Lactose Sensitivity and Lactose Malabsorption: The 2 Faces of Lactose Intolerance

Nonallergic Diseases Associated With Foods

Clinicians are faced with evaluating real and alleged reactions to foods that may be allergic or nonallergic. Pathogenesis, diagnosis, and treatment of various non-IgE-mediated diseases are discussed in this review. These food-related conditions range from mild to severe. Referral for an allergy workup may be pursued despite the lack of IgE-mediated symptoms. Diagnostic testing is available for defined non-IgE-mediated food diseases that are either immunologic or nonimmunologic. These include celiac disease and related disorders, carbohydrate maldigestion, pancreatic insufficiency, and histamine intolerance. In contrast, there is a paucity of definitive studies to prove food intolerance diseases. There are no definitive diagnostic criteria or testing for nonceliac gluten sensitivity. Functional gastrointestinal disorders, such as irritable bowel syndrome, are better stratified diagnostically but still lack reliable testing. Both nonceliac gluten sensitivity and irritable bowel syndrome are linked to dietary triggers including fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Therefore, dietary alteration alone may be diagnostic and therapeutic when all other conditions are ruled out. These conditions are important considerations when evaluating a patient with history of a food reaction. There is little evidence that foods are causative in other ailments such as acne, migraines, and nasal congestion and hypersecretion.

Strategies for Producing Low FODMAPs Foodstuffs: Challenges and Perspectives

In recent years, there has been a growing interest in a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) as a promising therapeutic approach to reduce the symptoms associated with irritable bowel syndrome (IBS). Hence, the development of low FODMAPs products is an important challenge for the food industry, and among the various foodstuffs associated with the intake of FODMAPs, cereal-based products represent an issue. In fact, even if their content in FODMAPs is limited, their large use in diet can be an important factor in developing IBS symptoms. Several useful approaches have been developed to reduce the FODMAPs content in processed food products. Accurate ingredient selection, the use of enzymes or selected yeasts, and the use of fermentation steps carried out by specific lactic bacteria associated with the use of sourdough represent the technical approaches that have been investigated, alone or in combination, to reduce the FODMAPs content in cereal-based products. This review aims to give an overview of the technological and biotechnological strategies applicable to the formulation of low-FODMAPs products, specifically formulated for consumers affected by IBS. In particular, bread has been the foodstuff mainly investigated throughout the years, but information on other raw or processed products has also been reported. Furthermore, taking into account the required holistic approach for IBS symptoms management, in this review, the use of bioactive compounds that have a positive impact on reducing IBS symptoms as added ingredients in low-FODMAPs products is also discussed.

The use of probiotics and prebiotics can enable the ingestion of dairy products by lactose intolerant individuals

OBJECTIVE

To investigate, through a systematic review, the efficiency of the clinical application of probiotic and prebiotic supplements in reducing the symptoms of lactose intolerance (LI).

METHODS

This systematic review was conducted without limits for publication time and followed the PRISMA 2020 guidelines. The study was registered at the PROSPERO platform (CRD42022295691). The inclusion criteria were: studies addressing the issue of LI associated with the use of probiotics and prebiotics of any nature; studies performed with adults; randomized, placebo-controlled trials; and open access scientific articles, theses, or dissertations. The studies were retrieved from the following databases: SciELO, PubMed, LILACS, ScienceDirect, and gray literature, with no restrictions imposed regarding the years of publication of the investigations. To document the risk of bias, the RoB 2.0 tool was adopted, and to assess the certainty of the evidence, the GRADE tool was used.

RESULTS

A total of 830 studies were found; however, after applying the inclusion and exclusion criteria, only five studies remained. Two studies used the prebiotic GOS (RP-G28) for the treatment of LI and, together, included 462 subjects. The results of these studies showed improvement of LI symptoms during treatment phase and up to 30 days after cessation of GOS use (RP-G28). Three studies used the probiotics Bifidobacterium bifidum 900791, Limosilactobacillus reuteri DSM 17938 (Lactobacillus reuteri), and Lactobacillus acidophilus DDS-1 to evaluate their effects on LI and comprised 117 subjects. The results showed that B. bifidum 900791 did not significantly improve LI symptoms, and only Limosilactobacillus reuteri DSM 17938 showed significant improvement in symptoms and in reduction of expired hydrogen, while Lactobacillus acidophilus DDS-1 showed significant improvement for LI symptoms. The risk of bias for studies on probiotics suggested concerns in all studies, whereas the risk of bias was low in investigations evaluating prebiotics, with only one study classified as concerning. The certainty of evidence was high for the studies using the GOS (RP-G28) prebiotic and low for the probiotics. Pooling for meta-analysis could not be performed due to the lack of similar probiotic strains or lack of common outcomes.

CONCLUSION

In summary, the probiotics Limosilactobacillus reuteri DSM 17938 and Lactobacillus acidophilus DDS-1 showed the best results in the management of LI symptoms. The prebiotic GOS (RP-G28) appeared to be more efficient in reducing post-treatment symptoms. However, it is noteworthy that evidence regarding the use of probiotics for the management of LI is considerably scarce; as for prebiotics, data are limited. Studies adopting robust methodologies, especially regarding the complete reporting of data, are therefore warranted.

Circulatory amino acid responses to milk consumption in dairy and lactose intolerant individuals

Background/objectives

Self-reported digestive intolerance to dairy foods is common. As dairy can be an important source of dietary protein, this study aimed to identify whether milk protein digestion is compromised in individuals with digestive intolerance.

Subjects/methods

Adult women (n = 40) were enroled in this double-blinded, randomised cross-over trial, with digestive symptoms characterised using a lactose challenge and self-reported digestive symptom questionnaire. Participants were classified as either lactose intolerant (LI, n = 10), non-lactose dairy intolerant (NLDI, n = 20) or dairy tolerant (DT, n = 10). In a randomised sequence, participants consumed three different kinds of milk (750 ml); conventional milk (CON), a2 Milk™ (A2M), and lactose-free conventional milk (LF-CON). Circulatory plasma amino acid (AA) concentrations were measured at baseline and every 30 min until 3 h post-ingestion.

Results

In all participants across all milk types, plasma AA concentrations (AUC_0-180) increased after milk ingestion with no significant differences in responses observed between milk types or participants (P > 0.05), with the exception of the suppressed lysine response in the DT group following A2M ingestion, relative to the other two groups and milk types (P < 0.05).

Conclusion

Milk protein digestion, as determined by circulatory AAs, is largely unaffected by dairy- and lactose- intolerances.

Blinded Oral Challenges with Lactose and Placebo Accurately Diagnose Lactose Intolerance: A Real-Life Study

Lactose intolerance (LI) is characterized by diarrhea, abdominal pain, or bloating occurring after lactose consumption in patients with lactose malabsorption. The National Institute of Health (NIH) proposed a double-blind placebo testing to identify LI individuals correctly. However, until now, no study used this approach in a real-life setting. We aimed to assess double-blind placebo challenge accuracy in diagnosing LI in patients with self-reported symptoms of LI. 148 patients with self-reported LI were consecutively enrolled and blindly underwent hydrogen breath test (HBT) after 25 g lactose or 1 g glucose (placebo) load. One week later, the subjects were challenged with the alternative substrate. Each subject completed a validated questionnaire, including five symptoms (diarrhea, abdominal pain, vomiting, bowel sounds, and bloating) scored on a 10-cm visual analog scale. Home questionnaire (HQ) referred to symptoms associated with the consumption of dairy products at home, while lactose questionnaire (LQ) and placebo questionnaire (PQ) referred to symptoms perceived throughout the 4-h after the administration of the substrates, respectively. After lactose load, HBT was positive in 81 patients (55%), of whom 60 (74%) reported relevant symptoms at LQ (lactose malabsorbers, LM). After placebo challenge, 45 out of 60 with a positive lactose challenge did not complain of symptoms and therefore were diagnosed as lactose intolerant, according to NIH definition. The blinded oral challenges with lactose and placebo accurately diagnose LI and identify patients who will likely benefit from a lactose-free diet.