Whey protein pdf

While recent critical or meta-analytic reviews have argued that protein timing is inconsequential after accounting for total protein intake 6 , 27 , there are two factors that must be taken into account when considering these conclusions. In most cases, the studies were not designed to compare time of administration, but rather type or quantity of nutrient or placebo ingested post-exercise.

Second, only a few of the included studies used trained subjects. Most employed novice exercisers. One of the studies that has found a benefit of protein timing 28 was conducted in experienced resistance-trained males. Again, this may lend credence to the notion that training status matters when considering protein supplementation strategies.

Additionally, it should be noted that strength improvements not reaching statistical significance may prove to be significant in areas of individual competition or performance. Very few studies have actually utilized highly trained individuals or athletes, so translating the current findings to this population should be done with caution.

Finally, it is worth noting that several studies have shown the addition of carbohydrate and creatine monohydrate to a protein supplement, typically whey protein, results in greater strength and hypertrophy improvements from resistance training programs Perhaps a driving factor in performance i. Recovery from exercise has been measured through many different methods in previous research.

Delayed onset muscle soreness DOMS , which is defined as an aching pain in a given muscle following a novel exercise bout, has been measured subjectively Though the cause of DOMS is multifaceted and tied to a cascade of events linked to muscle damage, it is not necessarily an indicator of the magnitude of muscle damage and, therefore, cannot be used by itself to determine muscular recovery and adaptations from exercise Specific biomarkers and MPS rates appear to be the most efficient and widely used methods of objectively determining muscle breakdown, recovery, and adaptation from exercise.

Acute elevations of cortisol and creatine kinase CK are two biological indicators of muscle damage and the subsequent recovery processes that can be measured through blood sample analysis 30 , Post-exercise muscle biopsies can be used to determine rates of MPS, which directly measure the magnitude of the recovery process immediately following exercise West et al. The protein group, however, appeared to improve whole body net protein balance over 24 h post-exercise.

As noted previously, the subjects were already consuming 1. Interestingly, there was no difference between total body net protein balance between the groups. It should be noted that whole body protein synthesis is not necessarily a reflection of skeletal muscle protein synthesis Kim et al. However, no differences were found in muscle protein synthesis between the 40 and 70 g dose. Thus, one must not conflate measures of whole body protein metabolism with those of skeletal muscle.

Nevertheless, the recovery of muscle function has been demonstrated in other studies 15 , 16 of milk protein supplementation after eccentric exercise, perhaps due to myofibrillar protein remodeling. The results of these studies further support the idea that protein consumed post-exercise is crucial for maximizing rates of protein synthesis in skeletal muscle.

The effect on total body protein balance, however, is still a bit unclear. Carbohydrates have been shown to have a protein sparing effect, therefore the combination of protein and carbohydrate to decrease rates of muscle protein breakdown MPB and increase rates of MPS may be the best strategy for shifting total body protein balance to the net anabolic side 34 , even if carbohydrate itself does not necessarily enhance MPS 35 , This may partially explain the benefits of the milk supplement used by Cockburn et al.

Perhaps there is a synergistic effect. In addition to the investigations discussed earlier regarding post-exercise protein quality and training adaptations, Burd et al. The researchers collected muscle biopsies and measured rates of MPS following resistance training. In the 0—2 h post-exercise window, the group that consumed 30 g of protein in the form of skim milk expressed higher rates of MPS than the group that consumed 30 g of protein from beef However, rates of MPS in the 2—5 h post-exercise window did not differ.

This may be explained by the rate of digestion and absorption of these protein sources. Protein from dairy, specifically the whey portion, appears to be absorbed faster, and elicit a faster MPS response than beef. The difference between whole egg and protein-equated egg white consumption post-exercise was also studied recently The researchers measured rates of MPS through muscle biopsies and found that the group that consumed the whole egg exhibited higher rates of MPS.

One limitation to this study was the lack of control for total calories and macronutrients. The whole egg treatment consisted of 18 g of protein, 17 g of fat, and kcal, while the egg white treatment consistent of 18 g of protein, 0 g of fat, and only 73 kcal While the discrepancy in calories between treatment groups may have impacted total daily calories, thus impacting MPS, one cannot ignore the possibility of the role that differences in macronutrients may play.

Lastly, a investigation looked at the differences between protein-equated native whey protein, whey protein concentrate, and milk Native whey protein is produced through the filtration of raw milk, while whey protein concentrate is a byproduct of cheese production. Native whey protein consists of undenatured proteins and has a higher leucine content The supplements were ingested immediately after and again 2 h post-exercise following a moderate intensity lower body resistance training session.

Results showed higher blood amino acids concentrations in native whey and whey protein concentrate than in milk. MPS was elevated in the whey protein condition from 1 to 3 h post, while it was elevated 1—5 h post in the native whey condition.

There was no difference in MPS 1—5-h post-workout between native whey and whey protein concentrate, though MPS was higher from 1 to 5 h post-workout in the native whey condition compared to milk Collectively, these data support that whey protein, regardless of its levels of processing i.

How this translates to long-term differences remains to be determined. While the majority of the literature regarding the effects of protein intake on performance has focused on anaerobic activities, more recent work has examined its role on endurance activities, but this has mostly been absent from the most recent reviews. Similar to resistance training, the impact appears to be at least somewhat dependent on the presence or absence of other nutrients, particularly carbohydrate.

A systematic review and meta-analysis compared 11 studies investigating the effects of consumption of protein and carbohydrate vs. To investigate if the increased caloric intake due to inclusion of protein was responsible for this improved performance, a further analysis of isocarbohydrate and isocaloric conditions was performed.

Examination of isocarbohydrate conditions yielded a When considering only those studies measuring performance by time trial 3 , improvements were not statistically significant.

However, studies utilizing time to exhaustion protocols 8 did result in statistically significant improvements. It is worth noting that in all studies showing statistically significant improvement, whey protein was the source of protein utilized, though differences between concentrate vs. Again, it is prudent to highlight that performance improvements not reaching statistical significance may have clinical or practical relevance, specifically for athletes. When discussing the impact of protein on performance, it is imperative to include the impact that protein may have on glycogen replenishment and subsequent exercise performance.

Standard discussions of glycogen replenishment focus solely on carbohydrate consumption. Recommendations for adequate post-exercise carbohydrate consumption are to consume 0. Carbohydrate consumption of 1.

In cases of suboptimal post-exercise carbohydrate consumption, the addition of protein can improve glycogen replenishment and decrease symptoms of muscle damage Practical applications of standard post-exercise carbohydrate consumption recommendations may be limited in real world situations.

Beyond just glycogen replenishment aspects, it has also been shown that the presence of protein in rehydration beverages can enhance intestinal fluid uptake, aiding in rehydration 44 and that BCAA consumption during endurance exercise may improve time trial performance and peak power output while improving markers of immune health 45 and attenuate serotonin levels, subsequently resulting in a delay of central fatigue A systematic review by Pasiakos et al. The authors included studies that measured markers of muscle damage followed by a test of physical performance or muscle function.

Populations of the review included healthy individuals with daily dietary protein intake at or above the current RDA of 0. While some of the endurance exercise studies included showed decreases in markers of muscle damage, such as CK, or decreases in muscle soreness in groups consuming protein after initial exercise bout 47 — 49 , many did not 50 — This may have resulted from the inclusion of studies utilizing both trained and untrained subjects, as well as individuals consuming suboptimal daily protein intakes.

This evidence suggests that plasma CK levels, perceived level of muscle soreness, and muscle function may only be modestly related or perhaps utilizing a single method of measure paints an inadequate picture of recovery due to individual variability 5.

Without additional studies to clarify these relationships, developing guidelines based on these markers as representing recovery may be ill-advised. Individuals must be cautious when attempting to measure recovery from exercise based on these metrics alone. On game days days 1 and 4 , the supplement was consumed immediately post-, 3 h post-, and 6 h post-match in three different doses of 25, 30, and 25 g, respectively, resulting in a total of 80 g. On training days days 2, 3, 5, and 6 , 20 g of the supplement was consumed with breakfast.

Additionally, knee extensor concentric strength recovered quicker after the first game following protein supplementation. Endogenous antioxidant concentrations were greater following game two only in the protein-supplemented condition.

Since , additional work investigating the impact of protein consumption on biochemical markers of metabolic status, physiological fatigue, and recovery in endurance-trained athletes has been performed For 5 weeks, elite or experienced marathon runners received either Blood samples were collected to assess biochemical markers of metabolism, muscle damage, and fatigue and took place prior to beginning the intervention, 1 day following the marathon, and 1 week following the marathon.

Runners who supplemented with whey protein displayed decreased AST and ALT compared to maltodextrin-supplemented runners.

CK and LDH, biochemical indicators of muscle damage, were significantly greater in the maltodextrin group post-marathon compared to the whey protein-supplemented group.

Elevations in CK and LDH were still significant 1-week post-marathon in the maltodextrin group compared to the whey protein group The whey protein group also showed significantly decreased triglycerides TG and total cholesterol TC compared to the maltodextrin group post-marathon.

The maltodextrin group actually showed increased TC levels. Only the whey protein group showed significant decreases in LDL post-marathon and at 1 week post-marathon The authors suggested that the decrease in TC seen in whey-supplemented runners may indicate that cholesterol was more efficiently converted to steroid hormones, resulting in improved physiological recovery and adaptations from the strenuous exercise bout.

One week post-marathon, most biomarkers of damage and stress were still significantly lower in the whey protein group compared to the maltodextrin group Together, these results indicate that whey protein supplementation during marathon preparation and recovery, and that the supplement aids in attenuating metabolic and muscular damage.

Daily dietary assessments were not included in this study 54 , thus limiting possible practical applications or recommendations. Further studies are necessary to elucidate the potential contribution of peri-workout whey protein ingestion on makers of muscle damage, recovery, and subsequent performance measures in endurance athletes. In real-world sport performance situations, recovery and performance must be evaluated in the context of an accumulated effect.

The ability to train consistently while remaining healthy is critical for continued progression and optimal performance. Endurance athletes in particular are at increased risk for upper respiratory tract infections Kephart et al. Additionally, Rowlands et al. Post-exercise consumption of protein at levels thought to maximally stimulate MPS would potentially not have this same impact.

Post-exercise protein consumption affects other systems and pathways and should not be considered only in terms of stimulating MPS. As further evidence of this notion, Levenhagen et al.

Although this supplementation protocol stimulated MPS, subjects were found to be in negative whole-body protein balance. Because prolonged bouts of endurance exercise i. Because of this, protein requirements and recommendations for endurance athletes must consider more than MPS, especially since short-term increases in MPS do not fully explain the dynamics of long-term whole-body net protein balance and various training adaptations. Overall, total daily energy and protein intake over the long term play the most crucial dietary roles in facilitating adaptations to exercise.

However, once these factors are accounted for, it appears that peri-exercise protein intake plays a potentially useful role in optimizing physical performance and positively influencing the subsequent recovery processes.

Difficulties also arise in attempting to define and quantify the concept of recovery. Additionally, both performance and recovery must be viewed in context depending on whether the emphasis is an immediate, short-term effect i. It should also be noted that protein timing, whether it is pre-, during, or post-workout, is often framed within the context of bodybuilding i.

It is evident that to use such a narrow frame of reference ignores the potential utility of protein timing within the context of endurance events i. For instance, if one competes in a weight-class sport e. In these situations, protein timing in particular may serve a useful role in recovery.

Translating research into practical application requires differentiation between novice or trained individuals, healthy normal weight or healthy overweight individuals, special populations, or those with certain metabolic or disease states.

Here, we specifically focus on healthy, exercising individuals and limit our conclusions to these individuals. It is important moving forward that the study populations used are appropriate for the goals of the study and desired applications. For example, it is of little use to have a sample of recreationally-trained individuals if the goal is to understand performance in high-level athletes.

Though protein-containing meals result in increase of MPS on their own, as does resistance training, the timing of ingestion of protein around exercise further enhances this increase of MPS 63 , It is worth noting that an upper limit for this acute dosing has not really been established, though there is evidence that 40 g of protein stimulates MPS to a greater degree than 20 g following whole-body resistance training A dose higher than this, however, has not been included using the same timing paradigm.

With regard to endurance exercise, protein consumption during exercise may not confer an immediate ergogenic benefit, especially when carbohydrate consumption is adequate. It may, however, aid in delaying central fatigue, reducing MPB, and contributing to a more positive, whole-body nitrogen balance. Additionally, protein consumption in and around intense or prolonged endurance activity may aid in reduction of upper respiratory tract infection incidence and improved immune system function.

It may also aid in upregulating gene expression of proteins necessary for improving bioenergetic pathways. The impact of this on subsequent training sessions should not be dismissed and is an important part of improving performance. The effect of protein consumption on resistance training is highly dependent on many variables not related to protein.

The combination of peri-training protein consumption with inadequate or ineffective resistance training protocols will not maximize improvements in strength or hypertrophy. Resistance training protocol interventions must be of adequate intensity, volume, and frequency with an emphasis on progressive overload to produce results. Additionally, adequate training interventions coupled with calorie-restricted nutrition protocols may require increased protein intake of 2.

Consideration must also be made for the age of resistance-trained individuals, as older adults require protein intake over and above that of their younger counterparts to receive the same benefits noted above In order to fully understand the role of protein or any substrate for that matter on performance, the practical application beyond the contrived training or recovery interventions presented must be addressed.

Daily training schedules of athletes require an ongoing ability to recover and perform. For comparative purposes, a competitive athlete may spend 3—10 times this amount of time training per week if not more. Protein dosing strategies need to take this into account. This becomes even more apparent when considering that the uniform distribution of protein throughout the day results in greater MPS than an uneven distribution even when total daily protein intake is equal Arciero et al.

These results suggest that the pattern of daily protein ingestion may also impact results from resistance training protocols and provides further evidence that we must look beyond the few hours following training to determine the impact that protein may have on performance and recovery.

Madzima et al. While no statistically significant changes were observed between groups, protein groups trended toward greater increases when compared to the carbohydrate group while morning fat oxidation was greatest in the casein supplemented group. Taken together, these data demonstrate the need for a more comprehensive view and methods of measuring recovery. Increased sensitization of muscle to protein and nutrients for 24—72 h following training coupled with multiple weekly training sessions results in an on-going state of recovery.

Because of this, we need to begin considering this longer stimulus window as an opportunity to maximize feeding, rather than as a reason why immediate post-workout ingestion may not be particularly important. In other words, consuming nothing post-workout would be an unwise strategy if the goal is to potentially optimize the adaptive response to exercise training. Overall, there appears to be no adaptive advantage to avoiding protein intake in the peri-workout period.

Stimulation of MPS in the acute period following training may not result in improvements in strength, hypertrophy, body composition, or performance without deliberate implementation of additional strategies during the prolonged recovery period.

As such, this much broader view should be considered with regard to future investigations. SA is on the Advisory Panel for Dymatize. JA is the CEO of the International Society of Sports Nutrition—an academic non-profit that receives grants in part from companies that sell dietary protein. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

National Center for Biotechnology Information , U. Journal List Front Nutr v. Front Nutr. Published online Sep Harry P. Cintineo , 1 Michelle A.

Arent , 1 Jose Antonio , 2 and Shawn M. Michelle A. Shawn M. Author information Article notes Copyright and License information Disclaimer. Reviewed by: Michael D. Kerksick, Lindenwood University, United States. Arent ude. This article was submitted to Sport and Exercise Nutrition, a section of the journal Frontiers in Nutrition. Received May 23; Accepted Aug The use, distribution or reproduction in other forums is permitted, provided the original author s and the copyright owner s are credited and that the original publication in this journal is cited, in accordance with accepted academic practice.

No use, distribution or reproduction is permitted which does not comply with these terms. This article has been cited by other articles in PMC. Keywords: protein, athlete, endurance, strength, nutrient timing. Many professional athletes have discovered that a dairy-free diet is key to enhancing their performance and maintaining their peak for years past their expected retirement age.

These leaders are moving the needle toward plant-based fuel in sport, but the misconception surrounding dairy and performance nutrition still lingers. To make whey-based protein supplements, the liquid whey is processed into a powder form. By analyzing a collection of whey protein studies, review authors found parallels between the findings that presented several adverse effects of whey protein consumption.

These included increased acne, liver toxicity, increased oxidative stress, kidney problems, gut issues, and the expression of anger.

In regards to dosage, authors found that 40 grams or more of whey protein a day resulted in these adverse effects. Even during short-term use, whey protein consumption was found to negatively affect kidney function. In a study, those who consumed whey protein during the experiment experienced increased plasma urea, urinary volume, and urinary calcium excretion while the pH of urinary citrate decreased.

Essentially, this indicates an increased taxing of the kidneys, which marks the first step in kidney disease. In regards to liver function, those who live generally sedentary lives are most affected. Researchers found that when not exercising, the proteins from the whey supplement ended up going to the liver for processing—instead of being used for muscle synthesis. Over time, sedentary participants showed signs of early liver injury.

While whey protein is heavily used by athletes, many non-athletes consume it as well. Whey protein can be found in meal replacement shakes and other diet-related food products that promise weight loss or increased muscle mass through food alone.

This becomes an issue because consumers are led to believe that whey is akin to a superfood, when in reality it could damage their liver over time. Athlete or not, no one wants to contend with these awful feelings on a day-to-day basis. Many young gym-goers fall into the whey protein mentality, and as a result, they exacerbate their teenage skin issues.

Even powdered protein supplements often contain milk powder or other derivatives. However, what constitutes as high is easily within the realm of typical for most athletes. One scoop of Muscle Milk protein powder contains 25 grams of whey protein. The truth is, it could be even worse than these initial outcomes. Those who consume whey protein supplements may not feel the effects now, but given the complications with liver and kidney function, they may fall victim to serious health issues later in life, and not even know it was connected to their whey-consuming, gym-going days.

No Whey, Man.