Category Archives: Protein

A New Source of Protein for the Athletic and the Sedentary?

A New Source of Protein?

This is an odd and interesting bit of research.  It relates to reaborption of nitrogen . . . and presents the possibility that more protein is conserved than previously thought.  First dietary nitrogen 101: Nitrogen is a major component of amino acids.  Amino acids are needed to form proteins.  We can synthesize some amino acids ourselves, but others need to be obtained through diet.  Dietary protein provides nitrogen and amino acids from plant or animal sources which are resynthesized into human proteins.  Unused nitrogen is converted into Ammonia and Urea and excreted.

Can nitrogen be reabsorbed from the intestines?

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The answer is a shocking “maybe.”  A new nutritional study (published ahead of print in the Journal of Nutrition) has found that nitrogen appears to be reabsorbed.  This makes little sense at first glance.  Until we consider the vast populations of microorganisms that reside in the gut.  Until recently, they were all thought of as “germs” that needed to be quashed.   That has changed.  We are learning more and more about how important they are for our health and even our survival.

The study is titled:

Nonprotein Nitrogen Is Absorbed from the Large Intestine and Increases Nitrogen Balance in Growing Pigs Fed a Valine-Limiting Diet.

Valine is an essential Amino Acid, so these animals were fed a protein-deficient diet.   Then researchers administered urea or casein into the cecum of pigs.  Let’s consider this research a step toward greater understanding of how nitrogen may be recycled in living animals.  Not a new way to increase protein for strength.  (Although who knows.  It might work.) The urea was synthesized using Nitrogen-15.  Dietary nitrogen is Nitrogen 14.  Using nitrogen-15 lets the team know where the cecum-delivered nitrogen ended up.

Findings:

Researchers found that more than 80% of the cecum delivered nitrogen was absorbed.  Some of it was excreted in urine, but some was retained. This is a shocker.  I know.   Humans cannot synthesize protein using nitrogen.  So WTF?  The researchers propose that urea traveled through the bloodstream and into to the small intestine.   Bacteria (some of which can make amino acids using urea or plain nitrogen) in the small intestine then used the extra urea to make amino acids.  Amino acids produced by bacteria could then be absorbed the host (animals).

Takeaway:

More research would need to be done to confirm that this happens.  But it is very interesting.  Humans vary in the types of bacteria they host.  Bacterial populations vary according to diet, environment, chance (?) and who knows what else.  Do people get extra protein from bacteria?  Does this happen under normal circumstances (i.e. not piped in through the back end.)?  One thing is sure: there is a lot to learn. ResearchBlogging.org

Columbus DA, Lapierre H, Htoo JK, & de Lange CF (2014). Nonprotein Nitrogen Is Absorbed from the Large Intestine and Increases Nitrogen Balance in Growing Pigs Fed a Valine-Limiting Diet. The Journal of nutrition PMID: 24647394

The Paleo Diet: Quinoa, protein, anti-oxidants and saponins.

What is Quinoa and is Quinoa Paleo (OK for the paleo diet?)

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Quinoa is (are?) seeds from a broad-leaf plant.  Grains are from grasses.  When cooked quinoa tastes mildly like toasted broccoli.  This is not as bad as it sounds.  Quinoa is grain-like and can be used in place of rice or pasta.  It is good for breakfast with nuts and cinnamon.   Quinoa does not contain Gluten.  So if you have celiac disease, or gluten sensitivity you should be fine with Quinoa.

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Is Quinoa Paleo?

If you are trying to follow the Paleo diet, quinoa should be fine too. Quinoa commonly contains many important minerals, including selenium.  Selenium is an important anti-oxidant and is protective against some cancers.  It is also important for synthesis of testosterone, among other things.
Quinoa has a number of other benefits. Quinoa provides more anti-oxidants and protein than wheat.  The anti-oxidants in quinoa appear to be more bio-available than anti-oxidants from wheat.  Bio-available simply means that the nutrients can be extracted by the digestive system and used.  Somethings are present in foods, but cannot be used.   Things that are not bio-available are dumped.   Other benefits of quinoa include an omega 6:Omega 3 ratio of about 6:1, and high vitamin E and protein content (~15%).  It also has a low glycemic index.

What about Saponins? Are Saponins Dangerous?

Some people in the CrossFit and the Paleo communities believe saponins are dangerous and will damage the intestines.   Quinoa does contain saponins. Followers of the paleo diet have placed quinoa on the forbidden list for this reason.  However, saponins are a class of chemical. There are many different saponins.  There are good ones and bad ones (Francis et al. 2002). Some saponins can damage cell membranes. However, others are beneficial.  Some saponins are protective and serve as anti-oxidants. The Saponin arjunolic acid is one of these.   This saponin has been proposed as a possible treatment for diabetes. P-coumaric acid, another saponin that is present in quinoa, may reduce risk of colon cancer. It is also an anti-oxidant. Like curcumin.  Saponins are also found in many other healthful foods such as vegetables and tea.

Some people think that increasing selenium intake will increase testosterone levels.  But, that is probably not true. You can read more about that here.

Francis G, Kerem Z, Makkar HPS, Becker K.  2002.  The biological action of saponins in animal systems: a review.  British Journal of Nutrition.  88(6): 587-605.

Laus MN, Gagliardi A, Soccio M, Flagella Z, Pastore D.  2012.  Antioxidant activity of free and bound compounds in Quinoa (Chenopodium quinoa willd.) seeds in comparison with durum wheat and emmer.  2012.  Journal of Food Science. doi: 10.1111/j.1750-3841.2012.02923.x. [Epub ahead of print]

Alvarez-Jubete L, Arendt EK, & Gallagher E (2009). Nutritive value and chemical composition of pseudocereals as gluten-free ingredients. International journal of food sciences and nutrition, 60 Suppl 4, 240-57 PMID: 19462323 Manna P, & Sil PC (2012). Arjunolic acid: beneficial role in type 1 diabetes and its associated organ pathophysiology. Free radical research, 46 (7), 815-30 PMID: 22486656

Manna P, & Sil PC (2012). Arjunolic acid: beneficial role in type 1 diabetes and its associated organ pathophysiology. Free radical research, 46 (7), 815-30 PMID: 22486656

Ferguson LR, Zhu ST, & Harris PJ (2005). Antioxidant and antigenotoxic effects of plant cell wall hydroxycinnamic acids in cultured HT-29 cells. Molecular nutrition & food research, 49 (6), 585-93 PMID: 15841493

CrossFit Masters Nutrition: Protein Intake for Muscle and Bone.

Current recommended protein intake for people over the age of 19 is 0.8 g/kg/day. A lot of strength trainers and CrossFit trainers will recommend a lot more.  CrossFit Masters may need more protein than younger athletes.  Masters CrossFit and older people may need more protein whether they are working out or not.   The muscles of Masters Athletes are less responsive to strength training. We can define Masters as over 35, 40 or 50.  But at what age, physiologically, does a need for greater protein intake occur?  Some sources state loss of muscle mass begins around age 25. While others say it begins much later.

Masters CrossFit.  How much Protein?

Some researchers believe that increasing protein intake may help older athletes.  As well as older people in general avoid loss of muscle mass and strength associated with age.   Spreading intake out over the course of the day may also help anabolic response to training.  Increasing protein intake may help with other things too.  Increasing protein intake increases calcium absorption.  So increasing protein intake may help with bone health.  We have probably all heard that calcium is needed to prevent osteoporosis.  And that strength training also prevents osteoporosis.  Some researchers are proposing that the recommended daily allowance (RDA) for Masters be increased from 0.8 g/kg/day to 1.0 to 1.2 g/kg/day.   For better calcium and nitrogen balance. This is still under what is recommended by many for strength training.  Sports nutritionists recommend 1.2 to 1.7 g/kg/day for athletes.

Strength training and increased protein to prevent muscle loss.

CrossFit Masters Shoulder Blues Mug.

Loss of muscle mass may begin as early as age 25.  But exercise is protective.  For Masters and for young athletes.  The question is open over whether or not Masters athletes need more protein than other athletes.  Sarcopenia (loss of muscle mass) is thought to affect about 1/3rd of people over age 60.   It is a problem affecting many people.  So far the best treatment is strength training and exercise.

How to track protein intake.

Try SuperTracker and keep track of what you eat over a week.  It is a USDA government website that will tell you how much protein (more or less) you are getting from a wide range of foods.  It will also give you a detailed report of many different nutrients and tell you where you are deficient.  You may be surprised at where your weaknesses are.

Gaffney-Stomberg E, Insogna KL, Rodriguez NR, & Kerstetter JE (2009). Increasing dietary protein requirements in elderly people for optimal muscle and bone health. Journal of the American Geriatrics Society, 57 (6), 1073-9 PMID: 19460090

Sumukadas, D. (2010). Optimal management of sarcopenia Clinical Interventions in Aging DOI: 10.2147/CIA.S11473

Sayer AA, Robinson SM, Patel HP, Shavlakadze T, Cooper C, & Grounds MD (2013). New horizons in the pathogenesis, diagnosis and management of sarcopenia. Age and ageing, 42 (2), 145-50 PMID: 23315797

Sumukadas, D. (2010). Optimal management of sarcopenia Clinical Interventions in Aging DOI: 10.2147/CIA.S11473

Dupuy C, Lauwers-Cances V, Abellan Van Kan G, Gillette S, Schott AM, Beauchet O, Annweiler C, Vellas B, & Rolland Y (2013). Dietary Vitamin D Intake and Muscle Mass in Older Women. Results from a Cross-Sectional Analysis of the EPIDOS Study. The journal of nutrition, health & aging, 17 (2), 119-24 PMID: 23364488

Masters Nutrition: Protein Intake for Bone Health

Current recommended protein intake for people over the age of 19 is 0.8 g/kg/day. A lot of strength trainers and CrossFit trainers will recommend a lot more.  CrossFit Masters may need more protein than younger athletes.  Masters CrossFit and older people may need more protein whether they are working out or not.   The muscles of Masters Athletes are less responsive to strength training. We can define Masters as over 35, 40 or 50.  But at what age, physiologically, does a need for greater protein intake occur?  Some sources state loss of muscle mass begins around age 25. While others say it begins much later.

Masters CrossFit.  How much Protein?

Some researchers believe that increasing protein intake may help older athletes.  As well as older people in general.   Spreading intake out over the course of the day may also help anabolic response to training.  Increasing protein intake may help with other things too.  Increasing protein intake increases calcium absorption.  So increasing protein intake may help with bone health.  We have probably all heard that calcium is needed to prevent osteoporosis.  And that strength training also prevents osteoporosis.  Some researchers are proposing that the recommended daily allowance (RDA) for Masters be increased from 0.8 g/kg/day to 1.0 to 1.2 g/kg/day.   For better calcium and nitrogen balance. This is still under what is recommended by many for strength training.  Sports nutritionists recommend 1.2 to 1.7 g/kg/day for athletes.

Strength training and increased protein to prevent muscle loss.

CrossFit Masters Shoulder Blues Mug.

Loss of muscle mass begins around age 25.  But exercise is protective.  For Masters and for young athletes.  The question is open over whether or not Masters athletes need more protein than other athletes.  Sarcopenia (loss of muscle mass) is thought to affect about 1/3rd of people over age 60.   It is a problem affecting many people.  So far the best treatment is strength training and exercise.

How to track protein intake.

Try SuperTracker and keep track of what you eat over a week.  It is a USDA government website that will tell you how much protein (more or less) you are getting from a wide range of foods.  It will also give you a detailed report of many different nutrients and tell you where you are deficient.  You may be surprised at where your weaknesses are.

 

Gaffney-Stomberg E, Insogna KL, Rodriguez NR, & Kerstetter JE (2009). Increasing dietary protein requirements in elderly people for optimal muscle and bone health. Journal of the American Geriatrics Society, 57 (6), 1073-9 PMID: 19460090

Sumukadas, D. (2010). Optimal management of sarcopenia Clinical Interventions in Aging DOI: 10.2147/CIA.S11473 Sayer AA, Robinson SM, Patel HP, Shavlakadze T, Cooper C, & Grounds MD (2013). New horizons in the pathogenesis, diagnosis and management of sarcopenia. Age and ageing, 42 (2), 145-50 PMID: 23315797

Protein intake and recovery for Masters Athletes

How much protein do Athletes need?

Younger athletes may benefit from increased protein intake in a number of ways. Increased protein intake may result in muscle strength gains in young adults in as quickly as six weeks (Candow et al. 2006).  Protein supplements may also increase strength in elderly people (average age 83) as well (Bjorkman et al. 2012).  The Bjorkman study of 106 elderly men and women showed a 2.1% gain in body weight with a high-leucine whey protein supplement vs. a 1.9% loss in weight with a placebo.  This was over a six month period.  Leucine is important because it serves as a trigger for muscle synthesis.  Leucine is also a branched chain amino acid (bcaa).  This does not mean supplements are better than a healthy diet. We have evolved to eat food, after all. However, we also seem to have evolved to not do as well as we’d like as we get older. Masters athletes may benefit from increased protein intake.
CrossFit Games Masters Competitor Ken Cutrer of CrossFit EST,

Protein may speed recovery.

Protein intake after exercise may also help speed recovery.  This would be important to athletes participating in an extended period of competition. The CrossFit games, for example. Or in similar high output situations. Whey protein hydrolysate increases the rate of recovery after resistance training.  When protein is hydrolysated it has been partially broken down.  This speeds absorption.  Unhydrolysated proteins (normal proteins from food) may take longer.   This may mean recovery takes 6 hrs. rather than 24 hrs (Buckley et al. 2010).

Masters athletes may benefit from protein supplements.

Older athletes take longer to recover, and lose ground faster during periods of inactivity. Hydrolysated protein supplements and supplements with high leucine content may help Masters Athletes.

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Candow DG, Burke NC, Smith-Palmer T, & Burke DG (2006). Effect of whey and soy protein supplementation combined with resistance training in young adults. International journal of sport nutrition and exercise metabolism, 16 (3), 233-44 PMID: 16948480

Buckley JD, Thomson RL, Coates AM, Howe PR, DeNichilo MO, & Rowney MK (2010). Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. Journal of science and medicine in sport / Sports Medicine Australia, 13 (1), 178-81 PMID: 18768358

Björkman, M., Finne-Soveri, H., & Tilvis, R. (2012). Whey protein supplementation in nursing home residents. A randomized controlled trial European Geriatric Medicine, 3 (3), 161-166 DOI: 10.1016/j.eurger.2012.03.010

Are Low-Carb High-Protein Diets Good for Masters Athletes?

This will be making headlines shortly: Atkins-Like Diets May Put Heart at Risk.
Post-Workout at CrossFit Seven in Fort Worth, TX.

The answer to the post headline is: low-carb high protein diets are probably not good for Masters.  Or for younger athletes either.  The news is that a major study found increased cardiovascular disease in women who consumed a lot of protein relative to carbohydrate.  The more carbohydrate intake was restricted the greater the risk of having a heart attack, stroke, embolism or vascular disease.  This supports findings from several other human studies (Fung et al. 2010, Lagiou et al. 2007, Trichopoulou et al. 2007).  Several of our posts have shown benefits from protein intake for masters athletes.  The messages to take away here are that excessively restrictive diets are not good and that carbohydrates are not bad.  You can harm yourself in being carbophobic.  Get enough protein to protect muscle strength but don’t go off the deep end. If you are following a Paleolithic Diet (The Paleo Diet, which is promoted by a lot of Cross Fit Boxes) you should still be able to eat a very reasonable amount of carbohydrates.  This is a Cross Fit Cross Fit matter.   A lot of CrossFitters are very detailed and committed to their training, diet and health in general.  Its good to be committed.  Just not good to be committed to, or go overboard on, something that’s not in your best interest. 

More study would be needed to see how protein source plays into cardiovascular disease.  High intake of vegetable protein is associated with smaller waist circumference and lower BMI.  People who eat a lot of animal protein tend to have a thicker waist circumference and higher BMI.

There are a lot of questions to raise with this including the possibility that people who eat less animal protein consume less animal fat.  Animal fat can be a rich source of bioactive, lipophilic contaminants.  It has recently been reported that exposure to “Persistent Organic Pollutants” which accumulate in fat  cause insulin resistance (Ruzzin et al. 2010). The problem may not be high protein intake.  It might be exposure to contaminated animal fat.  Or it might be low carbohydrate intake.  We don’t know yet.

BMI, blood lipid profiles and incidence of cardiovascular disease in matched cohorts of grass-fed/organic animal protein eaters vs. regular grocery store consumers have not been studied.  It will be interesting to see what comes up over the next few years.  In the meantime, remember that 22-year-olds who have been to a workshop are not necessarily the best sources of dietary information.  Go Masters!

Ruzzin J, Petersen R, Meugnier E, Madsen L, Lock EJ, Lillefosse H, Ma T, Pesenti S, Sonne SB, Marstrand TT, Malde MK, Du ZY, Chavey C, Fajas L, Lundebye AK, Brand CL, Vidal H, Kristiansen K, & Frøyland L (2010). Persistent organic pollutant exposure leads to insulin resistance syndrome. Environmental health perspectives, 118 (4), 465-71 PMID: 20064776

 Lin, Y., Bolca, S., Vandevijvere, S., De Vriese, S., Mouratidou, T., De Neve, M., Polet, A., Van Oyen, H., Van Camp, J., De Backer, G., De Henauw, S., & Huybrechts, I. (2010). Plant and animal protein intake and its association with overweight and obesity among the Belgian population British Journal of Nutrition, 1-11 DOI: 10.1017/S0007114510004642

Fung TT, van Dam RM, Hankinson SE, Stampfer M, Willett WC, & Hu FB (2010). Low-carbohydrate diets and all-cause and cause-specific mortality: two cohort studies. Annals of internal medicine, 153 (5), 289-98 PMID: 20820038

Trichopoulou A, Psaltopoulou T, Orfanos P, Hsieh CC, & Trichopoulos D (2007). Low-carbohydrate-high-protein diet and long-term survival in a general population cohort. European journal of clinical nutrition, 61 (5), 575-81 PMID: 17136037

Lagiou P, Sandin S, Weiderpass E, Lagiou A, Mucci L, Trichopoulos D, & Adami HO (2007). Low carbohydrate-high protein diet and mortality in a cohort of Swedish women. Journal of internal medicine, 261 (4), 366-74 PMID: 17391111

Are Whey-Based Protein Powders Best for Athletes?

Have not found any research on athletic performance and goat milk.

A lot of athletes, with CrossFit and others, supplement their protein intake with protein powders (such as whey) or by eating more meat and some from the old school swear by drinking a lot of milk.  So what’s best?

It turns out that for weight loss, whey is better at reducing appetite and food intake than red meat, soy protein or milk (Huang et al. 2008), and produces less of an insulin response.  Whey contains a protein/hormone called relaxin.  One of the things relaxin does is inhibit secretion of insulin.  This is not necessarily a good thing.  Inhibiting insulin may result in sugars remaining in the blood stream, and doing damage, longer than they would have if insulin was getting it out of there. (Relaxin is also believed to increase sperm motility . . . might be good if yours are sluggish, not good if you are emotionally drained and exhausted by the kids you already have . . . and inhibit collagen synthesis.  This is not good for weight lifters, but good for pregnant women getting ready to give birth).  Just speculation at this point as to whether or not eating a lot of whey would do any these things though. 
For bone strength, skim milk powder seems to produce better results than whey protein and calcium combined.  It sounds like there may be more to skim milk powder, and probably milk in general, that helps with growth and strength.  Oh, this would not be growth hormone because growth hormone will be found in milk fat.  The skim stuff is pretty safe.  Cow’s milk contains lactoferrin, which has recently been shown to increase production of angiogenic factors (these aid development of blood vessels and capillaries) in bone tissue (Nakajima et al. 2011). Since lactoferrin is a whey protein it is likely that whey supplements (as long they have not been heat treated) would provide similar benefits.

Here it is in plain English: Whey protein and skim milk may both offer a lot of benefits.  If you are trying to follow a Paleo-style diet (aka Paleolithic Diet), whey may be a good option, since milk is on the “no” list.  Some people will tell you whey is not Paleo, but from a scientific perspective that really doesn’t matter.  A lot of commercial products contain artificial sweeteners.  Natural plain whey protein is available too but does not dissolve well.  

In a nutshell:  There is evidence that whey protein:
1. is a good source of protein
2. will suppress appetite
3. is good for bone health
4. may reduce insulin levels
5. is low in some hormones and chemicals and so forth. 
6. more research is needed to find out if the hormones that are in whey have an effect on people.

ResearchBlogging.org
Graf S, Egert S, & Heer M (2011). Effects of whey protein supplements on metabolism: evidence from human intervention studies. Current opinion in clinical nutrition and metabolic care, 14 (6), 569-80 PMID: 21912246
 
Nakajima K, Kanno Y, Nakamura M, Gao XD, Kawamura A, Itoh F, & Ishisaki A (2011). Bovine milk lactoferrin induces synthesis of the angiogenic factors VEGF and FGF2 in osteoblasts via the p44/p42 MAP kinase pathway. Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine, 24 (5), 847-56 PMID: 21404021  

Yamamoto, H., Arai, T., Tasaka, R., Mori, Y., Iguchi, K., Unno, K., & Hoshino, M. (2009). Inhibitory Effect of Relaxin-3 on Insulin Secretion in Isolated Pancreas and Insulinoma JOURNAL OF HEALTH SCIENCE, 55 (1), 132-137 DOI: 10.1248/jhs.55.132

Fried A, Manske SL, Eller LK, Lorincz C, Reimer RA, & Zernicke RF (2012). Skim milk powder enhances trabecular bone architecture compared with casein or whey in diet-induced obese rats. Nutrition (Burbank, Los Angeles County, Calif.), 28 (3), 331-5 PMID: 22119485

Masters Athletes respond to protein intake and resistance exercise as well as young athletes.

CrossFit Masters Athletes and Protein Intake

This is an interesting bit of research.  It was published a year ago but doesn’t seem to have been picked up by news sources.  Here it is: Masters muscles respond to protein intake and resistance exercise by making more muscle as well as young adults.  The study (Patton-Jones et al. 2011) looked at 7 young adults and 7 adults with an average age of 67.  They did multiple reps of knee extensions and ate a meal of lean ground beef.  Its a small number of people, which limits its power, but its hard to recruit people for this kind of thing.  And . . . it required a muscle biopsy.  That might have hurt.  The authors didn’t mention if it did or not.  Thank you study people for doing this for us.

Crossfit Master Amy Kramer of Crossfit Seven,
 Competes in a Reebok CrossFit Fundraiser
at Luke’s Locker, Fort Worth, TX.

Do Masters Athletes need more protein?

This doesn’t mean that there aren’t important differences between people in their 60s and people in their 20s.  See this earlier post.  What the research tells us though is that the rate at which muscle proteins are synthesized following protein intake and resistance training does not appear to change with age.  At least not through our 60s.  The results are important because we all want to stay strong, and most of us would like to get stronger.  That, along with a desire for fun and camaraderie is why we do Crossfit.

Protein Intake and Sarcopenia

It seems like there are a lot of messages out there telling us we won’t be able to.  Stuff it.  Another reason why these results are important is because people tend to lose muscle mass as they age.  This is what sarcopenia is.  It can be a real problem for the elderly, and can severely limit their ability to get around and take care of the business of life.  The question of how much of sarcopenia is inevitable, and how much is due to inactivity hasn’t been completely answered.  But this study points to lack of resistance exercise as a possible major factor.

Symons TB, Sheffield-Moore M, Mamerow MM, Wolfe RR, & Paddon-Jones D (2011). The anabolic response to resistance exercise and a protein-rich meal is not diminished by age. The journal of nutrition, health & aging, 15 (5), 376-81 PMID: 21528164

Diet and protein: training, performance and long-term health.

Protein Intake, training and performance

Diet, protein intake and performance are interwoven issues. The aim of training is improve the body’s ability to perform certain tasks (and in the case of CrossFit it is to achieve a high degree of effectiveness and competence in a wide range of skills and efforts).

Lucas Allen and Summer Rogers at the SouthCentral
Crossfit 2012 Regionals.  Both are in their thirties.

The goal of nutrition in training is to help the body (the entire thing) adapt and remodel, or at least maintain what you have and can do. Bodies like efficiency. Your body will see no point in maintaining bone or muscle that does not look like it’s going to be used any time soon and will let it go. That’s why people who have been ill and disabled for a long time become so frail. When challenged your body (which means here not only muscle and bone, but brain, nerves, biochemical pathways and efficiency, cell proliferation and organelle numbers and function, and neurotransmitters) changes to meet that particular challenge. Protein is important here for repair, strengthen and reinforcement of stressed tissue. Strength-oriented athletes have traditionally made efforts to increase protein intake and there is some evidence that this is effective in increasing muscle mass. There is also evidence that increasing protein intake can reduce the rate of loss of muscle mass seen in aged people.  That’s good for us Masters too.

Cody Zamaripa, age 46, counts burpees during the 2012 Open
at Crossfit Seven, in Fort Worth, TX.

Not all of the protein you can consume will be used to increase mass. Your body will use what it needs, or what it anticipates needing in the near future (in case you persist in doing all those squats, jerks, kettle bell swings and pushups.) Consuming more than you need will probably not hurt you (unless you’ve really gone overboard). Not consuming enough will slow repair and limit your ability to adapt to physiological and mechanical stress.

 Endurance athletes have long been encouraged to eat plenty of carbohydrates since availability of carbs can be a limiting factor in performance. This is why consuming dilute fruit juice (or sugar water) can delay exhaustion and allow an athlete to continue to run, bike or whatever longer than they would if they had been drinking plain water. However if you are always running on carbohydrates you may not adapt biochemically speaking. Normally, if you are low on carbohydrates (or glycogen) your body will attempt to increase the rate at which is uses its own fat stores for energy. Being habitually low on carbs may increase your ability to generate energy by other means. You will probably be uncomfortable for at least a while, but you might improve at this the longer you train.    There are really too many unknowns floating around at present to know exactly what is best.  What is best probably varies by individual, situation, stage of life, and training goals. New information becomes available all the time. We’ll see how things fall out.

Churchward – Venne, T., Burd, N., Phillips, S., & Research Group, E. (2012). Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism Nutrition & Metabolism, 9 (1) DOI: 10.1186/1743-7075-9-40  

Logan-Sprenger, H., Heigenhauser, G., Killian, K., & Spriet, L. (2012). The effects of dehydration during cycling on skeletal muscle metabolism in females Medicine & Science in Sports & Exercise DOI: 10.1249/MSS.0b013e31825abc7c  

Symonsi, T., Sheffield-Moore, M., Mamerow, M., Wolfe, R., & Paddon-Jones, D. (2010). The anabolic response to resistance exercise and a protein-rich meal is not diminished by age The journal of nutrition, health & aging, 15 (5), 376-381 DOI: 10.1007/s12603-010-0319-z ResearchBlogging.org