Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Lactose Intolerance”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82Linked to original sources
PubMed1980

Genetic heterogeneity in human neuraminidase deficiency.

There is a deficiency of human alpha-N-acetylneuraminidase in several inherited diseases. In patients with mucolipidosis I (refs 1,2) and in adults with a variant form with out bony abnormalities and mental retardation, both also classified as sialidoses, it is the only deficient enzyme. In mucolipidosis II ('I-cell' disease) neuraminidase is one of many deficient lysosomal hydrolases and a third manifestation combines deficiency of neuraminidase and beta-galactosidase. We have investigated the genetic background of these various neuraminindase deficiencies by somatic cell hybridization and co-cultivation. The principal conclusions from work on mutant fibroblasts, reported here, are that at least three gene mutations are involved and that the combined beta-galactosidase/neuraminidase deficiency is likely to be due to defective post-translational modification of these enzymes.

Cell Communication↗
PubMed1999

Production of low-lactose milk by ectopic expression of intestinal lactase in the mouse mammary gland.

We have investigated, in mice, an in vivo method for producing low-lactose milk, based on the creation of transgenic animals carrying a hybrid gene in which the intestinal lactase-phlorizin hydrolase cDNA was placed under the control of the mammary-specific alpha-lactalbumin promoter. Transgenic females expressed lactase protein and activity during lactation at the apical side of mammary alveolar cells. Active lactase was also secreted into milk, anchored in the outer membrane of fat globules. Lactase synthesis in the mammary gland caused a significant decrease in milk lactose (50-85%) without obvious changes in fat and protein concentrations. Sucklings nourished with low-lactose milk developed normally. Hence, these data validate the use of transgenic animals expressing lactase in the mammary gland to produce low-lactose milk in vivo, and they demonstrate that the secretion of an intestinal digestive enzyme into milk can selectively modify its composition.

Animals↗
PubMed2003

Gene-culture coevolution between cattle milk protein genes and human lactase genes.

Milk from domestic cows has been a valuable food source for over 8,000 years, especially in lactose-tolerant human societies that exploit dairy breeds. We studied geographic patterns of variation in genes encoding the six most important milk proteins in 70 native European cattle breeds. We found substantial geographic coincidence between high diversity in cattle milk genes, locations of the European Neolithic cattle farming sites (>5,000 years ago) and present-day lactose tolerance in Europeans. This suggests a gene-culture coevolution between cattle and humans.

Animals↗
PubMed1999

Lactic acid bacteria and the human gastrointestinal tract.

OBJECTIVE: This review summarises the effects of lactic acid bacteria on lactose malabsorption, bacterial/viral or antibiotic associated diarrhoea, and describes the impact of lactic acid bacteria on cancer and the fermentative products in the colon. RESULTS: Eight studies (including 78 patients) demonstrated that lactase deficient subjects absorbed lactose in yogurt better than lactose in milk, while two studies (25 patients) did not support this. Two studies (22 patients) showed that unfermented acidophilus milk was absorbed better than milk, while six studies (68 patients) found no significant differences. Addition of lactose hydrolysing enzyme, lactase, to milk improved lactose malabsorption in seven studies (131 lactose malabsorbers), while one study (10 malabsorbers) demonstrated no improvement. Lactic acid bacteria alleviated travellers' diarrhoea in one study (94 individuals) while a study including 756 individuals was borderline statistically significant. One study (50 individuals) did not find an effect of lactic acid bacteria on travellers' diarrhoea. Six studies (404 infants) demonstrated a significant effect of lactic acid bacteria on infant diarrhoea, while one study (40 infants) did not. Lactic acid bacteria moderated antibiotic associated diarrhoea in three studies (66 individuals), while two studies (117 individuals) were insignificant. CONCLUSIONS: Lactase deficient subjects benefit from a better lactose absorption after ingestion of yoghurt compared with milk and from milk added lactase, whereas ingestion of unfermented acidophilus milk does not seem to improve lactose absorption. The majority of studies support that lactic acid bacteria alleviate bacterial/viral induced diarrhoea, especially in infants, while the effect on antibiotic associated diarrhoea is less clear. Experimental studies indicate an effect of lactic bacteria on human cell cancer lines, but clinical evidence is lacking. A 'stabilising' effect of lactic acid bacteria on the colonic flora has not been documented.

Colonic Neoplasms↗
PubMed1981

Turnover of beta-galactosidase in fibroblasts from patients with genetically different types of beta-galactosidase deficiency.

The turnover of lysosomal beta-galactosidase was studied in fibroblast cultures from patients with Gm1-gangliosidosis and combined beta-galactosidase and neuraminidase deficiency, which had 5-10% residual beta-galactosidase activity. beta-Galactosidase was specifically inactivated with the suicide substrate beta-D-galactopyranosylmethyl-p-nitro-phenyltriazene (beta-Gal-MNT) and from the subsequent restoration of enzyme activity in cell cultures turnover times were calculated. By using [3H]beta-Gal-MNT, the hydrolytic activity per molecule of beta-galactosidase was determined. 3H-labelled beta-D-galactopyranosylmethylamine, the precursor of [3H]beta-gal-MNT, was obtained by Raney-nickel-catalysed exchange with 3H2O. The rate of synthesis of beta-galactosidase in normal and all mutant cells tested was found to be 0.4-0.5 pmol/day per mg of cellular protein. The GM1-gangliosidosis cells tested contain the normal amount of 0.5 pmol of beta-galactosidase/mg of protein with a normal turnover time of about 10 days, but only 10% of beta-galactosidase activity per enzyme molecule. Cells with combined beta-galactosidase and neuraminidase deficiency contain only 0.3 pmol of beta-galactosidase/mg of protein with a decreased turnover time of 1 day and normal hydrolytic properties (200 nmol of 4-methylumbelliferyl galactoside/h pmol of beta-galactosidase).

Binding Sites↗
PubMed2001

Relationship between lactose digestion, gastrointestinal transit time and symptoms in lactose malabsorbers after dairy consumption.

BACKGROUND: The relationship of symptoms with objective measurements, as well as some of the mechanisms involved in lactose tolerance after yoghurt consumption, remain unclear. METHODS: The trial had a double-blind design in which 22 lactose malabsorbers received 25 g daily lactose in fresh (living bacteria > 108 cfu/g) yoghurt or heated (< 102 cfu/g) yoghurt for 15 days, followed by a cross-over (15 days) after a wash-out period (14 days). The lactose digestion was determined by the breath H2 test, the gastric emptying (GE) with a 13C-acetate breath test and the revealed transit time (OCTT) by 15N-lactose-ureide test. Subjects reported their gastrointestinal symptoms (GIS) in a validated questionnaire. RESULTS: Breath H2 test indicated more effective lactose digestion after fresh yoghurt intake. The OCTT was shorter after heated yoghurt ingestion as compared with the fresh. There was lower severity of GIS (P < 0.05) after fresh yoghurt intake, and this showed an inverse correlation with OCTT (P < 0.05). CONCLUSIONS: Delayed orocoecal transit time was associated with fewer gastrointestinal symptoms. The improved lactose digestion and tolerance of fresh yoghurt should be mainly attributed to the presence of living bacteria.

Adult↗
PubMed2002

Review article: lactose--a potential prebiotic.

Lactose maldigestion, which affects a large majority of the world's population, has been mostly linked with uncomfortable symptoms. In addition, dairy consumption is variably blamed or recommended for a number of ill effects. There is, however, emerging evidence that certain lactic acid-producing bacteria, which selectively consume prebiotics, may be beneficial against some lower intestinal diseases. Lactose maldigestion and lactose should perhaps be re-evaluated as a potential provider of such a prebiotic. This historical and observational review discusses lactose and argues the opinion that it has prebiotic potential. Moreover, in maldigesters, natural ingestion or lack thereof may be relevant in the pathogenesis of diseases such as colorectal cancer and inflammatory bowel diseases.

Dairy Products↗
PubMed2000

Lactose (mal)digestion evaluated by the 13C-lactose digestion test.

BACKGROUND: The prevalence of genetically determined lactase nonpersistence is based on the results of the lactose H2 breath test. This test, however, is an indirect test, which might lead to misinterpretation. DESIGN: We determined lactase activity in healthy Chinese and Dutch students using a novel 13C-lactose digestion test. The cut-off value of this test was established in a Chinese population with a homogenous genetic background of lactase nonpersistence and was compared with the results obtained in a Caucasian population. Twenty-five grams of a 13C-lactose solution was consumed by 12 known H2-positive and 5 H2-negative Chinese students and 48 Dutch students and, subsequently, 13C-glucose concentration in plasma and H2 excretion in breath were measured. RESULTS: A similar 13C-glucose response curve was found in all Chinese students. The mean response curve in the Dutch students was more pronounced (P < 0.01). The 1 h (peak) plasma 13C-glucose concentration was the best discriminator between lactose digesting and maldigesting subjects. The cut-off level of 2 mmol L-1 13C-glucose in plasma was defined in the H2-positive Chinese students group. Based on the 13C-glucose response the prevalence of lactose maldigestion in the Dutch subjects was 25%; based on the lactose H2 breath test 17%. CONCLUSIONS: Using the 13C-lactose digestion test the results demonstrate a higher prevalence of lactose maldigestion in a Caucasian population than indicated by the results of the H2 breath test. A moderate increase in the plasma 13C-glucose concentration after consumption of 13C-lactose in the young adult Chinese subjects indicates a residual lactase activity in that age group, even when a positive H2 breath test result is obtained. These results indicate that the 13C-glucose concentration in plasma more accurately reflects the small intestinal lactose digestion capacity than the lactose H2 breath test.

Adult↗