Protein Cycling Diet: 14

Anti-Oxidants

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Abstract

Chapter 14
The meaning of the term “anti-oxidant”

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Anti-Oxidants

In chemistry, oxidation is any chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent, often but not necessarily oxygen. Oxidation reactions can produce so-called free radicals, the reactive oxygen species ROS mentioned previously (also some reactive nitrogen species). Bearing an unpaired electron, these radicals can readily attack and destroy other molecules in the cell. Anti-oxidants are substances that remove free radicals. They do this by being oxidized themselves. In this sense, anything that a free radical can oxidize can be called an anti-oxidant. Note that this does not mean that a given anti-oxidant is beneficial because it is an anti-oxidant. Likely over half of biological compounds can be considered as anti-oxidants but only in the same sense as books and antique furniture can be considered fuel for a fireplace; their true role in the cell lies elsewhere. Controlled free radical production is necessary to many cellular enzymatic reactions and an over-zealous anti-oxidant could be poisonous. Further some anti-oxidants when oxidized then become a pro-oxidants in some situations; ascorbic acid (vitamin C) is a case in point.

Both inside and outside the cell, anti-oxidant activity is largely mediated through enzymes specific to that function. Anti-oxidation is a tightly controlled process in the cell and the idea that swamping it with small-molecule enzyme-independent anti-oxidants from the diet would be beneficial seems far-fetched.

Higher primates have unusually high levels of anti-oxidant activity compared to other mammals. Concurrent with the loss of the ability to synthesize ascorbic acid they have lost the ability to degrade uric acid. Uric acid is thus present in high levels in human serum where it acts as a highly-effective anti-oxidant. Indeed humans could be considered saturated in anti-oxidant potential compare to say mice and dietary supplementation beyond overt deficiency levels likely has little affect on health outcomes and explains why promising mouse studies on anti-oxidants invariably fail when performed on humans.The point of this discussion is to argue that measures to prevent ROS damage in the first place, most popularly currently by anti-oxidant supplementation, are not likely to be effective whereas measures to enhance clean-up of the damage afterwards such as provided by autophagy are more promising. In fact many of the substances touted as anti-oxidants more likely produce their benefits by enhancing autophagy; resveratrol, for instance. One issue that clouds all the studies is that ROS provokes a general response in the cell including anti-oxidant production and autophagy. In fact a lot of substances described as anti-oxidants are really just ROS mimics that provoke this response or even pro-oxidants that generate some ROS themselves that then provokes it (exercise for example). In the same way as a vaccine provokes an immune response, some level of ROS stress may needed to provoke the cell to a proper level of anti-oxidant activity and extinguishing it with exotic antioxidants could be counter-productive.

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6 Comments

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  1. Steve

    In Chapter 10, you wrote: “As becomes apparent, all staple foods have a protein percentage much greater than the 4% actually needed for protein synthesis by the body.” Your writing is peppered with “percentage of calories from protein”. Is the actual intake of grams of protein irrelevant??? So if the percentage of calories from protein in someone’s diet is 3%, but they are consuming 100 grams of protein at the same time, does autophagy still ensue?

    • remignery

      The 4% is premised on a steady weight diet. 100g protein = 400 calories. If 400 calories is 3% of total then you are consuming (400/.03) = 13,333 calories! You must weigh (170/2700)*13,333 = 840 lbs as a normally fit and active male for that to be a steady weight diet. In that most unusual case even 100 g protein would not meet your anabolic needs and autophagy would indeed be expected.

  2. Steve

    I think you have a typographical error in your book.
    From Chapter 13: “Lysine in rice protein, for example, is present in only 64% of the proportion needed for human protein synthesis. We then say its availabilityis 64%. Yet if you met your calorie requirements with rice alone, you would still get 256% of your lysine needs.”
    That should read: 256% of your PROTEIN needs.

    • remignery

      If lysine is limiting then your protein needs and your lysine needs are identical. The 256% value is, however, a miscalculation. 8% of rice calories are from protein. If your daily intake is 2700 calories and you ate only rice, you would get 8% of 2700 or 216 calories worth of rice protein or (216/4) = 54g protein. 216 calories from rice at 4 calories/g = 54g total protein. At 64% availability that is (54 *.64) = 34.6g usable protein or (34.6/25) = 138% of your protein needs. I will update accordingly.

  3. Steve

    My use of the Protein Cycling Diet is being predicated on the following manner of calculating the limiting amino acid percentage. I’m assuming it is correct! You would think that the first few pages of a Google search on the subject would describe the “how to” part. It doesn’t; an indication of how esoteric this subject is. Never mind the ideas that underpin your book.

    So if I go to cronometerdotcom and enter 2500 calories of cooked rice, it shows the following: weight – 1,923.08 grams; protein – 51.7 grams; calories from protein – 7.9%; lysine – 61%. Looking at all the essential amino acids, the lowest percentage is lysine. Is that the method for how to determine the limiting amino acid of a food? Select whichever essential amino acid percentage is less than 100%?

    To give another example, bananas. Going to cronometerdotcom, I enter 2500 calories of bananas. It shows the following: weight – 2,808.99 grams; protein – 30.6 grams; calories from protein – 4.1%; lysine – 46%. Is lysine at 46% the limiting amino acid for banana?

    And if I entered a dozen foods, consumed throughout the day, into cronometer. If at the end of the day, for those 12 foods, it showed isoleucine as being the essential amino acid with the lowest percentage at, say, 75%. Then would one say that isoleucine, at 75%, was the limiting amino acid for that day?

    To close, as I know you have a day job :), you make no mention of amino acid pools in the body. With straight caloric restriction, I’d imagine the pool is quickly depleted. The following paper gives these approximate datapoints: 86.5 grams in muscle pool of amino acids, of which 8.4% are essential amino acids, or 7.3 grams.
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3854183/

  4. Steve

    In Chapter 13, on Lysine and Methionine, you wrote: “Modern corn has often been genetically enhanced to produce more lysine and tryptophan so exploiting the limiting amino acids in corn can no longer be done reliably.”

    The last time that you revised your e-book was about five years ago. Does this chapter need to be re-written with regards to the starches that you list and their limiting amino acids? What you are saying is that one can’t rely on the promulgated values for amino acids in modern, comprehensive nutrient databases.

    Cronometer predominantly uses the data from the University of Minnesota Nutrition Coordinating Center Food and Nutrient Database. It’s more comprehensive than what the USDA has. http://www.ncc.umn.edu/products/comparison/

    I hardly eat any corn, but I’d rather not purposely avoid something if it’s not necessary. From a former Bostonian to a current Bostonian, what say you? Steve

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