Genetic predisposition for adult lactose intolerance and relation to diet, bone density, and bone fractures

Galacto-oligosaccharides alleviate experimental lactose intolerance associated with gut microbiota in mice

Introduction

Galacto-oligosaccharides (GOS) are beneficial for alleviating lactose intolerance (LI). GOS have the ability to modify the composition of the intestinal microbiota. The development of intestinal diseases could be influenced by the composition of the gut microbiota. Nevertheless, it remains unclear whether gut microbiota exerts an effect when GOS alleviate LI, whether alterations in composition of the intestinal microbiota influence inflammatory response and lactose digestion.

Methods

We first investigated the effects of GOS on mice with established lactose intolerance. Next, we demonstrated that prophylactic supplementation with GOS also conferred similar benefits.

Results

The results showed that GOS enhanced anti-inflammatory, antioxidant, and gut barrier function. We observed that GOS mediated a change in the gut microbiome by increasing the abundance of Lactobacillus. GOS pre-supplementation reduced incident LI, enhanced anti-inflammatory, antioxidant, and gut barrier function, and markedly altered the gut microbiome by significantly enriching Bifidobacterium. Collectively, the alleviation of LI by GOS suggests an intimate involvement of probiotics.

Discussion

This study demonstrates that GOS ameliorated LI in a gut microbiota-dependent manner. Our findings provide novel evidence that GOS substitute for lactase and serve as a potential modulator of the gut microbiota for the prevention of LI.

Alternative biological functions of lactose: a narrative review

Lactose, commonly known as "milk sugar," offers various health benefits beyond its role as an energy source. As a precursor for essential molecules, lactose impacts calcium absorption, has low cariogenicity, affects satiety, enhances athletic performance, and potentially functions as a prebiotic for gut health. However, not all individuals can digest lactose, with a minority of the population exhibiting gastrointestinal symptoms after its consumption. The ability to digest lactose during adulthood is a genetically conferred trait known as lactase persistence, which is also likely affected by epigenetic alterations and other endogenous factors. In the present review, we highlight the multifaceted health effects of lactose, including its impact on calcium absorption, its low cariogenicity, its role in satiety control, its ability to enhance athletic performance, and its potential benefits as a prebiotic for gut health. Since these benefits are inherently dependent on lactose intake trends and the digestion capacity of populations, we also present the latest available information on the current trends in lactose consumption around the world. Overall, the gathered evidence suggests that moderate lactose consumption is recommended, as it can foster multiple lifelong health benefits.

Association Between Self-Reported Lactose Intolerance, Additional Environmental Factors, and Bone Mineral Density in Young Adults

OBJECTIVES

This study examines the relationship between self-reported lactose intolerance (LI), environmental factors, and their effects on bone mineral density (BMD) in young adults from Slovakia.

METHODS

We assessed 985 adults aged 18-30 years, with an average age of 21.61 ± 2.32 years, who were enrolled in this pilot cross-sectional study during the period 2019-2023. Individual environmental factors (smoking status, alcohol consumption, physical activity, milk and milk product intake, and calcium intake) and self-reported LI were assessed using a detailed questionnaire. BMD was analyzed using the QUS device (Sunlight MiniOmni), and total weight was measured with the InBody 770 bioimpedance analyzer.

RESULTS

Linear regression analysis showed the independent influence of age, total weight, and the presence of LI on the speed of sound in meters per second (SOS; m/s) and Z-score parameters in women (p < 0.05), whereas in men, age and smoking status were significant predictors of SOS (p < 0.05), and age and LI status significantly influenced the Z-score (p < 0.05).

CONCLUSIONS

In the present study of young Slovak adults, the presence of self-reported LI and smoking had a negative effect on BMD, resulting in lower BMD in the radius.

Amoli M, Fana SE, Dimai HP, Obermayer-Pietsch B, Luegger B, Rivadeneira F, Nabipour I, Larijani B, Khashayar P. Protocol for preliminary, multicenteric validation of "PoCOsteo device": A point of care tool for proteomic and genomic study of osteoporosis

One of the goals of the HORIZON 2020 project PoCOsteo was to develop a medical device, which would measure and/or quantify proteomic as well as genomic factors as present in whole blood samples collected through finger prick. After validating the tool in the clinical setting, the next step would be its clinical validation based on the existing guidelines. This article presents the protocol of a validation study to be carried out independently at two different centers (Division of Endocrinology and Diabetology at the Medical University of Graz as a clinic-based cohort, and the Endocrinology and Metabolism Research Institute at the Tehran University of Medical Sciences as a population-based cohort). It aims to assess the tool according to the Clinical & Laboratory Standards Institute guidelines, confirming if the proteomics and genomics measurements provided by the tool are accurate and reproducible compared with the existing state-of-the-art tests. This is the first time that such a detailed protocol for lab validation of a medical tool for proteomics and genomic measurement is designed based on the existing guidelines and thus could be used as a template for clinical validation of future point-of-care tools. Moreover, the multicentric cohort design will allow the study of a large number of diverse individuals, which will improve the validity and generalizability of the results for different settings.

Generic Platform for the Multiplexed Targeted Electrochemical Detection of Osteoporosis-Associated Single Nucleotide Polymorphisms Using Recombinase Polymerase Solid-Phase Primer Elongation and Ferrocene-Modified Nucleoside Triphosphates

Osteoporosis is a multifactorial disease influenced by genetic and environmental factors, which contributes to an increased risk of bone fracture, but early diagnosis of this disease cannot be achieved using current techniques. We describe a generic platform for the targeted electrochemical genotyping of SNPs identified by genome-wide association studies to be associated with a genetic predisposition to osteoporosis. The platform exploits isothermal solid-phase primer elongation with ferrocene-labeled nucleoside triphosphates. Thiolated reverse primers designed for each SNP were immobilized on individual gold electrodes of an array. These primers are designed to hybridize to the SNP site at their 3'OH terminal, and primer elongation occurs only where there is 100% complementarity, facilitating the identification and heterozygosity of each SNP under interrogation. The platform was applied to real blood samples, which were thermally lysed and directly used without the need for DNA extraction or purification. The results were validated using Taqman SNP genotyping assays and Sanger sequencing. The assay is complete in just 15 min with a total cost of 0.3€ per electrode. The platform is completely generic and has immense potential for deployment at the point of need in an automated device for targeted SNP genotyping with the only required end-user intervention being sample addition.

Association between Dairy Product intake and Risk of Osteoporotic Fractures in Postmenopausal Japanese Women: Secondary Analysis of 15-Year Follow-Up data from the Japanese Population-Based Osteoporosis (JPOS) Cohort Study

OBJECTIVES

Few prospective cohort studies have evaluated the relationship between dairy product intake frequency and risk of osteoporotic fractures in Asians. This study aimed to investigate the association between habitual dairy product intake and risk of osteoporotic fractures.

DESIGN

Secondary analysis of prospective cohort study.

SETTING

Five municipalities of Japan.

PARTICIPANTS

This study included 1,429 postmenopausal Japanese women (age ≥45 years at baseline).

MEASUREMENTS

Baseline milk-intake frequency was obtained using nurse-administered questionnaires. Intakes of yogurt and cheese, and estimated calcium intake, were assessed using a validated food frequency questionnaire. Osteoporotic fracture was defined as a clinical fracture diagnosed using radiography. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

RESULTS

Over a median follow-up period of 15.1 years (interquartile range [IQR], 10.1-15.4 years; total, 18,118 person-years), 172 women sustained at least one osteoporotic fracture. The proportions of participants with milk intakes <1, 1, and ≥2 cups/d were 34.4%, 48.0%, and 17.6%, respectively. After adjustment for age, frequency of yogurt intake, frequency of cheese intake, body mass index, history of osteoporotic fractures, and frequency of natto intake, the HRs compared with that for milk intake <1 cup/d were 0.71 (95% CI: 0.51-0.98) and 0.57 (95% CI: 0.35-0.92) for 1 cup/d and ≥2 cups/d, respectively. After adjustment for bone mineral density, HR significance for milk intakes ≥2 cups/d remained significant. Yogurt and cheese intakes were not related to the risk of osteoporotic fractures.

CONCLUSION

High habitual milk intake, but not a habitual yogurt or cheese intake is associated with a decreased risk of osteoporotic fractures, independent of bone mineral density, in postmenopausal Japanese women.

Comparison of nutritional composition between plant-based drinks and cow's milk

The high decline in liquid milk consumption in Western countries has been compensated by the increased consumption of processed dairy products and the rapidly increasing number of new plant-based beverages constantly introduced in the market, advertised as milk substitutes and placed on shelves near milk products. To provide better understanding about the nutritional value of these drinks compared with cow's milk, 27 plant-based drinks of 8 different species and two milk samples were purchased from two big retailers in Switzerland, and their composition regarding protein, carbohydrate, fat, vitamin, and mineral contents and residue load [glyphosate, aminomethylphosphonic acid (AMPA), and arsenic] was analyzed quantitatively and qualitatively. Energy and nutrient intakes were calculated and compared with the dietary reference values for Germany, Austria and Switzerland (D-A-CH). In addition, the digestible indispensable amino acid score (DIAAS) was calculated to estimate the quality of the proteins. Milk contained more energy; fat; carbohydrate; vitamins C, B2, B12, and A; biotin; pantothenic acid; calcium; phosphorus; and iodine than most plant-based drinks. Soy drinks provided slightly more protein and markedly more vitamins B1 and B6, folic acid, and vitamins E and D2 (with supplemented vitamin D2) and K1, magnesium, manganese, iron, and copper than milk and the other plant-based drinks. However, with the exception of cow's milk and soy drinks, which had > 3% protein, most milk alternatives contained ≤ 1% protein; therefore, they cannot be considered good protein sources. In regard to protein quality, milk was outstanding compared with all plant-based drinks and exhibited higher calculated DIAASs. Our results show that the analyzed plant-based drinks are not real alternatives to milk in terms of nutrient composition, even if the actual fortification is taken into account. Improved fortification is still an issue and can be optimized using the most bioavailable and soluble derivatives. Complete replacement of milk with plant-based drinks without adjusting the overall diet can lead to deficiencies of certain important nutrients in the long term.

Nutrition in Patients with Lactose Malabsorption, Celiac Disease, and Related Disorders

Lactose malabsorption (LM), celiac disease (CD), non-celiac gluten sensitivity (NCGS), and irritable bowel syndrome (IBS) are conditions associated with food triggers, improvement after withdrawal, treatment with dietary restriction, and subsequent nutritional detriments. LM occurs when there is incomplete hydrolysis of lactose due to lactase deficiency and frequently produces abdominal symptoms; therefore, it can cause lactose intolerance (LI). A lactose-restricted diet is frequently recommended, although it can potentially lead to nutrient deficiencies. Furthermore, lactose is an essential component of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) and is subsequently associated with intolerance to these compounds, especially in IBS. LM commonly presents in CD. Nutritional deficits are common in CD and can continue even on a gluten-free diet (GFD). Conditions triggered by gluten are known as gluten-related disorders (GRDs), including CD, wheat allergy, and NCGS. IBS can also be associated with a gluten sensitivity. A GFD is the treatment for CD, GRDs, and gluten sensitive IBS, although compliance with this restricted diet can be difficult. Strict dietary therapies can have a negative effect on quality of life. This review aims to provide an overview of the difficult nutritional elements of these disorders, which are critical for medical providers to recognize when managing these patients.

Lactose intolerance: An update on its pathogenesis, diagnosis, and treatment

Lactose intolerance has a high prevalence worldwide, ranging between 57% and 65%. It is caused by a reduction or loss of the activity of the intestinal enzyme lactase-phlorizin hydrolase, responsible for the digestion of lactose. This alteration determines an increased osmotic load in the small intestine and the fermentation of lactose by the bacterial flora, which leads to a high production of short-chain fatty acids and gas. This is followed by the onset of abdominal pain, diarrhea, and flatulence. In addition to these problems, it was found that subjects with lactose intolerance have an increased risk of developing various extra-intestinal diseases, including cancers. The diagnosis is essential to undertake an adequate treatment and, for this purpose, different methods have been tested. These include genetic test, hydrogen breath test (HBT), quick lactase test, and lactose tolerance test. HBT is the most used method because it is non-invasive, inexpensive, and highly sensitive and specific, as well as easy to perform. In clinical practice, the other methods are mainly used as HBT integration tests. There are also many therapeutic options. An appropriate intervention concerns the dietetic style, such as the consumption of lactose-free foods, but with nutritional characteristics comparable to dairy products. Other valid choices are represented by the use of exogenous enzymes, probiotics, prebiotics, the selection of milk containing specific types of beta-caseins. This review is intended to illustrate the diagnostic methods currently available and the possible therapeutic options for lactose intolerance.

Development of Personalized Nutrition: Applications in Lactose Intolerance Diagnosis and Management

Recent discoveries in the “omics” field and the growing focus on preventive health have opened new avenues for personalized nutrition (PN), which is becoming an important theme in the strategic plans of organizations that are active in healthcare, food, and nutrition research. PN holds great potential for individual health optimization, disease management, public health interventions, and product innovation. However, there are still multiple challenges to overcome before PN can be truly embraced by the public and healthcare stakeholders. The diagnosis and management of lactose intolerance (LI), a common condition with a strong inter-individual component, is explored as an interesting example for the potential role of these technologies and the challenges of PN. From the development of genetic and metabolomic LI diagnostic tests that can be carried out in the home, to advances in the understanding of LI pathology and individualized treatment optimization, PN in LI care has shown substantial progress. However, there are still many research gaps to address, including the understanding of epigenetic regulation of lactase expression and how lactose is metabolized by the gut microbiota, in order to achieve better LI detection and effective therapeutic interventions to reverse the potential health consequences of LI.

Association of LCT -13910C>T polymorphism and hip fracture in a cohort of older adult population from Northern Spain

Hip fracture is a common health problem very frequent in the older adult population and is associated with significant morbidity, mortality, and societal costs. There are several factors that increase the risk of suffering a hip fracture, however, the effect of genetic lactase non-persistence is not clear-cut yet. For this reason, we investigated if the LCT -13910C>T polymorphism is a potential risk factor for osteoporotic hip fractures in older adult people from the Northern Spain population. A total of 740 individuals were included in this study. Of them, 364 belonged to the group of patients whit osteoporotic hip fracture while the control group consisted of 376 individuals without hip fracture. The genotypes for the LCT -13910C>T polymorphism were analyzed by using polymerase chain reaction and high resolution melting. The prevalence of the CC genotype, which is related to lactase non-persistence, did not differ significantly in both groups. Likewise, no differences were observed between groups when they were compared with regard to the C or the T allele, or when they were analyzed considering gender. Additionally, our results were compared with those obtained in a control group of 207 nonagenarian individuals originally from Northern Spain and no differences were observed. In conclusion, no significant association was observed between the LCT -13910C>T polymorphism and the risk for suffering hip fracture in the older adult population of Northern Spain.

Lactose intolerance in patients with inflammatory bowel diseases and dietary management in prevention of osteoporosis

Lactose intolerance affects 33% to 75% of the world population and may be associated with various genetic factors. Lactose in the diet can be found in milk and dairy products, which simultaneously constitute the primary sources of calcium. Gut microbiota also influences lactose tolerance. Patients with lactose intolerance often stop consuming milk and dairy products, which may lead to calcium and vitamin deficiency and osteoporosis. Insufficient production of lactase also occurs in patients with diseases of the gastrointestinal tract, such as inflammatory bowel diseases. Moreover, Crohn's disease and ulcerative colitis are risk factors for osteoporosis, and the intake of the proper amount of calcium is an essential element in preventing the decrease of bone mineral density. Diet may prevent the development of osteoporosis, thus, educating patients regarding proper diet should constitute a part of the treatment and prevention process. Patients should consume low-lactose, or lactose-free milk and bacterially fermented dairy products. Additionally, plant milk supplemented by calcium and vitamin D, mineral water with calcium, and certain vegetables also may be good sources of calcium.

Clinical Utility of LCT Genotyping in Children with Suspected Functional Gastrointestinal Disorder

Genetic testing is a good predictor of lactase persistence (LP) in specific populations but its clinical utility in children is less clear. We assessed the role of lactose malabsorption in functional gastrointestinal disorders (FGID) in children and the correlation between the lactase non-persistence (LNP) genotype and phenotype, based on exhaled hydrogen and gastrointestinal symptoms, during a hydrogen breath test (HBT). We also evaluate dairy consumption in this sample. We conducted a 10-year cross-sectional study in a cohort of 493 children with suspected FGID defined by Roma IV criteria. Distribution of the C/T-13910 genotype was as follows: CC, 46.0%; TT, 14.4% (LP allele frequency, 34.1%). The phenotype frequencies of lactose malabsorption and intolerance were 36.3% and 41.5%, respectively. We observed a strong correlation between genotype and both lactose malabsorption (Cramér’s V, 0.28) and intolerance (Cramér’s V, 0.54). The frequency of the LNP genotype (p = 0.002) and of malabsorption and intolerance increased with age (p = 0.001 and 0.002, respectively). In 61% of children, evaluated dairy consumption was less than recommended. No association was observed between dairy intake and diagnosis. In conclusion, we found a significant correlation between genotype and phenotype, greater in older children, suggesting that the clinical value of genetic testing increases with age.

The Role of Milk Components, Pro-, Pre-, and Synbiotic Foods in Calcium Absorption and Bone Health Maintenance

Increasing peak bone mass during adolescence and reducing bone loss in later life are two approaches to reduce the risk of osteoporosis with aging. Osteoporosis affects a large proportion of the elderly population worldwide and the incidence is increasing. Milk consumption is an accepted strategy in building peak bone mass and therefore may reduce the risk of osteoporosis. In childhood calcium, phosphorous, and growth factors are the important components to support bone growth but in adults the positive influence on bone density/maintenance may also be due to other bioactive proteins/peptides or lipids in milk acting directly in the gastrointestinal tract (GIT). Lactose has been known to increase calcium absorption; galactooligosaccharides (GOS) are derived from lactose and are non-digestible oligosaccharides. They have been shown to improve mineral balance and bone properties as well as causing increases in bifidobacteria in the gut, therefore a prebiotic effect. Supplementation with fortified milk and dairy products with added prebiotics, increased both calcium and magnesium absorption and caused some modulation of gut microbiota in animals and humans. Fermented milk is now also recognized to contain highly active components such as vitamins, peptides, oligosaccharides, and organic acids. In this review, the role of milk and milk components in improving calcium absorption and thereby supporting bone health is discussed. In addition, some reference is made to the significance of combining the inherent beneficial components from milk with fortificants/nutrients that will support bone health through adulthood. Novel data suggesting differences in diversity of the microbiota between healthy and osteoporotic women are provided.

Adult lactose intolerance, calcium intake, bone metabolism and bone density in German-Turkish immigrants

INTRODUCTION

Adult lactose intolerance (ALI) significantly alters calcium intake and absorption, and thus may promote osteoporosis. ALI is a recessive condition with a geographical north-south gradient characterised by decreased levels of intestinal lactase. PCR-based genotyping of lactase (LCT) gene polymorphisms is a safe and easy way to diagnose ALI and may complement diagnostic procedures to identify individuals at risk for reduced calcium intake and subsequently osteoporosis due to lactose malabsorption. Therefore, we investigated the frequency of ALI and its influence on calcium intake, markers of bone metabolism and bone mineral density (BMD) in a cohort of Turkish immigrants living in Germany.

MATERIALS AND METHODS

We investigated single nucleotide polymorphisms of the LCT gene, calcium intake, markers of bone metabolism and BMD in 183 Turkish immigrants.

RESULTS

ALI was diagnosed in 154 out of 183 (81%) probands. ALI was significantly associated with self-reported lactose intolerance (p < 0.001) and dislike for dairy products (p < 0.01). Osteopenia was diagnosed in 59 out of 183 (32%) and osteoporosis in 15 out of 183 (8%) probands. Probands with reduced BMD had ALI in 86%. All probands had a decreased calcium intake [mg/week]. There was no significant association between ALI, calcium intake, markers of bone metabolism or BMD.

CONCLUSION

Turkish immigrants mostly have ALI and overall show a reduced calcium intake per week. However, ALI did not significantly influence calcium intake, markers of bone metabolism or BMD in this cohort. Therefore, ALI in Turkish immigrants does not seem to be a risk factor for osteoporosis.

The Eurasian lactase persistence variant LCT-13910 C/T is associated with vitamin D levels in individuals living at high latitude, more so than exposure to sunlight

Rapid selection of a genetic variant that confers continuous life-long lactase production in Europeans (LCT-13910 C/T) has been attributed to the advantages of acquiring nutrients from consuming milk without the disadvantages of lactose malabsorption. Individuals with this genetic lactase persistence (LP) variant generally consume more milk and have been shown to have higher levels of serum vitamin D. Vitamin D is the principal regulator of Ca absorption and its synthesis in skin is dependent on UVB exposure. The primary aim of the present study was to compare serum vitamin D concentrations with LP variant and to control for UVB exposure. Data from over 100 000 individuals living in Norway, a country with low UVB exposure, was retrospectively retrieved for comparison of genetic LP variant, serum 25-hydroxyvitamin D (25(OH)D) concentration and the time of year when serum samples were taken. For comparison, a similar analysis was performed with a natural dairy micronutrient, namely vitamin B₁₂. It was found that individuals with the genetic LP variant had considerably higher levels of serum 25(OH)D (P < 2 × 10^-16, Cohen's d = 0·73) but lower levels of vitamin B₁₂ (P < 2 × 10^-16, Cohen's d = 0·11), compared with genetic lactase non-persistent individuals, even when controlled for seasonality, age and sex. The difference in serum 25(OH)D levels did not diminish in summer months, showing the role of vitamin D in LP variant selection in areas of low UVB irradiation. LP variant selection advantage through acquiring another dairy micronutrient, vitamin B₁₂, was not observed.

The Association and Interaction of Aldehyde Dehydrogenase 2 Polymorphisms with Food Group Intake and Probability of Having Non-Alcoholic Fatty Liver Disease

PURPOSE

This study investigated the association between the aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism, food group intake, and the probability of having non-alcoholic fatty liver disease (NAFLD) in a Chinese population.

PATIENTS AND METHODS

A total of 3506 adults were enrolled in this study, and all underwent physical examinations and genotyping of polymorphisms with polymerase chain reaction. Participants filled out a dietary questionnaire that was used to assess the frequency and quantity of food consumption.

RESULTS

We found that milk groups were associated with a lower probability of developing NAFLD. On the contrary, meat and salted and smoked foods were associated with a higher probability of NAFLD. However, the influences of salted and smoked foods and fresh fruit and vegetables on NAFLD were obviously different in the two genotype groups. Salted and smoked foods intake was a factor associated with a higher probability of having NAFLD or nonalcoholic steatohepatitis (NASH) in the A genotype group, but there was no effect in the G genotype group. Moreover, eating salted and smoked foods several times per week was associated with a higher probability of having NAFLD than seldom consuming them. Consumption of fresh fruit and vegetables was not a factor influencing the probability of having NAFLD in the A genotype group, and there was no effect in the G genotype group. Further analysis of the interaction indicated that the GA +AA genotype showed an interaction with fresh fruit and vegetables and salted and smoked foods. Moreover, it was not obvious that meat intake increased the probability of having NAFLD or NASH among different genotypes.

CONCLUSION

Our results indicate that ALDH2 rs671 GA and AA genotypes are factors associated with increased probability of NAFLD among Chinese subjects. This could stimulate the development of novel approaches for preventing NAFLD.

Lactose Intolerance and Bone Health: The Challenge of Ensuring Adequate Calcium Intake

Calcium is an important nutrient with impact upon many biological systems, most notably bone. Ensuring adequate calcium intake throughout the lifespan is essential to building and maintaining bone. Lactose intolerance may predispose individuals to low calcium intake as the number of lactose-free, calcium-rich food sources is limited. In this review, we summarize data from human and animal studies on the influence of lactose and lactase deficiency on calcium absorption and bone health. Based on the available evidence, neither dietary lactose nor lactase deficiency have a significant impact on calcium absorption in adult humans. However, lactose intolerance may lead to reduced bone density and fragility fractures when accompanied by decreased intake or avoidance of dairy. Recently published human trials and meta-analyses suggest a weak but significant association between dairy consumption and bone health, particularly in children. Given the availability of simple dietary approaches to building lactose tolerance and the nutritional deficiencies associated with dairy avoidance, multiple public health organizations recommend that all individuals—including those that are lactose intolerant—consume three servings of dairy per day to ensure adequate nutrient intakes and optimal bone health.

Lactose Intolerance, Dairy Avoidance, and Treatment Options

Lactose intolerance refers to symptoms related to the consumption of lactose-containing dairy foods, which are the most common source for this disaccharide. While four causes are described, the most common is the genetically-determined adult onset lactose maldigestion due to loss of intestinal lactase governed by control of the gene by a 14,000 kb promoter region on chromosome 2. Gastrointestinal symptoms from lactose have expanded to include systemic effects and have also been confounded by other food intolerances or functional gastrointestinal disorders. Partly because lactose maldigestion is often interpreted as lactose intolerance (symptoms), focus of therapy for these symptoms starts with lactose restriction. However, withholding of dairy foods completely is not appropriate due to a more favorable impact on health. Industrial efforts to substitute with plant-based products is not completely successful at this time. This narrative article reviews the complexities of the perception of lactose intolerance, its epidemiology, and pathogenesis. Treatments are discussed, including the inappropriateness of dairy avoidance. In conjunction, effects of dairy products on 19 common diseases are reviewed. Different methods of treatment, lactose-reduced products, plant-based dairy substitutes, adaptation, prebiotics, exogenous lactase, probiotics, and some other dietary interventions are further discussed.

Does primary lactase deficiency reduce bone mineral density in postmenopausal women? A systematic review and meta-analysis

Postmenopausal osteoporosis is a significant cause of morbidity and mortality. The role of primary lactase deficiency (PLD) in its development is not clear. This meta-analysis showed that PLD is a risk factor for osteoporosis in postmenopausal women. These women need special attention in terms of screening for osteoporosis and its prevention.

INTRODUCTION

Postmenopausal osteoporosis is an important predictor of bone fractures. The purpose of the study was to conduct a systematic review and meta-analysis of association of PLD and bone mineral density (BMD) in postmenopausal women.

METHODS

The electronic databases PubMed, Scopus, and Web of Science were searched over the course of July 2017 for any date of publication without language limitation. Studies were included in the meta-analysis if the diagnosis of PLD was made by genetic testing or H-2 breath tests and the diagnosis of osteoporosis was made by a modern reliable method for BMD measurement. Two investigators conducted a comprehensive, independent review of all the papers. Five of the studies initially identified met the inclusion criteria. We used MOOSE guidelines for abstracting data and assessing data quality and validity. Meta-analysis was performed using the random effects model.

RESULTS

Five case-control studies with 2223 participants and 763 lactase-deficient cases fulfilled the inclusion criteria. Meta-analysis showed a significantly higher bone density Z-score in absorbers (mean difference 0.20, CI (0.14-0.27), P = 0.000), with no significant heterogeneity among the studies. Moreover, the Z-score in the vast majority of the measured sites (femoral head, femoral neck, lumbar spine, radius, and Ward's triangle) was significantly higher in absorbers. There was no significant overall difference in BMD in g/cm² between absorbers and non-absorbers, but a significantly higher BMD using g/cm² was observed in absorbers in the total hip site.

CONCLUSIONS

Postmenopausal women with PLD had lower Z-scores at most anatomic sites compared to healthy controls.

Bone Health in Women

Bone health is critical to overall health and quality of life. Although genetic factors play a key role in bone formation, there are several external factors that can be modified to preserve bone health. Diet, exercise, menstrual irregularities, medications, disease states, weight, and environmental factors can all affect fracture risk. Osteoporosis is characterized by decrease in bone mass and microarchitectural changes in the bone that increases fracture risk. Screening for osteoporosis may help facilitate treatment before fractures occur. Preventing fractures needs patient and physician understanding of bone health to improve and requires a team effort.

Lactase persistence, milk intake, hip fracture and bone mineral density: a study of 97 811 Danish individuals and a meta-analysis

BACKGROUND

Whether a causal relationship exists between milk intake and reduced risk of fractures is unclear.

OBJECTIVES

We tested the hypothesis that genetically determined milk intake reduces the risk of fractures and increases bone mineral density (BMD).

METHODS

We investigated the association between milk intake, LCT-13910 C/T (rs4988235), which is associated with lactase persistence (TT/TC) in Northern Europeans, and hip fractures in three Danish prospective studies (N = 97 811, age ≥20 years). We added meta-analyses of LCT-13910 and fractures and BMD from five published Northern European population studies.

RESULTS

In the Danish studies, the adjusted hazard ratio (HR) for hip fracture per one glass per week higher milk intake was 1.00 (95% CI: 0.99-1.01). The per T-allele milk intake was 0.58 (0.49-0.68) glasses per week, but HR was 1.01 (0.94-1.09) for hip fracture. In meta-analyses of Danish studies with published Northern European population studies, the random effects odds ratio for any fracture was 0.86 (0.61-1.21; I² = 73%) for TT vs. CC and 0.90 (0.68-1.21; I² = 63%) for TC vs. CC. The standardized mean difference in femoral neck BMD was 0.10 (0.02-0.18; I² = 0%) g cm^-2 for TT vs. CC and 0.06 (-0.04 to 0.17; I² = 17%) g cm^-2 for TC vs. CC. There were no differences in lumbar spine or total hip BMD comparing TT or TC with CC.

CONCLUSION

Genetically lifelong lactase persistence with high milk intake was not associated with hip fracture in Danish population-based cohorts. A meta-analysis combining Danish studies with published Northern European population studies also showed that lactase persistence was not associated with fracture risk. Genetic lactase persistence was associated with a higher femoral neck BMD, but not lumbar spine or total hip BMD.

Gene-Dairy Food Interactions and Health Outcomes: A Review of Nutrigenetic Studies

Each person differs from the next by an average of over 3 million genetic variations in their DNA. This genetic diversity is responsible for many of the interindividual differences in food preferences, nutritional needs, and dietary responses between humans. The field of nutrigenetics aims to utilize this type of genetic information in order to personalize diets for optimal health. One of the most well-studied genetic variants affecting human dietary patterns and health is the lactase persistence mutation, which enables an individual to digest milk sugar into adulthood. Lactase persistence is one of the most influential Mendelian factors affecting human dietary patterns to occur since the beginning of the Neolithic Revolution. However, the lactase persistence mutation is only one of many mutations that can influence the relationship between dairy intake and disease risk. The purpose of this review is to summarize the available nutrigenetic literature investigating the relationships between genetics, dairy intake, and health outcomes. Nonetheless, the understanding of an individual’s nutrigenetic responses is just one component of personalized nutrition. In addition to nutrigenetic responses, future studies should also take into account nutrigenomic responses (epigenomic, transcriptomic, proteomic, metabolomic), and phenotypic/characteristic traits (age, gender, activity level, disease status, etc.), as these factors all interact with diet to influence health.

Association of lactase persistence genotype with milk consumption, obesity and blood pressure: a Mendelian randomization study in the 1982 Pelotas (Brazil) Birth Cohort, with a systematic review and meta-analysis

Background: Milk intake has been associated with lower blood pressure (BP) in observational studies, and randomized controlled trials suggested that milk-derived tripeptides have BP-lowering effects. Milk intake has also been associated with body mass index (BMI). Nevertheless, it is unclear whether increasing milk consumption would reduce BP in the general population.

Methods: We investigated the association of milk intake with obesity and BP using genetically-defined lactase persistence (LP) based on the rs4988235 polymorphism in a Mendelian randomization design in the 1982 Pelotas (Southern Brazil) Birth Cohort. These results were combined with published reports identified through a systematic review using meta-analysis.

Results: In the 1982 Pelotas Birth Cohort, milk intake was 42 [95% confidence interval (CI): 18; 67) ml/day higher in LP individuals. In conventional observational analysis, each 1-dl/day increase in milk intake was associated with −0.26 (95% CI: −0.33; −0.19) kg/m² in BMI and −0.31 (95% CI: −0.46; −0.16) and -0.35 (95% CI: −0.46; −0.23) mmHg in systolic and diastolic BP, respectively. These results were not corroborated when analysing LP status, but confidence intervals were large. In random effects meta-analysis, LP individuals presented higher BMI [0.17 (95% CI: 0.07; 0.27) kg/m²] and higher odds of overweight-obesity [1.09 (95% CI: 1.02; 1.17)]. There were no reliable associations for BP.

Conclusions: Our study supports that LP is positively associated with obesity, suggesting that the negative association of milk intake with obesity is likely due to limitations of conventional observational studies. Our findings also do not support that increased milk intake leads to lower BP.

Assessment of vitamin D status and serum CrossLaps levels in adults with primary lactose malabsorption

BACKGROUND/OBJECTIVES

Primary adult-type lactose malabsorption (PALM) is a widespread inherited autosomal recessive condition, which is considered to be associated with osteoporosis. This prospective study aimed at assessing the 25-hydroxy-vitamin D (25(OH)D) status and serum CrossLaps levels in individuals with PALM and normal controls.

SUBJECTS/METHODS

All participants (n=210) underwent genotyping for the LCT C/T-13910 polymorphism, 25(OH)D and CrossLaps measurements and clinical examinations. In addition, the anthropometric data (that is, height, weight and body mass index) were determined.

RESULTS

Fifty-five individuals with PALM (that is, LCT C/C-13910 homozygotes) showed lower 25(OH)D (mean: 24.95±10.04 vs 28.59±9.56 ng/ml, P=0.018) and higher CrossLaps serum levels (mean: 0.46±0.31 vs 0.43±0.49 ng/ml, P=0.251) compared with 155 normal controls (that is, LCT C/T-13910 hetero- or T/T-13910 homozygotes). Anthropometric data were similar between PALM probands and controls.

CONCLUSIONS

Individuals with PALM were found to have lower 25(OH)D and higher CrossLaps serum levels compared with normal controls. In order to preserve life-long bone health, routine 25(OH)D and CrossLaps serum measurements should be performed in individuals with PALM.

Do patients with lactose intolerance exhibit more frequent comorbidities than patients without lactose intolerance? An analysis of routine data from German medical practices

Background

The increase in food intolerances poses a burgeoning problem in our society. Food intolerances not only lead to physical impairment of the individual patient but also result in a high socio-economic burden due to factors such as the treatment required as well as absenteeism. The present study aimed to explore whether lactose intolerant (LI) patients exhibit more frequent comorbidities than non-LI patients.

Methods

The study was conducted on a case-control basis and the results were determined using routine data analysis. Routine data from the IMS Disease Analyzer database were used for this purpose. A total of 6,758 data records were processed and analyzed.

Results

There were significant correlations between LI and the incidence of osteoporosis, changes in mental status, and the presence of additional food intolerances. Comparing 3,379 LI vs. 3,379 non-LI patients, 34.5% vs. 17.7% (P<0.0001) suffered from abdominal pain; 30.6% vs. 17.2% (P<0.0001) from gastrointestinal infections; and 20.9% vs. 16.0% (P=0.0053) from depression. Adjusted odds ratios (OR) were the highest for fructose intolerance (n=229 LI vs. n=7 non-LI; OR 31.06; P<0.0001), irritable bowel syndrome (n=247 LI vs. n=44 non-LI; OR 5.23; P<0.0001), and bloating (n=351 LI vs. n=68 non-LI; OR 4.94; P<0.0001).

Conclusion

The study confirms that LI should not be regarded as an isolated illness but considered a possible trigger for further diseases. Additional research is necessary to assert more precise statements.

Self-reported lactose intolerance in clinic patients with functional gastrointestinal symptoms: prevalence, risk factors, and impact on food choices

BACKGROUND

Many patients complain of abdominal symptoms with dairy products; however, clinical and psychosocial factors associated with self-reported lactose intolerance (SLI) have not been assessed in large studies. In particular, data are lacking from lactase deficient populations. This prospective cohort study assessed the prevalence of, and risk factors for, SLI in Chinese patients attending a gastroenterology clinic.

METHODS

Consecutive patients completed questionnaires to assess digestive health (Rome III), psychological state (HADS), life event stress (LES), food intake, and quality-of-life (SF-8). A representative sample completed genetic studies and hydrogen breath testing (HBT) at the clinically relevant dose of 20 g lactose.

KEY RESULTS

SLI was present in 411/910 (45%) clinic patients with functional abdominal symptoms. The genotype in all subjects was C/C-13910. A small number of novel SNPs in lactase promoter region were identified, including C/T-13908 which appeared to confer lactase persistence. Over half of the patients (54%) completed the 20 g lactose HBT with 58% (285/492) reporting typical symptoms. Positive and negative predictive values of SLI for abdominal symptoms during HBT were 60% and 44%, respectively. Psychological state and stress were not associated with SLI in clinic patients. SLI impacted on physical quality-of-life and was associated with reduced ingestion of dairy products, legumes, and dried fruit (p ≤ 0.05).

CONCLUSIONS & INFERENCES

In a lactase deficient population, approximately half of patients attending clinic with functional gastrointestinal symptoms reported intolerance to dairy products; however, SLI did not predict findings on 20 g lactose HBT. Independent of psychosocial factors, SLI impacted on quality-of-life and impacted on food choices with restrictions not limited to dairy products.

Survey to determine why people drink raw milk

Background:

Fragility fractures associated with osteoporosis extract a large financial and personal toll on society. Pharmaceutical or dietary calcium intake is needed to increase bone mineral density to prevent fragility fractures. Although dairy products are a good source of calcium, patients who are unable to digest lactose tend to avoid them and are put at a greater risk for fracture than the general population. Anecdotal reports suggest that lactose maldigesters, when consuming raw milk, have a dramatic reduction in symptoms relative to pasteurized milk. The mechanism of the reported reduction in symptoms, if true, is unknown. The purpose of the current study was to survey raw milk drinkers to ascertain their health-related motivations for consuming raw milk, especially as they relate to lactose maldigestion.

Methods:

An online survey regarding raw milk was completed by 153 of 1527 members of a raw milk–buying community.

Results:

The primary reason the respondents cited for drinking raw milk was that they believed it was more healthful; 30% reported some gastrointestinal discomfort when drinking pasteurized milk, yet almost all (99%) reported consuming raw milk without discomfort. Despite the reports of gastrointestinal discomfort, only 5% of respondents had been diagnosed as lactose intolerant by a medical professional, and only 1% had been diagnosed as lactose intolerant via the gold-standard hydrogen breath test.

Conclusions:

The primary motivation for drinking raw milk is its perceived health value, not its digestibility. Although raw milk appears to be more easily digested than pasteurized milk in our survey sample, the mechanism of digestibility remains unknown.

[Disorders of calcium metabolism]

The majority of clinical complaints derive from disorders of calcium metabolism and are associated with a wide variety of clinical symptoms caused by numerous diseases with entirely different types of pathophysiology. The prognosis varies from favorable to fatal depending on the pathophysiology of the underlying disorder of calcium metabolism; therefore, the diagnostic work-up aims to quickly identify the underlying disease causing the disturbance in calcium homeostasis. Every clinical situation with a diminished state of calcium absorption is treated with calcium and vitamin D in varying doses whereas every disorder with an increased calcium absorptive or resorptive state is treated with improved diuresis in addition to antiresorptive drugs, such as bisphosphonates. In many situations the management of a disturbed calcium balance requires an interdisciplinary approach in order to treat the underlying disease in parallel with correction of the calcium homeostasis.

Lactose malabsorption and intolerance: pathogenesis, diagnosis and treatment

Lactose malabsorption is a common condition caused by reduced expression or activity of lactase in the small intestine. In such patients, lactose intolerance is characterized by abdominal symptoms (e.g. nausea, bloating, and pain) after ingestion of dairy products. The genetic basis of lactose malabsorption is established and several tests for this condition are available, including genetic, endoscopic, and H2-breath tests. In contrast, lactose intolerance is less well understood. Recent studies show that the risk of symptoms after lactose ingestion depends on the dose of lactose, lactase expression, intestinal flora, and sensitivity of the gastrointestinal tract. Lactose intolerance has recently been defined as symptoms developing after ingestion of lactose which do not develop after placebo challenge in a person with lactose maldigestion. Such blinded testing might be especially important in those with functional gastrointestinal diseases in whom self-reported lactose intolerance is common. However, placebo-controlled testing is not part of current clinical practice. Updated protocols and high-quality outcome studies are needed. Treatment options of lactose intolerance include lactose-reduced diet and enzyme replacement. Documenting the response to multiple doses can guide rational dietary management; however, the clinical utility of this strategy has not been tested. This review summarizes the genetic basis, diagnosis, and treatment of lactose malabsorption and intolerance.

Study on influence of age, gender and genetic variants on lactose intolerance and its impact on milk intake in adult Asian Indians

BACKGROUND

Lactase non-persistence (LNP) has been associated with the CC genotype of -13910C > T and GG genotype of -22018G > A polymorphisms present upstream of the lactase gene. Lactose intolerance (LI) is caused when gastrointestinal symptoms develop in individuals with low lactase activity.

OBJECTIVE

To analyse association of LNP genotype and LI symptoms with milk intake and determine whether factors such as age, gender and genotype affect LI status.

SUBJECTS AND METHODS

Genetic analysis and lactose tolerance test (LTT) were performed on 205 healthy Indian adults. The pattern of milk consumption was recorded using a dietary questionnaire.

RESULTS

LI was strongly associated with -13910CC genotype (OR = 10.28, 95% CI = 2.32-45.55, p = 0.002). Females were found to be at a higher risk of developing LI (OR = 2.47, 95% CI = 1.33-4.59, p = 0.004). The association of the ≥50 years age group with LI was marginally significant (OR = 1.86, 95% CI = 0.995-3.47, p = 0.05). Frequency and quantity of milk intake were lower in subjects belonging to the LNP genotype and LI groups (p < 0.05).

CONCLUSIONS

Subject study suggests that gender and genotype may be associated with development of LI. Association of age with LI was marginal. The data also indicate that LNP genotype and LI may play a role in influencing milk intake in individuals.

NADPH oxidase 4 limits bone mass by promoting osteoclastogenesis

ROS are implicated in bone diseases. NADPH oxidase 4 (NOX4), a constitutively active enzymatic source of ROS, may contribute to the development of such disorders. Therefore, we studied the role of NOX4 in bone homeostasis. Nox4(-/-) mice displayed higher bone density and reduced numbers and markers of osteoclasts. Ex vivo, differentiation of monocytes into osteoclasts with RANKL and M-CSF induced Nox4 expression. Loss of NOX4 activity attenuated osteoclastogenesis, which was accompanied by impaired activation of RANKL-induced NFATc1 and c-JUN. In an in vivo model of murine ovariectomy–induced osteoporosis, pharmacological inhibition or acute genetic knockdown of Nox4 mitigated loss of trabecular bone. Human bone obtained from patients with increased osteoclast activity exhibited increased NOX4 expression. Moreover, a SNP of NOX4 was associated with elevated circulating markers of bone turnover and reduced bone density in women. Thus, NOX4 is involved in bone loss and represents a potential therapeutic target for the treatment of osteoporosis.

Ancient DNA analysis reveals high frequency of European lactase persistence allele (T-13910) in medieval central europe

Ruminant milk and dairy products are important food resources in many European, African, and Middle Eastern societies. These regions are also associated with derived genetic variants for lactase persistence. In mammals, lactase, the enzyme that hydrolyzes the milk sugar lactose, is normally down-regulated after weaning, but at least five human populations around the world have independently evolved mutations regulating the expression of the lactase-phlorizin-hydrolase gene. These mutations result in a dominant lactase persistence phenotype and continued lactase tolerance in adulthood. A single nucleotide polymorphism (SNP) at C/T-13910 is responsible for most lactase persistence in European populations, but when and where the T-13910 polymorphism originated and the evolutionary processes by which it rose to high frequency in Europe have been the subject of strong debate. A history of dairying is presumed to be a prerequisite, but archaeological evidence is lacking. In this study, DNA was extracted from the dentine of 36 individuals excavated at a medieval cemetery in Dalheim, Germany. Eighteen individuals were successfully genotyped for the C/T-13910 SNP by molecular cloning and sequencing, of which 13 (72%) exhibited a European lactase persistence genotype: 44% CT, 28% TT. Previous ancient DNA-based studies found that lactase persistence genotypes fall below detection levels in most regions of Neolithic Europe. Our research shows that by AD 1200, lactase persistence frequency had risen to over 70% in this community in western Central Europe. Given that lactase persistence genotype frequency in present-day Germany and Austria is estimated at 71–80%, our results suggest that genetic lactase persistence likely reached modern levels before the historic population declines associated with the Black Death, thus excluding plague-associated evolutionary forces in the rise of lactase persistence in this region. This new evidence sheds light on the dynamic evolutionary history of the European lactase persistence trait and its global cultural implications.

Improving lactose digestion and symptoms of lactose intolerance with a novel galacto-oligosaccharide (RP-G28): a randomized, double-blind clinical trial

Background

Lactose intolerance (LI) is a common medical problem with limited treatment options. The primary symptoms are abdominal pain, diarrhea, bloating, flatulence, and cramping. Limiting dairy foods to reduce symptoms contributes to low calcium intake and the risk for chronic disease. Adaptation of the colon bacteria to effectively metabolize lactose is a novel and potentially useful approach to improve lactose digestion and tolerance. RP-G28 is novel galacto-oligosaccharide (GOS) being investigated to improve lactose digestion and the symptoms of lactose intolerance in affected patients.

Methods

A randomized, double-blind, parallel group, placebo-controlled study was conducted at 2 sites in the United States. RP-G28 or placebo was administered to 85 patients with LI for 35 days. Post-treatment, subjects reintroduced dairy into their daily diets and were followed for 30 additional days to evaluate lactose digestion as measured by hydrogen production and symptom improvements via a patient-reported symptom assessment instrument.

Results

Lactose digestion and symptoms of LI trended toward improvement on RP-G28 at the end of treatment and 30 days post-treatment. A reduction in abdominal pain was also demonstrated in the study results. Fifty percent of RP-G28 subjects with abdominal pain at baseline reported no abdominal pain at the end of treatment and 30 days post treatment (p = 0.0190). RP-G28 subjects were also six times more likely to claim lactose tolerance post-treatment once dairy foods had been re-introduced into their diets (p = 0.0389).

Conclusions

Efficacy trends and favorable safety/tolerability findings suggest that RP-G28 appears to be a potentially useful approach for improving lactose digestion and LI symptoms. The concurrent reduction in abdominal pain and improved overall tolerance could be a meaningful benefit to lactose intolerant individuals.

Study registration

ClinicalTrials.gov NCT01113619.

Adult-type hypolactasia and calcium intake in polycystic ovary syndrome

OBJECTIVE

Adult-type hypolactasia (ATH) is related to lower calcium and milk intake, which might be associated with obesity and metabolic disturbances. Women with polycystic ovary syndrome (PCOS) frequently suffer from metabolic disturbances including central obesity. We aimed to examine the association of ATH and calcium intake with anthropometric, metabolic and endocrine parameters in a cohort of PCOS and control women.

DESIGN

Metabolic, endocrine and anthropometric measurements and oral glucose tolerance tests were performed in 504 PCOS and 366 control women. Genotyping of ATH, defined by the -13910 variant of the MCM6 gene, was performed. Calcium intake was assessed by questionnaires.

RESULTS

Adult-type hypolactasia was more prevalent in PCOS women (29·8%) than in controls (23·5%) (P = 0·040). PCOS women with ATH had higher waist-to-hip ratio (WHR) (0·80 [0·75-0·88] vs 0·78 [0·73-0·85], P = 0·046), glucose 2 h (5·28 [4·57-6·33] mmol/l vs 5·67 [4·68-6·78] mmol/l, P = 0·037), HbA1c (5·2 [5·0-5·4]%vs 5·1 [5·0-5·3]%, P = 0·009), parathyroid hormone (3·72(2·91-4·86] pmol/l vs 3·61 [2·94-4·63] pmol/l, P = 0·030) and Ferriman-Gallwey-Scores (FG Scores) (7 [3-12] vs 4 [1-9], P = 0·002) and lower 25(OH)D levels (54·4 [35·2-80·6] nmol/l vs 68·4 [49·7-89·4] nmol/l, P < 0·001) than PCOS women without ATH. The association of 25(OH)D and FG-Scores with ATH remained significant in age-, BMI- and WHR-adjusted analyses. PCOS women within the highest quartile of calcium intake had significantly lower testosterone (P = 0·023) and androstenedione (P = 0·032) and significantly higher high-density lipoprotein (HDL) levels (P = 0·035) than PCOS women with lower calcium intake.

CONCLUSION

Our results indicate an association of ATH with PCOS susceptibility. Moreover, ATH might influence WHR, HbA1c and FG-Scores as well as 25(OH)D levels. Higher calcium intake was associated with lower androgens and higher HDL levels.

Osteoporosis in children and young adults: a late effect after chemotherapy for bone sarcoma

BACKGROUND

Premature bone loss after childhood chemotherapy may be underestimated in patients with bone sarcoma. Methotrexate (MTX), a standard agent in osteosarcoma protocols, reportedly reduces bone mineral density (BMD). The literature, however, has reported cases of BMD reduction in patients with Ewing's sarcoma treated without MTX. Thus, it is unclear whether osteoporosis after chemotherapy relates to MTX or to other factors.

QUESTIONS/PURPOSES

We therefore asked whether (1) young patients with a bone sarcoma had BMD reduction, (2) patients treated with MTX had lower BMD, and (3) other factors (eg, lactose intolerance or vitamin D deficiency) posed additional risks for low BMD.

METHODS

We retrospectively reviewed 43 patients with malignancies who had dual-energy x-ray absorptiometry (DEXA) (lumbar, femoral); 18 with Ewing's sarcoma (mean age, 26 ± 8 years), and 25 with an osteosarcoma (mean age, 27 ± 10 years). The mean time since diagnosis was 8 ± 4 years in the group with Ewing's sarcoma and 7 ± 5 years in the group with osteosarcoma. At last followup we determined BMD (computing z-scores), fracture rate, and lifestyle, and performed serum analysis.

RESULTS

BMD reduction was present in 58% of patients (37% had a z-score between -1 and -2 SD, 21% had a z-score less than -2 SD) in at least one measured site. Seven of the 43 patients (16%) had nontrauma or tumor-associated fractures after chemotherapy. Findings were similar in the Ewing and osteosarcoma subgroups. We found vitamin D deficiency in 38 patients (88%) and borderline elevated bone metabolism; lactose intolerance was present in 16 patients (37%).

CONCLUSION

Doctors should be aware of the possibility of major bone loss after chemotherapy with a risk of pathologic fracture. Vitamin D deficiency, calcium malnutrition, and lactose intolerance may potentiate the negative effects of chemotherapy, and should be considered in long-term patient management.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Lactase non-persistent genotype influences milk consumption and gastrointestinal symptoms in Northern Russians

BACKGROUND

Milk is an important source of nutrients. The consumption of milk, however, may cause abdominal complaints in lactose intolerant individuals. The frequency of -13910C/C genotype is known to be high among Northern Russians, exceeding the prevalence in northern Europe. In our study we tested two hypotheses: 1) subjects with lactase non-persistent genotype (-13910C/C) have more gastrointestinal (GI) symptoms associated with milk 2) subjects with lactase non-persistence avoid using milk.

METHODS

In total, 518 students aged 17 to 26 years were randomly selected from different departments in the Northern State Medical University (NSMU) for genotyping the lactase activity-defining -13910C/T variant. All subjects filled in a questionnaire covering their personal data, self-reported GI symptoms and milk consumption habits.

RESULTS

Northern Russians consume very small amounts of milk daily. Among carriers of the lactase non-persistent (LNP) genotype there were 10 percentage units of milk-consumers fewer than among lactase-persistent (LP) subjects (p = 0.03). Complaints of GI disorders caused by milk were different between the genotypes (p = 0.02). Among all types of food analyzed only milk was associated with increased GI symptoms among subjects with the LNP genotype (OR = 1.95, CI 1.03-3.69)

CONCLUSIONS

Subjects with -13910C/C have more GI symptoms from milk. Subjects with lactase non-persistent genotype avoid using milk. In the case of increasing milk consumption symptoms may increase the need for medical consultation. It is thus important either for people themselves or for health care staff to be aware of lactase persistence/non-persistence.

Effects of resistance and aerobic exercise on physical function, bone mineral density, OPG and RANKL in older women

This study compared the effects of a resistance training protocol and a moderate-impact aerobic training protocol on bone mineral density (BMD), physical ability, serum osteoprotegerin (OPG), and receptor activator of nuclear factor kappa B ligand (RANKL) levels. Seventy-one older women were randomly assigned to resistance exercise (RE), aerobic exercise (AE) or a control group (CON). Both interventions were conducted 3 times per week for 8 months. Outcome measures included proximal femur BMD, muscle strength, balance, body composition, serum OPG, and RANKL levels. Potential confounding variables included dietary intake, accelerometer-based physical activity (PA), and molecularly defined lactase nonpersistence. After 8 months, only RE group exhibited increases in BMD at the trochanter (2.9%) and total hip (1.5%), and improved body composition. Both RE and AE groups improved balance. No significant changes were observed in OPG and RANKL levels, and OPG/RANKL ratio. Lactase nonpersistence was not associated with BMD changes. No group differences were observed in baseline values or change in dietary intakes and daily PA. Data suggest that 8 months of RE may be more effective than AE for inducing favourable changes in BMD and muscle strength, whilst both interventions demonstrate to protect against the functional balance control that is strongly related to fall risk.

Lactase gene c/t(-13910) polymorphism, calcium intake, and pQCT bone traits in Finnish adults

Genetic lactase nonpersistence may influence calcium intake and thereby bone health. We investigated in the Cardiovascular Risk in Young Finn Study whether young adults aged 31-46 years with the C/C(-13910) genotype are more susceptible to reduced bone phenotypes, low-energy fractures, and low calcium intake than subjects with other lactase genotypes. We also analyzed the gene-environment interactions on bone with calcium intake and physical activity. Peripheral quantitative computed tomography bone traits were measured from the distal and shaft sites of the radius and tibia. The total number of those subjects whose nondominant forearm was measured and the lactase genotype was defined was 1551. Information on diet, lifestyle factors, and fractures was collected with questionnaires. The mean intake of calcium was the lowest in men with the C/C(-13910) genotype (P = 0.001). Men with the T/T(-13910) genotype had ~3% higher trabecular density at the distal radius and distal tibia compared to other lactase genotypes (P = 0.03 and 0.02, respectively). In women, we found no evidence of the gene effect at the radius and tibia. No major interactions of the C/T(-13910) polymorphism with calcium intake or physical activity on bone phenotypes were found in either sex. In conclusion, the C/T(-13910) polymorphism was associated with trabecular density at the distal radius and tibia in men. These differences may be due to the differences in calcium intake between the lactase genotypes.

Multicomponent training program with weight-bearing exercises elicits favorable bone density, muscle strength, and balance adaptations in older women

Physical exercise is advised as a preventive and therapeutic strategy against aging-induced bone weakness. In this study we examined the effects of 8-month multicomponent training with weight-bearing exercises on different risk factors of falling, including muscle strength, balance, agility, and bone mineral density (BMD) in older women. Participants were randomly assigned to either an exercise-training group (ET, n = 30) or a control group (CON, n = 30). Twenty-seven subjects in the ET group and 22 in the CON group completed the study. Training was performed twice a week and was designed to load bones with intermittent and multidirectional compressive forces and to improve physical function. Outcome measures included lumbar spine and proximal femoral BMD (by dual X-ray absorptiometry), muscle strength, balance, handgrip strength, walking performance, fat mass, and anthropometric data. Potential confounding variables included dietary intake, accelerometer-based physical activity, and molecularly defined lactase nonpersistence. After 8 months, the ET group decreased percent fat mass and improved handgrip strength, postural sway, strength on knee flexion at 180°/s, and BMD at the femoral neck (+2.8%). Both groups decreased waist circumference and improved dynamic balance, chair stand performance, strength on knee extension for the right leg at 180°/s, and knee flexion for both legs at 60°/s. No associations were found between lactase nonpersistence and BMD changes. Data suggest that 8 months of moderate-impact weight-bearing and multicomponent exercises reduces the potential risk factors for falls and related fractures in older women.

An Asian viewpoint on the use of vitamin D and calcium in osteoporosis treatment: physician and patient attitudes and beliefs

BACKGROUND

Osteoporosis treatment guidelines recommend calcium and vitamin D supplementation for both prevention as well as treatment, however, compliance with these guidelines is often unsatisfactory. This study investigated the opinion of Asian physicians and Asian patients regarding vitamin D and calcium and patients' use of both.

METHODS

Physicians selected from Malaysia, Taiwan, Philippines, Korea and Singapore were asked to grade the significance of vitamin D and calcium in the treatment of osteoporosis and their patients' use of these supplements. In addition, physicians recruited seven eligible osteoporotic women to answer a questionnaire to determine their use of vitamin D and calcium, and their attitudes and beliefs regarding these supplements.

RESULTS

In total, 237 physicians and 1463 osteoporosis patients completed the questionnaire. The results revealed that 22% of physicians in Malaysia, 12% in Taiwan, 72% in the Philippines, 50% in Korea and 24% in Singapore rated the importance of vitamin D supplementation as being extremely important. For calcium, 27% of physicians in Malaysia, 30% in Taiwan, 80% in the Philippines, 50% in Korea and 38% in Singapore rated the importance as being extremely important. Forty-three percent of patients in Malaysia, 38% in Taiwan, 73% in the Philippines, 35% in Korea and 39% in Singapore rated the importance of vitamin D as being extremely important. For calcium, 69% of patients in Malaysia, 58% in Taiwan, 90% in the Philippines, 70% in Korea and 55% in Singapore rated the importance as being extremely important. In addition, results of the patient questionnaire revealed that only a very small number regularly took both supplements. In addition, the results indicated that, with the exception of patients from the Philippines, the majority of patients had no or infrequent discussion with their physician about vitamin D and calcium.

CONCLUSIONS

There is generally suboptimal appreciation by both physicians and patients of the importance of vitamin D and calcium for maintenance of bone health as reflected in the low number of patients who reported regularly taking these supplements. Recognition of this problem should translate to appropriate action to improve education for both physicians and patients, with a goal to increase use of these supplements among Asian patients with osteoporosis.

LCT-13910C>T polymorphism-associated lactose malabsorption and risk for colorectal cancer in Italy

BACKGROUND

The activity of epithelial lactase (LCT) associates with a polymorphism 13910 bp upstream the LCT-encoding gene (LCT-13910C>T). The relationship between LCT-13910C>T polymorphism and risk for colorectal cancer is unclear.

AIMS

We examined the relationship between the LCT-13910C>T polymorphism causing lactose intolerance and risk for colorectal cancer/polyps onset in the Italian population.

PATIENTS AND METHODS

793 subjects (306 with colorectal cancer, 176 with polyps and 311 controls) were genotyped for the LCT-13910C>T variant by TaqMan real time-PCR.

RESULTS

Lactose malabsorption linked to the CC genotype did not associate with an increased risk for either colorectal cancer (OR=1.041; 95% CI=0.751-1.442; p=0.868) or polyps (OR=0.927; 95% CI=0.630-1.363; p=0.769). There was no association with colorectal cancer/polyps site. 60% of the subjects overall bore the CC genotype.

CONCLUSION

In the Italian population the LCT-13910C>T polymorphism is not associated to the risk for colorectal cancer or polyps.

Can lactase persistence genotype be used to reassess the relationship between renal cell carcinoma and milk drinking? Potentials and problems in the application of Mendelian randomization

BACKGROUND

Increased risk of renal cell carcinoma (RCC) with milk consumption has been reported from observational studies. Whether this represents a causal association or is a result of confounding or bias is unclear. We assessed the potential for using genetic variation in lactase persistence as a tool for the study of this relationship.

METHODS

Using a large, hospital-based case-control study, we used observational, phenotypic, and genetic data to determine whether the MCM6 -13910 C/T(rs4988235) variant may be used as a nonconfounded and unbiased marker for milk consumption.

RESULTS

Consumption of milk during adulthood was associated with increased risk of RCC [odds ratio (OR), 1.35; 95% confidence interval (95% CI), 1.03-1.76; P=0.03]. Among controls, consumption of milk was associated with the lactase persistence genotype at rs4988235 (OR, 2.39; 95% CI, 1.81-3.15; P=6.9x10(-10)); however, the same genotype was not associated with RCC (OR, 1.01; 95% CI, 0.83-1.22; P=0.9). In controls, milk consumption was associated with confounding factors, including smoking and educational attainment, whereas genotypes at rs4988235 showed negligible association with confounding factors.

CONCLUSION

The absence of an association between the MCM6 genotype and RCC suggests that observational associations between milk consumption and RCC may be due to confounding or bias.

IMPACT

Although these data suggest that associations between milk consumption and RCC may be spurious, if the association between genotype and behavioral exposure is weak, then the power of this test may be low. The nature of intermediate risk factor instrumentation is an important consideration in the undertaking and interpretation of this type of causal analysis experiment.