95% Cl 0.21-1.7). These results do not support the hypothesis that aspects of lactose and galactose intake and metabolism have a bearing on the etiology of ovarian cancer.

Adult↗
PubMed1982

Biosynthesis of lactosylceramide and paragloboside by human lactose synthase A protein.

Lactosylceramide and paragloboside were synthesized from their precursor glycolipids and UDP-galactose by lactose synthase A protein [UDP-Gal : GlcNAc beta-4-galactosyltransferase, EC 2.4.1.22] purified to homogeneity from human plasma. The partially purified human liver enzyme and an extract from human lymphoblastoid cells also exhibited the above activities. Rabbit antibody against the purified human plasma lactose synthase A protein neutralized the glycolipid synthesis activity as well as the activity for lactose synthesis by the enzyme preparations from plasma, liver and lymphoblastoid cells. These results suggest that lactose synthase A protein existing in plasma, liver and lymphoblastoid cells can synthesize not only lactose but also lactosylceramide and paragloboside in vitro. The enzyme could play a role in the synthesis of these two glycolipids in vivo.

Animals↗
PubMed1996

Does lactose maldigestion really play a role in the irritable bowel?

Patients who met International Congress of Gastroenterology criteria for irritable bowel syndrome (IBS) and had breath hydrogen lactose testing were interviewed to determine whether detection of lactose maldigestion (LM) had an impact on their symptoms. Of 199 patients initially evaluated, 161 (81%) were contacted and asked to rate their symptoms. At baseline, 47 (29%) of the IBS group had LM. Before testing, 23 (49%) were aware that ingestion of lactose-containing food was associated with their gastrointestinal symptoms. Lactose-maldigesting IBS subjects (IBSLM, n = 47) and those who had IBS and no LM (n = 114) were similar in terms of age, sex, and ethnic background. Interviews performed 41 +/- 1.1 (SEM) months after baseline evaluation revealed no significant differences in abdominal pain, altered bowel habits, bloating/distension, mucus, and relief with defecation among those with IBS or LMIBS. Overall symptoms resolved, improved, did not change, or worsened in a manner not statistically different between IBS and IBSLM groups. IBSLM subjects (a) felt that identifying LM helped them gain awareness of food-symptom relationships (78.7%), (b) experienced some improvement in symptoms (83%), (c) were avoiding lactose foods (87.2%), or (d) used lactase enzyme supplements (38.3%). Identifying LM did not significantly affect rated variables.

Breath Tests↗
PubMed1989

Milk lactose, citrate, and glucose as markers of lactogenesis in normal and diabetic women.

A study was undertaken to define an appropriate marker of lactogenesis II (the onset of copious milk secretion) in mothers, and to determine the effect of diabetes on this marker. Changes in the concentrations of three milk components--lactose, citrate, and glucose--were measured in 38 normal mothers and 6 type I diabetic mothers up to 10 days after birth. Milk yield was measured in 12 of the normal mothers, and all mothers were asked to note the time of milk "coming in" (the feeling of overfullness of the breasts). The average concentrations of lactose, citrate, and glucose in milk were low for the first 24 h after birth, then between 24 and 48 h after birth there was a rapid increase in the concentrations of lactose and citrate, and this transitional period was followed by a plateau period that began between 60 and 84 h after birth. For individual mothers the transitional period for citrate began 32 +/- 9 h (n = 13) and finished 77 +/- 10 h (n = 17) after birth, and for lactose the transitional period finished at 53 +/- 12 h (n = 29) after birth. For diabetic mothers these times were significantly later. The average 24-h milk intake by infants increased from 82 to 556 ml/24 h between 24 and 144 h after birth. Milk intakes were correlated with the concentration of lactose (r = 0.52, n = 51, p less than 0.001), citrate (r = 0.47, n = 47, p less than 0.001), and glucose (r = 0.69, n = 50, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗