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PubMed1994

A review of calcium preparations.

There are more than a dozen commonly prescribed calcium supplements and hundreds of different formulations commercially available. Numerous factors need to be considered when selecting a calcium preparation. Physical properties such as solubility, interference from coingested medications or foodstuffs, dosage, and timing can all affect the bioavailability of calcium. Medical conditions such as lactose intolerance, impaired gastric acid secretion, and high risk profile for kidney stone formation may impact on selection of a calcium supplement. This article will review the available literature and make general recommendations for the optimal use of calcium preparations.

Achlorhydria↗
PubMed1992

Nucleotide sequences of the arb genes, which control beta-glucoside utilization in Erwinia chrysanthemi: comparison with the Escherichia coli bgl operon and evidence for a new beta-glycohydrolase family including enzymes from eubacteria, archeabacteria, and humans.

The phytopathogenic bacterium Erwinia chrysanthemi, unlike other members of the family Enterobacteriaceae, is able to metabolize the beta-glucosides, arbutin, and salicin. A previous genetic analysis of the E. chrysanthemi arb genes, which mediate beta-glucoside metabolism, suggested that they were homologous to the Escherichia coli K-12 bgl genes. We have now determined the nucleotide sequence of a 5,065-bp DNA fragment containing three genes, arbG, arbF, and arbB. Deletion analysis, expression in minicell systems, and comparison with sequences of other proteins suggest that arbF and arbB encode a beta-glucoside-specific phosphotransferase system-dependent permease and a phospho-beta-glucosidase, respectively. The ArbF amino acid sequence shares 55% identity with that of the E. coli BglF permease and contains most residues thought to be important for a phosphotransferase. One change, however, was noted, since BglF Arg-625, presumably involved in phosphoryl transfer, was replaced by a Cys residue in ArbF. An analysis of the ArbB sequence led to the definition of a protein family which contained enzymes classified as phospho-beta-glucosidases, phospho-beta-galactosidases, beta-glucosidases, and beta-galactosidases and originating from gram-positive and gram-negative bacteria, archebacteria, and mammals, including humans. An analysis of this family allowed us (i) to speculate on the ways that these enzymes evolved, (ii) to identify a glutamate residue likely to be a key amino acid in the catalytic activity of each protein, and (iii) to predict that domain II of the human lactate-phlorizin hydrolase, which is involved in lactose intolerance, is catalytically nonactive. A comparison between the untranslated regions of the E. chrysanthemi arb cluster and the E. coli bgl operon revealed the conservation of two regions which, in the latter, are known to terminate transcription under noninducing conditions and be the target of the BglG transcriptional antiterminator under inducing conditions. ArbG was found to share a high level of similarity with the BglG antiterminator as well as with Bacillus subtilis SacT and SacY antiterminators, suggesting that ArbG functions as an antiterminator in regulating the expression of the E. chrysanthemi arb genes.

Amino Acid Sequence↗
PubMed1983

Congenital lactase deficiency. A clinical study on 16 patients.

There are at least 20 rare autosomal recessive disorders that are excessively common in Finland of which congenital lactase deficiency is one. During the last 17 years we have found 16 cases. In each case the mother noted watery diarrhoea, generally after the first feed of breast milk, and at the latest, by age 10 days. The lactose malabsorption was verified at a mean age of 36 (range 3-90) days, by which time the infants were dehydrated and 15 of them weighed less than at birth (mean weight for age was -2.8 SDs). On a lactose-free elimination diet (a group of 6 on Nutramigen and a group of 10 on soy-based formula) the children caught up in growth. One infant in each group showed allergic symptoms. While the infants were being breast fed their faeces contained 20 to 80 g/l lactose. In 24 peroral lactose tolerance tests, the greatest rise in blood glucose concentration was 0.8 mmol/l. Only 2 patients showed abnormal absorption when tested within a week of lactose elimination, and in each absorption tests became normal during the elimination period. Slight to partial villous atrophy of the jejunum was present in 4 early specimens, but in later ones the mean villous height was normal. The mean height of the epithelial cells was reduced and there were fewer intraepithelial lymphocytes in patients. The lactase activities in jejunal biopsy specimens were lower than in most patients with acquired lactase deficiency, with some overlap. The maltase and sucrase activities were normal.

Female↗
PubMed1974

Public health and genetic constitution of the San ("Bushmen"): carbohydrate metabolism and acetylator status of the Kung of Tsumkwe in the North-western Kalahari.

Intolerance to lactose owing to deficiency of lactase is particularly prevalent among non-Caucasian peoples. Special caution is therefore needed in offering them milk supplements. Lactose tolerance has been investigated among the!Kung in the north-western Kalahari. The opportunity was taken also to examine their acetylator status, as this affects their ability to detoxicate drugs given for the treatment of tuberculosis and other diseases.The preliminary studies reported here suggest that not more than 10% of the!Kung are tolerant to lactose, but only one person out of 30 was a slow acetylator.

Acetylation↗
PubMed2004

Probiotics and prebiotics in the elderly.

Probiotics (usually lactobacilli and bifidobacteria) and prebiotics (non-digestible oligosaccharides) have been shown to be useful in preventing certain disease conditions as well as possibly promoting specific aspects of health. In the present review, the evidence from clinical trials for benefits from probiotics and prebiotics to elderly populations is presented and discussed, specifically in respect of three common conditions found in the elderly. Both probiotics and prebiotics may be helpful in malnutrition, particularly in lactose intolerance and calcium absorption, and in constipation. Probiotics have been shown clearly to boost immunity in the elderly, but the clinical significance of this remains to be clarified. These results are encouraging, and further large scale studies seem justified to establish the place of probiotic and prebiotic supplements in elderly subjects.

Aged↗
PubMed1992

Surface denaturation of proteins: the thermal inactivation of beta-galactosidase (Escherichia coli) on wall-liquid surfaces.

Irreversible inactivation of dilute beta-galactosidase (Escherichia coli) at relatively low temperatures was found to occur as a result of interactions of beta-galactosidase with wall-liquid surfaces. The rate of inactivation was directly proportional to the wall-liquid surface area, but independent of the air-liquid surface area, and the rate was also dependent on the wall composition. A small portion of the beta-galactosidase molecules was found to bind strongly to the surfaces of vessels in which the beta-galactosidase was stored. Bovine serum albumin eliminated the inactivation and it also eliminated the binding of beta-galactosidase to the wall. On the other hand, EDTA eliminated the inactivation, but it did not decrease the amount of beta-galactosidase bound. The addition of some transition metals increased the rate of inactivation. Protection of beta-galactosidase from surface inactivation by EDTA is not, therefore, a result of decreased binding of the enzyme to the walls of the vessels, but is probably a result of the ability of EDTA to scavenge certain trace metal ions present in solution, which are needed for the inactivation. The content of protein in the solution did not change as a result of the inactivation and, thus, the inactive enzyme does not accumulate at the surface. Since beta-galactosidase is often stored for long periods of time and since it is used to decrease the lactose content of milk for lactose intolerant individuals, this study may have practical significance. The presence of metal chelators and extraneous proteins should improve the stability of the enzyme, especially for processes that are carried out at elevated temperatures.

Absorption↗
PubMed1982

Distribution of human adult lactose phenotypes in Egypt.

Lactose absorption was studied in 570 health adolescent and adult males in Egypt. Employing a field version of the noninvasive hydrogen breath test, 156 (27.4%) lactose absorbers and 414 (72.6%) lactose malabsorbers were identified. The age-specific prevalence of the lactose phenotypes indicated that lactase repression is complete at the age of 14 years in Egyptians. The regional distribution showed significant differences between the Nile Delta and the northern and southern part of Upper Egypt. The existence of a north-south gradient of decreasing frequencies of the hypolactasia gene from the Nile Delta to the Sudan is suggested.

Adolescent↗
PubMed1990

The biosynthetic basis of adult lactase deficiency.

The intestinal brush-border enzyme lactase splits lactose into its component monosaccharides, glucose and galactose. Relative deficiency of the enzyme during adulthood is a common condition worldwide and is frequently associated with symptoms of lactose intolerance. We studied the synthesis and processing of lactase in normal and adult hypolactasic subjects using human intestinal explants in organ culture. Metabolic labeling experiments in our control subjects with [35S]methionine followed by immunoprecipitation, sodium dodecyl sulfate-polyacrylamide-gel electrophoresis, and fluorography demonstrated that newly synthesized lactase is initially recognized as a precursor molecule with a relative molecular weight (Mr) of 205,000. Over the course of several hours most of the labeled lactase was converted to a mature form of 150,000 Mr. Transiently appearing forms of 215,000 and 190,000 Mr were identified and were felt to represent intermediary species generated during intracellular processing. We identified two distinct alterations in lactase biosynthesis accounting for adult hypolactasia. Studies in three deficient subjects demonstrated markedly reduced synthesis of the precursor protein though posttranslational processing appeared identical to normal. Multiple studies in a fourth deficient subject demonstrated synthesis of ample amounts of precursor lactase but reduced conversion to the mature active form of the enzyme.

Adult↗
PubMed2003

The impact of solid-phase gastric emptying studies in the management of children with dyspepsia.

Information on the utility of solid-phase gastric emptying studies (SPGES) in the evaluation of children with symptoms of upper gastrointestinal (GI) motor dysfunction is limited. This study was conducted to evaluate the impact of SPGES in the clinical management and outcome of children with upper GI symptoms suggestive of gastroparesis. The records of 45 children who underwent SPGES (31F; 3-17 years) were reviewed. All patients had GI symptoms suggesting gastroparesis. Patients were fed with Tc-99m-sulfur colloid-labeled chicken liver. Adult normal half-life (T1/2) values (F 103 +/- 14 minutes; M 66 +/- 13.6 minutes) were used. The relationships among symptoms, treatment, and outcome were evaluated. Of the 45 patients 9 had delayed, 16 had rapid, and 20 had normal gastric emptying. Six of 9 patients with delayed gastric emptying responded to cisapride. Four of 16 patients with rapid emptying were diagnosed with the dumping syndrome. Of the children with rapid gastric emptying, 87% were females. Twenty patients with normal emptying were diagnosed with gastroesophageal reflux (8), nonulcer dyspepsia (5), irritable bowel syndrome (2), Helicobacter pylori (1), lactose intolerance (1), eosinophilic gastroenteritis (1), duodenitis (1), and constipation (1). In patients who had SPGES for possible gastroparesis, 20% had gastroparesis, 36% had rapid gastric emptying, and 44% had normal gastric emptying. The high number of females in the rapid gastric emptying group might be secondary to normal adult female T1/2 values that were used. The practice of using adult normal T1/2 values in prepubertal girls may need to be revised. Patients with delayed gastric emptying responded to cisapride.

Adolescent↗
PubMed2003

Probiotics as functional foods.

Probiotic products have been widely used in Japan and Europe for years. Probiotics are now emerging as an important category of food supplement in the United States. Questions about the biologic nature, available products, claimed health benefits, and safety and regulation of probiotics are important for both consumers and nutrition professionals. Probiotics can be considered functional foods because they provide health benefits beyond the traditional nutrition function. With few exceptions, most probiotic products currently available contain lactic-acid-producing bacteria, which mainly belong to the genera Lactobacillus and Bifidobacterium. We reviewed the scientific papers published in major nutrition journals and abstracts available on the PubMed website regarding probiotics. Evidence suggests the following beneficial effects of probiotics: normalization of the intestinal microflora, ability to block the invasion of potential pathogens in the gut, prophylactic or therapeutic treatment for several types of diarrhea, relief of symptoms of irritable bowel syndrome and inflammatory bowel disease, amelioration of lactose intolerance, prevention of colon cancer, modulation of immune function, inhibition of Helicobacter pylori, and possible enhancement of calcium absorption and reduction of blood cholesterol levels. Mechanisms for the above benefits have been proposed, but none has been proven. An adequate level of viable bacteria in a probiotic product and an appropriate daily dose are critical to achieve a health benefit. Because probiotics are not known to be pathogenic and their upper tolerable level is high, they could be promoted as a beneficial food supplement. Currently, no disease-prevention or therapeutic claim for probiotics is legally allowed.

Journal Article↗
PubMedDate not supplied

Euglycemic control of gestational diabetes mellitus by specific dietary manipulation: a case study presentation.

Gestational diabetes is the most common complication of pregnancy. If maternal hyperglycemia is not well controlled, excess glucose is transmitted to the fetus, which can lead to fetal macrosomia and maternal and fetal complications. Dietary treatment for gestational diabetes varies among practitioners. A case review is presented of a 32-year-old white woman with gestational diabetes whose condition was complicated by her blood glucose intolerance to lactose in milk. By following a carefully monitored regimen using specific dietary manipulation to maintain normoglycemia, the woman was able to deliver a normal, healthy baby by spontaneous vaginal delivery.

Adult↗
PubMed2004

Osteoporosis-related life habits and knowledge about osteoporosis among women in El Salvador: a cross-sectional study.

BACKGROUND: Osteoporosis is a systemic skeletal disorder, characterized by reduced bone mass, deterioration of bone structure, increased bone fragility, and increased fracture risk. It is more frequent to find among women than men at a 4:1 ratio. Evidence suggests that to adopt changes on some life habits can prevent or delay development of osteoporosis. Several osteoporosis-risk factors have been confirmed in the US and western Europe, but in El Salvador there are neither reliable epidemiological statistics about this skeletal disorder nor studies addressing osteoporosis-risk factors in women. The aim of this study was to determinate the extent of osteoporosis knowledge, the levels of both daily calcium intake and weight-bearing physical activity, and the influence of several osteoporosis-risk factors on these variables in three age groups of Salvadorean women. METHODS: In this exploratory cross-sectional study, an osteoporosis knowledge assessment questionnaire including a food frequency and a physical activity record section were used to collect data and it was delivered through a face-to-face interview. A convenience sample (n = 197) comprised of three groups of women aged 25-35 years, 36-49 years, and over 49 years was taken. Among-group comparisons of means were analyzed by two-way ANOVA. To determinate the overall influence of osteoporosis-risk factors, the multivariate analysis was used. RESULTS: Study results indicated that better educated women had more knowledge about osteoporosis than women with a low education level, regardless of age, even though this knowledge was rather fair. Older women got more weight-bearing physical activity at home and less at place of employment than reported by the younger women; however, neither group performed sufficient high-intensity WBPA to improve bone mass. Regardless of age, the most women consumed 60% or less than the Dietary Reference Intake of calcium and depend on household income, lactose intolerance and coffee rather than milk consumption. CONCLUSION: In summary, the majority of women in this study have modest knowledge on osteoporosis. The knowledge base is not linked to preventive health habits, including sufficient calcium intake and performance of weight-bearing physical activities. They are thus at increased risk for low bone mass.

Adult↗
PubMed1999

Dietary calcium intakes of urban children at risk of lead poisoning.

Dietary calcium is well known to decrease gastrointestinal lead absorption and thereby reduce the risk for lead poisoning. Because children in economically deprived urban centers are especially likely to have excessive lead exposure, we surveyed dietary calcium intakes of 314 children from the greater Newark, New Jersey, area. The areas of Newark and adjacent communities studied had been previously identified as containing significant sources of environmental lead by geographic information systems technology. An abbreviated National Cancer Institute Health Habits and History Questionnaire, modified to focus on foods high in calcium, was used to determine dietary calcium. Calcium intakes were then compared to the new Dietary Reference Intake (DRI) guidelines. The respondents were primarily the parents of African-American and Hispanic children ranging in age from 1 to 8 years, with a mean age of 3.5 years. The most recent blood lead concentration was 11.4 +/- 0.8 microg/dL (mean +/- standard error), and 48.6% had concentrations at or above the current guideline of 10 microg/dL. Quintiles of calcium intake were: 221 +/- 13; 488 +/- 9; 720 +/- 6; 885 +/- 6; and 1,389 +/- 49 mg/day. Fifty-five of 175 (31.4%) children aged 1-3 years had calcium intakes below the DRI, as did 82 of 139 (59.0%) children aged 4-8 years. The percentage of mothers reporting lactose intolerance in their children was 2.5%. The observation that the children in the highest quintile easily exceeded the DRIs for calcium suggests that urban parents who include dairy foods in their childrens' meals can provide a diet that meets the DRI guidelines. Children in the lowest quintiles are at risk of increased absorption of the environmental lead to which they are inevitably exposed, as well as other problems associated with a low intake of dietary calcium. The data suggest that both lead exposure and low dietary calcium continue to pose significant health risks to urban minority children.

Calcium, Dietary↗