Category Archives: Nutrition

Recipe: Crock Pot Meat and Dairy-Free Pumpkin Chili

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I was asked to participate in the Meatless Monday Night campaign, to find good alternatives to the meat and dairy-laden meals that so many of us consume along with football.  Sounds fun?  Well, I am not a cook…at all.  I enjoy feeding my family and food preparation is an interesting challenge, but I have had at least as many failures as successes.  My kids are fierce critics.  They will never let me forget the slow-cooked meal that featured chicken, olives, and mustard.  

I decided to participate in this campaign because I think it should be possible, even for kitchen hacks, to produce enjoyable meat and dairy-alternative meals.  As an endurance athlete, I am always looking for good protein sources that are not dependent upon meat and dairy.  Finally, as an allergist, I recommend restricted diets every day and it is really good for me to get some experience with dietary “finesse.”

After scouring the internet, I found a nice recipe for crock pot pumpkin chili (from Heather@Kissmybrocolli) and modified it to my needs and, anticipated, family tastes.  Here it is:

 Ingredients:

  • Soy crumbles, 24 oz
  • Medium onion, chopped
  • Minced garlic, 1 Tbsp
  • Red kidney beans, 15 oz
  • Great northern beans, 15 oz
  • Stewed tomatoes, 15 oz
  • Tomato sauce, 15 oz
  • Pumpkin purée, 15 oz
  • Cumin, 1 Tbsp
  • Chili powder, 2 tsp
  • Garlic powder, 2 tsp
  • Cinnamon, 1 ½ tsp
  • Paprika, 1 tsp
  • Cayenne, 1 tsp
  • Silk Almondmilk, 1 cup (the secret ingredient!)

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 Instructions:

  • Start by lightly browning the soy crumbles in a large skillet on medium-high heat.
  • Add onions and minced garlic and continue cooking until the soy crumbles are fully browned (this is subjective, since they start brown, already)
  • Add the soy crumble/onion/garlic mixture to a slow cooker and then add the other ingredients
  • Give it a good stir, then cook on high for 2-3 hours

I also made rice in my fancy rice cooker.  A Zojirushi.  I like it because it is idiot proof.

Preparation took me about 30 minutes, because I am slow.

 IMG_2503 IMG_2504

So, how did it turn out?  Honestly, I was nervous.  My kids were kind enough to mention the previous olive/mustard fiasco before digging in to the chili.  But, we all loved it.  Five out of five kids, my pregnant wife (which gives her a vote and a half), and me.  The chili was very mildly spicy with cinnamon overtones.  The Silk almond milk seemed to give it a more mellow flavor that appeared to suit everybody.  I do have one daughter who is obsessed with spicy food.  She did add hot sauce.  Several of us topped the chili with Fritos.

This is an easily modifiable, easy to prepare, meat and dairy-free meal that is accessible to both children and adults.

Check out additional meat and dairy-free recipes from the makers of Silk products at www.silk.com/sidelinemeat.

Enjoy!

 

This conversation is sponsored by Silk. The opinions and text are all mine.

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Fast Food For Athletes?

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By now, many athletes have heard about the recent study that concluded that fast food and sport supplements, taken after exercise, result in similar recovery.  This information has been taken by many people to mean that they can do a little workout, then eat junk without consequences.  Let’s look at the data and see if that is true.

This trial was conducted with eleven men (average age 27.7 years) who were familiar with moderate to high intensity exercise.  The study subjects had good fitness with an average maximum power output of 309 watts.  The trial had a randomized, cross-over design. The subjects abstained from exercise for 24 hours and food for 12 hours before each trial.  Each subject then completed a 90 minute glycogen-depleting ride on an indoor cycle ergometer. They could drink all the water they wanted.  After the 90 minute ride, the study subjects rested and ate either fast food or sports supplements, at 0 and 2 hours, during a 4 hour recovery period.  Following the recovery period, the subjects completed a 20 km time trial on the same indoor cycle ergometer.  The subjects, as already mentioned, were randomized and ate either fast food or sport supplements on the day of their first time trial.  When the subjects returned for their second time trial, exactly the same protocol was followed, except they ate the opposite food items.

The foods the participants were fed, whether fast food or supplements, contained the same absolute amounts of macronutrients.  These were 1.54, 0.24, and 0.18 grams/kg of body weight for carbohydrate, fat, and protein, respectively.  The fast food items were from McDonald’s and included: hotcakes, hashbrowns, orange juice, hamburgers, Coke, and french fries.  The sports supplement items included: Gatorade, Kit’s Organic PB, Cliff Shot Bloks, Cytomax, Power Bar Recovery PBCC, and Power Bar Energy Chews.

Aside from performance measures on the cycle ergometer, the researchers also obtained data from muscle biopsies (for glycogen levels), blood sampling (for glucose, insulin, and lipid levels), and a “gastrointestinal discomfort questionnaire.”

The results are interesting, but, when the structure of the study is considered, not very surprising:

  • Time trial times were not significantly different between the two groups.
  • Muscle glycogen concentrations post-exercise were not significantly different between the two groups at either 0 or 4 hours of recovery.
  • Serum glucose concentrations were not significantly different between the two groups at 0, 30, 60, 120, 150, 180, and 240 minutes of recovery.
  • Serum insulin concentrations were not significantly different between the two groups at 0, 30, 60, 120, 150, 180, and 240 minutes of recovery.
  • Blood levels of total cholesterol, high-density lipoproteins, low-density lipoproteins, and triglycerides were not statistically different at 0 and 4 hours of recovery.
  • Feelings of sickness and discomfort were not statistically different between the two groups at 0, 1, 2, 3, and 4 hours of recovery.

This study has been portrayed to say that fast food can be used as a source of recovery nutrition.  But please note that this trial of fast food vs sport supplements was actually structured to compare the effects of these sources of nutrition on replenishing glycogen (energy stores) in preparation for a time trial.  This trial was not equivalent to the now-famous body of research that supports consuming chocolate milk after completing all exercise.

Another caveat to consider is the real-world applicability of measurement of the foods used in the trial.  Most people over-order food in fast food establishments.  In the example of this trial, the second fast food feeding consisted of a hamburger, medium Coke, and small fries.  To someone who has been fasting, then exercising, these portions may seem quite meager. Intuitively, it appears to me that sports nutritional supplements, with detailed packaging, may be easier to eat in appropriate quantities.

The bottom line is that energy-starved muscles will accept any source of replenishment.  When the macronutrients, carbohydrates, protein, and fat, are equivalent, the results of replenishment are going to be the same before and during an exercise challenge.

Reference:

Cramer MJ, Dumke CL, Cuddy JS, et al. Post-exercise Glycogen Recovery and Exercise Performance is Not Significantly Different Between Fast Food and Sport Supplements. Int J Sport Nutr Exerc Metab. 2015 (not yet published)

Pre-publication material is available at:

http://journals.humankinetics.com/AcuCustom/Sitename/Documents/DocumentItem/Hailes_ijsnem_2014-0230-in%20press.pdf

and at:

http://etd.lib.umt.edu/theses/available/etd-06102014-183050/unrestricted/Cramer_Michael_Thesis.pdf

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Testicular Cancer From Muscle-Building Supplements

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A study has recently been published that showed a link between testicular cancer and muscle-building supplements.  This is important news because muscle-building supplements are popular and are often viewed as safe.

This study was performed as retrospective interviews with matched controls.  356 men who had been diagnosed with testicular germ cell cancer were compared to 513 men who had not been diagnosed with testicular cancer.  Aside from questions about taking muscle-building supplements, the men were asked about a wide range of potentially confounding factors such as history of smoking, use of alcohol, history of exercise participation, prior injury to groin or testes, history of undescended testes, and family history of testicular cancer.

After accounting for the potentially confounding factors, as well as age and race, the researchers found a strong association between the use of muscle-building supplements and testicular cancer:

  • Almost 20% of study participants with testicular cancer had used muscle-building supplements.
  • A 65% increased rate of testicular cancer if supplements had been used at least once a week for at least four consecutive weeks.
  • An 177% increased rate of testicular cancer if more than one type of supplement had been used.
  • An 156% increased rate of testicular cancer if supplements were used for at least three years.
  • An 121% increased rate of testicular cancer if supplement use began at or before age 25 years.
  • An 155% increased rate of testicular cancer if supplements were used that contained creatine and proteins.

Since this study was retrospective, it did not prove that muscle-building supplements cause testicular cancer.  This study also was unable to show a mechanism whereby muscle-building supplements may cause testicular cancer.  However, the researchers did a good job in interviewing a large number of men and the association demonstrated in this study is quite compelling.  Furthermore, the data, beyond the 65% increased rate of testicular cancer for any use of muscle-building supplements, appears to support a causative role for these supplements in testicular cancer.  For example, use of increased variety of such supplements, increased duration of use, and use at a younger age would all be predicted to lead to higher rates of testicular cancer if any use at all of muscle-building supplements can cause testicular cancer.

Why is this study important?

Testicular germ cell cancer is the most common solid cancer in men age 15-39 years.  The incidence has been rising over time, from 3.7 cases per 100,000 men in 1975 to 5.9 cases per 100,000 men in 2011.

Muscle-building supplements, like all over-the-counter supplements sold in the United States, are sold and regulated like food products.  In other words, supplements are treated by regulatory authorities like boxes of breakfast cereal.  This is unfortunate, because MOST SUPPLEMENTS ARE MEDICINE, just like aspirin and antibiotics.  While regulatory authorities, like the FDA, are not perfect, they do require an amazing amount of safety research on pharmaceuticals before they can be prescribed and sold.

Patients often tell me that they are nervous about taking medications after they have read the warning sheets that accompany these medications.  But what these warning sheet show is that research has been done, often with tens of thousands of people, to carefully define all possible side-effects of these medications.  Supplements that do not contain these warning sheets are NOT safer because of a lack of warning data.  In fact, they are potentially LESS SAFE because safety research has NOT been done, due to a different type of regulation.  To put it another way, most people should be reassured when they see detailed warning information and should be worried when they do not see such information.

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How do these statements apply to muscle-building supplements?

  • Natural components in these supplements could act like artificial hormones.
  • Some of these supplements could contain impurities or less-active ingredients, which are not required to be listed on product labels.
  • Some of these supplements may contain hidden, unlisted, ingredients such as androgenic steroids.

An example of hidden dangerous ingredients arose this year. A muscle-building supplement called Tri-Methyl Xtreme was found to contain synthetic anabolic (androgenic) steroids.  These anabolic steroids can cause liver injury and other dangerous side effects.  Since anabolic steroids are drugs, the FDA was able to crack down on this product and warn about its use.

Please be careful if you plan to take muscle-building supplements.  You may do very well to stick to a healthy diet with lean meat and other non-laboratory sources of protein and other essential nutrients.

Stay healthy and safe!  I’ll see you in the gym!

Reference:

Li N, Hauser R, Holford T, et al.  Muscle-building supplement use and increased risk of testicular germ cell cancer in men from Connecticut and Massachusetts.  Br J Cancer. 2015 Mar 31:112 Suppl:1247-1250.

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All Calories Are Not Created Equal

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All calories are not the same.  This simple concept underscores the glycemic index and its usefulness in making decisions about diet. Foods with a high glycemic index, like processed sugar, often provide much more energy than the body needs at that time. The unused calories float around the bloodstream and the body responds by storing these extra calories as fat. Another problem is that these quick calories are used up so quickly that it is easy to soon become hungry again. A much better choice, clearly, is to consume calories that do not create a spike in the bloodstream and that are burned slowly enough that it takes a long time to become hungry again.  It is like the difference between taking a swallow from a fire hose and taking small, repeated, sips from a water fountain.  Which sounds more appealing?

The glycemic index of foods is expressed as a number from 0-100.  It reflects how quickly a food can be converted into glucose (sugar).  The higher the number, the faster the food can get turned into sugar and the greater the spike of sugar in the blood stream.  Pure glucose, for example, has a glycemic index of 100.  Here are target ranges for the glycemic index:

  • 55 or less = Low (good)
  • 56- 69 = Medium
  • 70 or more = High (bad)

There is a helpful webpage from Harvard University that lists the glycemic index for 100 common foods.  White rice, for example, has a glycemic index of 89, whereas soy beans have a glycemic index of 15.

The glycemic index of a food, however, can be changed by preparation.  For instance, added lemon juice or vinegar can lower the glycemic index of a food. Added fat or fiber can also lower the glycemic index.  If allowed to over-ripen, the glycemic index of fruit, such as bananas, can increase.  Finally, the glycemic indexes of pasta and other starchy foods is increased with longer cooking.

While the glycemic index is a useful starting point, there are other important considerations when choosing a food.  One such consideration is the size of a typical portion.  A food with a lower glycemic index may not be the best choice if more of this food is needed for a full portion. This is where the concept of glycemic load can be helpful.  The glycemic load of a food reflects both the glycemic index of that food and the typical size of a portion.

  • 1 to 10 = Low (good)
  • 11 to 19 = Medium
  • 20 or more = High (bad)

The webpage from Harvard University also has information about the glycemic loads of 100 common foods.

Another important limitation of the glycemic index is that it leaves out critical nutritional information.  For example, the amount of calories (carbohydrates), fats, vitamins, minerals, salt, and fiber are not described by the glycemic index.  All of these considerations are important in making decisions about diet.

The glycemic index is a great starting point in making choices about diet. Foods with a high glycemic index should generally be avoided in favor of foods with a lower glycemic index. However, it is important to consider the size of portions (reflected in glycemic load) and other nutritional content of foods to make the best choices possible.

Useful resources:

Harvard University has a database of the glycemic index and glycemic load of 100 common foods.

The Mayo Clinic has an article about the glycemic index and does a good job describing its limitations.

The University of Sydney is the global authority on the glycemic index.

WebMD has a helpful article about the glycemic index.

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Control Your Weight And Blood Sugar Through Sleep

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Most people think they gain weight when they lose sleep simply because they have more hours in the day to eat.  This makes sense.  I remember many nights on call as a Resident at St. Louis Children’s Hospital eating large amounts of high-calorie, unhealthy food as quickly as I could.  I got into this eating pattern because I didn’t know if I would be able to eat again all night.  As it turns out, this sort of eating pattern is not the full explanation for the relationship between less sleep and more weight.  There are decades of research on this subject that have shown that good sleep, both in quality and duration, is essential to help control weight and also to prevent type II (adult-onset) diabetes.

Epidemiological (population) research has shown an association between reduced sleep and increased rates of obesity and type II diabetes.  The numbers are surprising.  For example, a study has shown that children with reduced sleep were 89% more likely to be obese.  Adults with reduced sleep were 55% more likely to be obese.  Furthermore, there is a dose relationship.  The shorter the sleep, the greater the risk of obesity.  With regard to type II diabetes, reduced sleep increased the risk of developing this disease by 28%.  For people who have difficulty remaining asleep (fitful sleepers), the risk of developing type II diabetes is increased by 84%. Interestingly, people who had “long sleep” of more than 8-9 hours a night had a 48% increased risk of developing type II diabetes.  To be clear, epidemiological associations do not prove that stimulus X causes effect Y (e.g. decreased sleep causes obesity or diabetes), but that stimulus X is associated with effect Y.  In the case of sleep and obesity or diabetes, the association appears to be very strong.

The main mechanism that appears to link reduced sleep with obesity is the actions of the two hormones, leptin and ghrelin.  These hormones help regulate the feeling of hunger.  Leptin makes people feel full, while ghrelin makes people feel hungry.  Lack of sleep leads to less production in the body of leptin and more production of ghrelin.  Consequently, lack of sleep makes people both feel less full and more hungry.  To put this concept into real-life terms, a meal that would “fill-up” someone getting 7-9 hours of sleep a night (the national recommendations), wouldn’t feel like enough for someone who only gets 5 or 6 hours of sleep a night.

There are other mechanisms whereby reduced sleep can lead to obesity.  Sleep restriction is associated with stimulation of brain regions sensitive to food stimuli.  This suggests that sleep loss may lead to obesity through the selection of high-calorie food (sleep-deprived people are more likely to grab a bag of chips than a bag of carrots, for example).  In addition, there is evidence that restricted sleep can lead to the activation of genes that promote obesity. Supporting this concept is the observation that the inheritability of increased body mass index is increased in people who get little sleep.

Sleep loss also affects how people process glucose (sugar).  Studies have shown that sleep loss leads to decreased sensitivity, of the body, to the hormone, insulin.  This hormone is responsible for helping the body to process glucose and get it out of the blood stream.  If the body detects that there is too much glucose in the blood stream, such as what would happen if there is decreased sensitivity to the effects of insulin, then cells in the pancreas, called beta-cells, respond by making more insulin.  However, in sleep-deprived people the beta-cells do not make enough extra insulin to overcome the decreased sensitivity of the body to insulin. Therefore, sleep-deprived people have decreased glucose tolerance (they cannot get rid of extra glucose in the blood stream as well as they need to) and this leads to increased risk of developing diabetes.

Another reason why sleep-deprived people have decreased glucose tolerance is brain metabolism.  The human brain consumes up to two third of circulating glucose.  However, after sleep deprivation, utilization of glucose by the brain is reduced.  Therefore, sleep deprivation leads to another mechanism whereby blood glucose cannot be processed correctly, increasing the risk for developing diabetes.

Obesity and type II diabetes are metabolic diseases that have a tremendous impact on public health and society.  The role of poor sleep, either in terms of quantity or quantity, or both, is not commonly considered in the management of these conditions.  In clinical practice, it is, therefore, important to consider improving sleep as a therapeutic tool in the management of these obesity and type II diabetes.

For those people who are starting fitness programs, those people who are struggling to reach or maintain a goal healthy weight, or experienced athletes who desire to maintain an ideal body composition, it is important to think about good sleep.  Aside from the main targets of weight control: diet and exercise, good sleep, which is defined as 7-9 hours a night for adults age 18-64, is essential.

Please see my article, “Top 12 Tips To Improve Sleep,” to help you get started.

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Published April 4, 2015

References:

Copinschi G, Leproult R, Spiegel K. The important role of sleep in metabolism. Front Horm Res. 2014;42:59-72.

Morselli LL, Guyon A, and Spiegel K. Sleep and metabolic function.  Pflugers Arch. 2012 Jan;463(1):139-160.

Morselli L, Leproult R, Balbo M, et al. Role of sleep duration in the regulation of glucose metabolism and appetite. Best Pract Res Clin Endocrinol Metab. 2010 Oct;24(5):687-702.

 

 

Athletes: Is Caffeine Cheating?

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Is your cup of coffee giving you an unfair edge?

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The effects of caffeine on the performance of athletes have been studied and described for years.  A number of hypotheses have been suggested to explain these effects within a range of sports.  But is caffeine just a legal, and socially acceptable, form of doping?  Should certain groups: elites, amateurs, or adolescents, be banned or discouraged from using caffeine?

The strongest evidence for the enhancing effects of caffeine on exercise is in endurance sports (hence, the personal interest I have in this topic).  Studies have reported that 3-9 mg of caffeine per kilogram of body weight, consumed one hour prior to exercise, by highly trained runners and cyclists, enhanced their laboratory-measured endurance performances. Therefore, a 160 pound (72.6 kg) person would consume 218-653 mg of caffeine to get 3-9 mg of caffeine per kg of body weight. To put this in familiar terms, a 12 ounce (“tall”) Starbucks brewed coffee contains 260 mg caffeine and the same-sized Starbucks latte contains 75 mg. In contrast, a 12 ounce (“small”) McDonald’s coffee contains 109 mg of caffeine.  One 12 ounce Starbucks brewed coffee or two 12 ounce McDonald’s brewed coffees would provide enough caffeine to be in the dosage range of 3-9 mg/kg for a 160 pound person.

The mechanism to explain these improvements in endurance is unclear.  It has been demonstrated that muscle glycogen (an energy source) is spared early during submaximal exercise after caffeine doses at a range of 5-9 mg/kg.  However, at the lower end of the range of caffeine doses described above (3 mg/kg), there is no evidence that muscle glycogen is spared. Therefore, glycogen sparing is not a complete explanation for the ergogenic effects of caffeine on endurance exercise.

In addition to effects on endurance exercise, caffeine has been shown to improve performance during short-term exercise, lasting approximately 5 minutes, at 90-100% maximal oxygen uptake, in laboratory tests.  Hypotheses about the mechanisms underlying this improvement include enhancement in contraction of muscles, provision of anaerobic energy to muscles, or an effect upon the central nervous system related to sensation of effort.  Sprint performances of up to 90 seconds of intense exercise do not appear to be affected by caffeine.

Caffeine is defined as a “controlled or restricted substance” by the International Olympic Committee, which limits the amount of caffeine in urine to 12 micrograms per milliliter of urine. It is also restricted by the US National Collegiate Athletic Association, which uses 15 micrograms per milliliter of urine as its limit.  But these limits actually allow for the consumption of a great deal of caffeine.  For example, if an athlete were to consume 9 mg of caffeine per kg of body weight one hour before exercise, then exercise for 60-90 minutes, and then submit a urine sample, this sample would only approach the limit of 12 micrograms per milliliter of urine.  This is about 29 ounces of Starbucks brewed coffee or about 69 ounces of McDonald’s brewed coffee!  On the other hand, doses of caffeine of greater than 6 mg/kg of body weight can lead to a higher chance of side effects such as anxiety, jitters, inability to focus, gastrointestinal upset, insomnia, irritability, and, at higher doses, hallucinations and heart arrhythmias.  Therefore, the optimal dose to enhance performance and minimize side effects appears to be 3-6 mg of caffeine per kg of body weight.

With some basic information about dosing, it is easy for endurance athletes to use caffeine to enhance their performances “within the rules.”  However, is this fair?  What if athletes are at an unfair disadvantage because of religious beliefs, unusual sensitivity to caffeine (susceptibility to migraines, for instance), or, simply, not enjoying caffeinated products?  Another concern is young endurance athletes. A Canadian survey of young (11-18 years old) athletes found that 27% consumed caffeine over the previous year for the specific purpose of enhancing athletic performance.  Is this an indication that caffeine is a “gateway” drug to other, much more dangerous, performance-enhancing drugs?

 Posted March 4, 2015.

 Reference:

 http://www.acsm.org/docs/current-comments/caffeineandexercise.pdf

Is Soy Formula Safe?

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Thanks to www.thebloggingdoctors.com for allowing me to guest-blog this article.  Here is the opening paragraph:

A number of families I treat who have children with cow’s milk allergy have concerns about the safety of using soy-based formula or soy milk (per age appropriateness) as a substitute. These concerns have to do with the fact that estrogen is one of the primary female sex hormones and soy contains isoflavones, which, as phytoestrogens, are chemically similar to estrogens. Two major types of isoflavones, genistein and daidzein, can act like estrogen does in the body, but at much less potency than estrogen, itself. The concern with the safety of soy is the possibility that the isoflavones may have enough potency to have actual, relevant, biological effects. There has been a lot of research about these possible biological effects upon child development.

Please click here to read more!

Beer After Exercise?

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“Just 1 more mile until beer!”  How many times have you seen a sign like that while participating in a marathon, half-marathon, or triathlon?  We all feel like we have earned a drink, or two, after finishing a race.  But is consuming alcohol after exercise really a good idea?  The following is a summary of current research on this subject.  Unfortunately, this research is limited in quantity.

  • Rehydration – With considerable loss of fluids during exercise, rehydration is a priority.  The concern with alcohol is that it has been shown to increase output of urine.  Therefore, it has the potential to worsen dehydration.  This effect, however, is dose-dependent.   A study has shown that, after exercise, the consumption of doses of alcohol less than 0.49 gm per kilogram of body weight does not significantly affect rehydration.  In the United States, a standard drink is 14 grams.  Therefore, in a 160 pound person, which is about 72.6 kg, this dose (0.49 gm/kg) is about 35.6 grams, or about two and a half drinks.
  • Glycogen resynthesis – Another priority is restoring energy stores after they have been depleted by exercise.  A published report showed that, after exercise, a dose of alcohol up to 1.5 gm per kg of body weight (about seven and a half drinks for a 160 pound person) does not impair glycogen resynthesis as long as a high-carbohydrate meal is also consumed.
  • Immune function – Inflammation, which is mediated by the immune system, is an essential mechanism of recovery from exercise.  While studies have not been performed to assess the effects of alcohol on immune function after exercise, alcohol consumption has been shown both to reduce pro-inflammatory proteins and increase anti-inflammatory proteins.  The unproven implication is that alcohol consumed after exercise can, therefore, reduce the capacity of the immune system to aid in recovery from that activity.
  • Endocrine function – The endocrine system helps coordinate recovery and beneficial adaptations, such as muscle hypertrophy, from exercise.  Only a few studies have examined the effects of alcohol, consumed after exercise, on the endocrine system.  The most recent study was performed with subjects who were resistance-trained.  These athletes completed heavy-resistance exercise, then consumed 1.09 gm of alcohol per kg of body weight.  At 140-300 minutes post-exercise, testosterone levels were increased.  Since testosterone leads to muscle hypertrophy, these results imply that consuming alcohol after heavy-resistance training can lead to endocrine changes that could support muscle hypertrophy.  This finding is surprising, since alcohol is known to generally have inhibitory effects upon testosterone production.  Furthermore, a much older study showed that 1.5 gm of alcohol per kg of body weight, consumed after exercise, led to decreases in levels of testosterone.
  • Skeletal muscle repair – Intense exercise leads to damage of skeletal muscle.  The repair of this muscle is part of the process of adaptation and improvement that athletes receive from training.  In a model of exercise-induced muscle damage (repeated eccentric contractions of the quadricep muscles), lower doses of alcohol, such as 0.5 gm per kg of body weight, consumed 30 minutes after exercise did not lead to negative effects upon muscle performance.  However, doses of 1.0 gm per kg of body weight was shown to lead to reduced muscular performance.
  • Protein synthesis – As part of muscle repair, muscle proteins need to be synthesized.   In a recent study, subjects participated in resistance exercise (leg extensions), then cycling.  Immediately and 4 hours post exercise some of the subjects consumed 1.5 gm per kg of body weight of alcohol.  Muscle biopsies showed reduced rates of myofibrillar protein synthesis in the subjects who consumed alcohol (even in the subgroup who also consumed protein).

Alcohol consumption after exercise, especially beer, is a commonplace feature of endurance sports.  Aside from the sense that a cold beer is a nice reward to look forward to during a race, the consumption of alcohol is also a popular social event.  But is it deleterious?  Should we ask race directors to ban beer sponsors, based on the dangerous effects of the consumption of alcohol after exercise?  The current data, though limited, indicates that the answer to this question is “no.”  It appears that the negative effects that alcohol may have after exercise are probably dose-dependent.  Indeed, I was unable to find a study that demonstrated any negative biological effects of up to 0.49 mg of alcohol per kg of body weight (roughly two and a half American beers) consumed after exercise.  Please note, however, that all of the studies cited used male subjects.  Furthermore, there is a wide range of alcohol tolerance among different individuals.  Finally, the summary, above, is not intended to condone or encourage the consumption of alcohol, but to shed light on current research and to dispel some popular misconceptions, such as the idea that alcohol after exercise is universally dehydrating.  Indeed, when I began writing this summary, I expected to find data that would state that any alcohol after exercise is harmful.

Published February 11, 2015

References:

Barnes MJ. Alcohol: impact on sports performance and recovery in male athletes. Sports Med. 2014 Jul; 44(7):909-919.

Barnes MJ, Mundel T, Stannard SR. Acute alcohol consumption aggravates the decline in muscle performance following strenuous eccentric exercise. J Sci Med Sport. 2010;13(1):189–193.

Barnes MJ, Mundel T, Stannard SR. Post-exercise alcohol ingestion exacerbates eccentric exercise induced losses in performance. Eur J Appl Physiol. 2010;108(5):1009–1014.

Barnes MJ, Mundel T, Stannard SR. The effects of acute alcohol consumption and eccentric muscle damage on neuromuscular function. Appl Physiol Nutr Metab. 2011;37(1):63–71.

Barnes MJ, Mundel T, Stannard SR. A low dose of alcohol does not impact skeletal muscle performance after exercise-induced muscle damage. Eur J Appl Physiol. 2011;111(4):725–729.

Burke LM, Collier GR, Broad EM, et al. Effect of alcohol intake on muscle glycogen storage after prolonged exercise. J Appl Physiol. 2003;95(3):983–990.

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