The geographic hypothesis and lactose malabsorption. A weighing of the evidence

Soy, Rice and Oat Drinks: Investigating Chemical and Biological Safety in Plant-Based Milk Alternatives

During the last decades, plant-based milk has become very appreciated by consumers, becoming a staple ingredient, especially for alternative breakfasts. Milk contains lactose, which is a sugar hydrolysed by the lactase enzyme. Lactose intolerance and lactose malabsorption are very common food intolerances among individuals. However, a lot of consumers consider themselves as lactose intolerant on the basis of self-reported intolerance and start to avoid dairy products, ignoring that plant-based milk alternatives are not nutritionally comparable to animal milk, especially in terms of protein intake. The aim of this study is to grow folder knowledge of the security of plant-based drinks, helping competent authorities to issue a risk assessment and to apply national plans about consumer safety. Results show that proper sanitary practices, such as pasteurization, are necessary in plant-based milk alternatives as well as in dairy milk. Chemical analysis has highlighted that there are no pesticide risks for consumers.

The influence of Scandinavian presence on Greenlandic lactase persistence

BACKGROUND

The study aims to estimate the prevalence of lactase non-persistence (LNP) among Greenlandic Inuit and Scandinavians living in Nuuk and East Greenland. The C to T transition in LCT - 13910 (rs4988235) is an autosomal inherited variant that provides the ability to lifelong lactase production, necessary to digest milk. The transition is very common in North European populations. However, LNP has only been sparsely studied in Greenland and never in Eastern Greenland, and genotype data has not previously been reported.

METHODS

Whole blood samples were collected from 535 participants, and rs4988235 was typed using a PCR-based method. Ethnicity was defined by parents' place of birth. Results were compared between East and West Greenland and Inuit and Scandinavians using Pearson's Chi² test.

RESULTS

82.2% of the participants were Inuit, and 17.8% were of Scandinavian ancestry. Among Inuit, 88.5% had LNP compared to 7.5% among Scandinavians (p < 0.001). The prevalence of LNP in Inuit varied significantly between East and West Greenland (p < 0.001). In the capital, 67.6% of Inuit had LNP compared to 98.6% in Tasiilaq and 100% in the villages around Tasiilaq.

DISCUSSION

The difference in LNP between East and West Greenland and the Inuit and Scandinavian population found in our study suggests that the original Inuit population was lactose maldigesters. Our findings suggest that the -13910 T allele was introduced into the original Inuit population by the Danes.

White as milk: Biocentric bias in the framing of lactose intolerance and lactase persistence

The majority of the world population is lactose intolerant, as 65%-70% of people lose the enzymes to digest lactose after infancy. Yet, in the United States, where lactose intolerance is predicted to affect only 36% of people, this phenomenon is often framed as a deficiency as opposed to the norm. This is because the United States has a higher prevalence of people who are lactase persistent. Lactase persistence is a genetic trait most common among Europeans and some African, Middle Eastern and southern Asian groups with a history of animal domestication and milk consumption. In this study, we take the case of lactose intolerance to examine how popular media maintains biocentric biases. Analysing relevant articles published in The New York Times and Scientific American between 1971 and 2020, we document how ideas about milk, health and race evolve over time. Over this fifty-year period, writers shifted from framing lactose intolerance as racial difference to lactase persistence as evolutionary genetics. Yet, articles on the osteoporosis 'epidemic' and vitamin D deficiency worked to perpetuate lactose intolerance as a health concern and standardise the dairy-heavy American diet. Studying media portrayals of lactose intolerance and lactase persistence, we argue that popular discourses normalise biocentric biases through messages about eating behaviours and health.

Why and when was lactase persistence selected for? Insights from Central Asian herders and ancient DNA

The genetic adaptation of humans to the consumption of milk from dairying animals is one of the most emblematic cases of recent human evolution. While the phenotypic change under selection, lactase persistence (LP), is known, the evolutionary advantage conferred to persistent individuals remains obscure. One informative but underappreciated observation is that not all populations whose ancestors had access to milk genetically adapted to become lactase persistent. Indeed, Central Asian herders are mostly lactase nonpersistent, despite their significant dietary reliance on dairy products. Investigating the temporal dynamic of the -13.910:C>T Eurasian mutation associated with LP, we found that, after its emergence in Ukraine 5,960 before present (BP), the T allele spread between 4,000 BP and 3,500 BP throughout Eurasia, from Spain to Kazakhstan. The timing and geographical progression of the mutation coincides well with the migration of steppe populations across and outside of Europe. After 3,000 BP, the mutation strongly increased in frequency in Europe, but not in Asia. We propose that Central Asian herders have adapted to milk consumption culturally, by fermentation, and/or by colonic adaptation, rather than genetically. Given the possibility of a nongenetic adaptation to avoid intestinal symptoms when consuming dairy products, the puzzle then becomes this: why has LP been selected for at all?

Microencapsulation of Caramel Flavor and Properties of Ready-to-drink Milk Beverages Supplemented with Coffee Containing These Microcapsules

This study aimed to extend the retention of flavor in coffee-containing milk beverage by microencapsulation. The core material was caramel flavor, and the primary and secondary coating materials were medium-chain triglyceride and maltodextrin, respectively. Polyglycerol polyricinoleate was used as the primary emulsifier, and the secondary emulsifier was polyoxyethylene sorbitan monolaurate. Response surface methodology was employed to determine optimum microencapsulation conditions, and headspace solid-phase microextraction was used to detect the caramel flavor during storage. The microencapsulation yield of the caramel flavor increased as the ratio of primary to secondary coating material increased. The optimum ratio of core to primary coating material for the water-in-oil (W/O) phase was 1:9, and that of the W/O phase to the secondary coating material was also 1:9. Microencapsulation yield was observed to be approximately 93.43%. In case of in vitro release behavior, the release rate of the capsules in the simulated gastric environment was feeble; however, the release rate in the simulated intestinal environment rapidly increased within 30 min, and nearly 70% of the core material was released within 120 min. The caramel flavor-supplemented beverage sample exhibited an exponential degradation in its flavor components. However, microcapsules containing flavor samples showed sustained flavor release compared to caramel flavor-filled samples under higher storage temperatures. In conclusion, the addition of coffee flavor microcapsules to coffee-containing milk beverages effectively extended the retention of the coffee flavor during the storage period.

Co-microencapsulation of Lactobacillus plantarum and DHA fatty acid in alginate-pectin-gelatin biocomposites

The aim of this study was to investigate the co-microencapsulation of Lactobacillus plantarum and DHA-rich oil in a novel gastrointestinal-resistant biocomposite composed of alginate, pectin and gelatin. The optimal biocomposite consisted of 1.06% alginate, 0.55% pectin and 0.39% gelatin showed 88.66% survivability of the microencapsulated cells compared to the free cells (50.36%). In addition, co-microencapsule containing probiotic and DHA fatty acid was synthesized and physicochemically analyzed using SEM, FTIR, TGA, XRD. The results from SEM clearly confirmed that cells were completely entrapped in the matrix and DHA increased smoothness and compactness of the surface of the particles. FTIR spectra revealed the formation of hydrogen and Van der Waals bonds between macromolecules and the core materials. X-ray pattern of co-microencapsules identified amorphous structure compared to capsules containing only DHA or probiotic. TGA analysis revealed the thermal stability of DHA-loaded capsules compared to un-loaded ones.

Lactase Non-persistence and Lactose Intolerance

PURPOSE OF REVIEW

To evaluate the clinical and nutritional significance of genetically determined lactase non-persistence and potential lactose and milk intolerance in 65-70% of the world's adult population.

RECENT FINDINGS

Milk consumption is decreasing in the USA and is the lowest in countries with a high prevalence of lactase non-persistence. The dairy industry and Minnesota investigators have made efforts to minimize the influence of lactose intolerance on milk consumption. Some lactose intolerant individuals, without co-existent irritable bowel syndrome, are able to consume a glass of milk with a meal with no or minor symptoms. The high frequency of lactase persistence in offspring of Northern European countries and in some nomadic African tribes is due to mutations in the promoter of the lactase gene in association with survival advantage of milk drinking. Educational and commercial efforts to improve calcium and Vitamin D intake have focused on urging consumption of tolerable amounts of milk with a meal, use of lowered lactose-content foods including hard cheeses, yogurt, and lactose-hydrolyzed milk products.

Optimization of Manufacturing Conditions for Improving Storage Stability of Coffee-Supplemented Milk Beverage Using Response Surface Methodology

This study aimed at optimizing the manufacturing conditions of a milk beverage supplemented with coffee, and monitoring its physicochemical and sensory properties during storage. Raw milk, skim milk powder, coffee extract, and emulsifiers were used to manufacture the beverage. Two sucrose fatty acid esters, F110 and F160, were identified as suitable emulsifiers. The optimum conditions for the beverage manufacture, which can satisfy two conditions at the same time, determined by response surface methodology (RSM), were 5,000 rpm primary homogenization speed and 0.207% sucrose fatty acid emulsifier addition. The particle size and zeta-potential of the beverage under the optimum condition were 190.1 nm and - 25.94±0.06 mV, respectively. In comparison study between F110 added group (GF110) and F160 added group (GF160) during storage, all samples maintained its pH around 6.6 to 6.7, and there was no significant difference (p<0.05). In addition, GF110 showed significantly higher zeta-potential than GF160 (p<0.05). The particle size of GF110 and GF160 were approximately 190.1 and 223.1 nm, respectively at initial. However, size distribution of the GF160 tended to increase during storage. Moreover, increase of the particle size in GF160 was observed in microphotographs of it during storage. The L* values gradually decreased within all groups, whereas the a* and b* values did not show significant variations (p<0.05). Compared with GF160, bitterness, floating cream, and rancid flavor were more pronounced in the GF110. Based on the result obtained from the present study, it appears that the sucrose fatty acid ester F110 is more suitable emulsifier when it comes to manufacturing this beverage than the F160, and also contributes to extending product shelf-life.

Dietary approaches to alleviation of lactose maldigestion / Efectos de la dieta sobre la digestión de la lactosa

Because dairy products are a significant source of essential nutrients, elimination of all dairy foods in the diet would be nutritionally unwise and is usually not necessary in the case of lactose maldigestion. About 250 ml milk/d can generally be taken without adverse effects. If milk is taken in combination with solid foods, lactose malabsorption may be reduced by about 50%, probably due to a slower rate of colonic fermentation which may lower gastrointestinal symptoms in lactose malabsorbers. It is well established that, in lactase-deficient subjects, yoghurt is better tolerated than milk. This is only to some extent related to the fact that the lactose content of the products is reduced during fermentation, but is mainly attributed to the fact that the culture organisms- by virtue of being rich in lactase - are able to participate in the hydrolysis of ingested lactose. Up to 20 g of lactose in yoghurt is tolerated well by lactase-deficient persons. The enhanced absorp tion of lactose in yoghurt is explained as a result of the intestinal release of lactase from the yoghurt organisms. Ripened cheese is also tolerated very well by lactose-intolerant persons since virtually all of the lactose present is decomposed to lactic acid and other metabolites.

Lactose Intolerance and Symptom Pattern of Lactose Intolerance among Healthy Volunteers

Aims

To see the prevalence of lactose intolerance (LI) and related symptoms following oral lactose challenge in healthy volunteers.

Materials and methods

Symptoms of abdominal pain, nausea, borborygmi, flatulence, and diarrhea were noted for 24 hours and blood glucose was estimated at 0 hour and 30 minutes after 25 gm oral lactose load to healthy volunteers. Failure to rise blood glucose level ≥ 1.1 mmol/l at 30 minutes after lactose intake from fasting level was taken as lactose malabsorption (LM), i.e., LI.

Results

A total of 166 volunteers (123 males, 43 females) with a mean age 34.78 ± 11.45 years participated in this study. Lactose intolerance was found among 85.54% (n = 142, M = 104, F = 38). The main symptoms of LI were diarrhea (n = 83, 58.4.0%), borborygmi (n = 81, 57.04%), abdominal pain (n = 35, 24.65%), and flatulence (n = 27, 19.0%).

Conclusion

Lactose intolerance among healthy adults may be common in Bangladesh. Diarrhea and borborygmi were mostly associated symptoms of LI.

How to cite this article

Saha M, Parveen I, Shil BC, Saha SK, Banik RK, Majumder M, Salam MU, Nazmul Islam ASM. Lactose Intolerance and Symptom Pattern of Lactose Intolerance among Healthy Volunteers. Euroasian J Hepato-Gastroenterol 2016;6(1):5-7.

The Interrelationships between Lactose Intolerance and the Modern Dairy Industry: Global Perspectives in Evolutional and Historical Backgrounds

Humans learned to exploit ruminants as a source of milk about 10,000 years ago. Since then, the use of domesticated ruminants as a source of milk and dairy products has expanded until today when the dairy industry has become one of the largest sectors in the modern food industry, including the spread at the present time to countries such as China and Japan. This review analyzes the reasons for this expansion and flourishing. As reviewed in detail, milk has numerous nutritional advantages, most important being almost an irreplaceable source of dietary calcium, hence justifying the effort required to increase its consumption. On the other hand, widespread lactose intolerance among the adult population is a considerable drawback to dairy-based foods consumption. Over the centuries, three factors allowed humans to overcome limitations imposed by lactose intolerance: (i) mutations, which occurred in particular populations, most notably in the north European Celtic societies and African nomads, in which carriers of the lactose intolerance gene converted from being lactose intolerant to lactose tolerant; (ii) the ability to develop low-lactose products such as cheese and yogurt; and (iii) colon microbiome adaptation, which allow lactose intolerant individuals to overcome its intolerance. However, in a few examples in the last decade, modern dairy products, such as the popular and widespread bio-cultured yogurts, were suspected to be unsuitable for lactose intolerant peoples. In addition, the use of lactose and milk-derived products containing lactose in non-dairy products has become widespread. For these reasons, it is concluded that it might be important and helpful to label food that may contain lactose because such information will allow lactose intolerant groups to control lactose intake within the physiological limitations of ~12 g per a single meal.

Adult lactose digestion status and effects on disease

BACKGROUND

Adult assimilation of lactose divides humans into dominant lactase-persistent and recessive nonpersistent phenotypes.

OBJECTIVES

To review three medical parameters of lactose digestion, namely: the changing concept of lactose intolerance; the possible impact on diseases of microbial adaptation in lactase-nonpersistent populations; and the possibility that the evolution of lactase has influenced some disease pattern distributions.

METHODS

A PubMed, Google Scholar and manual review of articles were used to provide a narrative review of the topic.

RESULTS

The concept of lactose intolerance is changing and merging with food intolerances. Microbial adaptation to regular lactose consumption in lactase-nonpersistent individuals is supported by limited evidence. There is evidence suggestive of a relationship among geographical distributions of latitude, sunhine exposure and lactase proportional distributions worldwide.

DISCUSSION

The definition of lactose intolerance has shifted away from association with lactose maldigestion. Lactose sensitivity is described equally in lactose digesters and maldigesters. The important medical consequence of withholding dairy foods could have a detrimental impact on several diseases; in addition, microbial adaptation in lactase-nonpersistent populations may alter risk for some diseases. There is suggestive evidence that the emergence of lactase persistence, together with human migrations before and after the emergence of lactase persistence, have impacted modern-day diseases.

CONCLUSIONS

Lactose maldigestion and lactose intolerance are not synonymous. Withholding dairy foods is a poor method to treat lactose intolerance. Further epidemiological work could shed light on the possible effects of microbial adaptation in lactose maldigesters. The evolutionary impact of lactase may be still ongoing.

Milk intake and risk of mortality and fractures in women and men: cohort studies

OBJECTIVE

To examine whether high milk consumption is associated with mortality and fractures in women and men.

DESIGN

Cohort studies.

SETTING

Three counties in central Sweden.

PARTICIPANTS

Two large Swedish cohorts, one with 61,433 women (39-74 years at baseline 1987-90) and one with 45,339 men (45-79 years at baseline 1997), were administered food frequency questionnaires. The women responded to a second food frequency questionnaire in 1997.

MAIN OUTCOME MEASURE

Multivariable survival models were applied to determine the association between milk consumption and time to mortality or fracture.

RESULTS

During a mean follow-up of 20.1 years, 15,541 women died and 17,252 had a fracture, of whom 4259 had a hip fracture. In the male cohort with a mean follow-up of 11.2 years, 10,112 men died and 5066 had a fracture, with 1166 hip fracture cases. In women the adjusted mortality hazard ratio for three or more glasses of milk a day compared with less than one glass a day was 1.93 (95% confidence interval 1.80 to 2.06). For every glass of milk, the adjusted hazard ratio of all cause mortality was 1.15 (1.13 to 1.17) in women and 1.03 (1.01 to 1.04) in men. For every glass of milk in women no reduction was observed in fracture risk with higher milk consumption for any fracture (1.02, 1.00 to 1.04) or for hip fracture (1.09, 1.05 to 1.13). The corresponding adjusted hazard ratios in men were 1.01 (0.99 to 1.03) and 1.03 (0.99 to 1.07). In subsamples of two additional cohorts, one in males and one in females, a positive association was seen between milk intake and both urine 8-iso-PGF2α (a biomarker of oxidative stress) and serum interleukin 6 (a main inflammatory biomarker).

CONCLUSIONS

High milk intake was associated with higher mortality in one cohort of women and in another cohort of men, and with higher fracture incidence in women. Given the observational study designs with the inherent possibility of residual confounding and reverse causation phenomena, a cautious interpretation of the results is recommended.

Plant-based diets are traditional in developing countries: 21st century challenges for better nutrition and health

The chronic degenerative diseases were virtually unknown in original hunter-gatherer societies. At the dawn of the 21st century, however, they represent the most important public health challenge to populations of both the industrialized, affluent nations of the temperate zones and the low-income developing countries of the tropics. The developing countries most closely reflect the legacy of our traditional foreparents while constituting threequarters of the world's populace and public health interest. For economic, traditional, religious and cultural reasons, the majority of the dietary fares in the developing world are largely plant based. This is associated with high prevalences of deficiency states in vitamin A, iron, zinc, riboflavin and vitamin B12. Poor linear growth and chronic energy deficiency are concomitant conditions. Conversely, the major chronic diseases have low prevalences among the rural peasantry and tribal groups, with the exception of gastro-esophageal cancer, osteoarthritis and cataract. As a site for intensive research in food and nutritional sciences, Guatemala provides important lessons about the origin and evolvement of a congruent plant-based diet within a food system and which factors of demographic expansion, urbanization, environmental stress and food technology will carry it through the 21st century. We can conclude that, whatever was the 'original' dietary pattern of pre-agricultural humankind, a plant-based diet regimen provides the lowest content of promoters and the highest content of inhibitors of metabolic dysregulation that lead to the major causes of disease and debility in adults over 40 years of age. For developing countries, the challenge is to maintain and reinforce the traditional eating patterns while improving their delivery of micronutrients and obviating any adverse environmental consequences in their traditional preparation patterns. For developed countries, there is an opportunity to find a 'road map' of guidelines to allow correction of current, pathogenic dietary and lifestyle patterns by examining the food-ways of traditional developing societies' cuisines.

Lactase persistence/non-persistence genetic variants in irritable bowel syndrome in an endemic area for lactose malabsorption

BACKGROUND AND AIM

Lactase non-persistence is common in India. We evaluated: (i) frequency of lactase gene (C/T-13910 and G/A-22018) polymorphisms in irritable bowel syndrome (IBS) and healthy controls (HC), (ii) association between these polymorphisms and IBS-subtypes and symptoms.

METHODS

A total of 150 IBS patients (Rome-III criteria) and 252 age and gender-matched HC were evaluated for C/T-13910 and G/A-22018 genotypes using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Totals of 79 (52%), 52 (35%) and 19 (13%) patients had diarrhea-predominant IBS (D-IBS), constipation predominant IBS (C-IBS) and alternating diarrhea and constipation IBS (A-IBS), respectively (Rome-III). Frequency of C/T-13910 [genotypes: CC 102 (68%), CT 43 (29%), TT 5 (3%) vs CC 155 (61%), CT 83 (33%), TT 14 (6%), P > 0.05] and G/A-22018 [GG 97 (65%), GA 41 (27%), AA 12 (8%) vs GG 154 (61%), GA 78 (31%), AA 20 (8%), P > 0.05] were similar among IBS and HC. Patients with D-IBS more often had C/T-13910 and G/A-22018 genotypes than C-IBS (CC 71 [90%], CT 6 [8%], TT 2 [2%]) versus (24 [46%], 25 [48%], 3 [6%]), A-IBS (7 [39%], 12 [63%], 0, [0%]) and HC (155 [61%], 83 [33%], 14 [6%]), P < 0.0001 and (GG 69 [87%], GA 6 [8%], AA 4 [5%]) vs (22 [42%], 24 [46%], 6 [12%]) vs (6 [32%], 11 [58%], 2 [10%]), P < 0.0001. IBS with CC and GG genotypes more often had abdominal pain (P = 0.005), distension (P = 0.031) and higher stool frequency (P = 0.003) and reported symptoms following dairy products than non-CC (P < 0.0001).

CONCLUSION

Though C/T-13910 and G/A-22018 polymorphisms were comparable among IBS and HC, these were more common among D-IBS and reported some symptoms like abdominal pain, bloating and exacerbation by dairy products.

Identification of milk component in ancient food residue by proteomics

BACKGROUND

Proteomic approaches based on mass spectrometry have been recently used in archaeological and art researches, generating promising results for protein identification. Little information is known about eastward spread and eastern limits of prehistoric milking in eastern Eurasia.

METHODOLOGY/PRINCIPAL FINDING

In this paper, an ancient visible food remain from Subeixi Cemeteries (cal. 500 to 300 years BC) of the Turpan Basin in Xinjiang, China, preliminarily determined containing 0.432 mg/kg cattle casein with ELISA, was analyzed by using an improved method based on liquid chromatography (LC) coupled with MALDI-TOF/TOF-MS to further identify protein origin. The specific sequence of bovine casein and the homology sequence of goat/sheep casein were identified.

CONCLUSIONS/SIGNIFICANCE

The existence of milk component in ancient food implies goat/sheep and cattle milking in ancient Subeixi region, the furthest eastern location of prehistoric milking in the Old World up to date. It is envisioned that this work provides a new approach for ancient residue analysis and other archaeometry field.

Herders of Indian and European cattle share their predominant allele for lactase persistence

Milk consumption and lactose digestion after weaning are exclusively human traits made possible by the continued production of the enzyme lactase in adulthood. Multiple independent mutations in a 100-bp region--part of an enhancer--approximately 14-kb upstream of the LCT gene are associated with this trait in Europeans and pastoralists from Saudi Arabia and Africa. However, a single mutation of purported western Eurasian origin accounts for much of observed lactase persistence outside Africa. Given the high levels of present-day milk consumption in India, together with archaeological and genetic evidence for the independent domestication of cattle in the Indus valley roughly 7,000 years ago, we sought to determine whether lactase persistence has evolved independently in the subcontinent. Here, we present the results of the first comprehensive survey of the LCT enhancer region in south Asia. Having genotyped 2,284 DNA samples from across the Indian subcontinent, we find that the previously described west Eurasian -13910 C>T mutation accounts for nearly all the genetic variation we observed in the 400- to 700-bp LCT regulatory region that we sequenced. Geography is a significant predictor of -13910*T allele frequency, and consistent with other genomic loci, its distribution in India follows a general northwest to southeast declining pattern, although frequencies among certain neighboring populations vary substantially. We confirm that the mutation is identical by descent to the European allele and is associated with the same>1 Mb extended haplotype in both populations.

Ten questions for evolutionary studies of disease vulnerability

Many evolutionary applications in medicine rely on well-established methods, such as population genetics, phylogenetic analysis, and observing pathogen evolution. Approaches to evolutionary questions about traits that leave bodies vulnerable to disease are less well developed. Strategies for formulating questions and hypotheses remain unsettled, and methods for testing evolutionary hypotheses are unfamiliar to many in medicine. This article uses recent examples to illustrate successful strategies and some common challenges. Ten questions arise in the course of considering hypotheses about traits that leave bodies vulnerable to disease. Addressing them systematically can help minimize confusion and errors.

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.

Evolutionary adaptations to dietary changes

Through cultural innovation and changes in habitat and ecology, there have been a number of major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. The identification of signatures of adaptations to such dietary changes in the genome of extant primates (including humans) may shed light not only on the evolutionary history of our species, but also on the mechanisms that underlie common metabolic diseases in modern human populations. In this review, we provide a brief overview of the major dietary shifts that occurred during hominin evolution, and we discuss the methods and approaches used to identify signals of natural selection in patterns of sequence variation. We then review the results of studies aimed at detecting the genetic loci that played a major role in dietary adaptations and conclude by outlining the potential of future studies in this area.

Fortification of orange juice with vitamin D(2) or vitamin D(3) is as effective as an oral supplement in maintaining vitamin D status in adults

BACKGROUND

Vitamin D has been added to calcium-fortified orange juice. It is unknown whether vitamin D is as bioavailable from orange juice as it is from supplements.

OBJECTIVES

The objective was to compare the bioavailability of vitamin D(2) and vitamin D(3) from orange juice with that from vitamin D(2) and vitamin D(3) supplements. A secondary aim was to determine which form of vitamin D is more bioavailable in orange juice.

DESIGN

A randomized, placebo-controlled, double-blind study was conducted in healthy adults aged 18-84 y (15-20/group) who received 1000 IU vitamin D(3), 1000 IU vitamin D(2), or placebo in orange juice or capsule for 11 wk at the end of winter.

RESULTS

A total of 64% of subjects began the study deficient in vitamin D (ie, 25-hydroxyvitamin D [25(OH)D]) concentrations <20 ng/mL). Analysis of the area under the curve showed no significant difference in serum 25(OH)D between subjects who consumed vitamin D-fortified orange juice and those who consumed vitamin D supplements (P = 0.084). No significant difference in serum 25(OH)D(3) was observed between subjects who consumed vitamin D(3)-fortified orange juice and vitamin D(3) capsules (P > 0.1). Similarly, no significant difference in serum 25(OH)D(2) was observed between subjects who consumed vitamin D(2)-fortified orange juice and vitamin D(2) capsules (P > 0.1). No significant overall difference in parathyroid hormone concentrations was observed between the groups (P = 0.82).

CONCLUSION

Vitamin D(2) and vitamin D(3) are equally bioavailable in orange juice and capsules.

Determinants of geographic patterns of diseases: interaction of lactose/lactase status and sunshine exposure

Geographic patterns of diseases depend on multilayered causes. However, the division of the world's population into two phenotypes regarding lactose digestion and sunshine exposure to fixed areas of the globe are two relatively slow changing variables. It is hypothesized that it is a vectorial interaction between these two variables that provide a backbone to risk modification of many diseases. Lactase non persistence status tends to follow sunshine exposure particularly in Europe but Lactase persistence status is also been shown to be related to pastoral life styles in spotty regions of Africa, Middle East and China. Current emphasis of research favours the modifying role of vitamin D and sunshine. Nevertheless it was demonstrated that national digester/nondigester status has mathematical relationships to geographic distribution of some diseases. These relationships are also similar to that described for the effects of latitude through sunshine and vitamin D. This observation raises a question as to how each one affects disease outcome. In this paper lactose/lactase interactions are first reviewed for eight exemplary diseases. Based on population findings and corroborative meta-analyses gleaned from the literature 6 types of interactions may be classified. Then in a preliminary fashion lactose digester and maldigester status are related to relative annual sunshine exposure. Further the relative national annual sunshine exposure is evaluated to outcomes of the same exemplary diseases. The patterns related to sunshine reflect that obtained with national lactase status proportions and also corroborate a literature review. However, correlations are weak to moderate and only ovarian cancer reached conventional statistical significance. Because these comparisons are based on modest number of national data firm conclusions cannot be made. However, it is argued that evolutionary pressures exerted by regional sunshine exposure may have had influence on a number of relevant genetic polymorphisms in parallel with lactase status. Furthermore influences of ancestral herding and dairy food consumption also may have exerted independent influences on either lactose phenotype. As such both discussed variables are postulated to exert parallel as well as independent effects on modifying geographic disease patterns. These could partly explain both north to south and west to east directional changes.

Contribution of beverages to energy, macronutrient and micronutrient intake of third- and fourth-grade schoolchildren in Quetzaltenango, Guatemala

Beverages are selected based on availability, culture, taste preference, health, safety and social context. Beverages may be important to energy and to the macronutrient and micronutrient quality of overall intake. The aim of this study was to determine the contribution of beverages to the dietary energy and estimated macro- and micronutrient intake to the diet of young schoolchildren. We analyzed data from third- and fourth-grade urban Guatemalan school-children aged predominantly 8-10 years old. One-day pictorial registries of all beverages, foods and snacks consumed over a 24-h period were collected from children from private (n = 219) and public (n = 230) schools. Food composition nutrient values were assigned to the items consumed. Eleven main categories of beverages were identified. The contribution of each of the 11 beverage categories to energy, macro- and micronutrients was evaluated. The estimated intake of beverages was 475,300 mL, as reported by the 449 children. As a group, the beverage consumed in the greatest quantity was coffee (126,500 mL), followed by plain water (62,000 mL). Beverages represented a mean energy contribution of 418 +/- 26 kcal (21.5% of total dietary energy). The beverages varied in energy density from 0 (water) to 1.5 kcal mL(-1) (thin gruels). Beverages contributed one-third of the dietary carbohydrate. Through the contribution of fortified drinks, beverages were important sources of vitamin A (55%), vitamin C (38%), zinc (21%) and calcium (19%). Milk was an important source for vitamin D (10%). These results show the importance of drinks to nutrition and the balance of concerns of overweight/obesity with micronutrient quality.

Frequency of lactose malabsorption among healthy southern and northern Indian populations by genetic analysis and lactose hydrogen breath and tolerance tests

BACKGROUND

Lactose malabsorption (LM), the inability to break down lactose into glucose and galactose, is due to a deficiency in the small intestinal lactase phlorizin hydrolase enzyme. Ethnic and geographic variations of LM are known.

OBJECTIVE

The aim of this study was to compare the frequency of LM in healthy southern and northern Indian populations.

DESIGN

A total of 153 healthy volunteers (76 from southern and 77 from northern India) were evaluated for LM by using a lactose tolerance test (LTT), a lactose hydrogen breath test (lactose HBT), and polymerase chain reaction-restriction fragment length polymorphism to identify the lactase gene C/T-13910 polymorphism (confirmed by sequencing).

RESULTS

Volunteers from southern and northern India were comparable in age and sex. The LTT result was abnormal in 88.2% of southern Indians and in 66.2% of northern Indians (P = 0.001). The lactose HBT result was abnormal in 78.9% of southern Indians and in 57.1% of northern Indians (P = 0.003). The CC genotype was present in 86.8% and 67.5% (P = 0.002), the CT genotype was present in 13.2% and 26.0% (P = 0.036), and the TT genotype was present in 0% and 6.5% (P = 0.03) of southern and northern Indians, respectively. The frequency of symptoms after the lactose load (47.4% compared with 15.6%; P < 0.001) and peak concentrations of breath hydrogen (88.5 +/- 71.9 compared with 55.4 +/- 61.9 ppm; P = 0.003), both of which might indicate the degree of lactase deficiency, were higher in southern than in northern Indians.

CONCLUSION

The frequency and degree of LM is higher in southern than in northern Indian healthy populations because of genetic differences in these populations.

The origins of lactase persistence in Europe

Lactase persistence (LP) is common among people of European ancestry, but with the exception of some African, Middle Eastern and southern Asian groups, is rare or absent elsewhere in the world. Lactase gene haplotype conservation around a polymorphism strongly associated with LP in Europeans (-13,910 C/T) indicates that the derived allele is recent in origin and has been subject to strong positive selection. Furthermore, ancient DNA work has shown that the--13,910*T (derived) allele was very rare or absent in early Neolithic central Europeans. It is unlikely that LP would provide a selective advantage without a supply of fresh milk, and this has lead to a gene-culture coevolutionary model where lactase persistence is only favoured in cultures practicing dairying, and dairying is more favoured in lactase persistent populations. We have developed a flexible demic computer simulation model to explore the spread of lactase persistence, dairying, other subsistence practices and unlinked genetic markers in Europe and western Asia's geographic space. Using data on--13,910*T allele frequency and farming arrival dates across Europe, and approximate Bayesian computation to estimate parameters of interest, we infer that the--13,910*T allele first underwent selection among dairying farmers around 7,500 years ago in a region between the central Balkans and central Europe, possibly in association with the dissemination of the Neolithic Linearbandkeramik culture over Central Europe. Furthermore, our results suggest that natural selection favouring a lactase persistence allele was not higher in northern latitudes through an increased requirement for dietary vitamin D. Our results provide a coherent and spatially explicit picture of the coevolution of lactase persistence and dairying in Europe.

Should dairy be recommended as part of a healthy vegetarian diet? Counterpoint

Although cow milk has been widely recommended in Western countries as necessary for growth and bone health, evidence collected during the past 20 y shows the need to rethink strategies for building and maintaining strong bones. Osteoporotic bone fracture rates are highest in countries that consume the most dairy, calcium, and animal protein. Most studies of fracture risk provide little or no evidence that milk or other dairy products benefit bone. Accumulating evidence shows that consuming milk or dairy products may contribute to the risk of prostate and ovarian cancers, autoimmune diseases, and some childhood ailments. Because milk is not necessary for humans after weaning and the nutrients it contains are readily available in foods without animal protein, saturated fat, and cholesterol, vegetarians may have healthier outcomes for chronic disease if they limit or avoid milk and other dairy products. Bones are better served by attending to calcium balance and focusing efforts on increasing fruit and vegetable intakes, limiting animal protein, exercising regularly, getting adequate sunshine or supplemental vitamin D, and getting approximately 500 mg Ca/d from plant sources. Therefore, dairy products should not be recommended in a healthy vegetarian diet.

The survival advantage of milk and dairy consumption: an overview of evidence from cohort studies of vascular diseases, diabetes and cancer

OBJECTIVES

To conduct a detailed evaluation, with meta-analyses, of the published evidence on milk and dairy consumption and the incidence of vascular diseases and diabetes. Also to summarise the evidence on milk and dairy consumption and cancer reported by the World Cancer Research Fund and then to consider the relevance of milk and dairy consumption to survival in the UK, a typical Western community. Finally, published evidence on relationships with whole milk and fat-reduced milks was examined.

METHODS

Prospective cohort studies of vascular disease and diabetes with baseline data on milk or dairy consumption and a relevant disease outcome were identified by searching MEDLINE, and reference lists in the relevant published reports. Meta-analyses of relationships in these reports were conducted. The likely effect of milk and dairy consumption on survival was then considered, taking into account the results of published overviews of relationships of these foods with cancer.

RESULTS

From meta-analysis of 15 studies the relative risk of stroke and/or heart disease in subjects with high milk or dairy consumption was 0.84 (95% CI 0.76, 0.93) and 0.79 (0.75, 0.82) respectively, relative to the risk in those with low consumption. Four studies reported incident diabetes as an outcome, and the relative risk in the subjects with the highest intake of milk or diary foods was 0.92 (0.86, 0.97).

CONCLUSIONS

Set against the proportion of total deaths attributable to the life-threatening diseases in the UK, vascular disease, diabetes and cancer, the results of meta-analyses provide evidence of an overall survival advantage from the consumption of milk and dairy foods.

Molecular genetics of human lactase deficiencies

Lactase non-persistence (adult-type hypolactasia) is present in more than half of the human population and is caused by the down-regulation of lactase enzyme activity during childhood. Congenital lactase deficiency (CLD) is a rare severe gastrointestinal disorder of new-borns enriched in the Finnish population. Both lactase deficiencies are autosomal recessive traits and characterized by diminished expression of lactase activity in the intestine. Genetic variants underlying both forms have been identified. Here we review the current understanding of the molecular defects of human lactase deficiencies and their phenotype-genotype correlation, the implications on clinical practice, and the understanding of their function and role in human evolution.

Lactose digestion and the evolutionary genetics of lactase persistence

It has been known for some 40 years that lactase production persists into adult life in some people but not in others. However, the mechanism and evolutionary significance of this variation have proved more elusive, and continue to excite the interest of investigators from different disciplines. This genetically determined trait differs in frequency worldwide and is due to cis-acting polymorphism of regulation of lactase gene expression. A single nucleotide polymorphism located 13.9 kb upstream from the lactase gene (C-13910 > T) was proposed to be the cause, and the -13910*T allele, which is widespread in Europe was found to be located on a very extended haplotype of 500 kb or more. The long region of haplotype conservation reflects a recent origin, and this, together with high frequencies, is evidence of positive selection, but also means that -13910*T might be an associated marker, rather than being causal of lactase persistence itself. Doubt about function was increased when it was shown that the original SNP did not account for lactase persistence in most African populations. However, the recent discovery that there are several other SNPs associated with lactase persistence in close proximity (within 100 bp), and that they all reside in a piece of sequence that has enhancer function in vitro, does suggest that they may each be functional, and their occurrence on different haplotype backgrounds shows that several independent mutations led to lactase persistence. Here we provide access to a database of worldwide distributions of lactase persistence and of the C-13910*T allele, as well as reviewing lactase molecular and population genetics and the role of selection in determining present day distributions of the lactase persistence phenotype.

Hydrogen breath test for the diagnosis of lactose intolerance, is the routine sugar load the best one?

AIM: To evaluate the prevalence of lactose intolerance (LI) following a load of 12.5 g in patients diagnosed as high-grade malabsorbers using the hydrogen breath test (HBT)-25.

METHODS: Ninety patients showing high-grade malabsorption at HBT-25 were submitted to a second HBT with a lactose load of 12.5 g. Peak hydrogen production, area under the curve of hydrogen excretion and occurrence of symptoms were recorded.

RESULTS: Only 16 patients (17.77%) with positive HBT-25 proved positive at HBT-12.5. Hydrogen production was lower as compared to HBT-25 (peak value 21.55 parts per million (ppm) ± 29.54 SD vs 99.43 ppm ± 40.01 SD; P < 0.001). Symptoms were present in only 13 patients. The absence of symptoms during the high-dose test has a high negative predictive value (0.84) for a negative low-dose test. The presence of symptoms during the first test was not useful for predicting a positive low-dose test (positive predictive value 0.06-0.31).

CONCLUSION: Most patients with a positive HBT-25 normally absorb a lower dose of lactose and a strict lactose restriction on the basis of a “standard” HBT is, in most instances, unnecessary. Thus, the 25 g lactose tolerance test should probably be substituted by the 12.5 g test in the diagnosis of LI, and in providing dietary guidelines to patients with suspected lactose malabsorption/intolerance.

Impact of lactose containing foods and the genetics of lactase on diseases: an analytical review of population data

Dairy foods (DFs) contain complex ingredients that could affect different diseases. The control of lactose digestion phenotypically divides populations into those who can [lactase persistent (LP)] and those who cannot [lactase nonpersistent (LNP)] assimilate lactose. LNP subjects, however, can adapt to lactose intolerance through intestinal bacteria. The DF/LNP status interactions may function as disease risk modifiers. We evaluated the relationship between DF and LNP with colorectal, breast, prostate, ovarian, lung, and stomach cancer and inflammatory bowel diseases (IBD; Crohn's disease and ulcerative colitis). Yearly per capita DF consumption, LNP national prevalence, cancer mortality, and incidence of IBD were obtained from several sources. A negative binomial regression model was used to derive incremental risks. There were statistically significant (P <or= 0.05) increases in risk for colorectal and prostate cancer and ulcerative colitis with DFs and a statistically significant decreased risk for stomach cancer. There were trends (P<0.1) for lung and ovarian cancers and Crohn's disease. As LNP prevalence increased, stomach cancer risk increased, whereas risks of all other conditions decreased (P<0.01). In 3 cancers (prostate, ovarian, and breast), meta-analyses of case-based studies support ecological data. In colorectal cancer, on the contrary, meta-analyses of case-based studies suggest protection. The possible importance of distinguishing LNP/LP status in studies is discussed.