Genetically defined adult-type hypolactasia and self-reported lactose intolerance as risk factors of osteoporosis in Finnish postmenopausal women.
ABSTRACT To study the relationships of molecularly defined lactose malabsorption (LM) and self-reported lactose intolerance (LI) to bone mineral density (BMD) and fractures among Finnish postmenopausal women.
A cross-sectional study of two cohorts.
Helsinki University Central Hospital.
One cohort was population-based and comprised 453 women, aged 62-78 (mean 69) y. Another comprised 52 women, aged 69-85 (mean 75) y, with osteoporotic fractures and 59 control women, aged 69-83 (mean 74) y, without osteoporosis.
A single nucleotide polymorphism of the lactase (LCT) gene at chromosome 2q21-22 was studied. It shows complete association with intestinal disaccharidase activity, with the genotype CC(-13 910) meaning adult-type hypolactasia (primary LM) and the genotypes CT(-13 910) and TT(-13 910) lactose absorption. BMD of the heel was measured by dual-energy X-ray absorptiometry (DXA).
In the population-based cohort, 16.0% of women had self-reported LI but only 15.3% of them had the CC(-13 910) genotype. Calcium intake from dairy products (P = 0.10) and BMD, adjusted for age, weight, height, exercise, smoking, and estrogen use (P = 0.71) were similar for the genotypes. Women with self-reported LI had reduced calcium intake from dairy products (P < 0.0001) but they were more frequent users of calcium supplements than lactose-tolerants (P < 0.0001). Adjusted BMD was similar for lactose intolerant and tolerant women (P = 0.60). Of 104 women with previous fracture in the population-based cohort, 13.5% had the CC(-13 910) genotype, which did not differ from the prevalence of 19.3% among 347 women without fractures (P = 0.29). The frequency of the CC(-13 910) genotype (23.1%) for 52 women with established osteoporosis was similar as for 59 control women (15.3%) (P = 0.19).
Molecularly defined LM and self-reported LI are not risk factors for osteoporosis, if calcium intake from diet and/or supplements remains sufficient. Our study confirms the poor correlation between self-reported LI and LM established by different techniques.
SourceAvailable from: Ricardo Almon[Show abstract] [Hide abstract]
ABSTRACT: This study examines if lactase non-persistent (LNP) children and adolescents differ from those who are lactase persistent (LP) as regards milk avoidance and Ca intake. We also studied potential differences in anthropometric features related to obesity, and examined if milk avoidance is associated with lactase-persistence status. Additionally, we aimed to determine if heterozygous subjects showed an intermediary phenotype as regards Ca intake. Furthermore, we tested if LP and LNP influence vitamin D intake. The European Youth Heart Study is an ongoing international, multi-centre cohort study primarily designed to address CVD risk factors. Children (n 298, mean age 9·6 years) and adolescents (n 386, mean age 15·6 years) belonging to the Swedish part of the European Youth Heart Study were genotyped for the LCT-13910 C > T polymorphism. Mendelian randomisation was used. Milk avoidance was significantly more common in LNP adolescents (OR 3·2; 95% CI 1·5, 7·3). LP subjects had higher milk consumption (P < 0·001). Accordingly, energy consumption derived from milk and Ca intake was lower in LNP (P < 0·05 and P < 0·001, respectively). Heterozygous subjects did not show an intermediary phenotype concerning milk consumption. LP or LNP status did not affect vitamin D intake or anthropometric variables. LNP in children and adolescents is associated with reduced intake of milk and some milk-product-related nutritional components, in particular Ca. This reduced intake did not affect the studied anthropometric variables, indicators of body fat or estimated vitamin D intake. However, independently of genotype, age and sex, daily vitamin D intake was below the recommended intakes. Milk avoidance among adolescents but not children was associated with LNP.02/2013; 2(e26). DOI:10.1017/jns.2013.11
[Show abstract] [Hide abstract]
ABSTRACT: Introduction: A large portion of the world’s population undergoes a genetically programmed decrease in lactase synthesis and may experience symptoms of lactose intolerance (LI) after dairy consumption. Aim: The aim of the present study was to assess the effect of the same dose of lactose consumed by LI subjects in the form of different dairy products. Material and methods: Fifteen healthy young adults with LI were enrolled in the study. All subjects were symptomatic homozygotes –13910 C/C in the lactase promoter gene. The hydrogen-methane breath test was performed in each subject after a load of 400 ml of milk, kefir and yogurt. Clinical symptoms were assessed within the 12 h after each product consumption. Results: The excretion of gases was lower after ingestion of kefir and yogurt in comparison to milk. All examined subjects reported symptoms. After milk consumption, abdominal pain and intestinal rumbling were perceived as more severe. The number of stools was higher and their consistency was more liquid. Conclusions: Young adults with LI are not able to tolerate the typical dose of different dairy products as assessed by subjective and objective measures. The tolerance of kefir and yogurt is significantly better than that of milk.Przegląd Gastroenterologiczny 01/2011; 6(5):310-315. DOI:10.5114/pg.2011.25381 · 0.38 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Background and Study Aims: Lactase non-persistence (LNP), or primary hypolactasia, is a genetic condition that mediates lactose malabsorption and can cause lactose intolerance. Here we report the prevalence of lactose intolerance in a double-blind placebo study. Methods: The LCT C>T-13910 variant was genotyped by RT-PCR in 121 volunteers and lactose malabsorption was assessed using the hydrogen breath test (HBT) after consuming 25 g of lactose. Lactose intolerance was assessed by scoring symptoms (SS) using a standardized questionnaire following challenge with a lactose solution or saccharose placebo. Results: The LNP genotype was observed in 57% of the volunteers, among whom 87% were HBT(+). In the HBT(+) group the median SS was 9 and in the HBT(-) group the median SS was 3 (p < 0.001). No difference was observed in the SS when both groups were challenged with the placebo. The most common symptoms included audible bowel sounds, abdominal pain and meteorism. In the ROC curve analysis, an SS ≥6 demonstrated 72% sensitivity and 81% specificity for predicting a positive HBT. To estimate prevalence, lactose intolerance was defined as the presence of an SS ≥6 points after subtracting the placebo effect and 34% of the study population met this definition. Conclusions: The LNP genotype was present in more than half of subjects evaluated and the observed prevalence of lactose intolerance was 34%. © 2014 S. Karger AG, Basel.Digestion 07/2014; 90(1):18-26. DOI:10.1159/000363229 · 2.03 Impact Factor