Osteoporosis: Is milk a kindness or a curse?

Where Do Milk Microbes Originate? Traceability of Microbial Community Structure in Raw Milk

Variations in ecological environments (including milk collection equipment and milk storage tanks in the pasture) and seasonal changes may contribute to raw milk contamination, thereby affecting food safety. The composition, structure, and relationships between raw milk and microbial communities in these environments are not well understood. In this study, 84 samples from spring and autumn in Luxian County, Yunnan Province, China, were collected for high-throughput sequencing technology. The results showed that the skin on the nipple surface and the environment (including the wiping samples of the automatic milking machine and the inner cover of the milk tank) had the greatest impact on microbial community composition in raw milk, followed by dung. In addition, microbial diversity in autumn samples was significantly higher, likely due to seasonal factors, including increased rainfall and reduced ultraviolet radiation. By analyzing the microbial community of raw milk and its environmental source, this study traced the origin of microorganisms in milk, providing insights for further exploration of the interaction between the pasture environment and raw milk microorganisms.

Lipid Profile of Plant-Based Milk Alternatives (PBMAs) and Cow's Milk: A Comparison

Some consumers are replacing cow's milk with plant-based milk alternatives (PBMAs). The present study aimed to characterize the lipid profiles of cow's milk (n = 60) and PBMA types (soya, oat, rice, almond, coconut, and hazelnut; n = 10 per type). Significant differences were found in the fatty acid (FA) profiles of PBMAs and milk, particularly in FA diversity (15 FAs in PBMAs vs 54 FAs in milk) and the proportion of prime FA groups. The FA profile of coconut was dominated by saturated FAs (SFA), whereas monounsaturated FAs (MUFA) or polyunsaturated FAs (PUFA) were dominant in the remaining PBMA types. Cholesterol was not detected in any PBMA type. The FA profile of milk FAs was dominated by SFA; however, different individual SFA have varying health outcomes. Additionally, milk contains some FA groups with health-promoting properties, such as methyl-branched-chain FAs (BCFA) and conjugated linoleic acid (CLA), both of which are absent in PBMAs.

Relationship between Selected SNPs (g.16024A/G, g.16039T/C and g.16060A/C) of the FASN Gene and the Fat Content and Fatty Acid Profile in the Milk of Three Breeds of Cows

Fat is an important energy and nutritional component of milk and consists of fatty acids. FASN (fatty acid synthase) is an enzyme that regulates the synthesis of fatty acids in the milk and meat of cattle. It was hypothesized that knowing the relationships between the genotypes of the tested single nucleotide polymorphisms (SNPs) and the content of fat and specific fatty acids would make it possible to improve milk quality in the selection process during cattle breeding. This study aimed to analyze the relationships of SNPs (g.16024A/G, g.16039T/C) of the FASN gene and their genotypes with the fat and fatty acid content of the milk of the following breeds: Polish Red-White (ZR), Polish Red (RP), and Polish Holstein-Friesian Red-White (RW). The SNP g.16060A/C was included in the study, although its effect on the fat composition of cow's milk has not yet been widely studied. Milk was obtained during test milkings. SNP genotyping was performed using the real-time PCR (HRM) method. The milk from ZR and RP cows was more often characterized by a more favorable fatty acid profile than the milk from RW cows. This information can be used by cattle breeders and consumers of so-called functional food.

Cow's Milk in Human Nutrition and the Emergence of Plant-Based Milk Alternatives

Cow's milk is considered a complete food, providing high-quality protein and essential micronutrients, including vitamins and minerals. For medical reasons or as a lifestyle choice, consumers are replacing cow's milk with plant-based milk alternatives (PBMA); some perceive them as healthier alternatives to cow's milk due to their low saturated fatty acid content and no cholesterol content. However, the nutritional composition of PBMA is quite variable between different types and even within, which makes a comparison with cow's milk a complex issue. Furthermore, the consumption of PBMA has been associated with the development of some diseases in infants and children. Meanwhile, the consumption of cow's milk in human health is a controversial issue since it has been associated with a favorable effect in some diseases (such as obesity, type 2 diabetes, and Alzheimer's) and a negative effect in others (such as prostate cancer risk and Parkinson's disease); while in some diseases, there is no consensus in the cow's milk consumption effect. The aim of this review is to make a nutritional comparison of cow's milk with PBMA and to clarify the potential health issues related to their consumption.

The circadian rhythm of calcium and bone homeostasis in Maasai

OBJECTIVES

Ethnic groups differ in prevalence of calcium-related diseases. Differences in the physiology and the endogenous circadian rhythm (CR) of calcium and bone homeostasis may play a role. Thus, we aimed to investigate details of CR pattern in calcium and bone homeostasis in East African Maasai.

METHODS

Ten clinically healthy adult Maasai men and women from Tanzania were examined. Blood samples were collected every 2nd hour for 24 h. Serum levels of total calcium, albumin, parathyroid hormone (PTH), 25(OH)D, creatinine, C-terminal telopeptide (CTX), bone-specific alkaline phosphatase (BSAP), procollagen type 1 N-terminal propeptide (P1NP), and osteocalcin were measured. Circadian patterns were derived from graphic curves of medians, and rhythmicity was assessed with Fourier analysis.

RESULTS

PTH-levels varied over the 24 h exhibiting a bimodal pattern. Nadir level corresponded to 65% of total 24-h mean. CTX and P1NP showed 24-h variations with a morning nadir and nocturnal peak with nadir levels corresponding to 23% and 79% of the 24-h mean, respectively. Albumin-corrected calcium level was held in a narrow range and alterations were corresponding to alterations in PTH. There was no distinct pattern in 24-h variations of 25(OH)D, creatinine, osteocalcin, or BSAP.

CONCLUSIONS

All participants showed pronounced 24-h variations in PTH and bone turnover markers CTX and P1NP. These findings support that Maasai participants included in this study have typical patterns of CR in calcium and bone homeostasis consistent with findings from other ethnic populations.

Bone health in adolescence

Adolescence is a fundamental period for the formation of the skeleton, because is the stage in which bones grow more in both size and strength, laying a solid foundation for the future health of the skeleton. Any condition interfering with optimal peak bone mass accrual can increase fracture risk later in life. Up to 80% of peak bone mass is genetically determined while the remaining 20% is modulated by environmental factors that, if deleterious, may result in low bone mineral density (BMD) and an increased risk of fracture. The preferred test to assess bone health is dual-energy x-ray absorptiometry (spine or total body less head) using Z scores instead of T scores, even though in short stature or growth delay, should be used the height Z-score. The correction of risk factors is the first treatment for low BMD in children and adolescents. It's necessary having a correct lifestyle for preserving bone health: a proper nutrition, an adequate physical weight-bearing activity and avoidance of alcohol intake and tobacco smoke. Bisphosphonates could be used in children who sustained osteoporotic fractures, impairing quality of life, when spontaneous recovery is low for the persistence of osteoporosis risk factors. This clinical review discusses factors affecting bone health during childhood and adolescence and deals with diagnosis and treatment of low bone mass or osteoporosis in this age group.

Study of the Influence of Sociodemographic and Lifestyle Factors on Consumption of Dairy Products: Preliminary Study in Portugal and Brazil

Sociodemographic characteristics, including regional variations, have been associated with different food consumption patterns. Behavioral factors and lifestyle variables may also contribute to different food dietary trends. In this way, the present study intended to investigate the consumption habits of the most relevant types of dairy products around the world and relate them to sociodemographic factors, for example, age, sex, education and country as well as with some anthropometric and behavioral aspects, for example, body mass index, satisfaction with body weight and exercise or sedentary lifestyles. One other objective of the study was to categorize the lifestyles of the participants, according to measured variables linked with hours of inactivity or exercise, in order to use these as possible differentiating variables for the consumption of dairy products. The study involved a questionnaire survey undertaken on a non-probabilistic convenience sample of participants from Portugal (PT) and Brazil (BR), and participation was voluntary and anonymous. The data analysis involved different statistical techniques: basic statistics, chi-square tests, factor analysis, cluster analysis and tree classification analysis. The results showed that semi skimmed milk is never consumed by about half of the participants (47.4% for PT and 46.7 for BR), and those numbers increase for skimmed (64.8% for PT and 50.9% for BR), chocolate flavored milk (82.6% for PT and 65.6% for BR) and enriched milks (94.8% for PT and 85.3% for BR). Cheeses are also consumed in the two countries by small numbers of people. The number of participants consuming imported cheeses in both countries was particularly low (only 4.0% consume these more than once a week in both countries), suggesting national products may be preferred. It was further observed that those who consume cheese do it seldom (once a week) or sometimes (2–3 times per week). Butter is also consumed by only about half of the adult population (43.8% for PT and 49.5% for BR), but the percentage of those who never consume butter increases for skimmed butter (66.0% for PT and 82.6% for BR) and unsalted butter (70.2% for PT and 69.1% for BR). The consumption of yogurts also follows similar low consumption patterns. The most frequently consumed yogurt types in Portugal are liquid (30.5% consume regularly) and natural yogurts (34.8% consume regularly), while in Brazil the most frequent are creamy fruit pulp yogurt (14.4% consume regularly), liquid (13.7% consume regularly) and Greek type yogurt (10.2% consume regularly). A factor analysis and a cluster analysis established groups according to lifestyles, as follows: 1—Screeners, 2—Exercisers, 3—Travelers and 4—Others. These lifestyles were found to be influential in the consumption of dairy products for all classes of dairy tested: milk, cheese, yogurt and butter. For example, the screeners were found to consume more milk, more butter, more cheese and more yogurt. Additionally, other influential factors were age, sex, education, BMI and satisfaction with body weight. Nevertheless, country was not a meaningfully discriminant variable in relation to the other variables included in the classification analysis. The results concluded that, despite some small differences in the patterns of consumption of dairy products in both countries, the levels of consumption of dairy products are extremely low, for all classes studied (milk, cheese, yogurt or butter). Additionally, it was concluded that some factors are influential on the level of consumption of dairy products, and therefore decision makers can plan their interventions according to the characteristics of the targeted segments of the population, according to lifestyle, age, sex, education, BMI and satisfaction with body weight.

Milk Consumption for the Prevention of Fragility Fractures

Results indicating that a high milk intake is associated with both higher and lower risks of fragility fractures, or that indicate no association, can all be presented in the same meta-analysis, depending on how it is performed. In this narrative review, we discuss the available studies examining milk intake in relation to fragility fractures, highlight potential problems with meta-analyses of such studies, and discuss potential mechanisms and biases underlying the different results. We conclude that studies examining milk and dairy intakes in relation to fragility fracture risk need to study the different milk products separately. Meta-analyses should consider the doses in the individual studies. Additional studies in populations with a large range of intake of fermented milk are warranted.

Milk for Skeletal Muscle Health and Sarcopenia in Older Adults: A Narrative Review

Skeletal muscle aging manifests as a decline in muscle quantity and quality that accelerates with aging, increasing the risk of sarcopenia. Sarcopenia is characterized by a loss of muscle strength and mass, and contributes to adverse health outcomes in older adults. Intervention studies have shown that sarcopenia may be treated by higher protein intake in combination with resistance exercise (RE). In comparison, less is known about the role of whole protein-containing foods in preventing or treating sarcopenia. Liquid milk contains multiple nutrients and bioactive components that may be beneficial for muscle, including proteins for muscle anabolism that, alone or with RE, may have myoprotective properties. However, there is a lack of evidence about the role of milk and its effects on muscle aging. This narrative review considers evidence from three observational and eight intervention studies that used milk or fortified milk, with or without exercise, as an intervention to promote muscle health and function in older adults (aged 50–99 years). The observational studies showed no association between higher habitual milk consumption and muscle-related outcomes. The results of intervention studies using fortified milk in relation to elements of sarcopenia were also negative, with further inconclusive results from the studies using a combination of (fortified) milk and exercise. Although milk contains nutrients that may be myoprotective, current evidence does not show beneficial effects of milk on muscle health in older adults. This could be due to high habitual protein intakes (>1.0 g/kg BW/d) in study participants, differences in the type of milk (low-fat vs whole) and timing of milk consumption, length of interventions, as well as differences in the sarcopenia status of participants in trials. Adequately powered intervention studies of individuals likely to benefit are needed to test the effectiveness of a whole food approach, including milk, for healthy muscle aging.

Quantitative Ultrasound and Dual X-Ray Absorptiometry as Indicators of Bone Mineral Density in Young Women and Nutritional Factors Affecting It

Young adulthood is an important stage in the accrual of bone mass. Young women are often unaware of the need, and how to optimize modifiable risk factors, particularly intake of nutrients associated with good bone health. In this study, an accessible way to estimate osteoporosis risk, quantitative ultrasound (QUS), is compared to the gold-standard technique dual X-ray absorptiometry (DXA) in a group of 54 healthy young women (18–26 years) from Manawatu, New Zealand, and the relationship with nutrient intake is investigated. Broadband ultrasound attenuation and speed of sound (BUA, SOS) were assessed by QUS calcaneal scans and bone mineral concentration/density (BMC/BMD) were determined by DXA scans of the lumbar spine and hip (total and femoral neck). Dietary intake of energy, protein, and calcium was estimated using three-day food diaries and questionnaires. DXA mean Z-scores (>−2.0) for the hip (0.19) and spine (0.2) and QUS mean Z-scores (>−1.0) (0.41) were within the expected ranges. DXA (BMD) and QUS (BUA, SOS) measurements were strongly correlated. Median intakes of protein and calcium were 83.7 g/day and 784 mg/day, respectively. Protein intake was adequate and, whilst median calcium intake was higher than national average, it was below the Estimated Average Requirement (EAR). No significant relationship was found between dietary intake of calcium or protein and BMD or BMC. To conclude, QUS may provide a reasonable indicator of osteoporosis risk in young women but may not be an appropriate diagnostic tool. Increased calcium intake is recommended for this group, regardless of BMD.

Technical position on milk and its derivatives in adult health and disease from the Asociación Mexicana de Gastroenterología and the Asociación Mexicana de Gerontología y Geriatría

Milk is a liquid food that possesses an important quantity of highly bioavailable macronutrients. In addition, it is readily accessible, as well as relatively inexpensive. Given that the knowledge of physicians about nutrition and food composition is deficient, in general, many of the dietary interventions recommended in diverse clinical settings lack a scientific basis. The aim of the present review was to produce a technical opinion that serves as a frame of reference to best sustain recommendations for consuming milk and dairy products as daily nutrition in the adult and older adult. The effects of milk and dairy products during the pediatric stage are not addressed in the present work. The Asociación Mexicana de Gastroenterología and the Asociación Mexicana de Gerontología y Geriatría jointly discussed and analyzed topics dealing with the legal designation of milk, the classification and nutritional profile of cow's milk, its nutritional characteristics, its consumption in the adult, intolerance to cow's milk, and associations of milk consumption with digestive tract alterations and other conditions. Finally, certain aspects of milk consumption in the older adult and its relation to overall health are briefly discussed.

The effect of milk consumption on bone and fracture incidence, an update

Milk is a major source of high bioavailable calcium in most developed countries with an average calcium content of 1150 mg/L, providing a ready means of meeting the daily requirements. Its content in other minerals, phosphorus, vitamins, iodine, proteins, potassium and various nutrients is supposed to be beneficial for skeleton growth and bone strength. Studies on the effects of milk or whey extracts in animal trials and on surrogate markers in humanlike bone remodeling markers or bone mineral density and many observational studies in large cohorts show positive effects on bone health or risk of hip fracture. Nevertheless, a few contradictory epidemiological studies showed an increased risk of hip fractures in subjects drinking higher quantities of milk. These conflicting results may be due to the large number of confounders and methodological issues as recall bias. Most of the experts state that there are no proven effect of milk consumption on the risk of hip fractures in a way or the other. Of a scientific point of view, there is no reason to remove from the diet of large populations an aliment rich in calcium and other interesting nutrients.

Milk drinking and risk of hip fracture: the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS)

Milk provides energy and nutrients considered protective for bone. Meta-analyses of cohort studies have found no clear association between milk drinking and risk of hip fracture, and results of recent studies are contradictory. We studied the association between milk drinking and hip fracture in Norway, which has a population characterised by high fracture incidence and a high Ca intake. Baseline data from two population-based cohorts were used: the third wave of the Norwegian Counties Study (1985-1988) and the Five Counties Study (2000-2002). Diet and lifestyle variables were self-reported through questionnaires. Height and weight were measured. Hip fractures were identified by linkage to hospital data with follow-up through 2013. Of the 35 114 participants in the Norwegian Counties Study, 1865 suffered a hip fracture during 613 018 person-years of follow-up. In multivariable Cox regression, hazard ratios (HR) per daily glass of milk were 0·97 (95 % CI 0·92, 1·03) in men and 1·02 (95 % CI 0·96, 1·07) in women. Of 23 259 participants in the Five Counties Study, 1466 suffered a hip fracture during 252 996 person-years of follow-up. HR for hip fractures per daily glass of milk in multivariable Cox regression was 0·99 (95 % CI 0·92, 1·07) in men and 1·02 (95 % CI 0·97, 1·08) in women. In conclusion, there was no overall association between milk intake and risk of hip fracture in Norwegian men and women.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

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.