Whey protein supplementation and its potentially adverse effects on health: a systematic review

Whey protein and male acne: A double-blind, randomized controlled trial

BACKGROUND

Acne vulgaris (AV) exacerbation after whey protein (WP) consumption remains inconclusive among experts.

OBJECTIVES

To investigate the association between WP consumption and acne severity in men with acne.

METHODS

A noninferiority trial was conducted in men with mild to moderate facial and/or truncal acne. After randomization, participants in an intervention group took daily WP 30 g with a non-WP nutritional supplement 18 g (WP group, n = 25), while the control group took a non-WP nutritional supplement 46 g (non-WP group, n = 24). At each follow-up appointment, investigators evaluated acne count (total acne lesions, comedonal lesions, and inflammatory lesions) and severity.

RESULTS

Forty-nine participants had a mean age of 19.7 years (standard deviation [SD], 0.9) and 20.3 years (SD, 1.4) in the WP and non-WP groups, respectively. The mean differences in the facial and truncal total acne lesions for the WP and non-WP group were -5.99 (95% confidence interval [CI], -13.18 to 1.19, p = 0.09) and -2.18 (95% CI, -11.83 to 7.48, p = 0.65), respectively. For severity changes, only one (4.3%) participant in the non-WP group reported an increase in the Investigator Global Assessment scale of at least two levels.

CONCLUSIONS

In this 6-month trial, men with acne who undertook WP supplementation showed a noninferior difference in the changes in total acne lesions and severity of facial and truncal acne compared with the non-WP group.

Anabolic Strategies for ICU-Acquired Weakness. What Can We Learn from Bodybuilders?

The study aimed to show the potential clinical application of supplements used among sportsmen for patients suffering from Intensive Care Unit-acquired Weakness (ICUAW) treatment. ICUAW is a common complication affecting approximately 40% of critically ill patients, often leading to long-term functional disability. ICUAW comprises critical illness polyneuropathy, critical illness myopathy, or a combination of both, such as critical illness polyneuromyopathy. Muscle degeneration begins shortly after the initiation of mechanical ventilation and persists post-ICU discharge until proteolysis and autophagy processes normalize. Several factors, including prolonged bedrest and muscle electrical silencing, contribute to muscle weakness, resulting from an imbalance between protein degradation and synthesis. ICUAW is associated with tissue hypoxia, oxidative stress, insulin resistance, reduced glucose uptake, lower adenosine triphosphate (ATP) formation, mitochondrial dysfunction, and increased free-radical production. Several well-studied dietary supplements and pharmaceuticals commonly used by athletes are proven to prevent the aforementioned mechanisms or aid in muscle building, regeneration, and maintenance. While there is no standardized treatment to prevent the occurrence of ICUAW, nutritional interventions have demonstrated the potential for its mitigation. The use of ergogenic substances, popular among muscle-building sociates, may offer potential benefits in preventing muscle loss and aiding recovery based on their work mechanisms.

Continued elevation of creatinine and uric acid in a male athlete: A case report

Whey protein and other protein-fortified supplements are frequently consumed as nutritional supplements to aid in muscle hypertrophy and myogenesis. This case presents a 36-year-old athletic male with elevated creatinine and uric acid levels during routine laboratory evaluation. The patient had no history of kidney disease, diabetes, or hypertension. It was revealed that the patient had been regularly consuming whey protein as a dietary supplement for 2 months. Given the potential association between the elevated creatinine and uric acid levels and the use of whey protein, the patient was advised to discontinue the supplement. The patient then switched to protein-fortified milk to mitigate the possible harmful connection between the dietary intake and the laboratory findings. However, despite the dietary change, the increased levels of creatinine and uric acid persisted. This observation suggests that the elevated levels may be attributed to chronic whey protein consumption along with high-protein dietary consumption.

The Effect of Whey Protein Supplements on Acne Vulgaris among Male Adolescents and Young Adults: A Case-Control Study from North of Jordan

Background

Young people and athletes willing to gain muscle mass and strength are likely to consume whey protein supplements. The effect of milk as a dietary source of whey protein on acne is still controversial. At the same time, a few studies have suggested an acnegenic impact of whey protein supplements.

Objectives

To examine the association of whey protein supplements on acne risk among male adolescents and young adults.

Materials and Methods

201 male teenagers and young adults attending fitness centers in Irbid/Jordan were involved in an observational case-control research; those with acne were deemed cases, and those without acne were considered controls. The primary outcome was a comparison of the proportion of participants in each group who consumed whey protein supplements within the previous three months.

Results

100 acne-afflicted participants were compared to 101 healthy controls with similar demographics, including age, body mass index, educational level, and smoking habits, as well as intake of vitamin B12, corticosteroids, and anabolic steroids. However, considerably more participants in the acne group (47%) were taking whey protein supplements than in the control group (27.7%) (p=0.0047). The significance of this difference was maintained after multivariate analysis.

Conclusion

This case-control study provides evidence of a positive association between whey protein consumption and acne risk.

Whey protein supplementation reduced the liver damage scores of rats fed with a high fat-high fructose diet

Different functional foods with bioactive nutrients are being explored for the management of NAFLD. Whey proteins are rich in bioactive peptides and are suggested to show antioxidant and anti-inflammatory effects. We aim to test the hypothesis that the whey protein supplementation following a high fat-high fructose (HFHF) diet would protect against liver damage, inflammation, endotoxemia and steatosis in male Wistar rats. 36 rats were randomized into four groups for 8 weeks as the HFHF diet group, HFHF diet and whey protein isolate (WPI-200mg/kg/day) group (HFHF+WPI), control (C) group, and C+WPI (200mg/kg/day) group. Rats fed with a HFHF diet had higher final body weight compared to C and C+WPI groups (p = 0.002). Thus, WPI showed no significant effects for the body weight of rats with a HFHF diet. On the other hand, the HFHF+WPI group had significantly lower abdominal circumference when compared with the HFHF group (p<0,001). Higher serum CRP levels were observed in the groups with a HFHF diet (p<0,001) and WPI supplementation showed no effects on CRP levels. Whey protein supplementation resulted with lower total liver damage score in HFHF+WPI group compared with the HFHF diet group (p<0,001). Conversely, higher liver damage scores were observed with the C+WPI group compared to C group (p<0,001). HFHF diet resulted with higher expression of TLR-4 in the liver meanwhile WPI supplementation showed no effects on liver TLR-4 expression. We observed higher colon Occludin expression in HFHF+WPI and C+WPI groups compared with HFHF and C groups (p<0,001). Our results showed that, whey protein supplementation might help improve liver damage associated with a high fat-high fructose diet and increase the expression of Occludin in the small intestine and colon.

Effects of Whey Protein Combined with Amylopectin/Chromium on the Muscle Protein Synthesis and mTOR Phosphorylation in Exercised Rats

This study aimed to examine the impact of varying doses of whey protein (WP) and amylopectin/chromium complex (ACr) supplementation on muscle protein synthesis (MPS), amino acid and insulin levels, and the rapamycin (mTOR) signaling pathways in exercised rats. A total of 72 rats were randomly divided into nine groups: (1) Exercise (Ex), (2) Ex + WPI to (5) Ex + WPIV with various oral doses of whey protein (0.465, 1.55, 2.33, and 3.1 g/kg) and (6) Ex + WPI + ACr to (9) Ex + WPIV + ACr with various doses of whey protein combined with 0.155 g/kg ACr. On the day of single-dose administration, the products were given by oral gavage after exercise. To measure the protein fractional synthesis rate (FSR), a bolus dose of deuterium-labeled phenylalanine was given, and its effects were evaluated 1 h after supplementation. Rats that received 3.1 g/kg of whey protein (WP) combined with ACr exhibited the most significant increase in muscle protein synthesis (MPS) compared to the Ex group (115.7%, p < 0.0001). In comparison to rats that received the same dose of WP alone, those given the combination of WP and ACr at the same dosage showed a 14.3% increase in MPS (p < 0.0001). Furthermore, the WP (3.1 g/kg) + ACr group exhibited the highest elevation in serum insulin levels when compared to the Ex group (111.9%, p < 0.0001). Among the different groups, the WP (2.33 g/kg) + ACr group demonstrated the greatest increase in mTOR levels (224.2%, p < 0.0001). Additionally, the combination of WP (2.33 g/kg) and ACr resulted in a 169.8% increase in 4E-BP1 levels (p < 0.0001), while S6K1 levels rose by 141.2% in the WP (2.33 g/kg) + ACr group (p < 0.0001). Overall, supplementation with various doses of WP combined with ACr increased MPS and enhanced the mTOR signaling pathway compared to WP alone and the Ex group.

Investigating the Health Implications of Whey Protein Consumption: A Narrative Review of Risks, Adverse Effects, and Associated Health Issues

This narrative review critically examines the current research on the health implications of whey protein (WP) supplementation, with a focus on potential risks and adverse effects. WP, commonly consumed for muscle building and weight loss, has been associated with various health concerns. Our comprehensive analysis involved a thorough search of multiple databases, resulting in the inclusion of 21 preclinical and human studies that collectively offer a detailed overview of WP's health impacts. The review reveals significant findings, such as WP's potential link to liver and kidney damage, alterations in gut microbiota, increased acne incidence, impacts on bone mass, and emotional and behavioural changes. These findings underscore the complexity of WP's effects on human health, indicating both beneficial and detrimental outcomes in relation to different posologies in a variety of settings. Our study suggests caution for the protein intake in situations of hepatic and renal compromised functions, as well as in acne susceptibility, while possible beneficial effects can be achieved for the intestinal microbiota, humoral and behavioural level, and finally bone and muscle mass in elderly. We emphasizes the importance of balanced WP consumption and call for more in-depth research to understand its long-term health effects. Health professionals and individuals considering WP supplementation should be aware of these potential risks and approach its use with informed caution.

Protein supplementation: the double-edged sword

Protein supplements are widely consumed by athletes as well as young adults and teenagers going to the gym and are an excellent source to increase protein intake, build muscle mass, and enhance recovery. They are available in the form of powders, gummies, protein bars, and ready-to-drink shakes and have been shown to have effects on almost every system in the body. Subjects consuming whey protein-based supplements regularly show significantly lower systolic blood pressure, while subjects who consume soy-based protein supplements have been reported to show a significant decrease in their systolic and diastolic blood pressures. Favorable effects of soy protein consumption have been observed on the serum lipid profile, with significant decreases in serum low-density lipoprotein and triglyceride levels. Lower postprandial glucose levels have been observed in diabetic subjects as well, which can be attributed to the lower glycemic index of these supplements. This can lead to an indirect decrease in diabetes-related complications. While these supplements affect the body positively, caution has to be exercised while consuming them in excess, as they have been shown to cause hyperfiltration and increased urinary calcium excretion which can, in turn, lead to chronic kidney disease development. This article focuses on the effects of protein supplementation on the human body, with emphasis on the cardiovascular, endocrine, and renal systems.

Whey proteins as a functional food: Health effects, functional properties, and applications in food

Functional foods are defined as foods and ingredients that exhibit health benefits beyond their nutritional value. Research on functional foods is increasing rapidly as they may help prevent and manage some non-communicable diseases. Whey proteins are recognized as a high-quality nutrient source and known to contain some bioactive components. They are rich in essential amino acids such as cysteine, branched-chain amino acids such as leucine, valine, and isoleucine, and bioactive peptides. Whey proteins look promising as a potential functional food, given its antioxidant, anti-inflammatory, blood pressure lowering, anti-obesity, and appetite suppressing effects that is discussed in the literature. Whey proteins also show functional properties that play an essential role in food processing as an emulsifier, fat-replacer, gelling and encapsulating agent and are known to improve sensory and textural characteristics of food. This review focuses on the functional food aspects of whey proteins, associated health effects, and current food applications.

Protein supplement consumption prevalence, habits and complications in adolescents

INTRODUCTION

The consumption of nutritional and protein supplements by adolescents may have important consequences for their health.

METHODS

Prospective observational study based on a survey of adolescents enrolled in 6 schools selected at random in the city of Seville. Our primary objective was to determine the actual consumption of dietary supplements in the adolescent population and quantifying their protein content.

RESULTS

We obtained a total of 263 valid responses that showed a prevalence of consumption of nutritional supplements of any kind of 19.01%, of which 56.0% (10.64% of the total) corresponded to adolescents that consumed protein supplements for a mean protein intake of 0.26 g/kg/day (SD, 0.18). The profile of consumers of any type of supplements differed from that of nonconsumers in age, use of long-term medication and weight loss or high-protein diets. The comparison of adolescents who consumed protein supplements versus nonprotein supplements only evinced a significant difference in the control of supplement consumption. Although most of these adolescents were not subject to external control, 25.92% of those who consumed protein supplements were monitored by a professional, compared to 7.38% of consumers of nonprotein supplements. In the group that consumed protein supplements, 85.18% of adolescents achieved the desired effect and 18.51% reported some form of negative effect.

CONCLUSIONS

The prevalence of protein supplement consumption among adolescents in our area is 10.64%, with consumption of amounts corresponding to 25% of the recommended daily allowance of protein. The profile of protein supplement consumers is very similar to that of nonprotein supplement consumers.

A Qualitative Exploration of Older Patients' Experiences With Frailty and Related Management Strategies

BACKGROUND

Frailty is highly prevalent in hospitalized older patients and may increase the risk of adverse health outcomes. Understanding the experiences of older patients and the management strategies they use to recover from frailty is crucial to developing appropriate interventions.

PURPOSE

This study was designed to explore the frailty experiences of older adults and the management strategies they use to recover from frailty.

METHODS

Using purposive sampling, semistructured, face-to-face interviews were conducted with 16 older patients with frailty. Data were analyzed using content analysis.

RESULTS

The experiences of participants were classified into three phases, including the (a) individual sensing phase, (b) daily-living-threatening phase, and (c) acclimatization and acceptance phase. When experiencing frailty, the participants developed management strategies to facilitate recovery, which manifested in three phases: (a) making flexible adjustments to the daily routine, (b) using adequate support systems, and (c) adopting positive thinking.

CONCLUSIONS/IMPLICATIONS FOR PRACTICE

The results indicate that familial support and positive thinking are important management strategies for successful recovery in frail individuals. Older patients require adequate support systems. Positive thinking was also found to be an effective management strategy for recovery. Healthcare professionals should not only focus on providing supportive resources but also provide support to older patients to facilitate their adoption of positive thinking to face life changes brought on by frailty.

Whey Protein Hydrolysate Renovates Age-Related and Scopolamine-Induced Cognitive Impairment

Whey protein and its hydrolysates are ubiquitously applied in the food system. However, their effect on cognitive impairment remains unclear. This study aimed to investigate the potential ability of whey protein hydrolysate (WPH) to ameliorate cognitive degeneration. WPH intervention in Crl:CD1 (ICR, Institute for cancer research) mice and aged C57BL/6J mice in a scopolamine-induced cognitive impairment model for 10 days were evaluated. Behavioral tests indicated that WPH intervention improved the cognitive abilities in ICR and aged C57BL/6J mice (p < 0.05). Scopolamine enhanced the Aβ_1-42 level in the brain tissue, and the WPH intervention exhibited a similar therapeutic effect to donepezil in ICR mice. A noticeable reduction occurred in serum Aβ_1-42 level of aged mice treated with WPH. The histopathological study of the hippocampus showed that WPH intervention alleviates neuronal damage. Hippocampus proteomic analysis suggested possible mechanisms of WPH action. The relative abundance of Christensenellaceae, a gut microbe related to Alzheimer's disease, was altered by WPH intervention. This study demonstrated that short-term WPH intake protected against memory impairment induced by scopolamine and aging.

Hepatoprotective Effects of Rosmarinic Acid on Ovalbumin-Induced Intestinal Food Allergy Mouse Model

Rosmarinic acid (RA) has been proven to exert antianaphylaxis in atopic dermatitis, asthma, and allergic rhinitis. The aim of this study was to determine the hepatoprotective effects of RA on ovalbumin (OVA) challenge-induced intestinal allergy. The results exhibited that RA could relieve anaphylactic symptoms, decrease diarrhea, and prevent hypothermia in allergic mice. Moreover, the elevation of OVA specific IgE (OVA-sIgE), histamine, and mouse mast cell proteinases (mMCP-1) in the serum of OVA challenged mice were remarkably inhibited by RA. OVA challenge resulted in notable increases in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) activities, liver malondialdehyde (MDA) and nitic oxide (NO) levels, and a remarkable decrease in liver superoxide dismutase (SOD) activity and glutathione (GSH) level. RA treatments succeeded in improving these biochemical parameters and promote the redox homeostasis. Cytokine expression evaluation showed that RA effectively enhanced the expression of anti-inflammatory cytokines (IL-10 and FOXP-3) in the liver of OVA-challenged mice. Meanwhile, the elevation of pro-inflammatory cytokines (TNF-α, IL-4, IL-6, mMCP-1, and iNOS) were remarkably inhibited by RA. These findings suggest that RA possesses hepatoprotective effects on OVA challenge-induced liver injury. The anti-oxidative and anti-inflammatory activities of RA potentially play vital roles in this process.

Efficacy and safety assessment of protein supplement - micronutrient fortification in promoting health and wellbeing in healthy adults - a randomized placebo-controlled trial

Protein supplements are extensively used for muscle building, weight loss, recovery from exercise, improving endurance & cardio-performance. Major challenge with protein supplement is undigested protein and impaired gut health which results in nausea, dehydration, diarrhea, constipation, indigestion, stomach pain, and decreased appetite. Several studies have linked plant protein with reduced metabolic syndrome incidence. Probiotics can improve gut health as well. The objective of the study is to assess the efficacy and safety of protein supplement in promoting health and wellbeing in healthy adults. The present trial is a double blind, multi-center, randomized, placebo controlled, clinical trial involving 60 healthy individuals. The treatment duration was of 90 days. The subjects were randomized to receive either protein supplement treatment or placebo control. Protein supplement significantly improved quality-of-life score by 85.76%, VO₂ max by 42.92%, distance covered in 6 minutes, 100% individuals with at least 25% reduction in low energy events as compared to the control group. Protein supplement treatment reduced body weight (1.94 kg), waist circumference (2.46 cm), body mass index, waist circumference, hip circumference and body fat. Remarkable and significant improvement in digestive and sleep quality score, percent skeletal muscle was observed among protein supplement treated group. There were no clinically significant changes in hematological, biochemical and vital parameters; indicating safety of protein supplement. Present study concluded that protein supplement is safe and efficacious in weight management, improving high energy events, aerobic capacity, quality of life, digestive behavior score and sleep quality. This study ensures consumers about safety and effectiveness of protein supplement.

Micronuclei frequency and renal function markers in gym members: The moderating role of supplement intake

This research investigates the moderating role of dietary supplement intake in the relationship between MNi frequency and renal markers in gym members. A cross-sectional study was carried out with gym members of all sexes, between 20 and 59 years of age, with data on supplement use obtained via questionnaire. Renal markers (urea and creatinine) were assessed by blood collection. Buccal mucosa cells were collected to assess MNi frequency by buccal micronucleus cytome assay. Moderation was tested using multiple linear regression models by PROCESS macro for SPSS. Results showed significant interactions for supplement use (p = 0.001) and supplement type, ergogenic (p = 0.003) and sports food (p = 0.003), with MNi for urea. For creatinine, only supplement use showed interaction with MNi frequency (p = 0.048). In conclusion, supplement intake is a moderator in the relationship between MNi frequency and renal function markers in gym members.

Cheese Whey Milk Adulteration Determination Using Casein Glycomacropeptide as an Indicator by HPLC

Raw milk adulteration with cheese whey is a major problem that affects the dairy industry. The objective of this work was to evaluate the adulteration of raw milk with the cheese whey obtained from the coagulation process, with chymosin enzyme using casein glycomacropeptide (cGMP) as an HPLC marker. Milk proteins were precipitated with 24% TCA; with the supernatant obtained, a calibration curve was established by mixing raw milk and whey in different percentages, which were passed through a KW-802.5 Shodex molecular exclusion column. A reference signal, with a retention time of 10.8 min, was obtained for each of the different percentages of cheese whey; the higher the concentration, the higher the peak. Data analysis was adjusted to a linear regression model, with an R² of 0.9984 and equation to predict dependent variable (cheese whey percentage in milk) values. The chromatography sample was collected and analyzed by three tests: a cGMP standard HPLC analysis, MALDI-TOF spectrometry, and immunochromatography assay. The results of these three tests confirmed the presence of the cGMP monomer in adulterated samples with whey, which was obtained from chymosin enzymatic coagulation. As a contribution to food safety, the molecular exclusion chromatography technique presented is reliable, easy to implement in a laboratory, and inexpensive, compared with other methodologies, such as electrophoresis, immunochromatography, and HPLC-MS, thus allowing for the routine quality control of milk, an important product in human nutrition.

Dairy-Based Probiotic-Fermented Functional Foods: An Update on Their Health-Promoting Properties

Numerous studies have shown a link between the consumption of fermented dairy foods and improved health outcomes. Since the early 2000s, especially probiotic-based fermented functional foods, have had a revival in popularity, mostly as a consequence of claims made about their health benefits. Among them, fermented dairy foods have been associated with obesity prevention and in other conditions such as chronic diarrhea, hypersensitivity, irritable bowel syndrome, Helicobacter pylori infection, lactose intolerance, and gastroenteritis which all are intimately linked with an unhealthy way of life. A malfunctioning inflammatory response may affect the intestinal epithelial barrier’s ability to function by interfering with the normal metabolic processes. In this regard, several studies have shown that fermented dairy probiotics products improve human health by stimulating the growth of good bacteria in the gut at the same time increasing the production of metabolic byproducts. The fermented functional food matrix around probiotic bacteria plays an important role in the survival of these strains by buffering and protecting them from intestinal conditions such as low pH, bile acids, and other harsh conditions. On average, cultured dairy products included higher concentrations of lactic acid bacteria, with some products having as much as 109/mL or g. The focus of this review is on fermented dairy foods and associated probiotic products and their mechanisms of action, including their impact on microbiota and regulation of the immune system. First, we discussed whey and whey-based fermented products, as well as the organisms associated with them. Followed by the role of probiotics, fermented-product-mediated modulation of dendritic cells, natural killer cells, neutrophils, cytokines, immunoglobulins, and reinforcement of gut barrier functions through tight junction. In turn, providing the ample evidence that supports their benefits for gastrointestinal health and related disorders.

(Wh)olistic (E)ndocannabinoidome-Microbiome-Axis Modulation through (N)utrition (WHEN) to Curb Obesity and Related Disorders

The discovery of the endocannabinoidome (eCBome) is evolving gradually with yet to be elucidated functional lipid mediators and receptors. The diet modulates these bioactive lipids and the gut microbiome, both working in an entwined alliance. Mounting evidence suggests that, in different ways and with a certain specialisation, lipid signalling mediators such as N-acylethanolamines (NAEs), 2-monoacylglycerols (2-MAGs), and N-acyl-amino acids (NAAs), along with endocannabinoids (eCBs), can modulate physiological mechanisms underpinning appetite, food intake, macronutrient metabolism, pain sensation, blood pressure, mood, cognition, and immunity. This knowledge has been primarily utilised in pharmacology and medicine to develop many drugs targeting the fine and specific molecular pathways orchestrating eCB and eCBome activity. Conversely, the contribution of dietary NAEs, 2-MAGs and eCBs to the biological functions of these molecules has been little studied. In this review, we discuss the importance of (Wh) olistic (E)ndocannabinoidome-Microbiome-Axis Modulation through (N) utrition (WHEN), in the management of obesity and related disorders.

Liver and kidney function markers among gym users: the role of dietary supplement usage

Dietary supplements have been increasingly used by gym users and are often consumed without the guidance of a health professional. Moreover, the indiscriminate supplements use can have adverse health effects, such as changes in liver and kidney function. The aim of this study was to verify the association between dietary supplements intake with alterations in the liver and kidney function among gym users. A cross-sectional study was conducted with 594 gym users (mean age 37 (sd 14) years, 55·2 % women) from a city in southern Brazil. A questionnaire was used to evaluate the use of dietary supplements. The markers of the liver (alanine aminotransferase, aspartate aminotransferase (AST), alkaline phosphatase, γ-glutamyltransferase) and renal (creatinine and urea) function were also evaluated on a subsample of the study population. Data were analysed by binary logistic regression, adjusted for sex, age and education. The prevalence of dietary supplement intake was 36·0 %. Individuals who intake dietary supplements showed a higher prevalence to present slight alterations in the AST enzyme and in the urea after adjustments for potential confounders. In conclusion, the use of dietary supplement was associated with slight alterations in AST enzyme and in the urea among gym users. These findings show the importance of using supplements correctly, especially with guidance from professionals trained to avoid possible risks to health.

Dietary Whey Protein Supplementation Increases Immunoglobulin G Production by Affecting Helper T Cell Populations after Antigen Exposure

Whey protein is a by-product of cheese and casein manufacturing processes. It contains highly bioactive molecules, such as epidermal growth factor, colony-stimulating factor, transforming growth factor-α and -β, insulin-like growth factor, and fibroblast growth factor. Effects of whey protein on immune responses after antigen (hemagglutinin peptide) injection were evaluated in rats. Experimental diets were formulated based on NIH-31M and supplemented with 1% amino acids mixture (CON) or 1% whey protein concentrate (WPC) to generate isocaloric and isonitrogenous diets. Rats were fed the experimental diets for two weeks and then exposed to antigen two times (Days 0 and 14). Blood was collected on Days 0, 7, 14, and 21 for hematological analysis. The WPC group showed decreased IgA and cytotoxic T cells before the antigen injection (Day 0) but increased IgG, IL-2, and IL-4 after antigen injection due to increased B cells and T cells. Helper T cells were increased at Days 14 and 21, but cytotoxic T cells were not affected by WPC. WPC may activate adaptive immunity (IgG) against antigen by modulating helper T cells. Bioactive molecules might contribute to the immune-enhancing effects of whey protein concentrate.