Please enjoy these offerings of the most relevant milk and dairy research from April 2019! The Bulletin delivers a brief synopsis of the most current Human, Animal, and Environmental dairy research that is going on in the World, and also that which is of special interest to California dairy producers and consumers alike.
If you would like to peruse the most pertinent dairy research from months past, then visit the Dairy Research Bulletin Archive
Selected Articles on Social Responsibility, Environmental Management, and Sustainability
Impacts of weather, work rate, hydration, and clothing in heat-related illness in California farmworkers. Vega-Arroyo AJ, Mitchell DC, Castro JR, Armitage TL, Tancredi DJ, Bennett DH, Schenker MB. Am J Ind Med. 2019 Apr 9.
- The state of California produces a third of the country’s vegetables as well as two‐thirds of its fruits and nuts. Most of these commodities are grown and cultivated during the summer months, where temperatures can rise above 32°C and agricultural workers sometimes conduct arduous work for up to 12 hours a day under direct sunlight. It is these working conditions that put farmworkers at risk for heat‐related illnesses such as heat rashes, heat cramps, heat exhaustion, and heat stroke.
- Employers in California are required to provide water and encourage their workers to drink a cup (8 oz) water every 15 minutes to stay hydrated on hot days. Previous quantitative research in the city of Mendota, which is in the Central Valley of California, found that farm workers were not drinking enough water to stay hydrated throughout the day
- The primary aim of this study was to investigate the effects of work rate, hydration status, and clothing on core body temperature on California farmworkers.
- 287 farmworkers were recruited in the Summer of 2015, with 259 participants having sufficient data for analysis. The researchers collected core body temperature, ambient temperature, work rate, body weight loss, and clothing worn by each participant throughout the work day and demographic data from a questionnaire.
- The results showed statistically significant associations of core body temperature with work rate and suggest that among this population workload is the primary modifiable risk factor for heat-related illness.
Robust Biofilm-Forming Bacillus Isolates from the Dairy Environment Demonstrate an Enhanced Resistance to Cleaning-in-Place Procedures. Ostrov I, Paz T, Shemesh M. Foods. 2019 Apr 20;8(4). pii: E134.
- One of the main strategies for maintaining the optimal hygiene level in dairy processing facilities is regular cleaning and disinfection, which is incorporated in the cleaning-in-place (CIP) regimes. However, a frail point of the CIP procedures is their variable efficiency in eliminating biofilm bacteria.
- In the present study, the researchers evaluated the susceptibility of strong biofilm-forming dairy Bacillus isolates to industrial cleaning procedures using two differently designed model systems.
- According to the results, the dairy-associated Bacillusisolates demonstrate a higher resistance to CIP procedures, compared to the non-dairy strain of subtilis.
- Notably, the tested dairy isolates are highly persistent to different parameters of the CIP operations, including the turbulent flow of liquid (up to 1 log), as well as the cleaning and disinfecting effects of commercial detergents (up to 2.3 log).
- Moreover, these observations indicate an enhanced resistance of poly-γ-glutamic acid (PGA)-overproducing subtilis, which produces high amounts of proteinaceous extracellular matrix, to the CIP procedures (about 0.7 log, compared to the wild-type non-dairy strain of B. subtilis). Therefore, it is suggested that the enhanced resistance to the CIP procedures by the dairy Bacillusisolates can be attributed to robust biofilm formation.
- In addition, this study underlines the importance of evaluating the efficiency of commercial cleaning agents in relation to strong biofilm-forming bacteria, which are relevant to industrial conditions. Consequently, the findings of this study can facilitate the assessment and refining of the industrial CIP procedures.
Prevalence of Escherichia coli O157 and Salmonella spp. in solid bovine manure in California using real-time quantitative PCR. Chen Z, Biswas S, Aminabadi P, Stackhouse JW, Jay-Russell MT, Pandey PK. Lett Appl Microbiol. 2019 Apr 1.
- California is the largest dairy producer in the U.S. In 2014, there were 1.8 million dairy cattle that produced over 35 million tons of manure. The common agricultural practice of using bovine manure as biological soil amendments presents potential risks to public health if untreated manure containing human pathogens, such as E. coli O157 and Salmonella spp., is applied to cropland. Understanding the prevalence and levels of human pathogens in bovine manure is important to assess the public health risk of its application as biological soil amendments.
- The occurrence of E. coli O157 and Salmonella spp. in solid bovine manure was investigated through a multi-county survey in California.
- Solid bovine manure samples (n=91) were collected from 13 dairy farms located in multiple counties in California between June 2016 and August 2017.
- The prevalence of E. coli O157 and Salmonella spp. in solid bovine manure was 15.4% and 6.6%, respectively. E. coli O157 and Salmonella spp. levels in positive samples ranged considerably.
- Surface samples of manure piles had higher prevalence and levels of E. coli O157 and Salmonella spp. than subsurface samples, while no seasonal effects on pathogen occurrence were observed.
- These results indicated that solid bovine manure is a source of E. coli O157 and Salmonella spp. and the application of untreated manure as biological soil amendments may pose potential risks to public health.
Fate of Mycobacterium avium subsp. paratuberculosis and changes in bacterial diversity populations in dairy slurry after chemical treatments. Avilez C, Alfaro MA, Salazar F, Encina C, Verdugo C, Martínez O, Collins MT, Salgado M. J Appl Microbiol. 2019 Apr 22.
- A major drawback of using dairy slurry as fertilizer is that it may contains pathogens such as Mycobacterium avium subsp. paratuberculosis (MAP), and it could represent a risk to animal and public health.
- Thus, the aim of this study was to evaluate the fate of MAP and bacterial communities in dairy slurry after chemical treatments.
- Cattle slurry, naturally contaminated with MAP, was collected from a dairy herd and divided into 32 glass bottles which were assigned to eight different treatments (control, 3.0% CaO, 0.5% NaOH; 0.087%, 0.11% and 0.14% H2 SO4 ; and 1.0% and 2.5% KMnO4 ).
- Treated dairy slurry samples were evaluated at 0, 1, 3, 7, 15, 30- and 60-days following treatments application for viable MAP and dairy slurry pH, and in addition temperature in this material was monitored continuously.
- Model results indicated that only the 3.0% CaO treatment had a statistically important negative effect on MAP counts during the study period. For most treatments, MAP was undetectable immediately after chemical treatment but re-appeared over time, in some replicates at low concentrations. However, in those cases MAP counts were not statistically different than the control treatment.
- Regarding the fate of the other bacterial populations, the Firmicutes phylum was the dominant population in the un-treated slurry while Clostridia class members were among the most prevalent bacteria after the application of most chemical treatments.
- In conclusion, only the 3% CaO treatment had a statistically important negative effect on MAP viability in cattle slurry. This study provides evidence of MAP partial control in dairy slurry. This information should be considered as a best management practice to reduce MAP and other pathogens for slurry management on dairy farms.
The value of manure – Manure as co-product in life cycle assessment. Leip A, Ledgard S, Uwizeye A, et al. J Environ Manage. 2019 Apr 19;241:293-304.
- Livestock production is important for food security, nutrition, and landscape maintenance, but it is associated with several environmental impacts.
- To assess the risk and benefits arising from livestock production, transparent and robust indicators are required, such as those offered by life cycle assessment. A central question in such approaches is how environmental burden is allocated to livestock products and to manure that is re-used for agricultural production.
- To incentivize sustainable use of manure, it should be considered as a co-product as long as it is not disposed of, or wasted, or applied in excess of crop nutrient needs, in which case it should be treated as a waste.
- This paper proposes a theoretical approach to define nutrient requirements based on nutrient response curves to economic and physical optima and a pragmatic approach based on crop nutrient yield adjusted for nutrient losses to atmosphere and water.
- Allocation of environmental burden to manure and other livestock products is then based on the nutrient value from manure for crop production using the price of fertilizer nutrients.
Assessment of rumen bacteria in dairy cows with varied milk protein yield. Xue MY, Sun HZ, Wu XH, Guan LL, Liu JX. J Dairy Sci. 2019 Apr 10. pii: S0022-0302(19)30343-1.
- Many efforts have been made to increase milk protein yield, with the advancements being made to enhance either milk yield or milk protein via improvements in genetics, herd management, and nutrition.
- Although milk protein and milk yield are negatively correlated in dairy production, there are cows with both high milk protein content and high milk yield levels within a herd when the cows were fed the same diet.
- The present study was conducted to assess rumen bacteria in lactating cows with different milk protein yield, aiming to understand the role of rumen bacteria in this trait.
- Cows with high milk protein yield (high milk yield and high milk protein content, HH; n = 20) and low milk protein yield (low milk yield and low milk protein content, LL; n = 20) were selected from 374 mid-lactation Holstein dairy cows fed a high-grain diet.
- Measurement of the rumen fermentation products showed that the concentrations of ruminal total volatile fatty acids, propionate, butyrate, and valerate and the proportion of isobutyrate were higher in the HH cows than in the LL cows. Additional analysis of the rumen bacterial community revealed that the richness of rumen microbiota was higher in the LL cows than in the HH cows.
- Among the 10 predominant bacterial phyla, the relative abundance of Proteobacteria was 1.36-fold higher in the HH cows than in the LL cows. At the genus level, the relative abundance of Succinivibrio was significantly higher and that of Clostridium tended to be higher in the LL cows than in the HH cows. Sharpea was 2.28-fold enriched in the HH cows compared with the LL cows.
- Different relationships between the relative abundances of rumen microbial taxa and volatile fatty acid concentrations were observed in the HH and the LL animals, respectively. Succinivibrio and Prevotella were positively correlated with acetate, propionate, and valerate in the LL cows, whereas Sharpea was positively correlated with propionate and valerate concentrations in the HH cows.
- Collectively, these results revealed that rumen bacterial richness and the relative abundances of several bacterial taxa significantly differed between dairy cows with high and low milk protein yields, suggesting the potential roles of rumen microbiota in contributing to milk protein yield in dairy cows.
Selected Articles on Sustainable Nutrition
Greenhouse Gas Emissions in the United States Food System: Current and Healthy Diet Scenarios. Hitaj C, Rehkamp S, Canning P, Peters CJ. Environ Sci Technol. 2019 Apr 23.
- Every day, consumers make choices about what they eat, taking into account taste, nutrition, availability, safety, and cost, among other factors. Increasingly, consumers are also interested in the impact of food production on the environment, as shown by the growth in the organic industry and the emergence of other labels certifying sustainable production practices or packaging.
- The objective of this study was to estimate the impact on greenhouse gas emissions (GHGE) of shifting from the current average United States diet to four alternative diets that meet the 2010 Dietary Guidelines for Americans (DGA).
- This study combined a diet model and a biophysical model of land use for crops and livestock to estimate food system GHGE from the combustion of fossil fuels and from biogenic sources, including enteric fermentation, manure management, and soil management.
- The researchers found that an omnivore diet that meets the DGA while constraining cost leaves food system GHGE essentially unchanged relative to the current baseline diet (~3,191 kilograms of CO2 eq per capita per year), while a DGA-compliant vegetarian and a DGA-compliant omnivore diet that minimizes energy consumption in the food system reduce GHGE by 32% and 22%, respectively.
- These emission reductions were achieved mainly through quantity and composition changes in the meat, poultry, fish; dairy; and caloric sweeteners categories.
- Shifting from current to healthy diets as defined by the DGA does not necessarily reduce GHGE in the U.S. food system, although there are diets, including two presented here and by inference many others, which can achieve a reduction in GHGE.
Innovation to Create a Healthy and Sustainable Food System: A Science Advisory From the American Heart Association. Anderson CAM, Thorndike AN, Lichtenstein AH, Van Horn L, Kris-Etherton PM, Foraker R, Spees C. Circulation. 2019 Apr 29.
- Current dietary intakes of North Americans are inconsistent with the Dietary Guidelines for Americans. This occurs in the context of a food system that precludes healthy foods as the default choices.
- To develop a food system that is both healthy and sustainable requires innovation. This science advisory from the American Heart Association describes both innovative approaches to developing a healthy and sustainable food system and the current evidence base for the associations between these approaches and positive changes in dietary behaviors, dietary intakes, and when available, health outcomes.
- Innovation can occur through policy, private sector, public health, medical, community, or individual-level approaches and could ignite and further public-private partnerships. Some innovations have been observed to increase the purchasing of healthy foods or have increased diversity in food choices, but there remains limited evidence linking these innovations with health outcomes.
- The demonstration of evidence-based improvements in health outcomes is challenging for any preventive interventions, especially those related to diet, because of competing lifestyle and environmental risk factors that are difficult to quantify. A key next step in creating a healthier and more sustainable food system is to build innovative system-level approaches that improve individual behaviors, strengthen industry and community efforts, and align policies with evidence-based recommendations.
- To enable healthier food choices and favorably impact cardiovascular health, immediate action is needed to promote favorable innovation at all levels of the food system.
Environmental impacts of dietary quality improvement in China. He P, Baiocchi G, Feng K, Hubacek K, Yu Y. J Environ Manage. 2019 Jun 15;240:518-526.
- Dietary-related risks rank top among all the health risks in many countries. The 2nd United Nations Sustainable Development Goal aims to end hunger, achieve food security and improved nutrition and promote sustainable agriculture. Yet whether improving nutritional quality also benefits the environment is still under-explored, particularly for developing countries.
- China is an interesting and important case because of its rapidly changing dietary patterns distinct from the western countries studied in the literature, sub-national level heterogeneity, socio-economic characteristics and lifestyles, as well as its considerable population.
- This paper evaluates greenhouse gas (GHG) emissions, water consumption, and land appropriation resulting from shifting the Chinese population to healthy diets. The researchers quantified the environmental impacts of individual diets using the latest available data of China Health and Nutrition Survey (2011), and compared them with the environmental impacts of suggested healthy dietary patterns in accordance with the 2016 Chinese Dietary Guidelines.
- The results showed that if all Chinese would follow healthy diets rather than their current diets revealed in the survey, GHG emissions, water consumption, and land occupation would increase by 7.5% (63.9 Mt CO2e annually), 53.5% (510 billion m3), and 54.2% (1256 billion m2), respectively.
- These findings indicate an expense of increased GHG emissions, and consumption of water and land resources in improving health. They also highlight the need to focus on the effects of improved economic conditions and urbanization in reconciling environmental impacts and human nutritional adequacy.
Dietary Change Scenarios and Implications for Environmental, Nutrition, Human Health and Economic Dimensions of Food Sustainability. Chen C, Chaudhary A, Mathys A. Nutrients. 2019 Apr 16;11(4). pii: E856.
- Demand side interventions, such as dietary change, can significantly contribute towards the achievement of 2030 national sustainable development goals. However, most previous studies analyzing the consequences of dietary change focus on a single dimension of sustainability (e.g., environment) using a limited number of indicators and dietary scenarios.
- A multi-dimension and multi-indicator analysis can identify the potential trade-offs. Here, starting from the current food consumption data (year 2011), the researchers first designed nine alternative dietary scenarios (healthy Swiss diet, healthy global diet, vegetarian, vegan, pescatarian, flexitarian, protein-oriented and meat-oriented diets and a food greenhouse gas tax diet).
- Next the researchers calculated three nutritional quality (nutrient balance score, disqualifying nutrient score, percent population with adequate nutrition), five environmental (greenhouse gas, water, land, nitrogen and phosphorus use), one economic (daily food expenditure) and one human health indicator (DALYs) for current and alternative diets.
- The researchers found that transition towards a healthy diet following the guidelines of Swiss society of nutrition is the most sustainable option and is projected to result in 36% lesser environmental footprint, 33% lesser expenditure and 2.67% lower adverse health outcome (DALYs) compared with the current diet.
- On the other extreme, transition towards a meat or protein oriented diet can lead to large increases in diet related adverse health outcomes, environmental footprint, daily food expenditure and a reduction in intakes of essential nutrients (for Vitamin C, Fiber, Potassium and Calcium).
- The researchers found that shifting to the vegetarian and vegan diet scenarios might lead to a reduction in intakes of certain micronutrients currently supplied primarily by animal-sourced foods (Vitamin B12, Choline and Calcium).
- Results show that achieving a sustainable diet would entail a high reduction in the intake of meat and vegetable oils and a moderate reduction in cereals, roots and fish products and at the same time increased intake of legumes, nuts, seeds, fruits and vegetables.
- Overall, the analysis underscores the need to consider multiple indicators while assessing the dietary sustainability and provides a template to conduct such studies in other countries and settings. Future efforts should focus on assessing the potential of different interventions and policies that can help transition the population to sustainable dietary patterns.
Selected Articles on Dairy Intake and Human Health
Health benefits of yogurt among infants and toddlers aged 4 to 24 months: a systematic review. Donovan SM, Rao G. Nutr Rev. 2019 Apr 30. pii: nuz009.
- Health benefits of yogurt are well documented in adults and older children, but less is known about the effects of yogurt in infants and toddlers (aged 4 to 24 months).
- The aim of this qualitative systematic review was to assess the effects of yogurt and fermented milk products on the health of infants and toddlers.
- Randomized controlled trials, observational studies, and prospective cohort studies were included in this systematic review. The included studies (published between 1987 and 2017) were heterogeneous with respect to sample size, study population, and type of yogurt used.
- Five of six studies showed a positive effect of yogurt consumption on infectious diarrhea. Two studies reported a positive effect on gut microbiota composition. Two cohort studies reported a positive effect on reducing the incidence of atopic dermatitis, one of which also reported a positive impact on food sensitivity.
- In conclusion, published evidence, much of it decades old, supports a health benefit of yogurt consumption in infants and children. New short- and long-term studies are needed to better evaluate the impact of yogurt consumption in contemporary settings.
Interventions Aimed at Increasing Dairy and/or Calcium Consumption of Preschool-Aged Children: A Systematic Literature Review. Srbely V, Janjua I, Buchholz AC, Newton G. Nutrients. 2019. 27;11(4).
- Dairy product consumption is important during childhood, as dairy products provide nutrients to support growth and development. However, a high proportion of children globally are not meeting recommended daily intakes, which may have long-term health implications.
- Accumulating evidence suggests that interventions aimed at instilling healthy lifestyle habits are most effective when initiated during the preschool years. Therefore, the purpose of this review was to identify the characteristics of effective dairy and/or calcium interventions targeting preschool-aged children.
- A systematic literature review identified 14 intervention studies published between 1998–2018 addressing dairy/calcium intakes in the preschool population (1.5 to 5 years).
- Five of the 14 studies included in the review reported significant improvements in children’s dairy (4/5) or calcium (1/5) intake. Characteristics that may enable intervention effectiveness include the delivery of interventions in one setting (preschool facility), using specific behavior change techniques (environmental restructuring and teach to use prompts/cues), and targeting both parent and child.
- Overall, the interventions assessed demonstrated variable success and highlighted the need for developing effective interventions designed to increase dairy and/or calcium intakes in preschool-aged children.
The effect of high compared with low dairy consumption on glucose metabolism, insulin sensitivity, and metabolic flexibility in overweight adults: a randomized crossover trial. Eelderink C, Rietsema S, van Vliet IMY, Loef LC, Boer T, Koehorst M, Nolte IM, Westerhuis R, Singh-Povel CM, Geurts JMW, Corpeleijn E, Bakker SJL. Am J Clin Nutr. 2019 Apr 17. pii: nqz017.
- Dairy products contain many nutritious components that may benefit metabolic health. There are indications that glucose metabolism and insulin sensitivity, which are generally disturbed in overweight and obese individuals, may improve by increased dairy intake. This may also affect one’s metabolic flexibility.
- The aim of this study was to investigate the effects of high compared with low dairy intake on glucose metabolism, insulin sensitivity, and metabolic flexibility in overweight adults (aged 45-65 years).
- In this randomized intervention study, subjects consumed a high-dairy diet (5-6 dairy portions/day) and a low-dairy diet (≤1 dairy portion/day), for 6 weeks in a crossover design, with a washout period of 4 weeks in between. Dairy portions were 200 grams semi-skimmed yogurt, 30 grams reduced-fat (30+) cheese, and 250 milliliters semi-skimmed milk and buttermilk.
- The study was completed by 45 overweight men and postmenopausal women. Fasting glucose concentrations were similar between groups, whereas fasting insulin concentrations were lower after the low-dairy diet. This resulted in a higher measure of insulin resistance after the high-dairy diet. Postprandial glucose and insulin responses as well as glucose kinetics were similar after both diets.
- The amount of dairy intake during a 6-week period had a neutral effect on metabolic flexibility or postprandial glucose metabolism in middle-aged overweight subjects. More trials are needed to study the effects of specific dairy types and to differentiate between metabolic subgroups.
Dietary proteins and protein sources and risk of death: the Kuopio Ischaemic Heart Disease Risk Factor Study. Virtanen HEK, Voutilainen S, Koskinen TT, Mursu J, Kokko P, Ylilauri MPT, Tuomainen TP, Salonen JT, Virtanen JK. Am J Clin Nutr. 2019 Apr 9. pii: nqz025.
- Previous studies investigating protein intake in relation to mortality have provided conflicting results.
- The researchers investigated the associations of dietary protein and protein sources with risk of disease death in the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study. The study population consisted of 2,641 Finnish men, aged 42-60 y at baseline in 1984-1989.
- During the average follow-up of 22.3 years, the researchers observed 1,225 deaths due to disease. Higher intakes of total protein and animal protein had borderline statistically significant associations with increased mortality risk: in the highest compared with the lowest quartile for total protein intake and for animal protein intake.
- Higher animal-to-plant protein ratio and higher meat intake were associated with increased mortality. When evaluated based on disease history at baseline, the association of total protein with mortality appeared more evident among those with a history of type 2 diabetes, cardiovascular disease, or cancer (n = 1094) compared with those without disease history (n = 1547).
- Apart from meat intake, other protein sources—that is, dairy, fish, egg, and plant protein sources—were not associated with mortality risk.
Consumption of Meat, Fish, Dairy Products, Eggs and Risk of Ischemic Heart Disease: A Prospective Study of 7198 Incident Cases Among 409,885 Participants in the Pan-European EPIC Cohort. Key TJ, Appleby PN, Bradbury KE, et al. Circulation. 2019 Apr 22.
- There is uncertainty about the relevance of animal foods to the etiology of ischemic heart disease (IHD).
- For this study, the researchers examined meat, fish, dairy products and eggs and risk for IHD in the pan-European EPIC cohort.
- A prospective study of 409,885 men and women in nine European countries. During 12.6 years mean follow up, 7198 participants had a myocardial infarction or died from IHD.
- The results showed:
- The hazard ratio for IHD was 1.19 per 100 grams/day increment in intake of red and processed meat.
- Risk was inversely associated with intakes of yogurt per 100 grams/day increment), cheese per 30 grams/day increment) and eggs per 20 grams/day increment).
- Risk was not significantly associated with intakes of poultry, fish or milk.
- In analyses modelling dietary substitutions, replacement of 100 kcal/day from red and processed meat with 100 kcal/day from fatty fish, yogurt, cheese or eggs was associated with approximately 20% lower risk of IHD.
- Consumption of red and processed meat was positively associated with serum non-HDL cholesterol concentration and systolic blood pressure, and consumption of cheese was inversely associated with serum non-HDL cholesterol.
- In conclusion, the risk for IHD was positively associated with consumption of red and processed meat, and inversely associated with consumption of yogurt, cheese and eggs.
Effects of full-fat dairy products on subclinical vascular function in adults with elevated blood pressure: a randomized clinical trial. Roy SJ, Fico BG, Baker BD, Lapierre SS, Shah JA, Gourley DD, Delfausse LA, Tanaka H. Eur J Clin Nutr. 2019 Apr 25.
- High consumption of low- and non-fat dairy products improves vascular dysfunction associated with elevated arterial blood pressure (BP). Currently, it is unknown if conventional full-fat dairy products improve vascular functions.
- The aim of this study was to determine if adding whole milk and full-fat dairy products to the normal routine diet improves vascular function in adults with elevated BP.
- Sixty adults (58 ± 2 years) with elevated BP (systolic/diastolic; 120-159/ < 99 mmHg) were randomized into a controlled crossover intervention trial consisting of two 4-week dietary periods. The highdairy condition consisted of adding four daily servings of whole milk or full-fat dairy products to the normal diet and eliminated all dairy intake during the control (no dairy) condition. A 2-week washout period separated the dietary conditions.
- Carotid-femoral pulse wave velocity and brachial arterial flow-mediated dilation did not differ significantly between high dairy and nodairy conditions. The results were consistent when ultrasound-derived vascular distension measures (arterial compliance, beta-stiffness index, and elastic modulus) were evaluated. Cardiovagal baroreceptor sensitivity demonstrated no significant difference for either dietary condition.
- The solitary addition of whole milk and full-fat dairy products has no effect on subclinical vascular function in adults with elevated BP when compared to a no dairy diet.
Role of single serving form of dairy on satiety and postprandial glycaemia in young and older healthy adults. Vien S, Fabek H, Yamagishi Y, Lee YT, Luhovyy BL, Anderson GH. Appl Physiol Nutr Metab. 2019 Apr 30.
- Dairy proteins reduce appetite and improve postprandial glycemic response in adults. However, there are no reports of dairy in amounts usually consumed on satiety and postprandial glycemia in either young or older adults.
- In a randomized crossover design, 30 healthy young adults and 30 healthy/overweight older adults consumed one serving of skim milk (0.1% milkfat), whole milk (3.25% milkfat), plain Greek yogurt (2% milkfat), cheddar cheese (31% milkfat), and water (energy-free control) after a 12 h fast.
- All dairy treatments reduced post-treatment subjective appetite over 3 hours by 8-17% more than water. Greek yogurt reduced appetite more than skim and whole milk by 9 and 7%, respectively.
- Post-treatment blood glucose over 2 hours was 42% lower in young compared to older adults. It was also 52-78% lower after cheese compared to milks and yogurt. Post-treatment insulin after cheese was only 10-15% of that after milks and Greek yogurt.
- In conclusion, single servings of dairy differ in effect on postprandial satiety and glycemia and merit consideration in management of metabolic syndrome.