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Fixated on nitrogen

  1. Sep 28, 2014 #1
    There has to be a way around the nitrogen fixation issue with humans - it can't be the case, as so thoroughly stated everywhere, where we have to consume nitrogen in foods (amino acids?) in order to satisfy our nitrogen needs. Is there any outside the box thinking, any super sleuths with a better understanding than the usual wiki pedia posters, that would disprove this mandate (of sorts) - or at least show other ways in which the human body can work around or get around conventional means of procuring needed nitrogen. Perhaps from within.
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  3. Sep 29, 2014 #2


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    Why? (and it is a very serious question).
  4. Sep 29, 2014 #3
    Not sure what your 'why' is referring to. ?? Perhaps you mean why do we need a way around N fixation? The genesis of my query has to do with the essential amino acids and why we think they are essential. And too that, the only study that I know of is Dr Rose's done some 70 years ago - with sketchy parameters and even sketchier results. Was wondering if there were any new studies with the latest technologies and current chemistry minds that could corroborate, or disclaim, or make better sense of such a study.
    Basically, many every species can or cannot make something; a protein, a vitamin, or an amino acids say - and they are fine - they are not supplementing their diets to compensate for their natural (?) inability to synthesize one nutrient or another. Some species used to be able to make vitamin C - and at some point over time they stopped. But, they didn't switch up their respective diets say to then include oranges or kiwis etc. Their diets remained the same - and they remained fine. So too with humans.
  5. Sep 29, 2014 #4


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    If the supply of the needed nutrient (whatever it is) in the diet is sufficient, losing ability to synthesize won't have any effect, so there is no need to change the diet. So I don't see why your original statement

    should be true. We have no need to fixate nitrogen by ourselves, just like have no need to photosynthesize.

    Question about research on essential amino acids is a separate problem.
  6. Sep 29, 2014 #5
    The reason I linked the two questions/issues is because Dr Rose stated that if we deprived the body of an essential amino acids (an essential nutrient) there would be consequences - I don't see any consequences.
    Also, we have so many things, nutrients, in excess supply from our diets, yet the body doesn't stop synthesizing it, or lose the ability to do so.
    I guess another point I am trying to get at is, people constantly say that we need to have all the essentials because humans can't fixate nitrogen. One, i say we can, just not in the manner we think - there are other metabolic pathways, means to the same ends (the derivative nature of amino acids), and two, if we can't, we don't need to. We don't need to infuse in our diets any of the essential amino acids. Or nitrogen - and so long as we have trillions of gut flora bacteria we will have nitrogen. ??
    Just like with vitamin C, our bodies have figured out other means to get the same results - humans’ biological systems have responded to this “error”, this defect (of pseudogenes?), and we are just fine. "[Through evolution], we've created this system that takes out the oxidized form of vitamin C and transports the essential, antioxidant form.
    It is in this vain that I question the essential amino acids and the N fixation dynamic.
  7. Sep 29, 2014 #6
    And our bodies still do photosynthesize. It is an essential part of our being, our existence.
  8. Sep 29, 2014 #7


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    No idea what you are talking about.

    Not being a biologist the only sure example I can think of, that says your statement

    is incorrect, is not related to amino acid, but to vitamin C. Lack of vitamin C is killing, please read about scurvy.

    I am not aware of any research done of deprivation of humans of amino acids to find which if the are essential, but I also can't think of a way of doing such a research without putting research subjects at risk. We don't do test on humans.

    Do you have any reference for that?
  9. Sep 29, 2014 #8


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    I'm also a bit confused as there seem to be multiple questions rolled into one here. Firstly the issue of why you think that we must be able to fix nitrogen. I don't understand this, why do you think that humans must inherently be able to fix our own nitrogen when we evidently do not need to? Nitrogen fixing bacteria are common enough to allow access to ample nitrogen for plants. We eat these plants or animals that eat them thus what do we need to fix our own for? Regarding vitamin C there is a lot of literature on the loss of vitamin C synthesis. In short a series of mutations in the gulonolactone oxidase gene prevents its expression which in turn prevents the conversion l-gulono-g-lactone into vitamin C. You might think this would be a negative thing and that an organism born with such mutations would not be ad a disadvantage compared to its peers but because vitamin C is easy to obtain through human diet there is no disadvantage. Consequently the mutation is free to spread.

    Regarding not having consequences for essential amino acid deficiency there certainly are consequences. You can do a pubmed search on the subject and find plenty of papers looking into the underlying mechanisms and use of supplements in disease treatment. When you say you don't "see" any consequences what do you mean? Do you have references to peer-reviewed studies that refute the idea of essential amino acids or have you simply not found any of the studies that look into them?

    Lastly humans do not photosynthesise. Photosynthesis is the process where by light energy is converted into stored chemical energy. Whilst humans do utilise light for various metabolic processes (such as UV for vitamin D synthesis in the skin) this is not photosynthesis.
  10. Sep 29, 2014 #9


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    The OP must not like eating peanuts or PB & J sammiches, consuming legumes, synthesizing proteins, metabolism, etc.

    The proteins in our bodies are all composed of different amino acids linked together according to a template which is stored in our DNA, and the actual synthesis of proteins is carried out by RNA. The 20-odd amino acids are 'essential' in that respect: without it, out bodies could not grow or heal.

    Even legumes which are not normally consumed by humans are often cultivated because they can fix nitrogen in the soil and make it more fertile for growing other, edible crops. This was how soil was kept from being depleted of plant nutrients before the invention of chemical fertilizers: a patch of legumes would be grown one season and then different crops would be grown in the same patch of ground in following seasons on a rotation scheme.
  11. Sep 29, 2014 #10
    Borek - Well I appreciate your involvement in trying to help me figure out the nitrogen fixation dynamic (if there are other pathways etc.). If there is anyone out there who specializes in this field I will be grateful for your input. We do tests on humans all the time. The original Essential amino acids test was don't done on university students. Now I agree, in today's worlds we just can't go around willy nilly and testing humans, as they did back then, but there are still trials that exist today on many drugs and procedures etc that involve real life humans.
    And, half jokingly, as long as big pharma puts disclaimers and warnings on each label - there will be testing on humans...
    Vitamin C's link to scurvy is a mistep on wikipedias part which I discuss at length in other forums. Right now my issue is with Nitrogen fixation and the essentials. And there is a vitamin that the sun helps us with. D. Far superior than D supplements.The sun also enables, properly, other natural dynamics within the human body.
  12. Sep 30, 2014 #11


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    The issues about nitrogen fixation and essential amino acids are separate issues. Essential amino acids are not essential for their nitrogen content; rather, they are essential because animals lack the enzymes to build the required carbon skeletons.

    Many amino acids are synthesized from other amino acids or from intermediates of glucose metabolism. For example, in most organisms, lysine, methionine, and threonine are synthesized from aspartate (which itself can by synthesized from glucose). The first step in this process is catalyzed by an enzyme called aspartokinase, which animals lack. Thus, whereas most other species (plants, bacteria, fungi, etc.) can convert sugars into aspartate into lys, met, and thr, animals are incapable of performing these chemical reactions and thus must obtain these three amino acids from their diet. This applies to the other essential amino acids as well.

    Thus, good evidence for the essential amino acids comes from the human genome itself. We know what enzymes are required to synthesize each amino acid, and we can see which of these enzymes are encoded in the human genome. If the human genome lacks many of the enzymes critical for the synthesis of a particular amino acid, the amino acid must be obtained in our diet (the fact that these gene losses are evolutionarily conserved among animals adds further to this point).

    With regard to nitrogen fixation, we know what enzymes are involved in nitrogen fixation in bacteria, and humans lack enzymes that resemble these. We have sequenced the content of our gut microbiome and, although I have not looked at this data in detail, I do not think it contains nitrogen fixing bacteria. You may be interested in reading the following paper (which I found while browsing through the Voet & Voet chapter on amino acid metabolism for this post), which argues that amino acids are the primary source of nitrogen for animals:

    Katagiri and Nakamura. 2002. Animals are dependent on preformed alpha-amino nitrogen as an essential nutrient. Life 53:125. doi:10.1080/15216540211467
    Last edited: Sep 30, 2014
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