Protein I

Maintaining our body’s protein requirements is crucial for our health. Some people are a little overwhelmed with the type or amount of protein that should be consumed. Keep reading and I will explain the basics. 


To start with the basics, our muscles, skin, hair, connective tissues and organs are all built from protein. We pretty much consist of protein. Further, most enzymes, hormones, antibodies, neurotransmitters and general signaling processes which are responsible for our digestion, growth, and other pathways involve protein and serve important functions. 

One protein molecule consists of amino acids - AA (you can compare them with building blocks or bricks for a house). A protein is made up of 20 different AA, of which 11 are so-called “non-essential AA”. We are able to produce them ourselves. The remaining 9 AA are called “essential amino acids” which must be derived from food. Different configurations and combinations of AA result in different protein variations. (1)


PROTEIN QUALITY 

Humans require high-quality proteins for protein synthesis. Generally, animal-based foods (meat, poultry, eggs, milk, milk products and seafood) provide such complete quality proteins, containing all essential AA.

Plant proteins, however, show more diverse amino acid patterns and thus sometimes lack in some essential amino acids. The lacking amino acid is termed a limiting amino acid. In legumes it would be e.g. methionine, in whole grains its lysine.  The right combination of plant based food (e.g. beans and rice) results in complementary proteins, thus improving the protein quality. (1)

For easier understanding, imagine you eat a piece of meat, it includes all of the amino acids you need in order to synthesize body own protein. Easy! If you eat rice and veggies it does include protein, but not all AA you need to build protein. Thus, you should combine it with e.g. beans or other legumes to achieve the same “building” effect that meat does. Some exceptions such as soy, spirulina, hemp seeds, chia seeds, quinoa, buckwheat and amaranth do provide our body with all AA needed. (2)(3)(4)(5)(6)

For a long time, people believed that you have to eat certain combination at every meal to achieve proper protein nutrition. Nowadays, studies confirm that it is sufficient enough to consume them over the course of a day (e.g. simplified: beans in the morning and rice in the evening does the same job as combining them in one meal).


PROTEIN for VEGETARIANS - VEGANS


If you are on a vegan or vegetarian diet you need to ensure you consume a variety of foods to meet the protein requirements and all essential amino acids your body needs to build protein.

Therefore, it is crucial to eat a diversity of whole grains, legumes, seeds, vegetables, and nuts. Vegetarians can cover their protein needs sufficiently with eggs, milk and milk products. If fruits and vegetables make up the fundamental of the diet, deficiencies may occur due to a lack of protein quality and quantity.


This sounds like only animal protein is good protein. Completely wrong! Vegetarian diets are usually better in providing our bodies with essential vitamins, minerals, and fiber. Further, meat and dairy products tend to be high in saturated fats and hence linked to high blood pressure and cardiovascular diseases.


HOW MUCH DO WE NEED?

Our body continuously breaks down protein. We don't have a protein storage like the one for fat (you all know what I'm talking about) or sugar (Glycogen). Therefore, we need to consume sufficient protein to maintain body structures. Recommendations for protein vary depending on age, size, and need. 

(7)

The Recommended Dietary Allowance (RDA) for protein is 0,75g protein per kg body weight for women and 0,85g protein per kg bodyweight for men (or 10-15% of the total energy). Children, infants, pregnant and lactating women, and people 70+ years of age have a slightly higher requirement. Athletes and active people are recommended to consume between 1,2-2g protein/kg BW to prevent muscle loss.


EXAMPLE: 

Let’s say an adult healthy woman with 65kg works out 3-4 times a week and works a job which is mostly sitting and some walking/standing.

65kg x 1,2 = 78g protein per day 

78g protein per day would be the amount she has to consume in order to meet her body’s basic needs.


POSITIVE HEALTH EFFECTS

  • As mentioned above, protein serves as foundation for health, repayments, recovery and chemical messenger and enzymes in our body.

  • Protein deficiency can result in slowed growth, impaired brain and kidney functions, inadequate nutrient absorption and poor immunity.-

  • Protein increases fullness, satiety helps with weight loss due to reasons mentioned below. (8,9)(10)

  • It can increase muscle mass and strength and prevent muscle loss when losing weight. (11)(12)      

  • Snacking and cravings might be reduced when enough protein is consumed. Studies show that late night snacking was drastic reduced      when protein content in the diet was increased. 

  • Protein consumption can boost your metabolism. To digest protein our body makes use of something called a thermic effect of food (TEF), meaning it burns calories to digest the protein. (13–16)

  • The risk for osteoporosis and fractures in older people is lower when adequate protein is consumed. Especially women after their menopause are recommended to consume sufficient energy together with an active lifestyle. However, excessive protein intake is associated with negative calcium balance and could potentially lead to bone loss. Therefore, dose is key! (17–19)


NEGATIVE HEALTH EFFECTS

  • High protein diets can also trigger several chronic diseases such as heart disease, osteoporosis, cancer, obesity, kidney stones. However, no upper level (UL) was established so far, due to insufficient data. (20) (The institute of Medicine recommended the UL for adults at no more than 30% of total energy intake)

  • Self-explanatory, protein excesses are more like to be caused by an over consumption of animal protein. Most of these sources contain high amounts of saturated fats which may contribute to cardiovascular diseases. To blame cardiovascular diseases on protein alone is therefore, incorrect. (21) When red meat and high-fat milk products are substituted with vegetable protein combined with low-fat milk products, fish, and poultry, cardiovascular diseases are decreased. (22,23)

  • Cancer and protein consumption is a popular topic. Research shows that protein itself does not seem to increase the risk of cancer, however, protein-rich foods do. As mentioned above, high intakes of red meat and processed meats and their additives are associated with cardiovascular diseases and also cancers such as colon, pancreas, and ovaries. Conversely, protein rich plants may reduce the risk of some cancers. (24–26)

  • Kidney diseases are often linked to excessive protein intake. A diet high in protein does not cause kidney disease, however, it increases their workload. People with chronic kidney diseases often worsen their disease by consuming too much protein. It is generally recommended to drink more water in periods where protein intake is increased. 


FROM REQUIREMENTS TO GROCERIES

If you calculated your protein needs in the section above and have a number but no idea how to achieve those requirements, continue reading.

When I speak of “grams of protein” it means gram of the macronutrient protein and not grams of the protein source e.g. chicken.

Foods listed below contain significant high amounts of protein:

 
 
 
Example: Let’s take the same person as above (woman with 65kg works out 3-4 times a week and works a job which is mostly sitting and some walking/standing. 65kg x 1,2 = 78g protein per day)

Breakfast:
½ cup oats, 1 cup skimmed milk, 1 cup blueberries, 1 tbsp. chia seeds, ½ apple, 1 tbsp. peanut butter

Lunch:
Steamed broccoli, 1 grilled chicken breast, 1 cup cooked buckwheat, 1tsp. butter
Salad (baby spinach, ½ avocado, olive oil, balsamic vinegar, cherry tomatoes)

Snack:
1 Banana

Dinner:
3 Rice cakes, 3tbsp 2% cottage cheese, ½ cucumber, fresh herbs

As you can see, it is not that hard to maintain your protein requirements throughout the day. Please keep in mind that you have higher requirements when physical activities increase.

MY TAKE ON PROTEIN POWDERS and SUPPLEMENTS    

The sports and nutrition market is overloaded with protein powders and supplements. You can only get big and strong if you have a shake a day – that's what they say. I do not agree on that at all. However, protein powders may be a good alternative if there is not enough time to consume a balanced meal. By now you hopefully understand that getting enough protein is crucial to support health and muscle growth, but ingesting more than needed does not further enhance muscle function or growth. “Overdosing” with protein is very easy when consuming protein supplements. The plus is excreted by urine and will be flushed down the toilet if your kidneys are healthy. Protein powders provide amino acids to our body’s, however, protein in food sources supply the same and much more (minerals, vitamins, fiber etc.) and therefore my preferred source.

 - JZ

REFERENCES

1.        Whitney E, Rolfes S. Understanding nutrition. 14th ed. Belmont: Wadsworth; 2015. 928 p.

2.        USDA National Nutrient Database. Full report (all nutrients): 12012, seeds, hemp seed, hulled. 2016; Available from: https://ndb.nal.usda.gov/ndb/foods/show/3614?n1=%7BQv%3D1%7D&fgcd=&man=&lfacet=&count=&max=50&sort=default&qlookup=hemp+seeds&offset=&format=Full&new=&measureby=&Qv=1

3.        USDA National Nutrient Database. Full report (all nutrients): 12006, seeds, chia seeds, dried. 2016. Available from: https://ndb.nal.usda.gov/ndb/foods/show/3610?n1=%7BQv%3D1%7D&fgcd=&man=&lfacet=&count=&max=50&sort=default&qlookup=chia+seeds&offset=&format=Full&new=&measureby=&Qv=1

4.        USDA National Nutrient Database. Full report (all nutrients): 20137, quinoa, cooked. 2016; Available from: https://ndb.nal.usda.gov/ndb/foods/show/6587?n1=%7BQv%3D1%7D&fgcd=&man=&lfacet=&count=&max=50&sort=default&qlookup=quinoa&offset=&format=Full&new=&measureby=&Qv=1

5.        USDA National Nutrient Database. Full report (all nutrients): 20008, buckwheat. 2016; Available from: https://ndb.nal.usda.gov/ndb/foods/show/6479?n1=%7BQv%3D1%7D&fgcd=&man=&lfacet=&count=&max=50&sort=default&qlookup=buckwheat&offset=&format=Full&new=&measureby=&Qv=1

6.        USDA National Nutrient Database. Full report (all nutrients): 20001, amaranth grain, uncooked. 2016; https://ndb.nal.usda.gov/ndb/foods/show/6473?n1=%7BQv%3D1%7D&fgcd=&man=&lfacet=&count=&max=50&sort=default&qlookup=amaranth&offset=&format=Full&new=&measureby=&Qv=1

7.        AIS Sports Nutrition. Protein fact sheet [Internet]. 2009 [cited 2016 Nov 1]. Available from: http://www.ausport.gov.au/ais/nutrition/factsheets/basics/protein_-_how_much

8.        Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. United States; 2004 Oct;23(5):373–85.

9.        Weigle DS, Breen PA, Matthys CC, Callahan HS, Meeuws KE, Burden VR, et al. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005;82(1):41–8.

10.      Dhillon J, Craig BA, Leidy HJ, Amankwaah AF, Osei-Boadi Anguah K, Jacobs A, et al. The Effects of Increased Protein Intake on Fullness: A Meta-Analysis and Its Limitations. J Acad Nutr Diet [Internet]. Elsevier; 2016 Nov 11;116(6):968–83. Available from: http://dx.doi.org/10.1016/j.jand.2016.01.003

11.      Mettler S, Mitchell N, Tipton KD. Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc [Internet]. School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.; 2010;42(2):326–37. Available from: http://europepmc.org/abstract/MED/19927027

12.      Helms ER, Zinn C, Rowlands DS, Brown SR. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Int J Sport Nutr Exerc Metab. United States; 2014 Apr;24(2):127–38.

13.      Leidy HJ, Tang M, Armstrong CLH, Martin CB, Campbell WW. The effects of consuming frequent, higher protein meals on appetite and satiety during weight loss in overweight/obese men. Obesity (Silver Spring). United States; 2011 Apr;19(4):818–24.

14.      Johnston CS, Day CS, Swan PD. Postprandial thermogenesis is increased 100% on a high-protein, low-fat diet versus a high-carbohydrate, low-fat diet in healthy, young women. J Am Coll Nutr. United States; 2002 Feb;21(1):55–61.

15.      Veldhorst MAB, Westerterp-Plantenga MS, Westerterp KR. Gluconeogenesis and energy expenditure after a high-protein, carbohydrate-free diet. Am J Clin Nutr. United States; 2009 Sep;90(3):519–26.

16.      Veldhorst MAB, Westerterp KR, van Vught AJAH, Westerterp-Plantenga MS. Presence or absence of carbohydrates and the proportion of fat in a high-proteindiet affect appetite suppression but not energy expenditure in normal-weight human subjects fed in energy balance. Br J Nutr. England; 2010 Nov;104(9):1395–405.

17.      Bonjour J-P. Dietary protein: an essential nutrient for bone health. J Am Coll Nutr. United States; 2005 Dec;24(6 Suppl):526S–36S.

18.      Kerstetter JE, Kenny AM, Insogna KL. Dietary protein and skeletal health: a review of recent human research. Curr Opin Lipidol. England; 2011 Feb;22(1):16–20.

19.      Hannan MT, Tucker KL, Dawson-Hughes B, Cupples LA, Felson DT, Kiel DP. Effect of dietary protein on bone loss in elderly men and women: the Framingham Osteoporosis Study. J Bone Miner Res. United States; 2000 Dec;15(12):2504–12.

20.      Committee on Dietary Reference Intakes. Dietary Reference Intakes: Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. In Washington, D.C.: National Academies Press; 2005.

21.      Hackam DG, Khan NA, Hemmelgarn BR, Rabkin SW, Touyz RM, Campbell NRC, et al. The 2010 Canadian Hypertension Education Program recommendations for the management of hypertension: part 2 - therapy. Can J Cardiol. England; 2010 May;26(5):249–58.

22.      Preis SR, Stampfer MJ, Spiegelman D, Willett WC, Rimm EB. Dietary protein and risk of ischemic heart disease in middle-aged men. Am J Clin Nutr. United States; 2010 Nov;92(5):1265–72.

23.      Clifton PM. Protein and coronary heart disease: the role of different protein sources. Curr Atheroscler Rep. United States; 2011 Dec;13(6):493–8.

24.      Magalhaes B, Peleteiro B, Lunet N. Dietary patterns and colorectal cancer: systematic review and meta-analysis. Eur J Cancer Prev. England; 2012 Jan;21(1):15–23.

25.      Larsson SC, Wolk A. Red and processed meat consumption and risk of pancreatic cancer: meta-analysis of prospective studies. British Journal of Cancer. 2012. p. 603–7.

26.      Takachi R, Tsubono Y, Baba K, Inoue M, Sasazuki S, Iwasaki M, et al. Red meat intake may increase the risk of colon cancer in Japanese, a population with relatively low red meat consumption. Asia Pac J Clin Nutr. Australia; 2011;20(4):603–12.

27.      National Agricultural Library. USDA Food Composition Databases [Internet]. USDA; 2016. Available from: https://ndb.nal.usda.gov/ndb/nutrients/index