13910C>T and 22018G>A LCT gene polymorphisms in diagnosing hypolactasia in children

Cow's Milk: A Benefit for Human Health? Omics Tools and Precision Nutrition for Lactose Intolerance Management

Cow's milk (CM) is a healthy food consumed worldwide by individuals of all ages. Unfortunately, "lactase-deficient" individuals cannot digest milk's main carbohydrate, lactose, depriving themselves of highly beneficial milk proteins like casein, lactoalbumin, and lactoglobulin due to lactose intolerance (LI), while other individuals develop allergies specifically against these proteins (CMPA). The management of these conditions differs, and an inappropriate diagnosis or treatment may have significant implications for the patients, especially if they are infants or very young children, resulting in unnecessary dietary restrictions or avoidable adverse reactions. Omics technologies play a pivotal role in elucidating the intricate interactions between nutrients and the human body, spanning from genetic factors to the microbiota profile and metabolites. This comprehensive approach enables the precise delineation and identification of distinct cohorts of individuals with specific dietary requirements, so that tailored nutrition strategies can be developed. This is what is called personalized nutrition or precision nutrition (PN), the area of nutrition that focuses on the effects of nutrients on the genome, proteome, and metabolome, promoting well-being and health, preventing diseases, reducing chronic disease incidence, and increasing life expectancy. Here, we report the opinion of the scientific community proposing to replace the "one size fits all" approach with tailor-made nutrition programs, designed by integrating nutrigenomic data together with clinical parameters and microbiota profiles, taking into account the individual lactose tolerance threshold and needs in terms of specific nutrients intake. This customized approach could help LI patients to improve their quality of life, overcoming depression or anxiety often resulting from the individual perception of this condition as different from a normal state.

Genetic Predisposition to Primary Lactose Intolerance Does Not Influence Dairy Intake and Health-Related Quality of Life in Romanian Children: A Hospital-Based Cross-Sectional Study

BACKGROUND

Primary lactose intolerance (PLI) is characterized by the inability to digest lactose. Homozygotes for the lactase gene polymorphisms (CC or GG) are considered to be genetically predisposed to PLI. Still, symptoms may only be present later in life. The evidence supporting a link between PLI, dairy intake, and quality of life (QoL) is limited in children.

AIM

This study investigates the link between LCT polymorphisms and suggestive symptoms and the influence of the genetic predisposition to PLI on dairy intake and QoL in Romanian children.

MATERIALS AND METHODS

We recruited consecutive children evaluated in our ambulatory clinic. We asked all participants to complete a visual-analog symptoms scale, a dairy intake, and a QoL questionnaire. We used strip genotyping to identify genetic predisposition to PLI.

RESULTS

51.7% of children had a CC genotype, and 34.5% also had a GG genotype. Most children reported no or mild symptoms. Dairy intake and QoL were similar across study groups.

CONCLUSIONS

Our study shows that genetic predisposition does not necessarily assume the presence of specific symptoms. Genetic predisposition to PLI did not lead to dairy avoidance, nor did it negatively influence our children's QoL.

A Comprehensive Look at the -13910 C>T LCT Gene Polymorphism as a Molecular Marker for Vitamin D and Calcium Levels in Young Adults in Central and Eastern Europe: A Preliminary Study

Intolerance to dairy products resulting from the abnormal digestion of milk sugar (lactose) is a common cause of human gastrointestinal disorders. The aim of this study was to show that the -13910 C>T LCT gene polymorphism, together with genotypes of selected VDR gene polymorphisms and diet and nutritional status parameters, can impact the prevalence of vitamin D and calcium deficiency in young adults. This study was conducted on a group of 63 people, which comprised 21 individuals with primary adult lactase deficiency, and a control group of 42 individuals with no hypolactasia. The LCT and VDR gene genotypes were assessed using PCR restriction fragment length polymorphism (PCR-RFLP) analysis. A validated HPLC method was used to determine serum concentrations of 25(OH)D₂ and 25(OH)D₃. Atomic absorption spectrometry was used to determine calcium levels. Their diets (self-reported 7-day estimated food record), estimated calcium intakes based on the ADOS-Ca questionnaire and basic anthropometric parameters were assessed. The CC genotype associated with hypolactasia was found in 33.3% of the subjects. The presence of the CC variant of the LCT gene polymorphism in the study group of young Polish adults was found to be associated with significantly lower milk (134.7 ± 66.7 g/d vs. 342.5 ± 176 g/d; p = 0.012) and dairy product consumption (78.50 ± 36.2 g/d vs. 216.3 ± 102 g/d; p = 0.008) compared with lactase persistence. At the same time, people with adult-type primary intolerance were found to have statistically significant lower serum levels of vitamin D and calcium (p < 0.05). There was a higher chance of vitamin D and calcium deficiency and a lower intake in the group exhibiting lactase non-persistence (OR > 1). The AA variant of the VDR gene's BsmI polymorphism present in people with hypolactasia may further contribute to an increased risk of vitamin D deficiency. Exclusion of lactose from the diet, combined with impaired vitamin D metabolism, may also lead to inhibited calcium absorption by the body. Further research should be carried out on a larger group of subjects to clarify the relationship between lactase activity and vitamin D and calcium levels in young adults.

Can Lactose Intolerance Be a Cause of Constipation? A Narrative Review

Lactose intolerance and constipation are common in children and impact everyday life, not only for patients but also their families. Both conditions can be comorbid with other diseases or form a part of their clinical presentation, but constipation is not usually associated with lactose intolerance. The typical symptoms of lactose intolerance include abdominal pain, bloating, flatus, diarrhoea, borborygmi, and less frequently nausea and vomiting. In approximately 30% of cases, constipation can be a symptom of lactose intolerance. Constipation is characterized by infrequent bowel movements, hard and/or large stools, painful defecation, and faecal incontinence, and is often accompanied by abdominal pain. This paper provides a narrative review on lactose intolerance, its epidemiology, pathogenesis, the correlation between lactose intolerance and constipation in children, and potential mechanisms of such association.

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.

Ileal Lactase Expression Associates with Lactase Persistence Genotypes

(1) Background: Lactose digestion depends on persistence genotypes (including rs4988235), the frequency of which exhibits broad geographical variability. However, little is known about the relationship between lactase (LCT) genotypes and intestinal expression of LCT. We aimed to investigate ileal expression of LCT depending on main genetic polymorphisms (rs4988235, rs3754689, rs3739022), age, sex, smoking status, body mass index (BMI), and the expression of other genes; (2) Methods: phenotype, array-based genotype, and ileal mucosal biopsy expression data were obtained from the CEDAR study; (3) Results: analyses included 196 healthy Europeans (53.6% women) aged 53.0 ± 13.6 years with a mean BMI of 25.6 ± 4.2 kg/m², of whom 17.4% were smoking. Ileal LCT expression was mostly independent of age, sex, BMI, or smoking. Rs4988235 homozygous minor allele (GG) associated with lower LCT expression (vs. AG p = 2.2 × 10⁻⁶, vs. AA p = 1.1 × 10⁻⁷). Homozygous major allele of rs3754689 (GG) was related to higher LCT expression (vs. AG p = 1.7 × 10⁻⁵, vs. AA p = 0.0074). Rs3754689 genotype did not modify LCT expression (GG vs. AG p = 0.051) in rs4988235-heterozygous subgroup. Interestingly, CD14, which is a marker of monocytes and macrophages, was the strongest negative transcriptomic correlate of LCT expression (r = −0.57, p_FDR = 1.1 × 10⁻¹⁴); (4) Conclusions: both rs4988235 and rs3754689 associated with ileal LCT expression, which did not seem related to age, sex, smoking, or BMI. The inverse correlation between LCT and CD14 expression in the ileum is striking and requires further investigation.