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Results for “Lactose Tolerance Test”

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PubMed2004

The role of colonic microbiota in lactose intolerance.

In a previous study we observed a clear difference in lactose intolerance symptoms after a 25-g lactose load in two groups of persons with lactase nonpersistence and similar small intestinal lactase activity. From this observation we hypothesized a colon resistance factor. To identify this factor, the microbial composition of fecal samples of the two lactose intolerant groups (one with mild symptoms, n = 16, and one with diarrhea-predominant symptoms, n = 11) was compared using the fluorescent in situ hybridization technique. Large interindividual differences were found in the numbers of total bacteria and main groups of bacteria (CV: 0.65 and 0.64-0.82 respectively). The bacterial numbers were not significantly different between the two groups. A significant negative correlation, however, was found between the individual symptom scores of the intolerant persons and the numbers of total hybridizable bacteria (r(s) = -0.42, P = 0.03). The results suggest that an increased number of bacteria might contribute--by means of a higher fermentative capacity--to the reduction of lactose intolerance symptoms.

Adult↗
PubMed2006

Convergent adaptation of human lactase persistence in Africa and Europe.

A SNP in the gene encoding lactase (LCT) (C/T-13910) is associated with the ability to digest milk as adults (lactase persistence) in Europeans, but the genetic basis of lactase persistence in Africans was previously unknown. We conducted a genotype-phenotype association study in 470 Tanzanians, Kenyans and Sudanese and identified three SNPs (G/C-14010, T/G-13915 and C/G-13907) that are associated with lactase persistence and that have derived alleles that significantly enhance transcription from the LCT promoter in vitro. These SNPs originated on different haplotype backgrounds from the European C/T-13910 SNP and from each other. Genotyping across a 3-Mb region demonstrated haplotype homozygosity extending >2.0 Mb on chromosomes carrying C-14010, consistent with a selective sweep over the past approximately 7,000 years. These data provide a marked example of convergent evolution due to strong selective pressure resulting from shared cultural traits-animal domestication and adult milk consumption.

Adaptation, Biological↗
PubMed1991

The effect of carbohydrates in milk on the absorption of calcium by postmenopausal women.

The purpose of this investigation was to determine if the presence of carbohydrate in milk, either lactose or its hydrolysis products, enhance the bioavailability of calcium (Ca) in milk. Two studies were performed. In study A, fractional Ca absorption was measured in 11 lactose-tolerant postmenopausal women after an oral dose of 47Ca-equilibrated milk formula containing no carbohydrate (NOCHO), lactose (LACTOSE), or an equivalent amount of glucose plus galactose (SUGAR); all participated in three absorption studies in random order. The NOCHO formula contained 10.0 g protein and 217 mg Ca from a combination of milk mineral and protein isolates; the LACTOSE and SUGAR formulae contained in addition 12 g lactose or 6 g glucose plus 6 g galactose, respectively. In study B, fractional Ca absorption was measured in five postmenopausal women after an oral dose of 47Ca-equilibrated skim milk (217 mg Ca) and lactase-treated milk, each with sufficient carbohydrate added to equal 12 g. For both studies, the increase in forearm radioactivity 4 and 8 hours after oral 47Ca administration relative to the increase observed after IV administration was used to estimate fractional Ca absorption. The addition of lactose but not glucose plus galactose to the NOCHO formula enhanced Ca absorption (p less than 0.05). Fractional absorption at 4 hours was 0.386 from the LACTOSE formula compared with 0.310 for both the NOCHO and SUGAR formulae. Those individuals with the lowest absorption in the absence of carbohydrate had the greatest increase with lactose. In contrast, Ca absorption was the same from skim milk as from lactase-treated skim milk (study B).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1975

Relationship of milk consumption to blood glucose rise in lactose intolerant individuals.

Lactose intolerant populations are heterogeneous with respect to their milk-drinking habits. A gradation of lactase activity in the intolerant population may result in sufficient lactose hydrolysis to obviate symptoms and lead to continued milk consumption. This paper reports on differences in maximum blood sugar rise in lactose intolerant children who are observed to consume or reject milk. Of the 89 black elementary school children, 48 (54 per cent) evidenced a flat lactose tolerance curve. Twenty-eight of these 48 children (58 per cent) were defined as nonmilk drinkers. The maximum blood sugar rise was 12.3 mg/100 in the 20 lactose malabsorbers who were defined as milk drinkers. It appears that some lactose malabsorbing children may have sufficient, albeit lower, levels of lactase to hydrolyze moderate amounts of milk.

Adolescent↗
PubMed1976

Symptom response to lactose-reduced milk in lactose-intolerant adults.

The possible usefulness of low-lactose milk for those lactose-intolerant subjects who develop symptoms from milk consumption was investigated. In the first part of the study, 16 intolerant subjects (blood glucose rise less than 25 mg/100 ml) received low-lactose skim milk containing 15 g lactose (2.5 cups) and 7.5 g lactose (2.5 cups), regular skim milk containing 30 g lactose (2.5 cups), and all three milks plus a small breakfast. The low lactose milks produced significantly fewer symptoms. The food given with the milk had no significant effect on symptomatic response. The second group of 17 subjects received 25 g lactose in water (250 ml), skim milk (500 ml) and whole milk (500 ml); 10 g lactose in lactose-reduced skim (500 ml) and whole milk (500 ml) and whole milk (500 ml); and a placebo (250 ml). There was a significant positive relationship between amount of lactose consumed and symptom response. The form in which the lactose was administered (e.g., whole versus skim milk) was not significantly related to symptoms. It is concluded that in a symptomatic subjects a significantly greater quantity of low-lactose milk than regular milks can be consumed.

Adult↗
PubMed1977

Lactose malabsorption in Mexican-American adults.

Lactose malabsorption was determined in 277 Mexican-American (MA) and 142 Anglo-American (AA) adults aged 18 to 94 years old, and correlated with nutrient intake assessed from 24-hr dietary recalls, as well as with milk and dairy product consumption. Lactose malabsorption occurred in 144 of 277 (53%) MA and 21 of 142 (15%) AA. Analysis of dietary questionnaires revealed no differences between lactose absorbers and malabsorbers within each ethnic group in their consumption of protein, calories, riboflavin, vitamin A, or calcium. Vitamin A, calcium, and riboflavin intake was greater in AA than in MA subjects. Milk and dairy product consumption was the same in lactose absorbers and malabsorbers in both ethnic groups. Nearly 60% of MA malabsorbers and 24% of AA malabsorbers recognized experiencing symptoms after milk ingestion. Although group differences in milk consumption on the basis of lactose absorption status are not apparent, individual lactose malabsorbers may alter milk ingestion in response to lactose-induced symptoms. Lactose malabsorption occurs in over half of MA adults and may in some individuals present a clinically relevant problem.

Adolescent↗
PubMed1978

Lactose malabsorption among adult Indians of the Great Basin and American Southwest.

The prevalence of primary adult lactose malabsorption and the pattern of milk use were studied among 109 Indians from various tribes of the American Great Basin and Southwest. Included were 100 persons who reported being full-blooded Indians as well as three with Mexican admixture and 6 with some European ancestry. Lactose malabsorption was found in 92% of the full-blooded Indians but in only 50% Indians who acknowledged European admixture. These results agree with those of studies of native Americans done elsewhere which show very high prevalences of such lactose malabsorption among adults reported as fullblooded and lower prevalences among individuals with admitted European ancestors. The suggestion made is that in pre-Colombian times, before interbreeding with Europeans began on any scale, such lactose malabsorption may have been nearly universal among native American adults. Most of the Indians studied consumed abundant milk since childhood but were nevertheless predominantly malabsorbers as adults. This argues against the induction hypothesis advanced by some to explain the striking ethnic differences that occur around the world in primary adult lactose malabsorption.

Adult↗
PubMed1978

Poor predictability of lactose malabsorption from clinical symptoms for Chilean populations.

Clinical symptoms and lactose malabsorption may occur in persons intolerant to lactose. To predict malabsorption from symptoms and age, the authors used simple regression, multiple regression, and discrimant analysis on data from 436 Chileans. All individual r2 values from simple regression were less than 0.05. For the best stepwise multiple regression program, R2 was only 0.09, indicating that 91% of the variability in malabsorption was "unexplained" by the five best predictor variables. Because of so much unexplained variability, the authors could detect (using multiple regression) only 56 of 90 (62%) malabsorbers and only 14 of 38 (37%) absorbers. In conclusion, for their Chilean populations the authors poorly predicted malabsorption from symptoms.

Adolescent↗
PubMed1980

Comparative tolerance of adolescents of differing ethic backgrounds to lactose-containing and lactose-free dairy drinks. I. Initial experience with a double-blind procedure.

A lactose-free (LF) chocolate dairy drink and one containing 4.5% lactose (LC) were administered randomly in 240- and 480-ml volumes on 4 consecutive mornings under double-blind conditions to 110 healthy teenagers (14 to 19 years old) of differing ethnic backgrounds. Capillary blood glucose analysis after 50 g of oral lactose identified 67 of them as lactose malabsorbers. Neither absorbers nor malabsorbers reported significantly different gastrointestinal symptoms after 240 ml of LC compared with the same amount of LF. However, 17 absorbers and 21 malabsorbers reported symptoms inconsistent with intolerance due to lactose. These subjects had symptoms after LF only, after both LF and LC, or after 240 ml but not 480 ml of LC. After 480 ml of LC, 26 malabsorbers had symptoms, compared to 15 after 480 ml of LF. The prevalence of symptoms after 480 ml of LC, but not after 480 ml of LF, was 7% for absorbers, and 24% for malabsorbers. The results indicate that most of the individuals who reported gastrointestinal symptoms after ingestion of the two beverages did so for reasons other than their lactose content.

Adolescent↗