Six Nutrition and Metabolism Questions on: Diet and Cancer, Supplements, Childhood Obesity Electrolytes and Hypertension

Do you agree with athletes using supplements and if so which type(s) of supplements and why? If your against athletes taking supplements, why?

I do agree that athletes can use supplementation to enhance performance in and out of sport.  However I feel the term “supplement” needs to be taken literally; taken when unable to obtain from real whole foods.  The (National Institutes of Health (NIH), 2014) summarizes and well defines a “dietary supplement as a product that:

  • is intended to supplement the diet;
  • contains one or more dietary ingredients (including vitamins; minerals; herbs or other botanicals; amino acids; and other substances) or their constituents;
  • is intended to be taken by mouth as a pill, capsule, tablet, or liquid; and
  • is labeled on the front panel as being a dietary supplement

I think that supplements can make recovery, training, and nutrition easier when eating real whole foods isn’t an option.  Similar to foods, the source and make-up of the supplement is very important.  So many supplements have excess amounts of the nutrient needed, added ingredients, and aren’t bioavailable.  It is important to read the label on these supplements and make sure that they have been tested by independent companies that don’t have direct connections to these supplement companies.  I still think eating real whole foods when able (like on days off of work) is better due to the natural nutritional benefits that are hard to obtain without taking numerous supplements.  However I understand how busy work and life can be and it may be necessary to “supplement” for real food; for example having a protein shake or bar that has quality make-up with minimized added ingredients.  Unlike food and drugs, the FDA doesn’t regulate all of these supplements the same as other food and drugs; creating room for error in the supplement regulation standards (NIH, 2014).  I am all for a better testing process of these supplements through legislation similar to what the FDA uses on food.  In the mean time I recommend minimizing supplemental use; using them as a supplement and eating real whole foods when able.

A couple types of supplements that I think can be utilized and personally use for physical performance are: Creatine, Caffeine, Glucosamine, and Amino acids protein.  It is important to note that all these can be obtained from real food like creatine and protein from meat; and caffeine from cocoa or coffee.  Creatine can be supplemented in order to provide energy to the muscles by donating a phosphate to an ADP, making it an ATP or the energy source of the muscle.  Creatine is controversial because of potential risk with muscle cramps and kidney function (McGuire & Beerman, 2013, p. 398).  Amino acids or protein supplementation can help with growth and repair of muscles, but according to research-based evidence has no beneficial effects over whole food protein sources (McGuire & Beerman, 2013, p. 403).  Glucosamine/chondroitin can help repair damaged joints and caffeine can “increase mental alertness, improve athletic performance, enhance fatty acid metabolism, and delay fatigue” (McGuire & Beerman, 2013, p. 403).  Dependence and quantified use of caffeine does have lots of supporting research for and against use of caffeine.  Personally I don’t supplement with caffeine anymore, although I did when I played college football; I get it from drinking black coffee without any added sugars or cream.  I chose just a few supplements to talk about, it is important to note that other supplements can be used to enhance performance and may be medically necessary for certain people like insulin for a diabetic as an example.

Here is a website and podcast about that site that I utilize.  The podcast is an interesting talk about the supplement industry and would love to hear what my classmates think of if you have time to listen to the podcast (while cooking a healthy meal) or look at the website.

https://labdoor.com/how-labdoor-tests-and-grades-dietary-supplements

http://www.bengreenfieldfitness.com/2014/07/labdoor/

Should everyone be taking a daily multivitamin? Why or why not? Support your answer.

I don’t think that it is necessary that “everyone” take a daily multivitamin.  Everyone’s diet needs to individualized through: nutrient needs, availability and convenience of whole food sources, and ongoing health-care issues.  When a person is unable to get vitamins through whole food sources a supplemental form or multivitamin may be necessary.  Some cases where this may be necessary include: vegetarians (Vit. B12 from meats), cancer patients (Vitamin D3 and other vitamins linked to improvement), busy everyday people (various vitamin deficiencies), and more pronounced vitamin deficiencies like scurvy (Vitamin C).  In these cases, “Multivitamins may help supply these nutrients, but more often they don’t contain enough” or may have too much; making it important to understand the needed amount and read the label carefully (Tufts University, 2014, p. 5).  Vitamins are a supplement and therefore are regulated differently; they don’t have to be “preapproved” by the FDA for effectiveness for effectiveness (McGuire & Beerman, 2013, p. 452).  It is necessary to have a trustworthy source of your vitamin in order to prevent toxicity or deficiencies when relying on the supplement for your vitamin intake.  It is important to keep in mind that “supplements should never replace prescribed medications or the variety of foods important to a healthful diet” (McGuire & Beerman, 2013, p. 453).

More generally speaking a healthy diet should provide most of the vitamins that a person needs, but according to The Harvard School of Public Health (HSPH) “many people don’t eat the healthiest of diets” (HSPH, 2014).  According to (Saleeby), with  America’s use of fast food, use of processed foods in boxes and cans, and overall diet devoid of important nutrients; makes the need of multivitamin supplementation more important than ever before (2014, p. 58).  In this case I do feel that it is necessary that people take a multivitamin; keeping in mind that healthier diet and lifestyles need to still be promoted.

What role if any do you believe nutrition plays in regard to the risk of getting cancer? What foods possibly promote cancer? Prevent? Support your answer.

I think and many studies support that nutrition plays a vital and important role in regard to the risks of getting cancer and quality of life after getting it.  Nutrition plays a direct role in the risk of cancer because food choices can feed cancer growth (sugar for example) or fight cancer growth (plant based anticarcinogenic phytochemicals)  Food that possibly and do promote cancer are foods: high in added sugars and high-glycemic carbohydrates, moldy foods, red meat (controversial), excessive alcohol, diets low in plant-based foods (Miles, 2008, p.29-31).  These food choices are even worse especially in the absence of proper amounts of fiber and an active lifestyle.  “Numerous studies have found that the risk for cancer increases with high blood sugar, which makes sense, since cancer cells feed primarily on glucose” (Greenfield, 2014, p. 294).  It is important to remember that “there are also “internal” factors such as hormones, immune conditions, and mutations that occur spontaneously and initiate cancer” (McGuire & Beerman, 2013, p. 490).  Genetics, hormones, and other things do contribute to cancer risk and cause; but as recent epigenetic research has shown, what we eat can even affect our genetic make-up, therefore helping promote or prevent cancer.

From personal experience working on an inpatient oncology unit at the Mayo Clinic, I can see how lifestyle choices have a direct link to patient outcomes.  The great majority of my patients don’t just have cancer; they typically have multifactorial diseases or outcomes from lifestyle choices.  I commonly see people who are obese, have type 2 diabetes, have smoked or done drugs, eat high-sugar diets, don’t exercise, have high-stress jobs, and many other things linked to causation of cancer.  I also have had patients who have started eating cleaner, in particular diets low in added sugar and/or processed grains, and have seen better results in their prognosis.  On top of that, my patients that do eat healthier and exercise have better outcomes, even at the end-of-life.  Even those with chronic disease can benefit from positive lifestyle choices; I’ve seen it and heard it from my patients firsthand.

What are some things being done to address the fact that the percentage of overweight children is on the rise? Support your answer. What other ideas do you have that you think might help curb this epidemic?

In, 2008 the House of Representatives passed an act known as the “National Obesity Act of 2008” in an effort to “prevent and reduce obesity and to promote sound health and nutrition among Americans, and for other purposes” (110th Congress, 2008).  The National Obesity Act established a number of important initiatives to combat the ongoing and growing problem of obesity including an office of the national coordinator of obesity initiatives and a federal task force on obesity.  The duties of these groups included coordinating a national strategy to “eliminate the occurrence of obesity in the United States” through: the establishment of multiple government agencies working together, implementing goals, and evaluating goals by holding these agencies responsible for prevention and reduction in obesity rates (110th Congress, 2008).  Many programs like the myplate initiative, new food labels, and changing the way we educate our youth are all important to address the percentage of overweight children.  Obesity rates have tripled over the last three decades to an estimated 16.9 of our youth aged 2 to 19 years old (NCSL, 2013).

I believe false and/or misguided perceptions in nutrition and exercise have helped contribute to the ongoing problems in obesity in our country.  By educating our youth and their stakeholders, we can properly educate our youth on a variety of exercise options and healthy nutritional habits.  In youth and adolescence, habits that can last a lifetime are established with great evidence showing that it is easier to influence youth than adults.

Two things that I think can help curb this epidemic include: encouragement of exercise and educating the stakeholders of our youth on nutrition, amongst other things.  Education of Youth on Exercise and Diet, can be done by introducing our youth to a variety of different forms of exercise during physical education classes in order to find a form of exercise and cooking/eating healthy foods that are perceived as fun.  Students who enjoy exercise are more likely to do it habitually (Smith & Bird, 2004).  This can be promoted through enhanced promotion of higher education in the health fields through more exercise science programs, modern dietary programs, and health care professional programs; utilizing a better educated media.  Better and higher educated health professionals can in turn help educate our future youth and stakeholders.  Which leads into my second point, importance of educating the stakeholders on proper nutrition.  Education of: Teachers, Media, Public Health Programs, Parents, and other stakeholders who influence our Youth is important within the expanding media.  With better educated stakeholders in exercise and health, we can positively influence diet and exercise decisions in our youth; in turn reducing future obesity rates.  Need of new and better policies needs to be ongoing to better promote positive lifestyle choices.

In relation to reducing blood pressure which appears to be more helpful- reducing sodium or increasing potassium? Support your answer.

In relation to reducing blood pressure it appears that both sodium and potassium and important in regulation of blood pressure, however sodium intake appears to be more important.  Increasing sodium intake increases fluid retention and therefore raises volume within the body and increases blood pressure due to shear volume.  Like sodium, increased potassium in the body causes a reaction from the renin-angiotensin aldosterone system; however increased potassium is linked to lower blood pressure (McGuire & Beerman, 2013, p. 524).  However, there is some controversy with how much salt intake is linked to blood pressure because some people are more “salt sensitive than others” (McGuire & Beerman, 2013, p. 522).  Many things including: genetics, kidney function, physical activity, obesity, diabetes, and other factors are important in managing blood pressure as well as fluid/electrolyte balance.

According to (Mente et al., 2014), sodium intake caused greater impact on blood pressure across a variety of populations in a study more than potassium.  These populations included people on low and high sodium diets, different age groups, and people with different starting blood pressure baselines.  The positive link of sodium and blood pressure being more important in the relation to hypertension is important to consider.  The study also highlights the importance of kidney function and the human body’s ability to excrete fluid and electrolyte; not just limiting or increasing different foods.

(Adrogue & Madias, 2014) examined the blood pressure effects of: multiple high-sodium diets,  diets low in potassium, and then a diets in conjunction with both a high-sodium and low-potassium diet.  The studies with both “lend considerable fresh support to the thesis that the interaction of the sodium surfeit and potassium deficiency in the body, rather than either disturbance by itself, is the critical environmental factor in the pathogenesis of hypertension” (Adrogue & Madias, 2014, p. 257-258).

In summary, of the many studies that compared sodium and potassium effect on hypertension; sodium appeared to have a greater impact on hypertension.  However as the (Adrogue & Madias, 2014) study stated that both have great impact on hypertension in electrolyte imbalances.  Other factors, such as kidney function, are important in hypertension in relation to electrolytes.

Choose a vitamin or mineral and explain its role in the body. Also explain if other foods or drugs can affect absorption, increase or decrease, and if you there is a deficiency the best way to achieve the recommended intake.

Magnesium (Mg) is important in the body taking place in “more than three hundred reactions, including nerve and cardiac function, muscle contraction and relaxation, protein formation, and, perhaps most important for exercisers, synthesis of ATP-based energy (Greenfield, 2014, p. 201).  Mg is important in nerve and cardiac function making it an important mineral in everyone.  It is closely monitored in a clinical or hospital setting due to the cardiac dysfunctions a deficiency or excessive amount can cause.  A lack of Mg is also linked to muscle cramping and dysfunction of muscles during exercise; therefore Mg is utilized to relax muscles preventing spasms.  Linked to relaxation and Mg is its use with sleep and relaxation; people commonly supplement or increase dietary Mg to relax the body.  Relaxation of the body occurs when the body is using the parasympathetic nervous system; which is when our body best rests and digests foods.  Mg is also used to enhance digestion (like sleep) and is commonly used to treat constipation.  Finally it is utilized to neutralize negatively charged ions helping stabilize ATP and ADP which are important components in energy metabolism (McGuire & Beerman, 2013, p. 518).

There is a lot physiologically that goes into the proper levels of various vitamins and minerals in the body; Mg is no different.  Intestine function, kidney function, and other dietary choices can affect the bioavailability of of Mg.  The small intestine and kidney function regulate the amount of magnesium in the blood.  Dysfunction of the small intestine and kidney can result in Mg levels too high or too low; that can result in muscle, nerve, and even life-threatening issues like cardiac dysrhythmias.

According to (McGuire & Beerman, 2013) “some studies suggest that diets high in calcium or phosphorus decrease the bioavailability of magnesium.  In addition, protein deficiency may decrease magnesium absorption, and high levels of dietary fiber can decrease its bioavailability (p. 517).

If there is a deficiency you can naturally find Mg in a variety of food sources including: green leafy vegetables, seafood, legumes, nuts, and chocolate.  Athletes utilize a higher amount of Mg than the average person therefore supplementation may be necessary.  When using supplementation of Mg somes signs that Mg isn’t being absorbed properly or is in too high amounts include: diarrhea, GI dysfunction, and even cardiac issues (Greenfield, 2014, p. 201).

Magnesium is important for everyone and in particular athletes.  Mg can help our heart and muscles work properly, help us relax and sleep during our busy lives, and important in the ATP synthesis of energy.  It is important even vital to have the right amount and in most cases can be obtained from real whole foods.  Personally I get a blood panel once a year which I know may increase as I age because of the common problem the elderly have with kidney function.

References:

Adrogue, H. & Madias, N.E. (2014). The impact of sodium and potassium on hypertension risk. Seminars in nephrology 34(3), 257-272. doi:10.1016/j.semnephrol.2014.04.003

Burne, J. (2012, November 26). Could this elixir hold the key to weight loss? experts hope it’ll also treat diabetes, epilepsy and alzheimer’s. Retrieved from http://www.dailymail.co.uk/health/article-2238842/Could-elixir-hold-key-weight-loss-Experts-hope-itll-treat-diabetes-epilepsy-Alzheimers.html

Food Research and Action Center. (2014). Overweight and obesity in the U.S. Retrieved from http://frac.org/initiatives/hunger-and-obesity/obesity-in-the-us/

Harvard School of Public Health (HSPH). (2014). Vitamins. Retrieved from http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vitamins/

Hedayati, S. S., Minhajuddin, A. T., Ijaz, A., Moe, O. W., Elsayed, E. F., Reilly, R. F., & Huang, C.-L. (2012). Association of Urinary Sodium/Potassium Ratio with Blood Pressure: Sex and Racial Differences. Clinical Journal of the American Society of Nephrology : CJASN, 7(2), 315–322. doi:10.2215/CJN.02060311

McGuire, M. & Beerman, K.A. (2013). Nutritional sciences: From fundamentals to food. Belmont, CA: Wadsworth.

Mente, A., O’Donnell, M. J., Rangarajan, S., McQueen, M. J., Poirier, P., Wielgosz, A., & … Yusuf, S. (2014). Association of urinary sodium and potassium excretion with blood pressure. New England Journal Of Medicine, 371(7), 601-611. doi:10.1056/NEJMoa1311

Miles, L. (2008). The new WCRF/AICR report — Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective.Nutrition Bulletin, 33(1), 26-32.

National Institute of Health. (2011, June 24). Dietary supplements: Background information. Retrieved from http://ods.od.nih.gov/factsheets/DietarySupplements-HealthProfessional/

Saleeby, Y.M. (2014). Are multivitamins safe and necessary?. American Fitness, 32(4); 58-61.

Tufts University. (2014). Are you really benefiting from your multivitamins? Tufts University Health & Nutrition Letter, 32(1), 4-5.

National Conference of State Legislators. (2013). Childhood obesity- 2011 update of legislative policy options. Retrieved from  http://www.ncsl.org/research/health/childhood-obesity-2011.aspx

Smith, A. & Bird, S. (2004). From evidence to policy: Reflections on emerging themes in health-enhancing physical activity.  Journal of Sports Sciences, 22(8),791-799.

110th Congress. (2008). Text of the national obesity prevention act of 2008. Retrieved from https://www.govtrack.us/congress/bills/110/hr7179/text

 

Protein

Background on Proteins

Proteins have many functions in the body, but many athletes and people think of protein only in the process of the make-up of tissues.  When building muscle it is commonly assumed that the more protein the more muscle, but there is more to proteins and their functions than just loading the body with protein.  Not all protein sources are created equal; some provide more protein per gram than others, some provide more complete forms of amino acid chains, some provide additional nutritional benefits, and some are more easily digestible than others.  Proteins are made up of a combination of different amino acids, of which 9 are essential, 11 non-essential, and then some can conditionally-essentially amino acids  “In general meat, poultry, eggs, and dairy products are complete protein sources, whereas plant products are incomplete protein sources” (McGuire & Beerman, 2013, p. 165).  That said combining two plant-based sources can complete the essential amino acid profile (Elkaim, 2014, p. 87).

It is important to keep in mind that just because it is a complete protein source doesn’t mean that it is easily absorbed; it also needs to be easily absorbed to be a high-quality protein source.  Another issue with proteins is the disruption of a protein’s shape, called denaturation.  Denaturation of a protein can result in poor absorption, loss of essential amino acids, loss of function and can even have serious chemical issues like acid/base and heavy metal reactions in the body (McGuire & Beerman, 2013, p. 173).   So many protein powders have high amounts of protein in them, but aren’t high quality, easily absorbed and can be denatured in the production process; which results in excretion or storage of proteins as body fat.

Protein turnover, the ability to break down and use protein, is what is important in protein utilization and is regulated mainly by hormones (McGuire & Beerman, 2013, p. 185).  Eating high glycemic carbohydrate diets, resulting in high insulin, inhibits protein utilization because the body is trying to utilize carbohydrates.  However, the release of cortisol during various types of stress, including exercise, stimulates protein use.  After exercise your body secretes cortisol and utilizes sugars directly into muscle, which is why you can utilize carbohydrates and protein at higher levels post-exercise.

Protein status in the end needs to be examined in nitrogen balance which is the amount of protein intake compared with the amount of nitrogen lost in the body (McGuire & Beerman, 2013, p. 187).  To prevent illness and muscle breakdown we need our body to have nitrogen balance which is when protein or nitrogen loss is equal to intake.  In order to build muscle or recover from illness or a workout we need our bodies intake to exceed loss and be in positive nitrogen balance.  Human bodies use protein for enzyme formation, movement, transportation and communication, immune system protection, fluid and electrolyte balance, and many other important functions in the human body; therefore the quality and quantity of proteins is important for health in general.  So how much protein does everyone need?

Athletes

Athletes are causing more stress on the body from exercise than a non-athlete and need protein to rebuild muscle and prevent breakdown of the body seen with negative nitrogen balance.  The goal of sport and exercise needs to be determined in the amount of protein consumed.   Low and moderate-intensity endurance exercise does not affect dietary protein requirements, because low to moderate amounts of exercise are factored into the Recommended Dietary Allowances (RDA) of nutrients.  Athletes trying to put on muscle mass or endurance athletes that have strenuous training on the majority of days need a higher percentage of calories from protein.  There is some disagreement in recommendation levels of protein needed by athletes and (Philips, Moore, & Tang, 2007) did a review of different studies concluding that protein “timing and composition (quality) as well as consumption in combination with macronutrients such as carbohydrate; attention to these details, we contend, will enable athletes to perform to the best of their potential” (p. 71).  So it is important to keep in mind that even though there are recommended percentages and ranges for proteins within the athlete population, a number of factors need to go into recommended protein use.

Strength

In order to build muscle mass a person needs to be in positive nitrogen balance.  According to (Greenfield, 2014, p. 307) “there really isn’t much additional benefit to be gained by exceeding 0.55 grams per pound of body weight to maintain nitrogen balance.  That said when trying to exceed nitrogen balance and go into a state of positive nitrogen balance; studies suggest that you don’t need to go more than 25 percent above the .55 grams per pound of body weight, which ends up being .68 grams per pound of body weight (Wilson, 2006).  While being in a state of nitrogen balance it is important to remember that ammonia is a byproduct of the use protein and can be toxic to the body.  This means that having too much protein can result in toxic levels and can cause great strain on the body’s organs, in particular the kidneys.  Maintaining adequate water intake helps with the process of excreting the ammonia byproducts and therefore prevention of dehydration is very important in people with high protein intake (Greenfield, 2014, p. 308).  In summary, strength athletes need greater amounts of protein for a positive nitrogen balance, and is unnecessary to exceed 0.7 grams per pound of body weight on most days of the week because of the dangers ammonia can have on the body.

Endurance

Aerobic and low to moderate endurance exercise is recommended and factored into the Institute of Medicine’s recommended macronutrient ratios.  Therefore, low and moderate-intensity endurance exercise does not affect dietary protein requirements in terms of the recommended macronutrient ratio of 10-20% of energy coming from proteins (Phillips, Moore & Tang, 2007, p. S59).  According to Mark Tarnopolsky (2004), the only time that endurance athletes need to exceed the recommended 12-15% of energy from protein intake is when an athlete is training 4 to 5 days a week for longer than 60 minutes; at that point Tarnopolsky recommends a diet of 20-25% of energy intake to be from protein (p. 666).  Another recommendation, outside of using percentages, to maintain nitrogen balance is 0.55 grams per pound of body weight for an athlete (Meredith, 1989).  That said, it is recommended and more common that endurance athletes train using cross-training techniques, including lifting and strength exercises which demand a higher percentage of energy intake from protein.  Protein recommendations for endurance athletes is slightly increased over the amount recommended for the average person if the athlete trains for greater than 60 minutes at least 4 to 5 day a week.

 

Weight Loss

Protein has been linked to weight loss and improved body composition, when combined with a reduction in total energy intake and/or combined with greater total energy used with exercise.  Research also suggests that protein is more satiating than ingestion of carbohydrate or fat, helping with reduced energy consumption due to an increased feeling of fullness.  Weight loss can be enhanced by minimally increasing protein intake, partaking in an energy-controlled diet, and maintained by making feasible, not radical, lifestyle adaptations  (Paddon-Jones, Westman, Mattes, Wolfe, Astrup, and Westerterp-Plantenga, 2008, p. 1561S).  Protein is a great tool to use with weight loss, but once again total energy in needs to be less than total energy used when losing weight.

Across the Lifespan

The US Recommended Dietary Allowance (RDA is 0.36 grams of protein per pound of body weight, which was designed for most people to be in nitrogen balance (Greenfield, 2014, p. 306-307).  As discussed in the athlete sections, this number doesn’t need to be excessively greater in strength and endurance athletes.  Across the lifespan, groups that need more protein per body weight include infants, breastfeeding women, and the aging population.  Infants need more protein per pound of bodyweight because of the rapid rate of growth.  Lactating women need more protein due to the fact that they are the primary nutritional source for themselves and their child.  Finally, the aging population needs additional protein because of the natural effects of muscle-mass loss, but kidney function also decreases with age.  Protein requirements are typically met by increasing the rates of protein from the previously recommended 10-20 percent of dietary percentage to 20-30 percent in the elderly in particular (Greenfield, 2013, p. 316).  In conclusion, a slight increase in protein intake as well as strength and weight-bearing exercise can help maintain appropriate muscle mass across the lifespan, while monitoring kidney function closely in the elderly.

Conclusion

Protein requirements aren’t as simple as just giving an exact amount for every athlete or every person in general.  It is important to understand your exercise or fitness goals, energy in still needs to equal to energy out if trying to maintain body mass and is adjusted per fitness goals.  Protein needs to be of high-quality because the protein can be denatured or not easily utilized for energy.  Understand that too much protein can cause added fat or strain on excretion process, including kidney failure, which is why for the average person only 10-20% of calories should be from protein.  In conclusion, it gets down to individualizing goals, understanding proper timing, and understanding an individual’s ability to synthesize and excrete nitrogen.     

 

Here is a bonus link to a website that looks into the bioavailability and quality of protein powder: https://labdoor.com/

  • Don’t get all your protein from Protein Bars and Powders because even good sources don’t contain some of the nutritional benefits of “Real, Whole Foods”.  The 2010 Dietary Guidelines recommend getting “significant amounts of protein from at least 3 different food groups daily (McGuire & Beerman, 2013, p. 191)

References

Elkaim, Yuri. (2014). The all-day energy diet. Carlsbad, California: Hay House, Inc.

Greenfield, Ben. (2014). Beyond training: Mastering endurance, health, & life. Las Vegas: Victory Belt Publishing, Inc.

Meredith, C. (1989). Dietary protein requirements and body protein metabolism in endurance-trained men. Journal of Applied Physiology, 66(6), p. 2850-2856.

McGuire, M. & Beerman, K.A. (2013). Nutritional sciences: From fundamentals to food. Belmont, CA: Wadsworth.

Paddon-Jones, D., Westman, E., Mattes, R.D., Wolfe, R.R.,  Astrup, A., and Westerterp-Plantenga, M. (2008). Protein, weight management, and satiety. American Journal of Clinical Nutrition 87(5) p. 1558S-1561S.  Retrieved from http://ajcn.nutrition.org/content/87/5/1558S.full.pdf+html

Phillips, S. M., Moore, D. R., & Tang, J. E. (2007). A critical examination of dietary protein requirements, benefits, and excesses in athletes. International Journal of Sport Nutrition and Exercise Metabolism 20(7), S58-S76. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/18577776

Tarnopolsky, M. (2004). Protein requirements for endurance athletes. Journal of Nutrition (20)7, 662-668. doi:10.1016/j.nut.2004.04.008

Wilson, J. (2006). Contemporary issues in protein requirements and consumption for resistance trained athletes. Journal of International Social Sports Nutrition, 3(1), p. 7-27.