Welcome to the January 2019 Dairy Research Bulletin! 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 Publications on Animal Health, Food Safety, and Sustainability

Effect of dietary fat supplementation on methane emissions from dairy cows fed wheat or corn. Alvarez-Hess PS, Williams SRO, Jacobs JL, Hannah MC, Beauchemin KA, Eckard RJ, Wales WJ, Morris GL, Moate PJ. J Dairy Sci. 2019 Jan 16. pii: S0022-0302(19)30057-8.

  • Diets that contain high proportions of either wheat or supplementary fat have been individually reported to reduce enteric methane production.
  • The objective of this research was to determine the effect of dietary fat supplementation on methane emissions and milk yield from cows fed diets containing either corn or wheat grains. It was hypothesized that cows fed a diet containing wheat would produce less methane and have lower methane yield (i.e. methane per kg of dry matter intake) than cows fed a diet containing corn and that methane mitigation from fat supplementation would occur irrespective of the type of grain in the basal diet.
  • The experiment involved 32 Holstein-Friesian dairy cows allocated to 1 of 4 treatment groups (n = 8) and individually fed different diets restricted to approximately 90% of their mean ad libitum intake measured during a covariate period. All animals were offered 11.5 kg of dry matter/d of alfalfa hay, 1.8 kg of dry matter/d of solvent-extracted canola meal, and 1 of 4 dietary supplements. Dietary supplements were 8 kg of dry matter/d of either corn or wheat, or these same treatments with the addition of 0.8 kg of canola oil.
  • Cows fed a diet containing wheat had greater methane yield than cows fed a diet containing corn. Irrespective of the type of grain in the diet, increasing the fat concentration from 2 to 6% dry matter reduced methane yield. It is concluded that the grain component in the basal diet does not affect the mitigating effects of dietary fat supplements on methane yield.

Bulk tank raw milk microbiota differs within and between farms: A moving goalpost challenging quality control. Skeie SB, Håland M, Thorsen IM, Narvhus J, Porcellato D. J Dairy Sci. 2019 Jan 10. pii: S0022-0302(19)30020-7.

  • Microbial contamination of bovine raw milk often occurs at the farm.
  • To acquire a deeper knowledge of the microbiota of farm tank milk, the researchers studied milk from 45 farms situated in 2 geographical areas in Norway. Each farm was visited on 3 different occasions, with at least 2 wk between visits.
  • The predominant microbiota was dominated by spoilage genera, such as Pseudomonas and Bacillus, as well as the dairy fermentation genus Lactococcus and mastitis-causing organisms (Streptococcus). Analysis of the identified sequence variants within these genera showed that the populations of Pseudomonas and Lactococcus in milk had similar composition between the farms, but that Bacillus and, in particular, Streptococcus populations changed between collection days from the same farm and between farms and geographical areas.
  • Furthermore, the levels and composition of Bacillus and Paenibacillus were different between the 2 geographical areas. The results presented here provide new insight into the farm milk microbiota and show that this microbiota is a dynamic community highly subject to variation.

Fecal microbiota changes associated with dehorning and castration stress primarily affects light-weight dairy calves. Mir RA, Kleinhenz MD, Coetzee JF, Allen HK, Kudva IT. PLoS One. 2019 Jan 23;14(1):e0210203.

  • Gastrointestinal tract (GIT) microbiota and stress can impact animal health. Studies have shown that perturbations in the GIT microbiota can influence host health and productivity by affecting physiological homeostasis, metabolism, hematopoiesis and inflammation.
  • The present study aimed to evaluate possible effects of dehorning and castration stress on the GIT microbiota of dairy calves. Dehorning and castration are routinely performed on over 90% of dairy farms, and analgesics like flunixin meglumine (FLU) are given at the time of these procedures to reduce pain.
  • The researchers analyzed fecal microbiota of 24 weaned male dairy calves at two different stages in their life (at 10 weeks for dehorning and 36 weeks age for castration) to determine any GIT microbiota changes due to these stressful procedures and the FLU treatment.
  • The analysis showed that the Shannon diversity index was significantly higher in animals that were not dehorned compared to dehorned animals. Castration stress also resulted in a significant decrease in Shannon diversity index, which was more pronounced in lower weight calves.
  • The results indicate that dehorning and castration stress reduced microbial diversity of the GIT microbiota, but only in light-weight calves. This work is important for elucidating biological effects of stress on dairy calves and identifying potential modulation points in the microbiota of these food-producing animals to improve animal health and production.

Leveraging endogenous barley enzymes to turn lactose-containing dairy by-products into fermentable adjuncts for Saccharomyces cerevisiae-based ethanol fermentations. Lawton MR, Alcaine SD. J Dairy Sci. 2019 Jan 16. pii: S0022-0302(19)30067-0.

  • Acid whey, a by-product of strained yogurt production, represents a disposal challenge for the dairy industry. Utilization schemes are currently limited; however, acid whey contains valuable components that could be used to create value-added products.
  • One potential scheme would be the fermentation of acid whey into an alcoholic beverage. Sour beers are gaining popularity and acid whey, which is sour to begin with, could provide a new product opportunity. However, the main sugar of acid whey, lactose, cannot be fermented by the traditional brewer’s yeast, Saccharomyces cerevisiae. It has been reported that barley contains enzymes capable of hydrolyzing lactose to glucose and galactose, which are fermentable by S. cerevisiae.
  • The researchers investigated whether a barley-based mash resulted in detectable hydrolysis of lactose into sugars fermentable by S. cerevisiae.
  • They demonstrated the ability to hydrolyze lactose in acid whey using a barley-based mash, resulting in the average release of 3.70 g/L of glucose. Additionally, the subsequent liquid was fermented by S. cerevisiae to an average ethanol concentration of 3.23% alcohol by volume.
  • This work demonstrates the ability to hydrolyze the lactose in acid whey using barley and the opportunity to use acid whey as a fermentable sugar source in beer production.


Selected Articles on Sustainable Nutrition

Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Willett W, Rockström J, Loken B, Springmann M, et al. Lancet. 2019 Jan 16. pii: S0140-6736(18)31788-4. doi: 10.1016/S0140-6736(18)31788-4.

  • Providing a growing global population with healthy diets from sustainable food systems is an immediate challenge. Unhealthy diets pose a greater risk to morbidity and mortality than does unsafe sex, and alcohol, drug, and tobacco use combined. Food systems have the potential to nurture human health and support environmental sustainability; however, they are currently threatening both.
  • Although global food production of calories has kept pace with population growth, more than 820 million people have insufficient food and many more consume low-quality diets that cause micronutrient deficiencies and contribute to a substantial rise in the incidence of diet-related obesity and diet-related non-communicable diseases, including coronary heart disease, stroke, and diabetes.
  • Because much of the world’s population is inadequately nourished and many environmental systems and processes are pushed beyond safe boundaries by food production, a global transformation of the food system is urgently needed. Therefore, this report is set against the backdrop of defined scientific boundaries that would ensure a safe operating space within six Earth systems, towards sustaining a healthy planet.
  • The Commission quantitively describes a universal healthy reference diet, based on an increase in consumption of healthy foods (such as vegetables, fruits, whole grains, legumes, and nuts), and a decrease in consumption of unhealthy foods (such as red meat, sugar, and refined grains) that would provide major health benefits, and also increase the likelihood of attainment of the Sustainable Development Goals.

Nutrition from a climate change perspective. Macdiarmid JI, Whybrow S. Proc Nutr Soc. 2019 Jan 28:1-8.

  • Climate change is threatening future global food and nutrition security. Limiting the increase in global temperature to 1·5 °C set out in The Paris Agreement (2015) while achieving nutrient security means overhauling the current food system to create one that can deliver healthy and sustainable diets. To attain this, is critical to understand the implications for nutrition of actions to mitigate climate change as well as the impacts of climate change on food production and the nutrient composition of foods.
  • It is widely recognized that livestock production has a much greater environmental burden than crop production, and therefore advice is to reduce meat consumption. This has triggered concern in some sectors about a lack of protein in diets, which hence is driving efforts to find protein replacements. However, in most high- and middle-income countries, protein intakes far exceed dietary requirements and it would even if all meat were removed from diets.
  • Reduction in micronutrients should be given more attention when reducing meat. Simply eating less meat does not guarantee healthier or more sustainable diets. Climate change will also affect the type, amount and nutrient quality of food that can be produced. Studies have shown that increased temperature and elevated CO2 levels can reduce the nutrient density of some staple crops, which is of particular concern in low-income countries.
  • Nutrition from a climate change perspective means considering the potential consequences of any climate action on food and nutrition security.

Healthy Diet: A Step toward a Sustainable Diet by Reducing Water Footprint. Sobhani SR, Rezazadeh A, Omidvar N, Eini-Zinab H. J Sci Food Agric. 2019 Jan 13.

  • This paper aims to assess different scenarios that reduce water use by following healthy diet recommendations.
  • In this study, the food frequency questionnaire was used to assess usual food intake of a 723-individual sample, aged 20-64 years, from Urmia, Iran. In order to calculate water use for production of food items, the water footprint method was applied. Linear programming (LP) technique was used to find a healthy diet with low blue water footprint in three scenarios.
  • The biggest decline in water use compared with real intake (57%) was found in the first scenario, where the model-generated consider energy intake equal to usual energy intake. In the second scenario, in which the proportion of each food group was allowed to be in accordance with the Iranian Food Pyramid, reduction in water use was less than the first scenario (47%). In the third scenario, where the Recommended Dietary Allowance values were also added to the set of model restrictions, the water usage was 51% of the real diet.
  • A healthy diet with greater proportion of energy from fruit and dairy instead of a diet with high proportion of energy from “meat-fish-poultry-eggs” and “bread-cereal-rice-pasta” can supply all recommended dietary allowances while reducing water use.

Position of the Society for Nutrition Education and Behavior: The Importance of Including Environmental Sustainability in Dietary Guidance. Rose D, Heller MC, Roberto CA. J Nutr Educ Behav. 2019 Jan;51(1):3-15.e1.

  • It is the position of the Society for Nutrition Education and Behavior that environmental sustainability should be inherent in dietary guidance, whether working with individuals or groups about their dietary choices or in setting national dietary guidance.
  • Improving the nutritional health of a population is a long-term goal that requires ensuring the long-term sustainability of the food system. Current environmental trends, including those related to climate change, biodiversity loss, land degradation, water shortages, and water pollution, threaten long-term food security and are caused in part by current diets and agricultural practices.
  • Addressing these problems while producing more food for a growing population will require changes to current food systems. Dietary choices have a significant role in contributing to environmental impacts, which could be lessened by consuming fewer overconsumed animal products and more plant-based foods while reducing excess energy intake and the amount of food wasted.
  • Discussion of sustainability within governmental dietary guidance is common in many countries, is consistent with previous US guidelines, and is within the scope of authorizing legislation.
  • Dietary choices are a personal matter, but many American consumers are motivated by a concern for the environment and would welcome sound advice from credentialed nutrition professionals.

Carbon footprint of self-selected US diets: nutritional, demographic, and behavioral correlates. Rose D, Heller MC, Willits-Smith AM, Meyer RJ. Am J Clin Nutr. 2019 Jan 29.

  • A substantial portion of greenhouse gas emissions (GHGE) has been attributed to the food sector, but little is known about the association between the carbon footprint of individual self-selected diets in the United States and nutritional quality.
  • The aims of this study were to assess the GHGE from individual diets in the United States and examine their association with nutritional quality, demographic patterns, and food-related behaviors.
  • The dietary GHGE from US adults (N = 16,800) in the 2005-2010 National Health and Nutrition Examination Survey (NHANES) were calculated by linking all foods consumed in their 24-hour recall diets to a new database of food environmental impacts. Diets were ranked by GHGE/1000 kcal.
  • Diets in the bottom quintile accounted for one-fifth the total emissions of those in the top quintile, yet had significantly higher Healthy Eating Index scores by 2.3 ± 0.7 points on a 100-point scale. These low-GHGE diets contained higher amounts of fiber and vitamin E and lower amounts of sodium and saturated fats, whereas high-GHGE diets contained higher amounts of vitamins A and D, choline, calcium, iron, and potassium.
  • Low-GHGE diets had less meat, dairy, and solid fats, and more poultry, plant protein foods, oils, whole and refined grains, and added sugars. Food patterns responsible for lower GHGE had a better overall diet quality and were more nutritious on several key dimensions, although not all.
  • These results can inform dietary guidance and other policies that seek to address the goals of improved dietary intakes and reduced food-related emissions.


Selected Articles on Dairy Intake and Human Health

Dairy Product Intake and Cardiometabolic Diseases in Northern Sweden: A 33-Year Prospective Cohort Study. Johansson I, Esberg A, Nilsson LM, Jansson JH, Wennberg P, Winkvist A. Nutrients. 2019 Jan 28;11(2). pii: E284.

  • Dairy products are important constituents of most diets, and their association with adverse health outcomes remains a focus.
  • The researchers characterized dairy food intake and examined associations with the incidence of type 2 diabetes (T2D), myocardial infarction (MI) or stroke among 108,065 Swedish men and women.
  • This prospective study found that non-fermented milk was associated with an increased risk for developing T2D and MI and that subjects abstaining from dairy products or choosing low-fat variants were at greater risk. However, the overall cardiometabolic risk of consuming non-fermented milk intake was judged as low, since the effect sizes were small.

Fermented dairy foods intake and risk of cardiovascular diseases: A meta-analysis of cohort studies. Zhang K, Chen X, Zhang L, Deng Z. Crit Rev Food Sci Nutr. 2019 Jan 17:1-6.

  • Since the associations of fermented dairy foods intake with risk of cardiovascular diseases (CVD) remained inconsistent, we carried out this meta-analysis on all published cohort studies to estimate the overall effect.
  • 10 studies met the inclusion criteria for this study, with 385,122 participants, 1,392 Myocardial infarction, 4,490 coronary heart disease (CHD), 7,078 stroke, and 51,707 uncategorized CVD cases.
  • Overall, statistical evidence of significantly decreased CVD risk was found to be associated with fermented dairy foods intake. In subgroup analysis, cheese and yogurt consumptions were associated with decreased CVD risk for cheese and for yogurt.
  • This meta-analysis indicated that fermented dairy foods intake was associated with decreased CVD risk.

Dairy Product Consumption and Metabolic Diseases in the Di@bet.es Study. Lago-Sampedro A, García-Escobar E, Olveira G. et al. Nutrients. 2019 Jan 24;11(2). pii: E262.

  • To date it is not clear what the role of dairy products is in metabolic diseases like diabetes, obesity, and hypertension.
  • The aim of this study is to test the association between dairy product consumption and those pathologies.
  • A cross-sectional study was conducted with 5081 adults included in the di@bet.es study, from 100 health centers around Spain. Food frequency questionnaires were carried out concerning consumption habits, which included dairy product consumption.
  • Women had a higher consumption of milk, cheese, or yogurt than men, but men consumed more sugar dairy products. People who live in the North of Spain consume more dairy products than those who live in the East.
  • Dairy product consumption was inversely associated with the presence of hypertension regardless of age, sex, geographical region, and body mass index (BMI). The presence of obesity was inversely associated with dairy consumption regardless of age, sex, and geographical region. Milk consumption was not associated with diabetes.
  • These results show that consuming dairy products is associated with a better metabolic profile in the Spanish population.

Increased Dairy Product Intake Modifies Plasma Glucose Concentrations and Glycated Hemoglobin: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. O’Connor S, Turcotte AF, Gagnon C, Rudkowska I. Adv Nutr. 2019 Jan 17.

  • Dairy product intake is inversely associated with the risk of type 2 diabetes (T2D) in numerous cohort studies; yet, the beneficial effects of increased dairy product intake on T2D risk factors such as fasting plasma glucose, fasting insulin, insulin resistance with the homeostasis model assessment, and glycated hemoglobin (HbA1c) remain inconclusive in clinical trials.
  • The objective of this study was to systematically review clinical trials observing the effects of elevated compared with minimal intake of dairy products on T2D risk factors in subjects without diabetes. The review outcomes were fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and HbA1c.
  • Fasting glucose was positively associated with elevated dairy intake. Fasting insulin and HOMA-IR were not associated with elevated dairy consumption. HbA1c was negatively associated with elevated dairy product intake in 4 studies. Most studies had high risk of bias and the quality of evidence was very low or low.
  • In conclusion, evidence suggests that elevated dairy product intake is associated with increased fasting plasma glucose concentrations together with reduced HbA1c in nondiabetic subjects. Hence, the clinical significance of these results remains uncertain. Additional well-designed, long-term studies are required.

Higher Dairy Intakes Are Associated with Higher Bone Mineral Density among Adults with Sufficient Vitamin D Status: Results from the Boston Puerto Rican Osteoporosis Study. Mangano KM, Noel SE, Sahni S, Tucker KL. J Nutr. 2019 Jan 2.

  • Dairy foods have been shown to improve bone mineral density (BMD) in non-Hispanic whites. Puerto Rican adults have a higher prevalence of osteoporosis and vitamin D deficiency than non-Hispanic whites. However, there is little understanding of lifestyle influences on bone in this population.
  • The aim of this study was to examine associations of dairy intakes with BMD among adults from the Boston Puerto Rican Osteoporosis Study with and without adequate serum vitamin D status.
  • A total of 904 participants in this cross-sectional analysis provided dietary intakes with a culturally tailored food-frequency questionnaire.
  • In the full sample, higher intakes of modified dairy foods and milk were associated with higher femoral neck BMD. Among those who were vitamin D sufficient, higher intakes of total dairy, fluid dairy, and milk were significantly related to higher femoral neck and lumbar spine BMD, respectively. Among vitamin D-insufficient participants, dairy intakes were not associated with BMD.
  • Dairy food intakes were associated with higher BMD among adults, particularly those with sufficient vitamin D status.

The Impact of Dairy Protein Intake on Muscle Mass, Muscle Strength, and Physical Performance in Middle-Aged to Older Adults with or without Existing Sarcopenia: A Systematic Review and Meta-Analysis. Hanach NI, McCullough F, Avery A. Adv Nutr. 2019 Jan 8.

  • Sarcopenia is an age-related condition associated with a progressive loss of muscle mass and strength. Insufficient protein intake is a risk factor for sarcopenia. Protein supplementation is suggested to improve muscle anabolism and function in younger and older adults. Dairy products are a good source of high-quality proteins.
  • This review evaluates the effectiveness of dairy proteins on functions associated with sarcopenia in middle-aged and older adults. Randomized controlled trials were identified using and were quality assessed.
  • Fourteen studies involving 1424 participants aged between 61 and 81 years met the inclusion criteria.
  • Dairy protein significantly increased appendicular muscle mass; however, it had no effect on improvement in handgrip or leg press. The effect of dairy protein on the Short Physical Performance Battery was inconclusive. Nine studies reported the dairy protein to be well tolerated with no serious adverse events.
  • Although future high-quality research is required to establish the optimal type of dairy protein, the present systematic review provides evidence of the beneficial effect of dairy protein as a potential nutrition strategy to improve appendicular muscle mass in middle-aged and older adults.

Proprietary Milk Protein Concentrate Reduces Joint Discomfort While Improving Exercise Performance in Non-Osteoarthritic Individuals. Ziegenfuss TN, Kerksick CM, Kedia AW, Sandrock J, Raub B, Lopez HL. Nutrients. 2019 Jan 28;11(2). pii: E283.

  • Milk and dairy products are known to contain various bioactives with potential anti-inflammatory and immune modulating effects. Previous research has indicated that milk produced from hyperimmunized cows provided meaningful health benefits to individuals suffering from varying degrees of osteoarthritis and rheumatoid arthritis.
  • This study was designed to examine the impact of MicroLactin®, a proprietary milk protein concentrate, on joint discomfort and physical function, exercise performance, and quality of life. Non-osteoarthritic men and women with mild to moderate knee pain during physical activity were randomized in a double-blind, placebo-controlled fashion to consume daily either a placebo or MicroLactin® for a period of 8 weeks.
  • Distance covered in the 6-min walking significantly improved 9% in the MicroLactin® group versus 2% in the placebo group. Additionally, MicroLactin® also improved overall perceptions of neck and back health compared to placebo. Serum and whole blood indicators of clinical safety remained within normal ranges throughout the study.
  • In comparison to placebo, daily doses of MicroLactin®yielded improvements in several components of the osteoarthritis questionnaires, multiple measures indicative of joint health and stability, discomfort and pain, as well as significant improvements in distance covered during a 6-min walking test. Supplementation was well tolerated with no significant changes in whole-blood or serum markers of clinical safety.