Supplement Performance - Search for the Ultimate Post-exercise Recovery Drink
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crap about the minimum amount of protein necessary to sustain normal body functions.
Rather, they are interested in maximal gains in muscle mass and/or strength.
2 This is in line with the recent data by Borsheim and co-workers, who showed3 In sharp contrast, amino acid ingestion alone significantly increases60 However, consumption of both amino57 suggesting an75 Thus, nutrient timing76,77,78,79Given the fact that raising the blood insulin level is key to stimulating muscle protein
synthesis and limiting protein degradation following exercise,
hardcore gym rats abuse insulin to increase muscle mass and strength. According to MD´s
own drug guru William Llewellyn, insulin injections can produce "rapid and noticeable
[muscle] growth ... almost immediately after starting insulin therapy."
43 it’s not surprising that some4Most athletes choose to administer insulin immediately after a workout.
apparently realize that it’s the most anabolic time of the day to use this hormone. However,
insulin abuse is extremely risky business— one mistake in dosage and/or diet can be fatal or
leave one as a vegetable.
Fortunately, recent studies have focused on safe nutritional mixtures containing
protein hydrolysates, certain added amino acids (especially leucine) and high-glycemic (fastacting)
carbs.
this same issue).
Based on the best available evidence, I would suggest that dietary supplementationinduced
post-exercise hyperinsulinemia (a high level of insulin in the blood) supported by
protein hydrolysate and leucine ingestion-induced hyperaminoacidemia (high levels of amino
acids in blood) increases net protein deposition in muscle, leading to increased skeletal
muscle hypertrophy and strength in conjunction with appropriate resistance training. Let’s
examine some science behind my hypothesis.
Amino Acid & Insulin Secretion
Insulin is a peptide hormone produced by the beta cells of the pancreas. It was once
believed that insulin secretion was controlled almost entirely by blood glucose concentration,
i.e., by eating carb-containing foods. However, scientists later realized that amino acids also
play a very important role in controlling insulin secretion. Certain amino acids cause insulin
release in humans, even under conditions where the blood sugar changes little from its basal
level.
beta cells to individual amino acids. Studies on isolated perfused rat pancreas and islets
have demonstrated that physiological amino acid mixtures and even pharmacological
concentrations of individual amino acids require the presence of permissive levels of glucose
to be effective beta cell stimulants.
belief, oral arginine isn’t an effective insulin booster.
4 They12,14,15,16,17 (For more info on high-glycemic carbs, see "Nutrition Performance" in5 However, changes in blood sugar levels markedly influence the responsiveness of5 However, leucine is an exception.35 Contrary to popular15Leucine & Muscle Protein Synthesis
8 most likely via increases in circulating insulin. In addition, leucine9 After10 The important bottom line is that insulin10 If you wish to read a more detailed review, see the recent paper by Norton6 Hydrolysis process mimics our own digestive actions; thus, many experts feel20 Extensively hydrolyzed proteins containing mostly di- and tripeptides6,7,21 The considerably greater21Current evidence indicates that only di- and tripeptides are absorbed intact.
peptides appear to require hydrolysis before their breakdown products can be absorbed.
48 Larger48While the starter protein and method of hydrolysis affect absorptive characteristics, the
peptide-chain length is the most important variable. Protein hydrolysates produced from
various sources showed increased amino acid absorption in humans when the proportion of
di- and tripeptides was increased.
protein hydrolysate should contain mainly di- and tripeptides. Such a protein hydrolysate
seems to produce the most immediate hyperaminoacidemia. In general, it’s the kinetics of the
absorption (rather than the net absorption of amino acids) determining the greater nutritional
value of the protein hydrolysates.
The use of a protein hydrolysate in post-exercise drinks is preferred because it
results in a faster increase in blood amino acid concentrations during a two-hour, postexercise
period than does intact protein
the blood regulate muscle protein synthesis.
protein hydrolysate-containing supplement immediately after exercise without getting bloated
and not excessively suppressing appetite, so one can eat another meal sooner, possibly
optimizing the post-exercise "anabolic window." In addition, protein hydrolysates strongly
stimulate insulin secretion.
48 Thus, in order to maximize the absorption rate, the ideal15 And in turn, the levels of essential amino acids in61 A practical advantage is that one can ingest a14,17Clearly, hydrolyzed whey protein is the most popular protein hydrolysate among
athletes. Whey protein has been singled out as the ultimate source of protein based on an
excellent amino acid profile.
6,23Whey may offer other benefits, too.
some protein mixtures, but I prefer whey hydrolysates. By the way, the biological value of
hydrolyzed collagen (also known as gelatin) is zero; thus, collagen supplementation as a
protein source isn’t recommended, so stay away from those poor-quality protein bars
containing collagen. However, it’s been suggested that hydrolyzed collagen may be useful in
counteracting degenerative joint diseases (e.g., osteoarthritis).
6,23,26,27,28,31,32 Casein hydrolysate is also utilized in24,25Finally, some commercial products are enriched with wheat gluten hydrolysate (i.e.,
"glutamine peptides"). Wheat gluten has a unique amino acid profile: glutamyl residues
account for about 40 percent of the amino acids.
cells of the immune system, and may have specific immunostimulatory effects.
29 Glutamine is an important fuel for some30Protein Hydrolysate/Carb/Leucine Drinks, Insulin Secretion & Nitrogen Utilization
11 Four different 600 mL solutions were used. The glucoseı
blood insulin. In fact, protein hydrolysates stimulated an increase in blood insulin that was
two and four times greater than that produced by the intact milk protein solution and
glucose solution, respectively.
Ingestion of glucose and protein hydrolysate results in synergistic and fast increases inı
proteins, as reflected by the rapid increase in the blood concentration of amino acids in
peripheral blood.
Protein hydrolysates are absorbed at a faster rate from the gut than are intact milkı
postprandial (occurring after meal) period. The authors attributed this difference to
the rapid increase in blood amino acids evoked during the first 40 minutes of the
digestive period, during which the increase was about 37 percent greater after the
ingestion of whey protein hydrolysate solution than after ingestion of the intact milk
protein solution.
It’s likely that the high levels of blood amino acids and increased insulin explains a
superiority of protein hydrolysates over intact proteins in promoting better nitrogen utilization
(i.e., protein anabolism). The co-ingestion of carbs appears to affect the absorption kinetics,
as Calbet and Holst showed that whey and casein proteins and their respective hydrolysates
administered alone produce similar rates of intestinal absorption of amino acids.
be noted that the degree of hydrolysis (i.e., the peptide-chain length) also affects absorption
kinetics. Unfortunately, many scientists don’t provide any information on protein hydrolysates
used in their studies.
More recently, Kaastra and colleagues determined the extent to which the combined
ingestion of high-glycemic carbs and a casein protein hydrolysate, with or without additional
leucine, can increase insulin levels during post-exercise recovery.
were subjected to three randomized crossover trials in which they performed two hours of
exercise. Thereafter, subjects were studied for three and a half hours during which they
ingested carbs only (0.8 g/kg/h), carbs protein hydrolysate (0.8 and 0.4 g/kg/h,
respectively), or carbs protein hydrolysate free leucine (0.8, 0.4 and 0.1 g/kg/h,
respectively) in a double-blind fashion.
The results revealed that blood insulin responses were 108 percent and 190 percent
greater in the carbs protein hydrolysate and carbs protein hydrolysate leucine trial,
respectively, compared with the carbs-only trial. This study also indicated that the addition of
free phenylalanine, as applied in earlier studies,
insulin responses.
Similarly, Manders and co-workers examined blood insulin responses after coingestion
of casein protein hydrolysate, with and without additional free leucine, with a single
bolus of high-glycemic carbs.
insulin responses were determined after the ingestion of beverages of different composition:
carbs only (0.7 g/kg), carbs protein hydrolysate (0.7 and 0.3 g/kg, respectively) or carbs
protein hydrolysate leucine (0.7, 0.3 and 0.1 g/kg, respectively). The results indicated that
blood insulin responses were 66 and 221 percent greater in the healthy subjects in the carbs
protein hydrolysate and carbs protein hydrolysate leucine trials, respectively, compared
with those in the carbs only trial. In other words, this study also demonstrated that coingestion
of a protein hydrolysate with additional leucine strongly augments insulin secretion
after the consumption of a single bolus of carbs.
The notion that the protein hydrolysates have strong insulin-boosting properties is
also supported by the studies examining the effects of intact protein-containing post-exercise
drinks. Ivy and co-workers compared effects of carb intact protein drink (80 g of carbs, 28 g
of protein, 6 g of fat), low-carb drink (80 g of carbs, 6 g of fat), or high-carb drink (108 g of
carbs, 6 g of fat) and concluded that blood insulin levels didn’t differ at any time among
treatments.
carbs intact protein treatment (112 and 40.7 g, respectively) were somewhat higher than
those for the carbs-only treatment (112 g of carbs).
mixture of free amino acids also has a potent effect on insulin secretion.
dose of amino acids can cause gastrointestinal discomfort.
Protein Hydrolysate/Carb/Leucine Drinks and Post-exercise Muscle Anabolism
A sophisticated study by Koopman and colleagues investigated post-exercise muscle
protein anabolism and whole body protein balance following the combined ingestion of highglycemic
carbs, with or without whey protein hydrolysate and/or leucine.
protocol was rather rigorous; the subjects received a beverage volume of 3 ml/kg every 30
minutes to ensure a given dose of 0.3 g high-glycemic carbs/kg and 0.2 g/kg of a protein
hydrolysate every hour, with or without the addition of 0.1 g/kg/h leucine. Repeated boluses
were taken every 30 minutes until t = 330 minutes after exercise. The results revealed that
the whole body protein synthesis rates were highest in the carbs protein hydrolysate
leucine trial. Similarly, muscle anabolism in the vastus lateralis muscle was significantly
greater in the carbs protein hydrolysate leucine trial compared with the carbs-only trial,
with intermediate values observed in the carbs protein hydrolysate trial. Thus, the authors
concluded that, "The additional ingestion of free leucine in combination with protein and
carbohydrate likely represents an effective strategy to increase muscle anabolism following
resistance exercise." This study used rather large doses of added leucine; however, other
recent studies have shown that relatively small doses can improve exercise performance
Whey protein hydrolysate elicited the greatest availability of amino acids during the threehour22 It should14 Fourteen male athletes15,16 isn’t necessary to obtain such high postexercise17 Again, the subjects participated in three trials in which blood46 However, Zawadzki and colleagues observed that blood insulin levels for the47 A post-exercise drink containing a57 However, a large12 Their nutritional18and enhance the acquisition of strength.
19Although the Koopman study indicates that dietary supplementation-induced, postexercise
hyperinsulinemia plus hyperaminoacidemia can have favorable effects on the acute
phase response to resistance training, the effects of repeated supplementation on long-term
adaptations to resistance training are currently unclear. To shed some light on this issue, Bird
and co-workers examined the effects of chronic, high-glycemic carb and/or essential amino
acid supplementation on hormonal and muscular adaptations in untrained young men.
subjects followed the same supervised, resistance-training protocol two times per week for
12 weeks. Following resistance exercise, the subjects consumed either a high-glycemic carb,
an essential amino acid (6 g), a combined high-glycemic carb essential amino acid
supplement, or a placebo containing only aspartame and citrus flavoring. The results
revealed that carb essential amino acid supplementation enhances muscular and hormonal
adaptations to a greater extent than either carbs or essential amino acids consumed
independently. Specifically, carb essential amino acid ingestion demonstrated the greatest
relative increase in type I muscle fiber cross-sectional area. Changes in type II muscle fibers
exhibited a similar trend.
While beyond the scope of this article, it’s very likely that chronic reductions in the
exercise-induced cortisol response associated with post-exercise carb-amino acid ingestion
also positively impact the skeletal muscle hypertrophic adaptation to resistance training via
reductions in hormone-mediated protein degradation.
You Can Have Your Protein Shake & Drink It, Too!
Contrary to some beliefs, higher protein intake has no adverse effects on healthy
kidneys,
on bone health, as they increase circulating insulin-like growth factor I (IGF-1), which plays
an important role in bone formation.
protein supplement during a strength and conditioning program led to an increase in blood
concentrations of IGF-I in those subjects compared with the concentrations in a group of
persons who also trained, but consumed an isocaloric carb supplement.
alkaline phosphatase concentrations increased over time and tended to be higher in the
protein group than in the carb group, indicating increased bone formation.
In addition, IGF-I plays a critical role in development, growth, repair and maintenance
of skeletal muscle.
(especially bodybuilders) feel that a very high protein intake is beneficial for skeletal muscle
hypertrophy. Indeed, studies indicate increased positive nitrogen balance when protein intake
is increased;
requirements in those attempting to increase muscle mass is settled.
66 All36,37 fluid status,42 or bone.36,38,39,41 In fact, proteins appears to have positive effects39 For example, Ballard and co-workers reported that a40 Also, serum bone44 Thus, IGF-I may partially explain why many strength-power athletes45 however, more research is clearly needed before the mystery of protein45,49,50,54Traditionally, the term "protein requirement" has meant the amount of dietary protein
that must be consumed to provide the amino acids needed for the synthesis of those proteins
irreversibly catabolized in the course of the body's metabolism. It should be noted, however,
that strength-power athletes don’t give a crap about the minimum amount of protein
necessary to sustain normal body functions. Rather, they are interested in maximal gains in
muscle mass and/or strength. Other potential benefits of higher protein intake should be
considered, too.
51,52,53,63,80Summing Up
The studies reviewed in this article clearly indicate that nutritional mixtures containing
protein hydrolysates, added leucine and high-glycemic carbs strongly augment insulin
secretion, compared with the high-glycemic carbs-only trial. When post-exercise
hyperinsulinemia is supported by protein hydrolysate and leucine ingestion-induced
hyperaminoacidemia, net protein deposition in muscle should occur. Thus, I would suggest
that post-exercise recovery drinks containing these nutrients can lead to increased skeletal
muscle hypertrophy and strength in conjunction with appropriate resistance training.
PS. Obviously, there are other potentially useful ingredients for post-exercise
supplements, but they are discussed in my future MD articles. —AM
A study at the Copenhagen Muscle Research Center was implemented to determine
the effects different protein-containing solutions have on insulin response and amino acid
availability in healthy humans.
solution (control) contained only glucose (25 g/L), and the three additional solutions
contained the same quantity of glucose plus protein (0.25 g/kg body mass), but proteins were
derived from different sources: whey hydrolysate, pea hydrolysate and a complete cow’s milk
solution. This study indicated that:
The key branched-chain amino acid leucine acts as a nutrient signal to stimulate
muscle protein anabolism. Leucine affects muscle protein metabolism by decreasing the rate
of protein degradation,
activates key molecules involved in the regulation of protein synthesis, which has been
shown to occur even in the absence of an increase in circulating insulin concentrations.
exercise, recovery of muscle protein synthesis requires dietary protein or branched-chain
amino acids to increase tissue levels of leucine.
and leucine allow skeletal muscle to coordinate protein synthesis with physiological state and
dietary intake.
and Layman in The Journal of Nutrition (136:533S-537S, 2006).
Rapidly Absorbed Protein Hydrolysates
Protein hydrolysates (i.e., pre-digested proteins) are produced from purified protein
sources by heating with acid or preferably, the addition of enzymes, followed by purification
procedures.
it’s an ideal way to process dietary protein, especially when rapid absorption is important
(e.g., immediately after exercise). However, extreme bitterness is a negative attribute
associated with most protein hydrolysates ("Dude, this stuff taste like donkey ball extract").
Fortunately, specific debittering methods have produced relatively neutral-tasting
protein hydrolysates.
(chains of two and three amino acids) are absorbed more rapidly than free-form amino acids,
and much more rapidly than intact (nonhydrolyzed) proteins.
absorption rate of amino acids from the di- and tripeptides than from the amino acid mixture
appears to be the result of uptake by a system that has a greater transport capacity than the
amino acid carrier system, thus minimizing competition among its substrates.
:
It should be noted, however, that strength-power athletes don’t give a"Performance enhancement is not against the spirit of sport; it is the spirit of sport. To
choose to be better is to be human. Athletes should be given this choice." —J Savulescu et
al. British Journal of Sports Medicine, 2004;38:666-670.
Appropriate resistance exercise leads to significant increase in skeletal muscle mass
(hypertrophy), which can occur through an increase in muscle protein synthesis, a decrease
in muscle protein degradation, or both. While stimulus (i.e., resistance exercise) is important
for muscle hypertrophy, nutrient availability plays a critical factor in regulating the degree of
hypertrophy. Obviously, the muscle’s hormonal milieu also has a major impact on muscle
protein synthesis.
Insulin, Amino Acids & Protein Anabolism
It’s now clear that both increased insulin and increased availability of amino acids are
important to maximize muscle protein anabolism. The importance of availability of amino
acids for the stimulatory effects of insulin to be evident was highlighted by Bennet and
colleagues, who reported that insulin, given with sufficient amino acids, can significantly
stimulate protein anabolism via stimulation of protein synthesis and inhibition of protein
breakdown.
that protein balance over the muscle remains negative after resistance exercise, when only
carbs are ingested.
muscle protein anabolism after resistance exercise.
acids and carbs result in much greater effects on muscle protein anabolism,
interactive effect between insulin, amino acid availability and resistance exercise. Also, it’s
well-established that the stimulatory effect of amino acids after exercise is greater than the
effect of amino acids on muscle protein synthesis, when given at rest.
is also an important consideration.
