January 11, 2016

Day 11: Protein and Amino Acids


Today, let’s talk about protein. To some people, protein seems like the least fun nutrient to eat, compared to fats and carbs, but it is still absolutely essential to the human diet. Fortunately, if you are living in North America, your diet is very rich in protein, even if you are a vegetarian. And more than likely, you are eating too much protein. So there may not even be a need for you to supplement with expensive protein powders. The only way to tell is to track what you eat. Have you ever added up what you ate for an entire day and then added up the nutritional content? In an upcoming post we are going to cover how to read nutrition and ingredient labels and give you some tips on how to calculate your needs and excesses.
 
As you may have noticed in other posts on our blog, our priorities are to empower you with new knowledge, then to motivate and encourage you, and finally to offer tips and favorite recipes. We feel that there is much to be gained in teaching you the principles and then letting you make your own choices according to your tastes. We ourselves are in the continual process of figuring out the best foods, sources, and methods that work for our family to achieve optimal nutrition and health. What works for your family may look different than ours, and that’s ok. We are just excited to have good company on the journey!

I compiled and abbreviated the following information on protein from about a dozen different sources that I researched. There was overlapping, widely accepted information at each source, so I'm not going to cite every line like a research paper. But there will be about 20 linked words.

Our bodies are full of amino acids. At least 500 different amino acids have been discovered in the miraculous human body. The amino acids serve many different roles: 
  • Amino acids are the basic building blocks of the body and are present in every cell. 
  • Act as the precursors to neurotransmitters in the brain 
  • Help with digestion as enzymes
  • Help regulate the body’s metabolism
  • Make up certain hormones and antibodies within the immune system 
  • Transport oxygen and nutrients in the body

Proteins are a specialized form of amino acids:
  • Second only to water, proteins are the most abundant kind of molecules in the body. 
  • Protein serves as a source of energy like carbohydrates and fats (lipids).
  • Amino acids, the building blocks of proteins, are used for building muscle tissue and repairing damaged tissues. 
  • Protein is THE major structural component of all cells in the body including organs, skin, and hair.

It makes you want to eat your protein, doesn’t it! And it makes you want to eat the best proteins possible. There are 20 main amino acids in proteins, which are broken down into two main types: essential amino acids (you must get them from food) and non-essential amino acids (your body can make them, unless you’re suffering major disease). Essential amino acids have their own recommended amounts to consume daily. In the USDA nutrition database, protein content is listed for each food and broken out into 18 out of the 20 specific amino acids. (They leave out glutamine and asparagarine. See here for explanation why). However, their names and amounts are rarely displayed on food nutrition labels for anything except protein powders. Even then, that is mostly just to wow and impress you, since the names, amounts, and %’s mean nothing to most people.

The daily recommendation for essential amino acids has varied over the last 20 years. The USDA, WHO (World Health Organization), and Institute of Medicine of the National Academies each have their own opinions, which differ. Combined they would say that 23-36% of the protein that you eat should come from essential amino acids. See chart below with links to the sources and also to individual articles on each of the essential amino acids: 

9 Essential Amino Acids  IOM Rec mg per g of Protein to be complete   WHO Rec. mg per day for 136 lb adult   USDA Rec. mg per day for 154 lb adult 
Leucine 55 2418 3900
Lysine 51 1860 3000
Valine 32 1612 2600
Phenylalanine+Tyrosine 47 1550 2500
Isoleucine 25 1240 2000
Threonine 27 930 1500
Methionine+Cystine 25 930 1500
Histidine 18 620 700
Tryptophan 7 248 400
Totals 287 g 11,408 g 18,100 g
Notes  As little as 28.7% of our protein needs to be from Essential amino acids to be complete   11.4g (23%) out of your 46-56g of protein daily needs to come from essential amino acids   18.1g (36%) out of your 46-56g of protein daily needs to come from essential amino acids 
  
So how much protein does our body need? According to the USDA guidelines (see p76 of appendix, p89 of the PDF), children ages 1-3 need 13g of protein daily, ages 4-8 need 19g, ages 9-13 need 34g, and teenagers and adults need 46 grams of protein for females and 56g for males. Active people and athletes need an extra 25-100% of those amounts (estimates vary by several different medical, sports, and nutrition organizations).

A complete protein (or whole protein) is a source of protein that contains an adequate proportion of all nine of the essential amino acids. Nearly all foods contain all twenty amino acids in some quantity, and nearly all animal-based foods contain the essential amino acids in sufficient quantity. Some plant-based sources of protein contain sufficient values of ALL essential amino acids. These include: chickpeas, black beans, pumpkin seeds, cashews, cauliflower, quinoa, pistachios, turnip greens, black-eyed peas, Kasha, amaranth, buckwheat, hempseed, spirulina, chia seeds, and soybeans. 

Other vegetables, seeds, legumes, and grains are lower in one or more essential amino acids especially lysine, and to a lesser extent methionine and threonine. The good news is that by consuming a mixture of plant-based protein sources you can meet the entire need. For example many cultures that eat rice and beans together. Complementary proteins need not be eaten at the same meal for your body to use them together. Studies now show that your body can combine complementary proteins that are eaten over the course of the day. 

Several different research measures have been produced by scientists to try to come up with the best system of classifying the "quality" or "value" of different proteins. Measures include the biological value, net protein utilization, protein efficiency ratio, protein digestibility-corrected amino acid score and complete protein concept. Feel free to follow these links if you would like to read more. 

We have not talked a lot about meat in this article and it’s not because we feel that it is bad. Our family eats lean chicken and fish a few meals per week and we enjoy it. But we do strongly believe that you can obtain more than adequate protein in your diet from eating and enjoying vegetables, seeds, legumes, and grains and that meat and dairy are not necessary to be healthy.

Our challenge for you is to measure just how much protein you eat in a single day and see if you get to 46-56g. Then measure it again the next day. If those are pretty average, ordinary meal days, then you can probably take heart that you are getting sufficient protein in your diet and don't worry too much about supplementing it.

This is not the end discussion of proteins. There is so much more that we want to learn and share with you. Let us know what your questions, opinions, and results are and we are happy to help you any way we can. Thanks for reading this somewhat technical article and congratulations for making it to the end!

Scott

 #MoreFoodLessCrap #NewYear #Food #Health #Protein #Fitness #Diet @MorFoodLessCrap

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