Enter the Dairy Research Institute New Product Competition

As part of the dairy checkoff funders' commitment to dairy research and innovation, the Dairy Research Institute launched a new product competition to recognize outstanding student teams who develop an innovative dairy beverage that  is on trend with current industry insights. This opportunity supports the importance of dairy research and provides a platform for students to bring their knowledge and expertise to dairy beverage innovation. Learn more.

Consuming Fat-Free Chocolate Milk After Endurance Exercise Significantly Enhances Recovery and Subsequent Performance

A new published study concluded that endurance athletes and individuals who engage in aerobic exercise “can consider fat-free chocolate milk as a viable option for post exercise nutrition to support skeletal, muscle and whole-body protein recovery.” After completing 45 minutes of endurance exercise as part of a clinical trial, eight male runners consumed fat-free chocolate milk and then protein-related metabolic responses were measured over three hours of recovery.

Post-exercise consumption of fat-free chocolate milk resulted in a statistically significant 38 percent higher rate of muscle protein synthesis, as well as a suppression of markers of muscle breakdown during the three-hour recovery period compared with a protein-free carbohydrate control beverage. In addition, fat-free chocolate milk consumption improved performance by 23 percent compared with the carbohydrate beverage during a subsequent time-to-exhaustion treadmill run following the recovery period. Fat-free chocolate milk was as effective as the control beverage at maintaining muscle glycogen (carbohydrate stores) during the recovery period.

Participants ate a controlled diet during the 14-day study that provided 1.5 grams of protein per kilogram of body weight per day, a fat intake of 30 percent of total calories and a carbohydrate intake of 6 grams per kilogram per day. Subjects completed two trials (milk or control) separated by seven days for each of the two studies. Study 1 included exercise, chocolate milk or control beverage consumption, and a recovery period. Study 2 included all components of Study 1 plus a time-to-exhaustion trial after the recovery period. During each trial, subjects ran for 45 minutes at 65 percent of their aerobic capacity. Following exercise, participants consumed approximately 2 cups (480 mL) of either fat-free chocolate milk (16g protein, 58g carbohydrate) or a carbohydrate-only control beverage containing 74g of carbohydrate. Both beverages supplied 296 calories.

Few studies have examined the influence of consuming a whole food protein-carbohydrate source, such as fluid milk, on indicators of subsequent endurance performance. Although further research is needed to identify the mechanisms of performance enhancement, the results of this study add to previous research showing the beneficial effects of milk as a recovery beverage after aerobic and resistance exercise.

Lunn WR, Pasiakos SM, Colletto MR, et al. Chocolate milk and endurance exercise recovery: Protein balance, glycogen, and performance. Med Sci Sports Exerc. [Epub ahead of print]. 2011 September 7.

Dairy's Nutrient-rich Package May Be Key to Reducing Risks of Metabolic Syndrome

Metabolic syndrome poses a significant public health threat in the United States. Affecting more than one-third of American adults, it is a cluster of symptoms that increases the risk of cardiovascular disease and type 2 diabetes and accounts for billions of dollars of health care costs annually. Research has associated dairy consumption with a reduced risk of metabolic syndrome and its related diseases. A new scientific review, published in Advances in Nutrition, discusses how components of dairy's unique nutrient package may account for dairy's positive effects. The review was authored by research scientists at the Dairy Research Institute, an organization founded under the leadership of dairy farmers who have a commitment to product, nutrition and sustainability research.
Press Release

Rice BH, Cifelli CJ, Pikosky MA, Miller GD. Dairy components and risk factors for cardiometabolic syndrome: Recent evidence and opportunities for future research.
Adv Nutr. 2011;2:396-407.

Low-fat Dairy Consumption Associated With Reduced Risk of Type 2 Diabetes in Post-menopausal Women

Low-fat dairy product and yogurt consumption are associated with a decreased risk of type 2 diabetes among post-menopausal women, according to a recent prospective study published in the November issue of The Journal of Nutrition.

Approximately 350 million people worldwide are affected by diabetes. This research, in addition to other studies completed over the last few years, shows that one of the reasons dairy may play a role in potentially reducing the risk of type 2 diabetes is that it can improve glucose tolerance. The study was funded by the National Heart, Lung, and Blood Institute, the National Institute of Health and the U.S. Department of Health and Human Services.

This study adds to a growing body of research, including research reviewed by the Dairy Research Institute, finding that adequate dairy intake improved key components of metabolic syndrome, like high blood pressure and insulin resistance, which also affects the risk of type 2 diabetes. Exploring dairy's potential benefit on metabolic health and its capability to reduce the risk of type 2 diabetes is a key priority area for the Dairy Research Institute.
Press Release

Margolis KL, Wei F, de Boer IH, et al. A diet high in low-fat dairy products lowers diabetes risk in postmenopausal women. J Nutr. [Epub ahead of print]. 2011 Sept 21.

Whey Protein Consumption May Beneficially Affect Glucose Metabolism and Muscle Protein Synthesis

A review of 25 recently published intervention trials examined the effects of whey protein supplementation on the musculoskeletal system, lipid and glucose metabolism, blood pressure and vascular function. The analysis most strongly supported the role of whey protein in lowering blood glucose concentrations and enhancing the effects of exercise on muscle protein synthesis. While there is not enough evidence to support final recommendations about amount and duration of supplementation to achieve these benefits, the authors said most studies with beneficial results employed 20-25 grams of whey protein and/or daily supplementation of more than 50 g.

The authors said the magnitude of blood glucose reduction after whey protein consumption was similar to that of a common glucose-lowering drug, indicating how whey supplementation may be a potential option to help manage type 2 diabetes.

Regarding the benefits of whey protein for muscle accretion, the authors cited published review papers and recent individual studies which demonstrated that pre- and post-exercise ingestion of whey protein stimulates muscle protein synthesis and gains in muscle mass in both young and older individuals.

Further research is needed on the acute and long-term effects of whey protein consumption in at-risk populations, such as those with type 2 diabetes or metabolic syndrome, and the elderly.

Two studies flagged by the authors of the review to be of special interest were summarized in previous issues of this newsletter:

• Pal and Ellis, Br J Nutr, 2011 (March issue of Dairy Research Insights)
  Read More
• Pennings, et al., Am J Clin Nutr, 2011 (May issue of Dairy Research Insights)
  Read More

Graf S, Egert S, Heer M. Effects of whey protein supplements on metabolism: evidence from human intervention studies. Curr Opin Clin Nutr Metab Care. 2011;14(6):569-580.

Higher Frequency of Cheese Intake Associated with Lower Risk of Metabolic Syndrome and Lower Body Mass Index

Previous data from the Oslo Health study linked higher frequency of cheese intake to improvements in blood triglyceride levels and HDL-cholesterol – two components of the metabolic syndrome, a collection of symptoms that increase the risk of cardiovascular disease and type 2 diabetes. Recently, a more comprehensive analysis of the data by the same Norwegian researchers found that a higher frequency of self-reported cheese intake in adults ages 30-76 years was significantly associated with lower odds of having metabolic syndrome, fewer metabolic syndrome risk factors and improvement in individual metabolic syndrome components. In addition, a higher frequency of cheese intake was also associated with a significantly lower body mass index in all but the oldest women (75 or 76 years) and a lower estimate of risk for cardiovascular disease and type 2 diabetes. These relationships consistently prevailed even after adjustment for many potentially confounding factors.

Metabolic syndrome is defined in this study as a high waist circumference and at least two other risk factors, including elevated blood triglycerides, high fasting blood glucose, low HDL-cholesterol and elevated blood pressure. Only non-fasting blood samples were collected for this study, therefore blood glucose data were not used for the analysis given that a meal can have a relatively larger impact on glucose than blood triglycerides or HDL-cholesterol.

Current dietary guidelines emphasize reducing saturated fat intake. Although cheese is a source of saturated fat in American and European diets, the authors referenced previous studies showing that fat consumption from cheese may affect blood lipids and body weight differently from what might be expected based on its saturated fat content alone. The results of the current study indicate that cheese can be included in meal patterns without adversely affecting cardiovascular and metabolic health.

Høstmark AT, Tomten SE. The Oslo Health Study: cheese intake was negatively associated with the metabolic syndrome. J Am Coll Nutr. 2011;30(3):182-190.

Frequent Dairy Food Intake Associated with Better Cognitive Performance in Adults

Although little is known about how dairy foods might influence cognition, findings from existing observational studies have been positive. A community-based study of 972 dementia-free adults ages 23 to 98 years found that those who consumed dairy products at least once per day had significantly higher scores on all eight domains of cognitive testing compared with those who never or rarely consumed dairy foods. After adjustment for other lifestyle, cardiovascular and dietary factors, these associations remained significant for all but one of the cognitive domains.

The study expands on previous knowledge by using a thorough neuropsychological battery of tests to assess cognitive performance in adults across the lifespan who were enrolled in the Maine-Syracuse Longitudinal Study. The researchers hypothesized that dairy food intake would be associated with better cognitive outcomes.

Dairy food consumption may benefit cognitive status through its favorable effect on cardiovascular risk factors such as obesity, type 2 diabetes, hypertension and abnormal blood lipids levels – factors that have been linked with an increased risk of cognitive impairment. Since adjustment for these factors only slightly changed the beneficial relationship between dairy intake and cognition, the authors said these factors do not entirely explain the association between dairy food intake and better cognitive functioning.

Cognitive deficits in younger adults increase the risk of dementia as they get older. As the proportion of older people in the population increases, cognitive decline is expected to put increasing strain on the health care system. The research linking dairy food intake with better cognitive function looks promising, but additional longitudinal studies and ultimately clinical trials are needed to enhance understanding of this possible association.

Crichton GE, Elias MF, Dore GA, Robbins MA. Relation between dairy food intake and cognitive function: The Maine-Syracuse Longitudinal Study. Int Dairy J. [Epub ahead of print]. 2011 Sept 1.

Calcium Does Not Influence Total Energy Expenditure or Fat Oxidation in Adolescents on a Weight Maintenance Calorie-controlled Diet

Numerous studies in adults have shown that dairy and calcium intakes are associated with increased fat excretion and oxidation of body fat, which helps contribute to a healthy body weight. This randomized, controlled feeding study aimed to evaluate these potential mechanisms in adolescent boys and girls who were supplemented with calcium from calcium carbonate or dairy foods. Results showed that increasing calcium through supplements or dairy foods as part of a calorie-controlled diet did not influence energy balance under controlled conditions that encouraged weight maintenance.

Forty-two overweight, adolescents participated in two, three-week treatment periods, with a three-week break between treatments. Participants consumed a low-calcium control diet providing about 750 milligrams of calcium per day and either a diet supplemented with 650 mg of calcium from calcium carbonate or from dairy for a total of about 1400 mg of calcium per day. Both intervention diets provided roughly the amount of calcium recommended for adolescents. Diets were strictly controlled and matched for macronutrient content, and energy intakes were calculated to maintain body weight.

Regardless of calcium source, calcium balance (e.g., intake minus excretion or retention) was significantly improved with increased calcium intake. However, calcium treatment did not affect energy or fat balance (intake minus excretion) in overweight adolescents. Although calcium from either dairy or calcium carbonate increased fecal and urinary calcium excretion and retention, the amount remaining in the gut available to bind with dietary fat may not have been enough to increase fat excretion. However, when the data from both calcium sources was pooled, calcium excretion was associated with fecal fat excretion.

An accompanying editorial states that the relationship between calcium intake and fat excretion in adolescents seen in this study actually is consistent with a previous meta-analysis in adults – and indicates a causal relationship. The data in adults and adolescents together “suggests that dietary calcium binds fat and can increase fecal excretion” of energy.

While the results of this study do not support previous findings in adults, aspects of the study design may have precluded the authors from observing a beneficial effect of dairy or calcium on energy metabolism. For example, the authors speculated that high calcium absorption during adolescent growth may reduce the amount of calcium that passes through the gut, which reduces the opportunity for fat excretion. It is possible that increased dairy or calcium may increase fecal fat excretion and assist in weight loss in younger or older subjects who are in a period of slower growth.

Results from observational and clinical studies show that dairy food and dietary calcium consumption have either a beneficial or neutral effect on body weight or body composition in children and adolescents. Overall, the body of scientific literature continues to demonstrate that the consumption of three servings of milk and milk products as part of a nutrient-rich, balanced diet may help maintain a healthy weight and body composition in children and adolescents.

Weaver CM, Campbell WW, Teegarden D, et al. Calcium, dairy products, and energy balance in overweight adolescents: a controlled trial. Am J Clin Nutr. [Epub ahead of print]. 2011 Sep 14.

Editorial: Astrup A. Calcium for prevention of weight gain, cardiovascular disease, and cancer. Am J Clin Nutr. [Epub ahead of print]. 2011 Oct 12.

Inverse Associations Found Between Milk Intake and Percent Body Fat in Children in a Cross-sectional Analysis

Researchers in Boston and the U.K. have collaborated to better understand the relationship found by epidemiologic studies between milk intake and body composition in children. They conducted a cross-sectional (one point in time) analysis among more than 2,000 children enrolled in the Avon Longitudinal Study of Parents and Children, which found that higher intake of full-fat milk, but not reduced-fat milk, at age 13 was associated with significantly less body fat after adjustment for many potentially confounding factors.

When the same children were examined prospectively (over time), no association was found between milk intakes at age 10 and body fat at age 11 and 13. Though the authors conducted a rigorous analysis employing different study designs in a large sample of children, they said more work is needed to further clarify the relationship between milk and body fat in children. They said it is especially important to account for dietary reporting errors, which can cloud these relationships. Thus, no firm conclusions can be drawn from this body of research.

Noel SE, Ness AR, Northstone K, Emmett P, Newby PK. Milk Intakes Are Not Associated with Percent Body Fat in Children from Ages 10 to 13 Years. J Nutr. [Epub ahead of print]. 2011 Sept 21.

Italian Pediatricians Rebut Critics Who Say Milk is Harmful to Children

A recent review written by two Italian pediatricians reinforces the value of milk in children's diets while answering public criticism from the media and others who presume milk is harmful to children. Using the scientific literature, the authors brought new clarity to the topics of iron deficiency anemia, lactase deficiency, cow's milk protein allergy, autistic spectrum disorders, type 1 diabetes, metabolic syndrome, chronic-degenerative disorders and cancer. The authors confirmed the nutritional quality of cow's milk, saying compared with other animal sources (i.e. beef and eggs), “it is the richest source of calcium and vitamin D and . . . the cheapest source of protein, calcium, phosphorus, and vitamin D.” They encouraged regular milk consumption by children as an important way to close nutrient gaps – and said milk is “suggestive of a functional food.”

Here are some examples of the paper's top-line conclusions on key health concerns:

• The American Academy of Pediatrics recommends cow's milk to children 12 months of age and older. After one year of age, up to 2 cups of cow's milk can be included in the child's diet daily with no harmful effects on iron status — as long as the diet contains iron-enriched foods and other relevant nutrients.
• “Lactose intolerance can be easily managed. There is no need for eliminating dairy foods and milk . . .”
• “Allergy to cow's milk proteins is usually transient.”
• “The connection of cow's milk with autistic spectrum disorders is lacking.”
• “A cause-effect relationship with type 1 diabetes is not established . . .”

This paper is a solid, well-researched resource that brings together facts about the value of milk in children's diets.

Agostoni C, TurcK D. Is Cows' Milk Harmful for a Child's Health? J Pediat Gastroenterol Nutr. [Epub ahead of print]. 2011 Sept 14.

A Dietary Pattern Including Higher Intakes of Low-fat Dairy Products is Associated with Two Indicators of Metabolic Health in Older Adults

“A dietary pattern high in low-fat dairy products, fruit, whole grains, poultry, fish and vegetables may be associated with greater insulin sensitivity and lower systemic inflammation in older adults,” the authors of a recent study concluded. Participants, ages 70-79, who ate according to that pattern, dubbed the “healthy foods” dietary pattern, had significantly lower fasting insulin and glucose, lower markers of insulin resistance and a lower blood level of interleukin-6 – a marker of systemic inflammation – than other dietary patterns identified in this population.

Researchers identified six dietary patterns in 1,751 older adults enrolled in the Health, Aging and Body Composition (Health ABC) Study in order to assess the overall dietary influence on metabolic risk factors. They used cluster analysis to group individuals according to their dietary patterns. Six cluster patterns were identified and named according to the food groups that contributed the most to total energy intake: “healthy foods,” “breakfast cereal,” “meat and alcohol,” “sweets and desserts,” “refined grains” and “high-fat dairy products”.

Compared with other dietary patterns, the “healthy foods” pattern most closely complied with the 2010 Dietary Guidelines for Americans recommendations, as indicated by the Healthy Eating Index Score. The 2010 Dietary Guidelines recommends an eating plan that includes three servings of low-fat and fat-free dairy foods daily. The authors said the “healthy foods” pattern should be encouraged in older adults to help reduce the risk of chronic disease.

Anderson AL, Harris TB, Tylavsky FA, et al. Dietary patterns, insulin sensitivity and inflammation in older adults. Eur J Clin Nutr. [Epub ahead of print]. 2011 Sept 14.

Milk Consumption and Lactase Persistence Associated with Height in Swedish Teens

Between 80 to 90 percent of body height is genetically determined and about 10 to 20 percent is influenced by environmental factors such as nutrition. A cross-sectional study in 597 Swedish preadolescents and adolescents found that milk consumption was significantly, and positively, associated with body height, as was the genetic predisposition to digest lactose (milk sugar).

The ability to digest lactose is genetically controlled and is dependent on sufficient expression of the enzyme lactase. A variation in the lactase gene renders individuals either lactase persistent (continue to produce the enzyme) or non-persistent(no longer produce the enzyme). Researchers in Sweden used two age groups, 9 and 10 year old preadolescents and 15 and 16 year old adolescents to investigate whether variations in the lactase gene influenced milk intakes and body height.

Nine percent of the youth studied were lactase non-persistent based on genetic testing. After adjustment for potentially confounding factors including parental height, milk intake – expressed in quintiles – was significantly lower in those with lactase non-persistence vs. those with lactase persistence. In addition, lactase persistence showed a significant positive relationship with height.

The authors reported that there is increasing evidence to indicate that milk has a positive influence on growth. The 2010 Dietary Guidelines recognizes lower lactose and lactose-free milk products as readily available options for those with lactose intolerance. Effective strategies for keeping dairy in the diets of those with lactose intolerance include drinking lactose-free milk, drinking smaller amounts of milk with meals, choosing natural cheeses and eating yogurt with active cultures. A white paper on lactose intolerance and the unintended consequences of dairy avoidance is available on the National Dairy Council website.

Almon R, Nilsson TK, Sjöström M, Engfeldt P. Lactase persistence and milk consumption are associated with body height in Swedish preadolescents and adolescents. Food Nutr Res. [Epub ahead of print]. 2011 Sept 6.

Scientific Review Explores Current and Future Commercial Applications of Probiotics

Probiotics, defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit to the host,” are available worldwide in a number of food products, including dairy. Probiotics have been associated with dairy for quite some time and fermented dairy products continue to be the predominant foods and beverages for delivering probiotics. This comprehensive review compiles the scientific evidence showing the diversity of probiotic applications to improve human health. The review includes both current and potential applications in the future. The most commonly used probiotic applications that have demonstrated clinical effectiveness involve the management of lactose intolerance and improving other gastrointestinal conditions such as inflammatory bowel disease, irritable bowel syndrome and diarrhea. Emerging evidence indicates that probiotics may help reduce the risk of or benefit people with allergies, immune disorders, obesity and diabetes.

Different probiotic strains have been shown to confer specific health benefits. Researchers have characterized the properties of different probiotic strains in order to understand strain-specific benefits or those achieved by a combination of strains for a targeted benefit. According to the authors, any disorder that is associated with an imbalance of microbiota (i.e., gut bacteria) or an inappropriate immune response is a potential target for probiotic intervention including diverticulitis, frailty in the elderly, patients with severe systemic inflammation or multiple sclerosis. So far probiotics have not been adequately tested in these settings, but indicate potential targets for the future.

The Dairy Research Institute, through its digestive health research program, has been working to better understand the role of dairy foods in delivering probiotic benefits.

Collado MC, Gueimonde M, Perez-Martinez G. Current and future applications of probiotics. Curr Nutr Food Sci. 2011;7(3):170-180.

Review Surveys Milk Lipids and Their Potential Health Benefits

A review published in Current Nutrition & Food Science summarized current knowledge on milk fat, as part of a special issue on bioactive lipids. Research over the last 10 years has revealed the presence of lipid compounds in milk fat with important biological activity and the potential to promote human health. After a brief overview of the fatty acid composition of milk, including short chain, medium chain, branched chain fatty acids and conjugated linoleic acid (CLA), the authors focused on the biological properties and health benefits that provide value beyond basic nutrition.

For example:

• Butyric acid, present in milk fat in concentrations of 2-5 percent, has been shown to inhibit growth in a wide range of human cancer cell lines.
• Phytanic acid, a branched chain fatty acid, has been shown to decrease fat accumulation in the liver of mice.
• Rumenic acid, the most abundant form of CLA, may have anticancer and antiatherosclerotic properties. When tested in breast cancer cells, rumenic acid acted as a human estrogen blocking agent.
• Phospholipids, such as sphingolipids, are associated with the milk fat globule membrane. In cell culture studies and animal models, active metabolites of sphingolipids, ceramides and sphingosines have been shown to be effective antibacterial agents and have tumor-suppressing properties.

Components of milk fat with potentially health promoting activity may have application in the development of functional foods – whether used to enrich dairy products or as functional ingredients. The diversity of milk lipids, the variety of bioactive components, and their physiological functions are still not completely understood. Before value-added products can be created, more research is needed to better understand the metabolic pathways of bioactive lipids as well as randomized clinical trials to assess their potential to improve human health.

Fontecha J, Rodriquez-Alcala LM, Calvo MV, Juarez M. Bioactive milk lipids. Curr Nutr Food Sci. 201;7(3):155-159.

Prospective Study Among British Adults Finds Non-Significant Trend of Lower Blood Pressure with Higher Dairy Intakes

A prospective study of 1,750 British men and women found a trend of lower blood pressure and risk of incident hypertension with increased total dairy intake, but it was not statistically significant. There was also no clear dose-response relationship between dairy intake and blood pressure.

When investigating the role of low-fat and full-fat dairy foods separately, the researchers found that higher consumption of low-fat and fermented dairy foods (mainly yogurt) was associated with higher systolic blood pressure and risk of developing hypertension. After removing overweight and obese participants from the analysis, however, the positive association was lost, leading the researchers to conclude that overweight participants likely consumed more low-fat dairy products in an attempt to lose weight.

Participants represented a sample of middle-aged British men and women followed from birth in 1946. Systolic and diastolic blood pressure, prevalent hypertension and diet were assessed at age 43 in 1989. Blood pressure and hypertension status were assessed again 10 years later at age 53. Intakes of full-fat, semi-skimmed and skimmed milk, milk-containing beverages, full-fat cheese, low-fat cheese, full-fat and low-fat yogurt, fruit-flavored yogurt and milk-based puddings were assessed by five-day diet record at baseline in 1989.

The authors noted that previous studies have linked dairy food intake to lower risk of cardiometabolic disease and that calcium, magnesium, potassium and bioactive peptides in dairy foods may contribute to lower blood pressure. More research is needed to adequately understand the role of dairy foods and their nutrients in metabolic processes linked to blood pressure management.

Heraclides A, Mishra GD, Hardy RJ, et al. Dairy intake, blood pressure and incident hypertension in a general British population: the 1946 birth cohort. Eur J Nutr. [Epub ahead of print]. 2011 Aug 30.

Whey Protein Supplementation Had Neutral Effects on Bone Mass or Strength in Older Women With Adequate Protein Intake

A two-year randomized, double-blind, placebo-controlled study of protein supplementation in 219 healthy Australian women aged 70-80 years, with relatively high average protein intakes at baseline, found that drinking a high protein drink containing 30 grams of whey protein before breakfast did not improve bone mass when compared with that of a placebo. In addition, although protein supplementation increased the body's estimated acid production thought to induce bone loss, calcium loss in the urine and bone mass did not differ between groups. The authors said that increased acid production may have been offset by the positive effect of protein on calcium absorption, as seen in previous studies.

Participants in the protein group received one cup of a high-protein drink consisting of skim milk plus whey protein isolate providing 30 g of protein. Participants in the placebo group received a skim milk-based drink providing only 2.1 g protein. Both drinks contained 600 milligrams of calcium and the same amount of calories. Those in the protein group had significantly higher total daily protein intakes than those in the placebo group at year 1 and year 2 of the study (1.4 g/kg/d vs. 1.1 g/kg/d, respectively).

According to the authors, an adequate protein intake is important for the maintenance of bone mass in the elderly, who have a high rate of bone turnover. They said the participants' relatively high baseline protein intake of 1.1 g per kilogram of body weight likely explains why protein supplementation lacked effectiveness. They suggested that protein supplementation may be more effective in populations with low protein intake.

Further research is needed to assess potential benefits of whey protein supplementation for bone health in older adults.

Zhu K, Meng X, Kerr DA, et al. The effects of a two-year randomized, controlled trial of whey protein supplementation on bone structure, IGF-1, and urinary calcium excretion in older postmenopausal women. J Bone Min Res. 2011;26(9):2298-2306.

Quick Method Developed for Measuring Lactose in Milk

A novel and rapid method for the routine measurement of lactose in dairy products will enable dairies to monitor the amount of lactose in filtered milks destined for cheese making, in lactose-free fluid products and in media for fermentations. Lactose measurement traditionally has been a time-consuming and expensive testing procedure, which means that “carbohydrate-by-difference“ (meaning lactose) is often used as shortcut for labeling purposes. In contrast, blood glucose meters are easy to use, relatively inexpensive and provide rapid results. Investigators at the Midwest Dairy Foods Research Center at South Dakota State University developed a test for lactose using the simple blood glucose measuring technique to replace more expensive and complex standard methods for lactose determination.

Some blood glucose meters use an immobilized enzyme and other reagents to measure glucose, not lactose. The researchers' approach was to first treat the milk with lactase, so that the lactose would then be hydrolyzed into glucose and galactose. The glucose could then be measured using the blood glucose meter and the amount of lactose calculated. The researchers also found that a new calibration curve was needed with each lot of the test strips. The method was only tested in relationship to lactose concentration in skim milk, but, with proper modifications, could be useful for lactose determination in other dairy products.

Amamcharia JK, Metzger LE. Development of a rapid method for the measurement of lactose in milk using a blood glucose biosensor. J Dairy Sci. 2011;94(10):4800-4809.

Quantifying Shear Allows for Optimum Product Quality and Less Product Loss

New research from the Southeast Dairy Foods Research Center at North Carolina State University can help processors reduce input energy and minimize product damage by better calculating the amount and type of shear energy to put into a system. Shear is the amount of mechanical energy added to a food due to processing through homogenizers, mixers, pumps and lines.

Shear aids in the reduction of particle size. An increase in shear beyond required levels to achieve the desired particle size results in wasted energy and damaged product. In the case of whipped cream, excess shear may damage the milkfat globule and result in less stable foam.

Researchers developed equations that will assist engineers in relating energy inputs to particle size after processing. They tested and confirmed the equations by using a model system of Polysorbate 20 (an emulsifier), water and corn oil. The homogenization pressure and number of passes through the homogenizer were the shear inputs. Using this type of information, process engineers will be able to select proper equipment and processing conditions to minimize energy input, optimize product quality and reduce product loss.

Yurgec MJ, Osborne J, Steffe JF, Daubert CR. Quantifying Shear Effects on a Model Emulsion System. J Food Proc Eng. [Epub ahead of print]. 2011 Aug 3.

Comparative Analysis of L. helveticus Protease and Peptidase Genes Shows Why Different Strains Develop Different Products

Lactobacillus helveticus is widely used as a flavor adjunct in cheeses and also is one of the primary cultures in Swiss and some Italian cheeses. Bioactive peptides in milk fermented with L. helveticus have demonstrated the ability to help lower blood pressure and increase immune response in experimental studies, prompting consideration for development as functional foods of the future.

Since flavors and bioactive peptide production varies between L. helveticus strains, an international consortium of investigators examined the genetic basis for these functional differences. The researchers performed a characterization of various strains on a microarray based on the widely recognized strain CNRZ 32. Correlation between genes and functional attributes will allow more rapid strain selection in the future. The findings also could help provide a method to ensure desirable traits are not lost through propagation and fermentations.

New methods of genetic analysis were used to demonstrate that differences among peptidases of 38 strains of L. helveticus are not always detectable at the gene level despite differences in the expression, specificity and activity of the individual enzymes. Cell envelope proteinases were more easily detectable and may be very important causes of differences in activity, growth and bioactive peptide production in dairy products.

Broadbent JR, Cai H, Larsen RL, et al. Genetic diversity in proteolytic enzymes and amino acid metabolism among Lactobacillus helveticus strains. J Dairy Sci. 2011;94(9):

Controlling β-Lactoglobulin Denaturation Determines the Viscosity of Final Beverage Product

Specially aggregated whey proteins can be used to make a unique ingredient that could be used to make gels that would result in instant yogurts or milk shakes. The gels can range in viscosity from thin, which are primarily used in beverages, to thicker gels that could be used in shakes or puddings. Part of the process to make this ingredient is to aggregate the proteins in a controlled manner before drying. Researchers at the Southeast Dairy Foods Research Center at North Carolina State University gained insights on the aggregation process while developing parameters to control the aggregation.

When a β-Lactoglobulin solution is heated at low pH, individual protein molecules unfold and begin to stick together. At very low pH (2.0), this happens quickly and the proteins stick together in long strings. At slightly higher pH (3.35), the reaction is a bit slower and the strings that are formed are somewhat shorter. Regardless of pH, the rate of the unfolding/aggregation reaction is dependent on the original concentration of the protein. Higher protein concentration, up to 8%, produces a faster reaction. Controlling the pH as well as heating time and temperature controls the size and number of strings formed, which ultimately determines the viscosity of the fluid or beverage where the protein strings are used.

Researchers have found that lots of shorter protein strings make a liquid as thick as a few really long strings. Using this information, processors can formulate higher-protein drinks using the shorter protein strings.

Mudgal P, Daubert CR, Foegeding EA. Kinetic study of β-lactoglobulin thermal aggregation at low pH. J Food Eng. 2011;106(2):159-165.

New Research on Reducing Calcium Lactate Crystals in Cheese

Sodium gluconate is known to prevent calcium lactate crystals in cheese, but until now it has not been known why. Calcium lactate crystals appear on the outside of cheese as a white haze and are often mistaken for mold by consumers. Investigators at the Midwest Dairy Foods Research Center at South Dakota State University created model systems with 5.3 percent calcium lactate and varying concentrations of sodium gluconate. They then monitored formation of crystals for 21 days. Crystals were noted in the control without gluconate after the first day. Only a minute amount of crystals were formed when 0.5 percent gluconate was in the solution.

Analysis of the solutions after filtration led to a proposed calcium-lactate-gluconate structure that may be present in the cheese preventing the haze formation. Understanding how the gluconate works will allow researchers to more accurately control its addition and minimize its use.

Phadungath C, Metzger LE. Effect of sodium gluconate on the solubility of calcium lactate. J Dairy Sci. 2011;94(10):4843-4849.

Routine Milk Urea Nitrogen Test Can Help Dairy Producers Reduce Ammonia Emissions

Ammonia is a potent atmospheric pollutant that contributes to natural ecosystem degradation while reducing air quality and negatively affecting human health. Dairy cows contribute to atmospheric ammonia as urea excreted in manure is rapidly converted into ammonia and released into the atmosphere. This contribution is exacerbated when nitrogen, which is included in the cow feed, is fed in excess or is poorly utilized by the dairy cow.

Using nitrogen efficiently in the cow's diet and the effect on ammonia emissions are of particular interests as the Innovation Center for U.S. Dairy^® continues to broaden its sustainability focus.

The authors of this article suggest that milk urea nitrogen (MUN) tests can be used as a management tool to reduce ammonia emissions from dairy farms. MUN is measured routinely on dairy farms to monitor the metabolic fate of dietary nitrogen and serves as an indicator of dairy cows' overall nitrogen excretion into the environment.

The MUN value of 14 milligrams per deciliter (mg/dl) was identified as the industry average benchmark against which relative reductions in MUN and its associated ammonia emissions were measured or calculated. Since milk protein yields are apparently maintained within the MUN range of 14 to 10 mg/dl, the researchers suggest that a decrease from 14 to 10 mg/dl MUN will result in at least a 20 percent reduction in ammonia emissions. Most of the reductions in MUN can be achieved by formulating better balanced total mixed rations that allow reductions in the total amount of nitrogen fed to the cows.

The researchers also suggest that the use of MUN as a management tool could encourage the adoption of beneficial practices that reduce nitrogen excretion and ammonia emissions while increasing profitability.

Powell JM, Wattiaux MA, Broderick GA. Short communication: Evaluation of milk urea nitrogen as a management tool to reduce ammonia emissions from dairy farms. J Dairy Sci. 2011;94(9):4690–4694.

Review: Production and functionality of active peptides from milk

Urista CM, Fernandez RA, Rodriquez FR, Cuenca AA, Jurado AT. Food Sci Technol Int. 2011;17(4):293-317
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Childhood overweight and obesity: Introduction into epidemiology and prevention strategies

Muckelbauer R, Kalhoff H, Muller-Nordhorn J, Kersting M. Curr Nutr Food Sci. 2011;7(3):191-199
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Vitamin D and type 2 diabetes: a systematic review

Mitri J, Muraru MD, Pittas AG. Eur J Clin Nutr. 2011;65(9):1005-1015.
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Is vitamin D a determinant of muscle mass and strength?

Marantes I, Achenbach SJ, Atkinson EJ, Khosla S, Melton LJ III, Amin S. J Bone Min Res. [Epub ahead of print]. 2011 Sept 14
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Dairy Plant Food Safety Workshop
February 8-9, 2012
Green Bay, WI

Meeting information
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14th Annual Dairy Ingredients Symposium
March 1 -2, 2012
InterContinental Mark Hopkins, San Francisco

Meeting information
Table of Contents