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Friday, March 24, 2006

Requirements and Usage of Amino Acids - four questions

Hello Nutrition community,

I have questions regarding "Requirements and Usage of Amino Acids".

I have not found a list of a recommended daily intake of essential and non-essential amino acids per day (not just the general recommendation of protein intake). Does anyone know if there is such a list on the web?

A second question is: What happens in our body to all the amino acids that do not make a complete protein? Are they still used for something in our body. For example, if you eat beans, they might contain 10 grams of protein per 100 grams, but because they don't make a complete protein and might have a biological value of 30, does that mean that only 3grams of protein is actually used by your body? And what happens to the remaining 7grams of protein (amino acids that cannot be combined)? Are they used in any way in your body or are they just discarded by your body?

Re! garding kidneys: Lets assume that your body discards the protein that do not contribute to a complete protein. I assume that excess protein is filtered by the kidney. Does that mean that the kidney has to filter out more protein, if one consumes incomplete proteins?

Finally, I like to learn more about how to combine certain plant foods in order to obtain complete proteins. While I have read much about general recommendations about how to combine certain plant food on the net: e.g., chickpeas and sesame seeds, peanut butter and whole wheat bread, etc., I have not found information about which ratio of these foods make a complete protein. For example, How many chickpeas should be combined with sesame seeds? 100grams to 20grams? 50grams 50grams? Does anyone know these ratios?

I appreciate help a lot, as I have spent much time on finding answers and wasn't successful!

cheers, Chris

8 Comments:

  • At 9:23 AM, Anonymous TC said…

    Just eat meat, fish and eggs and save yourself all the worrying. You'll feel better and be healthier.

    TC

     
  • At 2:53 PM, Anonymous cguttman said…

    I am eating meat, eggs and fish. I need this protein, because I do sports every day. But I think I eat too much animal meat at the moment (typical day: 1 egg in the morning, 250 of mince, 2 steaks in evening). Thus I was wondering if I can combine certain foods to produce a complete protein. I have actually found the recommended daily intake for the different amino acids, so I guess, I have to look at individual food items and then calculate how they match and provide a high biological value?

    Chris

     
  • At 5:23 PM, Anonymous cguttman said…

    Thanks DZ. This was helpful. Your video is impressive :) I am glad if I manage 10 chinups...

    I wonder if I should take on your advice (which is backed up by scientific evidence), because the authors of the sources that you attached admitted that determining the intake of protein for an athlete is (and remains) a difficult issue. ... Meaning that there are researchers who believe that the intake of protein is proportional to the exercise that you are doing.

    Having seen your video, I assume that you do not aim to gain any muscle? You try to maintain your fitness at the current level? Maybe it is an interesting hypothesis that if one aims to gain muscle the protein intake should be slightly higher when training with weights and resistance, so that muscle tissue can be build?

    Chris

     
  • At 11:08 PM, Anonymous Ron Peterson said…

    The RDA for amino acids is given in http://www.anyvitamins.com/amino-acids/rda-amino-acids.htm. IIRC, the RDA for protein is about 0.8 g/Kg of body weight.

    You need to look at the amino acid concentration of the different foods. I think that lysine is the only one that is difficult to find. You might simply take that as a supplement, since not much is required.

    My fellow meat eaters have a simple solution, but it doesn't help the vegetarians. There are intermediate possibilities such as using the protein from milk, eggs, or fish depending on the type of vegetarian a person is.

     
  • At 12:53 AM, Anonymous cguttman said…

    This is interesting, but I havent fully understood:

     > One of the adaptations to exercise is the

    So, how do you hold what you have? By eating the right amount at the right time? But when and what would that be exactly? Just to get an impression take my example, currently, I eat a banana and a bit of protein right after exercise. In the evening, just before sleep, I eat low glycemic index food and some cottage cheese. Do you have more/better suggestions?

    Any suggestions here? What do you figure is the best exercise routine for you?

    Chris

     
  • At 5:08 AM, Anonymous MMu said…

    "cguttman" <4everclev@web.de> schrieb im Newsbeitrag ...

    Biological value compares the profile of the amino acids (how much of each amino acid is in there) of the food to the profile of the amino acids in our own body and takes digestion into account as well.

    So its not meant to be read as percentage of the food being utilized but rather: similarity between food and human body amino acid composition.

    You can combine foods for a 100% biological value if you match a pattern that is equal to our body composition of amino acids.

    Generally: meat, fish and eggs are closer in BV than vegetables (which has its reason in evolution.. plants need other properties for their proteins than animals do- and we are in effect an animal).

    No, generally not. Protein is not taken up as protein but cut in the digestion tract by different enzymes into amino acids. Those amino acids are then taken up by specific transporters.

    The amino acids are then used to build new protein, to build other - non essential - amino acids out of them, or to simply generate energy.

    Usually you use 1:1 ratios in these. Its not useful to try to compute amino acid scores for each and every food you eat since in western countries protein quality is not a problem at all... other food components IN that protein.containing food are the problem. (having said this I would definitely not recommend you to eat 2 steaks a day)

    ..As someone else already said: Bodybuilders feaverishly eat massive ammounts of protein to have weight gain since it seems that protein can have a mild anabolic effect (in some studies). This is, however, just relevant for people spending a lot of time of their lives in the gym and a VERY strict diet (meaning diet times and calories, food compositions etc). You can easily gain muscle if you stick to the recommendations of a normal average diet (ie. the recommendations).

    No healthy western person needs a protein shake a day.

     
  • At 5:53 AM, Anonymous cguttman said…

    Very helpful. Thank you.

    I am not a bodybuilder. I like to improve my LNB, and consume a healthy mix of animal proteins and plant based protein. One of your definitions is not entirely clear to me:

    By "the food to the profile of the amino acids in our own body...", do you mean the amino acids that are *needed* by our body or the amino acids that our body *consists of*?

    And one more:

     > Usually you use 1:1 ratios in these. Its not useful to try to compute  > amino acid scores for each and every food you eat since in western  > countries protein quality is not a problem at all... other food  > components IN that protein.containing food are the problem. (having >  > said this I would definitely not recommend you to eat 2 steaks a day)

    A 1:1 ratio sounds a bit rough. If I make hummus, I dont mix 500grams tahini with 500grams chickpeas. Are you sure that this rule of thumb is reasonable?

    Also, my impression is that "quality of protein" seems to play a role if someone's main nutritional source of protein are grains. In such a case, this someone would ultimately lack essential amino acids, no? Even in western countries?

    Chris

     
  • At 7:08 AM, Anonymous MMu said…

    "cguttman" <4everclev@web.de> schrieb im Newsbeitrag ...

    The amino acids our body consists of are the amino acids our body needs so you won't find much difference there- but to be exact: the amino acids needed by our body as determined by nitrogen balance.

    The reason for combining food is to equal out amino acid profiles. This is a matter of the limiting (lowest) amino acid. In real life (ie not in laboratory conditions) it does not matter if you mix 1:1 , 3:1, 2:1 or 1:2 unless you eat so little of the combined food that even the combination of both is not enough to supply you with the limiting amino acid (the one that is lowest in your combined food). Usually amino acid profiles are picked that complement each other in a (roughly) one to one way. So, yes, this is correct when it comes to figuring out diets.

    I seriously doubt that the main nutritional source for protein are grains for anyone living in western countries. But if someone would *exclusively* eat grains: yes, he will probably develop a lack of essential amino acids (probably lysine which is, if I remember correctly, the limiting amino acid there).

     

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