Skip to Main Content

Nutrition Challenges For Aging: The Impact of Protein on Satiety and Energy Intake

Road running, fitness and senior couple training together on a exercise and workout run. Sports and health motivation of elderly man and woman runner in retirement living a healthy lifestyle.

The process of aging causes multiple physiological, psychological and social changes that affect food choice and consumption. Advancing age alters food reward signals, reduces food craving behavior, and suppresses appetite and energy intake, all of which contribute to a condition termed the “anorexia of ageing”. Compared with younger adults, older adults are reported to consume approximately 30% less energy per day. Dietary diversity (the number of different foods or food groups consumed over a given reference period) is also attenuated with ageing, with lower consumption of protein reported in older populations. Inadequate regulation of food and protein intake increases the risk of developing conditions such as sarcopenia and osteoporosis. Therefore, protein-energy homeostasis is considered a fundamental dietary-related determinant of healthy aging.

Dietary protein requirements increase with age, attributed partly to an increase in anabolic resistance to muscle protein synthesis (MPS), which accelerates loss of skeletal muscle mass and function. Maintaining muscle mass is essential to protect against falls, which are a leading cause of injury-related mortality in older people and a consequence of anorexia of ageing.

Despite the highly satiating effects of protein, interestingly, evidence suggests that older adults exhibit a blunted satiety response to protein consumption compared with younger adults. In fact, whey protein drinks have been shown to increase short-term total daily energy and protein intake in older people, even when the protein content of the drinks is very high. Another promising strategy for promoting energy and protein consumption in later life is the fortification of foods with protein. Increasing food volume to meet energy requirements is often unachievable in older groups, therefore, increasing energy and protein density while not affecting or reducing portion size, would be beneficial. As it is frequently reported that older adults consume inadequate amounts of protein, supplementing a healthy diet with additional high-quality protein may sufficiently stimulate MPS, without adversely affecting habitual appetite and food intake. However, further studies investigating compliance with long-term protein supplementation and the effects on satiety and energy intake are warranted.    

With the global population ageing (current UN projections expect 1.5 billion people over the age of 65 by 2050), innovative strategies to support protein-energy homeostasis are essential. Adopting a co-production approach involving academia, industry, practitioners and members of the public may stimulate the design of effective nutritional interventions, which consider age-related changes in physiology, cognition and lifestyle that affect appetite and dietary needs and preferences.

Further references and reading:

Bauer, J., Biolo, G., Cederholm, T., Cesari, M., Cruz-Jentoft, A.J., Morley, J.E., Phillips, S., Sieber, C., Stehle, P., Teta, D. and Visvanathan, R., 2013. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors association14(8), pp.542-559.

Dent, E., Hoogendijk, E.O. and Wright, O.R., 2019. New insights into the anorexia of ageing: from prevention to treatment. Current Opinion in Clinical Nutrition & Metabolic Care22(1), pp.44-51. 

Lonnie, M., Hooker, E., Brunstrom, J.M., Corfe, B.M., Green, M.A., Watson, A.W., Williams, E.A., Stevenson, E.J., Penson, S. and Johnstone, A.M., 2018. Protein for life: Review of optimal protein intake, sustainable dietary sources and the effect on appetite in ageing adults. Nutrients10(3), p.360.

Morley, J.E., 1997. Anorexia of aging: physiologic and pathologic. The American journal of clinical nutrition66(4), pp.760-773.

Nishimura, Y., Højfeldt, G., Breen, L., Tetens, I. and Holm, L., 2021. Dietary protein requirements and recommendations for healthy older adults–A critical narrative review of the scientific evidence. Nutrition research reviews, pp.1-48.

Highlights From the International Lactoferrin Conference

Every second year for the past 30 years, the top lactoferrin researchers gather to present, disseminate, and discuss the most recent research on this incredible ingredient for health, growth and development in infants and adults. With almost 11,000 published scientific papers on the topic, much is already known about its benefits; however, the presentations and wide-ranging research that is ongoing highlighted that many benefits and mechanisms are only just being discovered.   

Lactoferrin is a whey protein fraction that occurs naturally in both bovine and human milk. First isolated in 1939 and used in infant formula since the ‘80s, it’s an iron-binding glycoprotein that’s also found in supplements, gummies and even dental products. Its most researched benefits are highlighted in figure 1.  

Figure 1. Lactoferrin Benefits

Presenters from across the globe presented the influence of lactoferrin on many areas of health, including: 

  • Cystic fibrosis 
  • Inhibition of SARS-CoV2 virus 
  • Antifungal properties 
  • Hyper-ferritinemia (excess levels of the iron-binding protein, ferritin) 
  • Lowering iron levels in infant formula without negatively impacting growth or iron status 
  • Hair greying abstract. 
  • Cancer treatment and reduced tumor growth  
  • Cognitive function and protection 
  • Parkinsons Disease  
  • Reduced recurrence of bacterial vaginosis 

With so many potential benefits, it can sometimes seem too good to be true. But when digging into the mechanisms behind it, lactoferrin’s ability to bind iron is key in its function across many conditions of health and disease.  

Lactoferrin has a greater iron-binding capacity than the more commonly recognized protein, transferrin, which is renowned for transporting iron throughout the body. This iron-binding capacity helps enhance the iron status in adults and infants. This was highlighted in a couple of presentations; 1. Where the addition of lactoferrin to an infant formula meant the level of additional iron in the formula could be reduced, and still had the same benefit on overall infant growth and iron status. 2. Hyper-ferritinemia, a condition in which the body has too much iron, was also improved with lactoferrin supplementation.  

When it comes to its anti-microbial properties, there is no doubt of this protein’s benefits. In vitro work highlighted its ability to favorably impact the response to rotavirus infection, RSV and SARS-CoV2. It was a similar story when looking at the influence of bovine lactoferrin on fungal strains like Candida albicans, with an inhibition of growth with lactoferrin compared to control.  

An emerging area is the impact lactoferrin can have on bacterial vaginosis, BV, a persistent, recurring condition who’s treatment is mainly antibiotics that do not help mitigate recurrence.

Alpha-lactalbumin: Enabling Higher Quality Infant Formula

Care, woman feeding her baby with bottle and in living room on the sofa at their home. Family love, drinking or nutrition and black mother feed her newborn child on couch of their house with formula.

Breastfeeding is recommended by the World Health Organization as the best option for the developing infant1. Where breastfeeding is not possible, infant formulas provide a nutritious substitute, with advances in technology enabling more sophisticated formulas to be produced.

Both human and bovine milk are complex matrices of nutrients and bioactive compounds, developed by nature to support growth and development. The protein in both human and bovine milk is composed of two main types: whey and casein, although the ratio of these varies between species; from 60:40 whey:casein in mature human milk, to 20:80 in cows’ milk. Both types of proteins are high quality, meaning they have an excellent essential amino acid profile that is well digested and absorbed by the body.

Whey and casein themselves are composed of different protein fractions and figure 1 shows the differences in whey protein fractions between these milk sources2.

Figure 1. Whey protein profiles of breastmilk and cows’ milk (from sweet whey)2

Whey proteins in general and their constituent fractions have shown many nutritional and physiological benefits across the lifespan, not least, supporting infant growth and development. During digestion in the small intestine, whey proteins are broken down to amino acids and peptides, with the latter being suggested to exert physiological effects beyond just amino acid absorption.


Sleep-wake cycle

Sleep is critical for infant growth and development, particularly brain development3. Serotonin and melatonin are known to be key regulators of sleep across the lifespan; however, serotonin cannot cross the blood-brain barrier, thus it must be synthesized within the brain. The amino acid tryptophan is a precursor for serotonin and an amino acid able to cross the blood-brain barrier, hence it plays an important role in serotonin production.

Figure 2. Transport of TRP across blood-brain-barrier and subsequent serotonin synthesis.

The mean concentration of tryptophan in breast milk is around 2.5%, whereas standard formulas are only around 1-1.5%2. As discussed later, utilizing bovine alpha-lactalbumin in infant formulas can close this gap, as alpha-lactalbumin rich ingredients are higher in tryptophan than standard whey protein powders.

The influence of tryptophan-rich infant formula on sleep has been demonstrated in clinical trials. In one study, researchers looked at the influence of either tryptophan-rich infant formula during the day with standard formula at night (INV), vs tryptophan-rich formula at night with standard formula during the day (EXP), vs a standard formula control4. The standard formula contained 1.5% tryptophan, whereas the experimental formula contained 3.4% tryptophan. The researchers found that the EXP group had a greater total sleep time, better sleep efficiency (total time in the crib/total sleep time), more immobility time, and fewer night movements and waking episodes than the other groups (see figure 3).

Gastrointestinal and Immune Function

The infant gut is immature, and a number of factors influence its development, most notably the nutrients and bioactive compounds found in milk. With protein being a main component of mammalian milk, it’s no surprise this key nutrient influences gut and immune function.

Specifically, alpha-lactalbumin likely exerts some of its beneficial impact on gut development and immune health through the release of bioactive peptides in the small intestine. For example, it has been reported that three of the bioactive peptides released from alpha-lactalbumin, rather than alpha itself, demonstrate anti-microbial properties5.

In addition to serotonin’s influence on the sleep/wake cycle and central nervous system, it has also been reported to play a key role in gut motility and immune capability, while tryptophan itself has regulatory roles within the gut2.

Differences in the microbiome of breastfed and formula fed infants have been observed, with breastfed infants predominantly showing Lactobacillus and a diverse population of Bifidobacterium, while formula fed infants microbiome is more reflective of adults with more diversity6. Meanwhile, peptides from alpha-lactalbumin digestion have been reported to exert prebiotic benefits7.

One study investigated the incidence of E-coli induced diarrhea incidents in rhesus monkeys fed either standard formula, alpha-enriched formula or breastmilk8. Researchers found that not only were there fewer incidents in the alpha-fed monkeys than those fed standard formula, but this group also did not differ from the breastfed group, highlighting a closer match to the gold-standard recommendation.


o ensure sufficient intake of amino acids in standard formulas, the overall protein level has traditionally been higher than that of breastmilk. However, this has been suggested as a cause of some of the longer term metabolic and health differences observed between breastfed and formula fed infants9. It is also thought to be a factor in the growth differences observed between breastfed and formula fed infants2.

By better matching the protein profile of breastmilk through ingredients such as alpha-lactalbumin, the overall protein content of infant formulas can be lowered, while still meeting infant’s amino acid needs and without compromising growth, development and long term 


Although standard bovine whey protein does contain some alpha-lactalbumin (~15-20% of total whey protein), utilization of advanced membrane and processing technologies enables manufacturers to increase the level of alpha-lactalbumin in whey protein ingredients, thus allowing infant formula producers to bring formulations closer to the composition of breastmilk.

This closer matching to breastmilk is supported by the similar amino acid composition of bovine and human alpha-lactalbumin, as shown figure 2.11.

Figure 4. Amino acid composition of alpha-lactalbumin from both cows’ milk and human milk11


Whey protein is composed of several protein fractions, with alpha-lactalbumin being the largest fraction in human milk. Bovine alpha has a very similar amino acid profile to human alpha and utilizing it as an ingredient in infant formula enables growth, development and nutritional support closer to breastfed infants. Alpha has been shown to have a number of benefits, including supporting the sleep-wake cycle, immune system and gut development. Breastfeeding is recommended as the optimal choice for infant growth and development. When this is not possible, sophisticated formulas – such as those containing alpha-lactalbumin – provide a valuable substitute.

NutriPRO™ Alpha-lac Offerings

At Milk Specialties Global, our scientists and engineers work relentlessly to create high-quality ingredients designed to optimize health and nutrition. With this in mind, our NutriPRO™ Alpha-Enriched range was developed to enable infant formula manufacturers to provide more sophisticated products that better support infant growth and development. Within this range are both whey protein concentrates and isolates, with 2 to 3 times the level of alpha in standard whey protein.


  1. Victoria et al (2016). The Lancet, 387:475-490
  2. Layman et al (2018). Nutr Rev 76(6):444-460
  3. Nieuwenhuizen et al (2008). Br J Nutr 101(12):1859-1866
  4. Aparicio et al (2007). Nutritional Neuroscience, 10:3-4, 137-143
  5. Pellegrini et al (1999). Biochimica et Biophysica Acta (BBA), 1426(3)
  6. Harmsen et al (2003). J Paed Gast Nutr, 30:61-67
  7. Kee et al, 1998. Korean J Dairy Sci, 20:61-68
  8. Bruck et al (2003). J Ped Gastr Nutr, 37:273-280
  9. Sandström et al (2008). Am J Clin Nut, 87 (4):921-8
  10. Oropeza-Cej et al (2018). Nutrients, 10:886
  11. Lönnerdal and Lien (2003). Nutr Rev, 61(9):295-305

Casein: The Slow Protein For Overnight Recovery and Muscle Support

Casein makes up 80% of the protein in milk (whey being the other 20%) and has gained more attention in recent years for its nutritional and functional benefits.

As a high-quality protein from milk – and the major the protein in a milk protein concentrate or isolate – casein has a high level of essential amino acids (EAA), accounting for almost 50% of the protein, in a form that is highly digested and absorbed by the human body. While the leucine content is not as high as its partner, whey protein, it is still higher than other dietary protein sources.

Overnight recovery 

Muscle is constantly turning over, with cycles of muscle building and breakdown happening throughout the day and night. The overnight period has traditionally been a time of fasting, and therefore muscle breakdown, but research in recent years has looked at whether delivery of nutrients (particularly protein) during this period could favorably influence muscle protein synthesis.

Figure 1. Schematic representation of the process of muscle protein synthesis and muscle protein breakdown throughout the day.

Due to the slower absorption kinetics, casein is often used as the main protein source in overnight recovery products. Since this is generally the longest period of the day without nutrient delivery, casein can provide prolonged delivery of amino acids when consumed before bed. This could be particularly beneficial certain groups of the population who have higher protein requirements or struggle to consume enough protein during the day, such as those engaged in heavy training and the aging consumer (who has a naturally reduced appetite).

Figure 2. Plasma leucine, branched-chain amino acids, essential amino acid, and total amino acid concentrations in the fasting state and after the ingestion of 25 g: micellar casein or native whey protein in healthy young men.

Studies have shown that pre-sleep consumption of 40g casein can increase muscle protein synthesis (Trommelen and van Loon, 2016), with recent work demonstrating that this tactic can also increase the production of muscle connective tissue in older adults undergoing a resistance training program (Holwerda et al, 2021).

Joy et al (2018) also demonstrated that nighttime consumption of 35g casein was as effective as daytime casein intake at increasing strength and muscle building, in response to a 10-week resistance training program. With the resistance training taking place in the morning, this study demonstrated that looking at overall 24hr nutrition is important, rather than just focusing on nutrient delivery straight after an exercise bout.

While there is limited data regarding the effect of nighttime protein consumption on metabolic parameters, Allman et al (2020) found no difference in lipolysis (breakdown of fats by the body) whether casein was consumed during the day or pre sleep, highlighting that “pre-sleep protein is a viable option for increasing protein consumption in resistance-trained women because it does not blunt overnight lipolysis, and will therefore likely not lead to increases in subcutaneous abdominal fat.”

In conclusion, casein is a slowly digested, high-quality protein that can be utilized pre-sleep to favorably influence muscle protein synthesis, and be a key part of 24hr nutrition intake.  

Milk Specialties CasPRO™ Range

Milk Specialties Global has developed the CasPRO™ range of casein and caseinates, delivering the functional and nutritional benefits of high quality protein that works across applications. For more information, please check out our website or reach out to a member of our team. 

Feeding Rumen-Bypass Methionine in Transition and Early Lactation Cows

Agricultural business owner inspecting milking carousel system on dairy farm. Cowshed employee checking organic milk production on modern husbandry facility. Robotic technology in farming concept.


Feeding rumen-protected bypass methionine (RP-Met) in pre-fresh and lactating cow rations is common in the dairy industry. Methionine is considered one of the first two limiting amino acids in modern diets, along with lysine. There is considerable literature on the effects of feeding RP-Met on milk and component production, especially that of milk protein. Many factors impact what effect RP-Met will have on lactating cows, including nutrient makeup of the diet, production level, and management. Rumen-protected amino acid products are typically expensive ingredients and nutrition consultants and dairy managers should consider what response they would need to achieve in order to have a positive return on investment (ROI). Feeding RP-Met to transition and early/mid lactation cows may prove to be a positive investment regardless of milk and component pricing. This article will focus on the benefits of feeding RP-Met to transition cows as well as evaluating these products for lactating cows in general.

Feeding RP-Met to Transition Cows:

The onset of lactation brings large demands for protein and energy, and management and nutrition strategies focusing on transition cows are well-researched topics. Rumen-protected methionine and rumen-protected choline (RP-Chol) products that are often fed to transition cows. These nutrients are involved in different biological pathways but both have a variety of benefits. The major reason for feeding RP-Chol in transition diets is because it is a precursor for phosphatidylcholine, which is needed for the export of fat from the liver, whereas methionine is biologically useful to cows throughout lactation. Both of these products potentially have their places in transition cow programs. This article will focus on RP-Met.

A study by Zhou et al. (2016) looked at the effects of feeding RP-Met to transition cows. Cows were fed either 0g (control) or 13g RP-Met pre-fresh (-21 days) and 0g or 18g RP-Met in the post-fresh (30 days) diets (Table 1). Supplementation of RP-Met increased DMI in both pre- and post-fresh cows compared to the control group. The RP-Met treatment also increased milk yield 6.2 lbs., milk protein concentration and yield by 0.24% and 0.37 lbs., and butterfat concentration and yield by 0.14% and 0.33 lbs. respectively. Overall, energy-corrected milk (ECM) was increased 9.48 lbs. in RP-Met supplemented cows compared to the control group. Toledo et al. (2021) ran a similar study feeding additional RP-Met to both pre- and post-fresh cows at two separate universities and found that there was an overall effect of methionine to increase butterfat concentration by 0.10% and protein concentration and yield by 0.12% and 0.11 lbs. respectively, but had no impact on other production measures or DMI.

The transition period is a critical time for dairy cow health. Although RP-Chol can be a great tool for transition cows, many farms do not have a separate pen for their fresh cows, and RP-Choline does not likely have much biological or economic return after the transition period. Feeding RP-Met can have a significant impact on milk and component production for cows in many stages of lactation. For every pound of milk at peak, cows may increase production by 250 lbs. over the course of their lactation and feeding RP-Met can increase milk and component production for fresh and high-producing cows.

Overall Results Feeding RP-Met

As previously stated, RP-Met is commonly fed to cows of all lactation stages. A meta-analysis of feeding different sources of RP-Met was published by Zanton et al. (2014). Briefly, the impact on DMI and milk production when feeding RP-Met was variable, with some studies reporting slight increases and others small decreases. Authors showed an average of 0.07-0.08% milk protein concentration increase when feeding RP-Met, and milk fat concentration had a numerical increase as well. Increases in milk protein and fat yield showed a lot of variation but overall had positive numerical impact. The data on health events and somatic cell count observed while supplementing RP-Met are inconsistent.

Evaluating RP-Met supplementation is often dependent on many factors including stage of lactation, production level, and nutrient makeup of the diet. Energy-deficient diets may be limited in responses to RP-Met supplementation. Finally, there is a growing body of research showing the importance of amino acids other than methionine and lysine. Research regarding the importance of histidine, leucine, and isoleucine is ongoing. 

Overall Conclusions:

Feeding RP-Met can be a great tool to increase milk protein concentration and yield in cows of all stages of lactation for farms of all sizes. Supplementing RP-Met to transition cows can improve milk and component yield for cows in the first month of lactation. Given the large increase in production from fresh cows, supplementing RP-Met to these groups may be warranted regardless of milk and component prices. Nutrition consultants should rely on ROI calculations when supplementing RP-Met in non-transition lactating cow diets by evaluating the milk and component response. Proper amino acid balance and adequate energy levels have an impact on the response that RP-Met delivers. Finally, there are many RP-Met products on the market, and farms and consultants should be aware of costs, availability, and quality of the products they are selecting. 

Table 1. Overall intake and production responses when supplementing cows with rumen-protected bypass methionine in the pre- and post-fresh periods.

  • *Adaptd from Zhou et al. (2016)
  • 1Treatments were either 0g of RP-Met in both the pre- and post-fresh rations (Control) or 13g and 18g RP-Met in pre- and post-fresh rations, respectively.
  • 2P-values of the overall response of the inclusion of RP-Met
  • 3Energy-corrected milk (ECM) is calculated by ECM = (0.327 x milk yield) + (12.95 x fat yield) + 7.65 x protein yield)
  • 4ECM / DMI is used as a proxy for feed efficiency


  • Toledo, M.Z., M.L. Stangaferro, R.S. Gennari, R. V. Barletta, M.M. Perez, R. Wijma, E.M. Sitko, G. Granados, M. Masello, M.E. Van Amburgh, D. Luchini, J.O. Giordano, R.D. Shaver, and M.C. Wiltbank. 2021. Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations. J. Dairy Sci. 104:7583–7603. doi:10.3168/jds.2020-19021.
  • Zanton, G.I., G.R. Bowman, M. Vázquez-Añón, and L.M. Rode. 2014. Meta-analysis of lactation performance in dairy cows receiving supplemental dietary methionine sources or postruminal infusion of methionine. J. Dairy Sci. 97:7085–7101. doi:10.3168/jds.2014-8220.
  • Zhou, Z., O. Bulgari, E. Trevisi, M.A. Ballou, F.C. Cardoso, and D.N. Luchini. 2016. Rumen-protected methionine compared with rumen-protected choline improves immunometabolic status in dairy cows during the peripartal period. J. Dairy Sci. 99:1–14. doi:10.3168/jds.2016-10986.

Whey Can Increase Protein Levels Without Negatively Impacting Overall Dietary Intake In Older Adults

Sarcopenia – the loss of muscle mass and strength that occurs naturally with aging – can be mitigated by ensuring sufficient protein intake. Reducing the rate of muscle loss is a key factor for maintaining a free and active lifestyle in the advancing years. However, since protein is the most satiating nutrient and appetite diminishes with age, it could be supposed that adding more protein to the diet could lead to an overall reduction in calorie and nutrient intake at a time when they are critical.

While the current UK recommended nutrient intake (RNI) for protein is 0.75g per kg body weight, and the US RNI is 46g for women and 56g for men, other groups have recommended higher levels to be optimal for this group, as shown in the table below.

However, many adults are not achieving their optimal intake, with 36% failing to meet the UK recommendations and a monstrous 85% failing to meet the ESPEN recommendations. Furthermore, protein intake tends to be skewed to the evening, though achieving 25-30g protein at each meal and spreading protein intake throughout the day has been shown to be optimal.

A recent study looked at whether adding a daily whey protein supplement in the form of a gel containing 20g whey protein impacted appetite and overall nutrient intake in 50–75-year-olds. In a cross-over design, Tuttiett et al (2021) also investigated whether there was any impact from having the whey gel in the morning after breakfast, or in the evening before bed.

The researchers found that the addition of a gel did not impact overall appetite or habitual macronutrient intake, i.e. they did not alter the amount of protein, fat and carbohydrate they naturally consumed when excluding the contribution from of protein from the gel. However, the gel did increase overall protein intake.

With regards to the timing of protein supplementation, there was no difference in hunger, satisfaction or eating desire between morning and evening feedings. Since protein intake is typical skewed to the evening, a post-breakfast protein supplement can offer a beneficial strategy to increase protein intake at a time when it is typically low.

Further references and reading:
Department of Health. Dietary Reference Values for Food Energy and Nutrients Report of the Panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy; Report on Health and Social Subjects 41; HMSO: London, UK, 1991.
Bauer, J.; Biolo, G.; Cederholm, T.; Cesari, M.; Cruz-Jentoft, A.J.; Morley, J.E. Evidence-based recommendations for optimal dietary protein intake in older people: A position paper from the PROT-AGE Study Group. J. Am. Med. Dir. Assoc. 2013, 14, 542–559.
Paddon-Jones, D.; Rasmussen, B.B. Dietary protein recommendations and the prevention of sarcopenia. Curr. Opin. Nutr. Metab. Care 2010, 12, 86–90.
International Protein Board. Protein Matters: The Need to Re-evaluate the Adequacy and Application of Protein Requirements.

Improve Dry Matter Intake

Nutritionists and dairymen alike have been trying to maximize dry matter intake of their lactating cow diet.

Wide angle background image of industrial cowshed with cows in rows eating hay, copy space

Allen, 2000 stated, “Energy intake is a primary limitation on milk yield for high producing dairy cows and is determined by net energy content of the diet and DMI. The maximal productive capacity of an animal will depend on its genetic potential and will vary over the animal’s lifetime according to its age, physiological status (e.g. lactating, pregnant), and climate. Each animal has a maximal rate at which it can utilize nutrients and metabolic fuels and unless DMI is limited by physical capacity, mechanisms must exist that balance supply with demand for nutrients.”

Allen, 2000

Dry matter intake (DMI) is determined by meal size and meal frequency that are influenced by animal and dietary factors affecting satiety and hunger. Certain feed additives and nutrients can cause changes in DMI. The interest of this publication is to explore fatty acids (FA) and their effect on DMI.

Allen, 2000 published a review on factors affecting feed intake including certain FA. Supplemental fat sometimes depresses feed intake due to effects of fat on ruminal fermentation and gut motility, acceptability of diets containing added fat, release of gut hormones, and oxidation of fat in the liver. Significant decreases in DMI were observed for Ca-PFA for 11 of 24 comparisons. In addition, Ca-PFA resulted in a numerical decrease in DMI in 22 of the 24 comparisons. Other sources of fat had less consistent effects on DMI and there were few significant decreases in DMI by added FA for each category of fat. A summary of these findings is illustrated in Table 1.

Table 1. Effects of fatty acid source on DMI in Lactating cows. (adapted from Allen, 2000).

The effects of Ca salts of PFAD (CAS) on DMI reduction was linear indicating significance when included as low as 1% of the diet DM. The data shows us that fat alone is not responsible for the reduction in DMI. The composition of FA within in a fat source appears to be the cause. Allen 2000 concluded “ Although energy utilization is more efficient for digested fat than digested carbohydrate, it is clear that addition of fat to the diet does not always result in increased net energy intake and that reduction in DMI is one of the primary reasons. 

There have been several meta-analyses regarding the effects FA on DMI depression. These results are shown in Table 2.

Table 2. Published Meta-Analyses on Fat Type and DMI. (Adapted from Chilliard 1993, Raibee 2013, Boerman and Lock 2014)

These meta-analyses all indicate that Ca salts of PFAD (CAS) cause significant reduction in DMI based on dozens of published reports. The question then becomes what physical or chemical characteristics lead to the issues with DMI depression. Palatability of fat sources has been researched by Grummer et al. 1990 as a possible factor involved in decreased DMI from fat sources. They reported that some fat sources tested reduced DMI initially, but cows became adjusted after a period of time except for one—CAS. Cows do not become accustomed to CAS presence in the diet. Some other factor is causing DMI depression with respect to CAS.

Degree of unsaturation of FA has been another potential factor involved in FA effect on DMI. DMI depression has been observed with increased degree of unsaturation. Drackley et al 1992 observed when unsaturated LCFA were infused into the abomasum, increased degree of unsaturation reduced DMI more than saturated FA. These researchers suggested that unsaturated LCFA reaching the small intestine of dairy cows affects gastrointestinal motility and DMI. That brings us to another potential mechanism involving gut hormones such as CCK and GLP-1.

Choi and Palmquist 1996 observed increases in CCK and a consequent reduction in DMI when 0, 3%, 6%, or 9% CAS was added to the diet. Fat supplementation increased post-feeding plasma cholecystokinin concentrations and linearly increased plasma pancreatic polypeptide (GLP-1) concentrations. The effects of CAS on CCK plasma concentrations are reported in Figure 1.

Figure 1.The effects of CAS on Plasma CCK, DMI, and NEL intake in lactating cows. (Adapted from Choi and Palmquist 1996)
Figure 2. Effects of specific FA on CCK in humans.

There are at least 10 hormones that activate the stomach and intestines, induce gastric secretions, regulate glucose metabolism, and influence satiety centers in the brain (Song et al 2015). Among these CCK and GLP-1 are the primary hormones affecting satiety. Administration of CCK to humans and animals reduces meal size and duration. CCK causes sensations of satiety as well as reducing gastric emptying and stimulating pancreatic enzyme secretions (Wren and Bloom 2007). When specific FA, such as palmitic and oleic acids, empty into the duodenum, CCK receptors begin sending satiety signals to the brain reducing gastric emptying which, in turn, reduces meal size and duration. This happens every time these FA enter the duodenum in sufficient quantity. The sequence of events is controlled and modulated hormonally. 

Published research work by Relling and Reynolds 2007 and Bradford et al 2008 in lactating dairy cows has shown similar results comparing EB 100 to CAS. EB 100 is a FA source containing mostly saturated FA high in stearic acid while CAS is primarily palmitic and oleic acids. CAS significantly increased CCK while EB 100 was similar to the control. Piantoni et al 2013 observed a significant increase in CCK comparing an 85% palmitic acid FA source to the control. These data suggest that FA sources high in palmitic and oleic acids increase CCK potentially leading to DMI depression, while a FA source high in stearic acid does not. These reports are shown in Table 3.

Table 3. Effects of FA source on CCK in lactating cows

These published reports show the mechanism by which specific FA such as palmitic and oleic cause increases in CCK when fed to lactating cows. This in turn may lead to depressed DMI. To further investigate this hormonally modulated effect, a meta-analysis performed by Sellers et al. 2017 compared FA sources to the control. These findings are in Table 4.

Table 4. Meta-analysis results comparing EB 100, CAS, and 85% palm product. (Adapted from Sellers et al. 2017.)

The advantage that EB 100 has over CAS and 85% Palm is improved DMI. This has multiple positive effects ranging from higher NEL intake, higher milk yield, better BCS and body weight gain throughout lactation, improved reproductive parameters from conception rates to days open, and higher value as measured by IOFC. This is a mammalian phenomenon. The appetite of humans, mice, cows, apes, pigs, etc. are all affected similarly by these specific FA. EB 100 is the consultant’s choice for improved performance from milking to breeding. Contact your Milk Specialties Global representative for more details on their Energy Booster line of products.

References available upon request.

Tryptophan: Part of Alpha-lactalbumin’s Superpower? 

Alpha-lactalbumin is the main protein fraction in human milk and the second most abundant fraction in bovine milk. By utilizing advanced filtration and processing technologies, our NutriPRO™ Alpha-lactalbumin products contain more than twice the amount of alpha-lact as a standard whey protein. With this, comes an increased level of the essential amino acid, tryptophan. The alpha-lactalbumin fraction itself provides as much as 77% more tryptophan than standard whey protein1

Read me a bedtime story. Little girl and her father on bed at home.

Tryptophan plays a key role in many metabolic functions and is a precursor to the neurotransmitter, serotonin (5-hydroxytryptamine), which is critical to sleep, mood, and appetite, among many other functions. Thus, it’s no surprise that it is considered in the management of depression and sleep disorders2. Tryptophan supplementation has been reported in a recent review to decrease anxiety and increase positive mood in healthy individuals, although a reduction in aggressive feelings was not found3. The amount of tryptophan studied and shown to beneficially influence mood varies from 0.13g to 3g per day, on top of what would be consumed from a meal. This is easily achieved in small serve of alpha-enriched whey protein.  

The higher tryptophan level is likely part of the reason why alpha-lactalbumin has been shown in clinical trials to improve measures of sleep and morning wakefulness. For example, Markus et al, 2005, found that evening alpha-lactalbumin intake significantly increased plasma tryptophan levels before bedtime, and modestly but significantly​ reduced sleepiness the following morning4. They also reported improved brain-sustained attention processes, as shown by the number of errors on a cognitive test, the following morning. The differences were particularly clear in poor sleepers.​ 

More recently, the effect of alpha-lactalbumin was tested in female semi-professional rugby union players5. During 4 x one week blocks (to represent the different types of weeks the players experience), the players wore wrist actigraphy watches and had either an alpha-lac rich product or placebo every night, two hours before bedtime. Sleep onset latency was found to be significantly reduced in the alpha-lac group during the away game week and bye week (no competition game scheduled). 

With the increased level of sleep disorders and mental health challenges in the general population, many are turning to their diet to improve their overall health and wellbeing. Alpha-lactalbumin provides tryptophan alongside all the other essential amino acids as an easily digested, high quality protein.   

Lactoferrin’s Health Benefits: Immunity and Beyond 

Lactoferrin is a whey protein fraction that naturally occurs in milk in small amounts. By utilizing advanced processing methods, lactoferrin can be extracted to provide an ingredient at up to 95% purity, meaning consumers can easily experience the health benefits of this powerful bioactive protein in a small dose. While many consumers know lactoferrin for its immune boosting properties, the science suggests the benefits go much further, and provide opportunities for manufacturers to support consumers health and wellbeing goals.  

Women practicing yoga sitting on beach. Rear view of happy women in fitness clothes relaxing at the beach.

While there currently aren’t any permitted health claims on lactoferrin, there are a number of clinical trials that have shown lactoferrin promotes a healthy immune system and gut microbiome1, gut-immune axis2 and increases T cell activation3. These benefits have been shown with as small a dose as 200mg in adults, with doses up to 600mg shown to speed recovery from summer colds4. Lactoferrin was also tested in Covid patients with mild-to-moderate symptoms, with a dose of 1000mg orally and 16mg nasally showing a significant improvement in symptoms and faster time to a negative PCR test compared with both standard pharmaceutical treatment and no treatment5.  

The health benefits – and potential structure function claims – of lactoferrin extend beyond just immunity. A similar dose of just 200mg has been shown to increase antioxidant state by up to 18%2, it can play a role in eye health and has even been shown to lead to moister looking and softer feeling skin during winter months6.  

As an iron-binding protein, it’s no surprise that lactoferrin can improve iron status, with evidence in a population where iron levels are often a challenge – pregnant women. With iron supplements often causing gastrointestinal upset, lactoferrin was shown to lead to health total body iron and hemoglobin levels more effectively than iron sulfate supplementation, and without any of the side effects7.  

Lactoferrin’s benefits can also begin at the start of the gastrointestinal tract – in the mouth. A 20mg dose has been shown to improve elderly oral hygiene when consumed in a lozenge after meals8. This has been supported in other studies that have shown a similar 20mg lactoferrin dose in tablet form to reduce the level of volatile sulfur compounds (VSCs) in oral cavity air compared with placebo9. VSCs play an important role in the progression of periodontal disease. 

With many published papers on lactoferrin, there is a wide array of potential structure-function claims covering a number of health areas. To learn more about our lactoferrin ingredients, please contact us or see our Product Page

Whey Protein for Blood Glucose Control

The prevalence of diabetes in 2019 was estimated to be over 9% of the global population, with projections that this will rise to over 10% by 2030 and almost 11% by 2045. These figures are also reflected in those with impaired glucose tolerance, at an estimated 7.5% of the global population and growth rates anticipated around the same (Saeedi et al, 2019).

Couple going for jog

Postprandial hyperglycemia (the increase in blood glucose after consuming a meal) is a major determinant of overall glycemic control and an independent risk factor for cardiovascular disease. Co-ingesting protein and carbohydrates can favorably influence blood glucose response to a meal, and whey protein is particularly beneficial in this realm, hence has gained increased attention for its potential role either with a meal or as a pre-load.

While whey has been shown previously to be particularly beneficial in reducing postprandial hyperglycemia in younger adults, the question remained – is this also effective in older adults who are predisposed to type 2 diabetes?  This question was answered recently by researchers in Australia and New Zealand Oberoi et al (2022).

Ten healthy younger men (~29 years) and 10 older men (~78 years) were recruited in a randomized double-blind crossover study, in which they consumed drinks containing either 30g glucose, 30g whey protein, 30g whey protein plus 30g glucose or flavored water as a control. Blood glucose, plasma insulin and glucagon concentrations were measured for 180 min afterwards.

The results showed that co-ingestion of protein with glucose significantly reduced the increase in blood glucose concentrations compared to glucose alone in both younger and older men (see graph). Furthermore, it had a synergistic effect on increases in insulin concentration, regardless of age. Peak insulin concentrations after protein were unaffected by age.

The real-world potential application for this study was summed up in the researchers conclusion that “the ability of whey protein to reduce carbohydrate-induced postprandial hyperglycemia is retained in older men and that protein supplementation may be a useful strategy in the prevention and management of type 2 diabetes in older people.”

Furthermore, whey protein can also help maintain the body’s key metabolic tissue, skeletal muscle. This is especially important with an aging population and, given whey protein’s widespread availability and ease of use in the diet, can be easily incorporated into the diet for multiple, synergistic health benefits.


Saeedi et al. Diabetes Res Clin Pract. 2019;157:107843

Oberoi et al. Nutrients. 2022;14(15):3111.