Welcome to the November 2020 Dairy Research Bulletin. The Dairy Research 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

Contributions of dairy products to environmental impacts and nutritional supplies from United States agriculture. Liebe DL, Hall MB, White RR.J Dairy Sci. 2020 Nov;103(11):10867-10881.

  • Questions regarding the balance between the contribution to human nutrition and the environmental impact of livestock food products rarely evaluate specific species or how to accomplish the recommended depopulation.
  • The objective of this study was to assess current contributions of the US dairy industry to the supply of nutrients and environmental impact, characterize potential impacts of alternative land use for land previously used for crops for dairy cattle, and evaluate the impacts of these approaches on US dairy herd depopulation.
  • Researchers modeled 3 scenarios to reflect different sets of assumptions for how and why to remove dairy cattle from the US food production system coupled with 4 land-use strategies for the potential newly available land previously cropped for dairy feed. Scenarios also differed in assumptions of how to repurpose land previously used to grow grain for dairy cows.
  • The current system provides sufficient fluid milk to meet the annual energy, protein, and calcium requirements of 71.2, 169, and 254 million people, respectively. Vitamins supplied by dairy products also make up a high proportion of total domestic supplies from foods, with dairy providing 39% of the vitamin A, 54% of the vitamin D, 47% of the riboflavin, 57% of the vitamin B12, and 29% of the choline available for human consumption in the United States.
  • Retiring (maintaining animals without milk harvesting) dairy cattle under their current management resulted in no change in absolute greenhouse gas emissions (GHGE) relative to the current production system. Both depopulation and retirement to pasture resulted in modest reductions (6.8-12.0%) in GHGE relative to the current agricultural system.
  • Most dairy cow removal scenarios reduced availability of essential micronutrients such as α-linolenic acid, Ca, and vitamins A, D, B12, and choline. Those removal scenarios that did not reduce micronutrient availability also did not improve GHGE relative to the current production system.
  • These results suggest that removal of dairy cattle to reduce GHGE without reducing the supply of the most limiting nutrients to the population would be difficult.

Consumer perception of the sustainability of dairy products and plant-based dairy alternatives. Schiano AN, Harwood WS, Gerard PD, Drake MA.J Dairy Sci. 2020 Oct 14:S0022-0302(20)30822-5. 

  • Plant-based dairy alternative beverage sales have increased in recent years. Plant-based dairy alternatives often advertise on a platform of sustainability and environmental commitment. To successfully position and market dairy products in this competitive environment, dairy companies must understand the consumer definition of and importance placed on sustainability, as well as communicate sustainability information effectively.
  • The objective of this study was to characterize consumer perception of the sustainability of milk and dried dairy ingredients and their respective plant-based alternatives.
  • Focus groups and 2 online surveys were conducted. In the first survey, maximum difference scaling was used to rank the importance of specific dairy product attributes to sustainability, along with an exercise in which respondents selected whether a fluid milk or protein powder product was sustainable.
  • A follow-up survey included 2 exercises in which respondents selected whether generic dairy products or dried dairy ingredients were sustainable, natural, healthy, trustworthy, or ethical.
  • Over half of dairy product consumers reported that they looked for sustainability-related information. Consumers who purchased both plant-based dairy alternative and dairy products placed a higher self-reported importance on sustainability than those who purchased dairy products only.
  • Focus group and survey maximum difference scaling results identified 5 key attributes for sustainability: minimal carbon footprint/greenhouse gas emissions, few/no preservatives, animal happiness and welfare, and simple/minimal ingredients.
  • Product labels were the most common source of sustainability information, although consumers also sought information on websites affiliated and unaffiliated with dairy companies.
  • Dairy companies may be able to differentiate themselves by helping consumers make these choices by simplifying sustainability-related messaging and by maintaining open, transparent communication regarding sustainability.

Recent food safety and fraud issues within the dairy supply chain (2015-2019). Montgomery H, Haughey SA, Elliott CT.Glob Food Sec. 2020 Sep;26:100447.

  • Milk and milk products play a vital role in diets around the globe. Due to their nutritional benefits there has been an increase in production and consumption over the past thirty years. For this growth to continue the safety and authenticity of dairy products needs to be maintained which is a huge area of concern. Throughout the process, from farm to processor, different sources of contamination (biological, chemical or physical) may occur either accidently or intentionally.
  • Through online resources (the EU Rapid Alert System for Food and Feed (RASFF) and HorizonScan) safety and fraud data were collected from the past five years relating to milk and milk products.
  • Cheese notifications were most frequently reported for both safety alerts (pathogenic micro-organisms) and fraud incidences (fraudulent documentation). Alongside the significant number of biological contaminations identified, chemical, physical and inadequate controls (in particular; foreign bodies, allergens, industrial contaminants and mycotoxins) were also found. Although the number of incidents were significantly smaller, these contaminants can still pose a significant risk to human health depending on their toxicity and exposure.
  • Grey literature provided a summary of contamination and fraud issues from around the globe and shows its potential to be used alongside database resources for a holistic overview. In ensuring the integrity of milk during ever changing global factors (climate change, competition between food and feed and global pandemics) it is vital that safety and authenticity issues are continually monitored by industry, researchers and governing bodies.

The state of phosphorus balance on 58 Virginia dairy farms. Pearce A, Maguire R.J Environ Qual. 2020;49(2):324-334.

  • Managing a sustainable dairy farm requires balancing phosphorus (P) imports and exports that enter and leave through the farm gate. Over the long term, P surpluses will elevate soil-test P concentrations above crop requirements through routine land applications of manure.
  • The objectives of this study were aimed at Virginia dairy farms (a) to determine P mass balances, (b) to define potential guidelines for a sustainable and feasible zone of operation based on P balance and P use efficiency, and (c) to assess risk factors driving P surplus and P use inefficiencies.
  • Data on farm-gate P imports and exports via feed, manure, crops, fertilizers, bedding, animals, and milk were collected for 58 dairy farms in Virginia. There was no relationship between farm P balance and milk production, indicating that a P surplus was not necessary for good milk productivity.
  • A feasible P balance limit was calculated below which 75% of farms could operate, and this was 18.7 kg P ha-1. Two risk factors were identified for farms having a P balance above this limit: (a) land application of poultry litter and (b) excessive import of P through feed.
  • Combined dairy and beef operations generally had more land and a lower P balance, whereas having combined dairy and poultry did not raise the P balance as long as poultry litter was exported. Dairy farms in Virginia can operate with a sustainable P balance as long as they avoid using excessive poultry litter and pay attention to P imported through purchased feed.

Bacterial Community Dynamics Distinguish Poultry Compost from Dairy Compost and Non-Amended Soils Planted with Spinach. Neher DA, Limoges MA, Weicht TR, Sharma M, Millner PD, Donnelly C.Microorganisms. 2020 Oct 18;8(10):1601.

  • In 2015, the use of manure-derived fertilizer occurred in 11.7% of U.S. fruit and vegetable farms, a significant 2.6% increase from six years prior. Much of this increase is attributable to the growing popularity of composted manure, which increased in use by 6.2% in the same period.
  • The aim of this study was to determine whether and how poultry litter compost and dairy manure compost alter the microbial communities within field soils planted with spinach.
  • In three successive years, separate experimental plots on two fields received randomly assigned compost treatments varying in animal origin: dairy manure (DMC), poultry litter (PLC), or neither (NoC).
  • Bacteria in the phylum Bacteriodetes, classes Flavobacteriia and Spingobacteriales (FluviicolaFlavobacteriia, and Pedobacter), were two to four times more abundant in soils amended with PLC than DMC or NoC consistently among fields and years.
  • Fungi in the phylum Ascomycota were relatively abundant, but their composition was field-specific and without treatment differences.
  • The data verify that the effects of PLC and DMC on soil communities are based on their microbial composition and not a response to the C source or nutrient content of the compost.

Consumers preferences on nutritional attributes of dairy-alternative beverages: hedonic pricing models. Yang T, Dharmasena S.Food Sci Nutr. 2020 Aug 24;8(10):5362-5378.

  • Dairy products, especially milk play a crucial role in assuring dietary quality for U.S. households. However, due to taste, nutrition, health and environmental concerns, households increasingly prefer to consume dairy alternative beverages instead of conventional milk in the U.S.
  • This work is motivated by the need to take into consideration of intrinsic characteristics and differences of such characteristics when analyzing the changes of consumers’ purchasing behavior of and willingness to pay for dairy alternative beverages and conventional milk products.
  • The results show that consumers exert the highest weights and assign highest evaluation on such qualitative characteristic as nutritional attributes which include calories, protein, fat, vitamin A and vitamin D in which protein is the most valued attribute and other characteristics such as package size, multi pack and brand.
  • The hedonic pricing order and value of these qualitative characteristic are indicative of consumers’ purchasing behavior and thus provide essential information for manufacturers to better differentiated their products and develop products catering to consumer’s preferred attributes.

Designing a healthy, low-cost and environmentally sustainable food basket: an optimisation study. Eini-Zinab H, Sobhani SR, Rezazadeh A.Public Health Nutr. 2020 Oct 29:1-10.

  • Sustainable diets are diets with low environmental impacts and high affordability which contribute to food and nutrition security.
  • The present study aimed to develop a healthy, low-cost and environmental-friendly food basket for Iran based on current consumption.
  • 100,500 households in urban and rural areas of Iran, participated in The Households Income and Expenditure Survey. Linear Programming was used to obtain the optimal diets, separately, for each goal of the sustainable food basket:
    1. Diet with maximum Nutrient Rich Food (NRF) index
    2. Diet with minimum cost
    3. Diet with the minimum water footprint
    4. Diet with the minimum carbon footprint
  • In the ‘optimal model’, compared with the usual consumption, the amount of the ‘bread, cereal, rice, and pasta’, ‘meat, poultry, fish, eggs, legumes, and nuts’ and ‘fats, oils, sugars, and sweets’ groups was decreased. Inside those food groups, cereals, poultry and vegetable oil subgroups were increased. Also, dairy, fruits and vegetable groups were increased.
  • In this model, there was a 14 % reduction in the total water footprint, a 14 % decrease in the total carbon footprint, a 23 % decrease in the cost and a 7 % increase in NRF of diet compared with the usual consumption.
  • Increasing the consumption of dairy, fruits and vegetables and reducing the consumption of bread, rice, pasta, meat, fish, eggs, legumes, nuts, hydrogenated fats and sugars are required to achieve a sustainable food basket.


Selected Articles on Dairy Intake and Human Health

MILK Symposium review: The importance of milk and dairy foods in the diets of infants, adolescents, pregnant women, adults, and the elderly. Givens DI.J Dairy Sci. 2020 Nov;103(11):9681-9699.

  • The ongoing increase in life expectancy is not always accompanied by an increase in healthy life span. There is increasing evidence that dietary exposure in early life can substantially affect chronic disease risk in later life.
  • Milk and dairy foods are important suppliers of a range of key nutrients, with some being particularly important at certain life stages. It is now recognized that milk protein can stimulate insulin-like growth factor-1 (IGF-1), essential for longitudinal bone growth and bone mass acquisition in young children, thus reducing the risk of stunting.
  • Low milk consumption during adolescence, particularly by girls, may contribute to suboptimal intake of calcium, magnesium, iodine, and other important nutrients. Given the generally low vitamin D status of European populations, this may have already affected bone development, and any resulting reduced bone strength may become a big issue when the populations are much older.
  • Suboptimal iodine status of many young women has already been reported together with several observational studies showing an association between suboptimal iodine status during pregnancy and reduced cognitive development in the offspring.
  • There is now good evidence that consumption of milk and dairy foods does not lead to an increased risk of cardiovascular diseases and type 2 diabetes. Indeed, some negative associations are seen, notably between yogurt consumption and type 2 diabetes, which should be researched with urgency.
  • There is an ongoing, often too simplistic debate about the relative value of animal versus plant food sources for protein in particular. It is important that judgments on the replacement of dairy products with those from plants also include the evidence on relative functionality, which is not expressed in simple nutrient content (e.g., hypotensive and muscle synthesis stimulation effects). Only by considering such functionality will a true comparison be achieved.

Plant-based dietary practices in Canada: examining definitions, prevalence and correlates of animal source food exclusions using nationally representative data from the 2015 Canadian Community Health Survey-Nutrition. Valdes M, Conklin A, Veenstra G, Black JL.Public Health Nutr. 2020 Oct 27:1-10.

  • While plant-based dietary practices (PBDPs) have been recommended to improve both population health and environmental sustainability outcomes, no nationally representative Canadian studies have described the prevalence or correlates of excluding animal source foods.
  • The current study therefore: (1) created operationalised definitions of PBDPs based on animal source food exclusions to estimate the prevalence of Canadians who adhere to PBDPs and (2) examined key correlates of PBDPs.
  • Researchers collected cross-sectional data from Canadians aged 2 years and above (n = 20 477) coming from all 10 provinces in the 2015 Canadian Community Health Survey-Nutrition. Respondents’ PBDPs were categorised as:
    1. vegan (excluded red meat, poultry, fish, eggs and dairy)
    2. vegetarian (excluded red meat, poultry and fish)
    3. pescatarian (excluded red meat and poultry)
    4. red meat excluder (excluded red meat)
  • In 2015, approximately 5 % of Canadians reported adhering to any PBDP (all categories combined) with the majority (2·8 %) categorised as a red meat excluder, 1·3 % as vegetarian, 0·7 % as pescatarian and 0·3 % as vegan. South Asian cultural identity and higher educational attainment were significantly associated with reporting a vegetarian/vegan PBDP.
  • Despite growing public discourse around PBDPs, only 5 % of Canadians reported PBDPs in 2015. Understanding the social and cultural factors that influence PBDPs is valuable for informing future strategies to promote environmentally sustainable dietary practices.

Replacing the consumption of red meat with other major dietary protein sources and risk of type 2 diabetes mellitus: a prospective cohort study. Würtz AML, Jakobsen MU, Bertoia ML, Hou T, Schmidt EB, Willett WC, Overvad K, Sun Q, Manson JE, Hu FB, Rimm EB.Am J Clin Nutr. 2020 Oct 23:nqaa284.

  • Greater consumption of red meat has been associated with a higher risk of type 2 diabetes mellitus (T2DM). A decreased intake of red meat and simultaneous increased intake of other high-protein foods may be associated with a lower risk of T2DM. These analyses of specific food replacements for red meat may provide more accurate dietary advice.
  • Researchers examined the association between a decrease in intake of red meat accompanied by an increase in other major dietary protein sources and risk of T2DM.
  • The researchers prospectively followed 27,634 males in the Health Professionals Follow-up Study, 46,023 females in the Nurses’ Health Study, and 75,196 females in the Nurses’ Health Study II. Diet was assessed by a validated FFQ and updated every 4 years.
  • During 2,113,245 person-years of follow-up, the researchers identified 8,763 incident T2DM cases from 1990 to 2013. In the pooled analyses, a decrease in total red meat intake during a 4-year period replaced with another common protein food was associated with a lower risk of T2DM in the subsequent 4-year period.
  • The hazard ratio per 1 serving/d was 0.82 for poultry, 0.87 for seafood, 0.82 for low-fat dairy, 0.82 for high-fat dairy, 0.90 for eggs, 0.89 for legumes, and 0.83 for nuts. The associations were present for both unprocessed and processed red meat, although stronger for the replacement of processed red meat.
  • In conclusions, replacing red meat consumption with other protein sources was associated with a lower risk of T2DM.

Dairy Consumption and Metabolic Health. Timon CM, O’Connor A, Bhargava N, Gibney ER, Feeney EL. Nutrients. 2020 Oct 3;12(10):3040.

  • Milk and dairy foods are naturally rich sources of a wide range of nutrients, and when consumed according to recommended intakes, contribute essential nutrients across all stages of the life cycle.
  • Seminal studies recommendations with respect to intake of saturated fat have been consistent and clear: limit total fat intake to 30% or less of total dietary energy, with a specific recommendation for intake of saturated fat to less than 10% of total dietary energy.
  • However, recent work has re-opened the debate on intake of saturated fat in particular, with suggestions that recommended intakes be considered not at a total fat intake within the diet, but at a food-specific level.
  • A large body of evidence exists examining the impact of dairy consumption on markers of metabolic health, both at a total-dairy-intake level and also at a food-item level, with mixed findings to date. However the evidence suggests that the impact of saturated fat intake on health differs both across food groups and even between foods within the same food group such as dairy.
  • The range of nutrients and bioactive components in milk and dairy foods are found in different levels and are housed within very different food structures. The interaction of the overall food structure and the nutrients describes the concept of the ‘food matrix effect’ which has been well-documented for dairy foods.
  • Studies show that nutrients from different dairy food sources can have different effects on health and for this reason, they should be considered individually rather than grouped as a single food category in epidemiological research.
  • This narrative review examines the current evidence, mainly from randomised controlled trials and meta-analyses, with respect to dairy, milk, yoghurt and cheese on aspects of metabolic health, and summarises some of the potential mechanisms for these findings.

Effects of Post-Exercise Whey Protein Consumption on Recovery Indices in Adolescent Swimmers. McKinlay BJ, Theocharidis A, Adebero T, Kurgan N, Fajardo VA, Roy BD, Josse AR, M Logan-Sprenger H, Falk B, Klentrou P.Int J Environ Res Public Health. 2020 Oct 23;17(21):E7761.

  • This study examined the effect of whey protein consumption following high-intensity interval swimming (HIIS) on muscle damage, inflammatory cytokines and performance in adolescent swimmers.
  • Fifty-four swimmers (11-17 years-old) were stratified by age, sex and body mass to a whey protein (PRO), isoenergetic carbohydrate (CHO) or a water/placebo (H2O) group. Following baseline blood samples (06:00 h) and a standardised breakfast, participants performed a maximal 200 m swim, followed by HIIS.
  • A total of two post-exercise boluses were consumed following HIIS and ~5 hours post-baseline. Blood and 200 m performance measurements were repeated at 5 h, 8 h and 24 h from baseline. Muscle soreness was assessed at 24 h. Creatine kinase, interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α) were measured in plasma.
  • No difference in 200 meter swim performance was observed between groups. Creatine kinase activity was elevated at 5 hours compared to baseline and 24 hours and at 8 hours compared to all other timepoints, with no differences between groups.
  • Muscle soreness was lower in PRO compared to H2 Anti-inflammatory IL-10 increased at 8 hours in PRO, while it decreased in CHO and H2O.
  • In conclusion, post-exercise consumption of whey protein appears to have no additional benefit on recovery indices following HIIS compared to isoenergetic amounts of carbohydrate in adolescent swimmers. However, it may assist with the acute-inflammatory response.

The Associations between Dairy Product Consumption and Biomarkers of Inflammation, Adipocytokines, and Oxidative Stress in Children: A Cross-Sectional Study. Aslam H, Jacka FN, Marx W, Karatzi K, Mavrogianni C, Karaglani E, Mohebbi M, Pasco JA, O’Neil A, Berk M, Nomikos T, Kanellakis S, Androutsos O, Manios Y, Moschonis G.Nutrients. 2020 Oct 6;12(10):3055.

  • The association between dairy product consumption and biomarkers of inflammation, adipocytokines, and oxidative stress is poorly studied in children.
  • Therefore, these associations were examined in a representative subsample of 1338 schoolchildren with a mean age of 11.5 (±0.7) years in the Healthy Growth Study. Information on dairy product consumption was collected by dietary recalls.
  • Total dairy consumption was calculated by summing the intake of milk, yogurt, and cheese. Inflammatory markers, i.e., high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and adipocytokines, i.e., leptin, adiponectin, and the antioxidant enzyme glutathione peroxidase (GPx) were analysed.
  • Multivariable regression analyses adjusted for age, sex, energy intake, physical activity, parental education, Tanner stage, and fat mass were used to assess the associations between consumption of total dairy, milk, yogurt, cheese, and markers of inflammation, adipocytokines, oxidative stress, and adiponectin-leptin ratio.
  • The results showed that milk consumption was inversely associated with leptin (β: -0.101; 95% CI: -0.177, -0.025, p= 0.009) and positively associated with the adiponectin-leptin ratio (β: 0.116; 95% CI: 0.020, 0.211; p = 0.018), while total dairy, cheese, and yogurt consumption were not associated with inflammatory, adipocytokine, or antioxidant markers.

The Nutritional Impact of Milk Beverages in Reducing Nutrient Inadequacy among Children Aged One to Five Years in the Philippines: A Dietary Modelling Study. Mak TN, Angeles-Agdeppa I, Tassy M, Capanzana MV, Offord EA.Nutrients. 2020 Oct 29;12(11):E3330.

  • Around half of Filipino children are not consuming any dairy products on a given day, which has shown to be associated with increased risk of inadequate nutrient intakes.
  • The current study applies dietary modelling to assess the nutritional impact of meeting dairy recommendations in reducing nutrient inadequacy in children aged one to five years in the Philippines.
  • Dietary intake data of Filipino children aged one to five years (n= 3864) were analyzed from the 8th National Nutrition Survey 2013. Children who did not meet national dairy recommendations were identified. Two scenarios were applied, based on two types of commonly consumed milk products by the survey participants. In scenario one, one serving of powdered milk was added to the diet of these children. In scenario two, one serving of a young children milk (YCM) or preschool children milk (PCM) was added to the diet of children aged one to two years and three to five years, respectively.
  • Scenario one demonstrated improvement in calcium, phosphorus, sodium, vitamin A and riboflavin intakes, while in scenario two, further improvement of intakes of a wider range of nutrients including iron, selenium, zinc, magnesium, potassium, vitamins C, D, E, thiamin, niacin, vitamins B6, and B12 was observed. In both scenarios, if all children would meet their dairy recommendations, theoretical reductions in population nutrient inadequacy would be observed for all micronutrients, for example, only 20% of children aged one to two years would be inadequate in vitamin A instead of the current 60%, iron inadequacy would see a 5% reduction, and approximately 10% reduction for calcium and 20% reduction for folate.
  • The present study is the first to apply dietary modelling to assess the theoretical impact of meeting dairy recommendations on nutrient inadequacy in children in the Philippines. Dairy consumption should be encouraged as part of the strategy to reduce nutrient inadequacies. Calcium, iron, vitamins D, E, and folate are of concern in the Philippines as the level of inadequacies are extremely high in early years, YCM and PCM can help increase the intake of these nutrients.