Faster metabolism: Increasing ATP reserves.

         The “Peatosphere” and the general fitness blogosphere speak of increasing metabolism quite frequently. Peat speaks of it to include mostly ATP production with some uncoupling as beneficial, where as the fitness blogosphere speaks of it as a tool to increase the rate of fat loss, which usually entails a great degree of uncoupling. All of the pathways that have been characterized describe ATP formation from the reassembly of the dephosphorylated ADP molecule with an corresponding inorganic phosphate (Pi).  Thus, speaking of increasing ATP by this process does not increase the cells ATP reserved but rather increases the relative number of ATPs in comparison to the already existing adenine nucleotides. But what if your cells are actually deficient in the raw number of ATP as well ? A true increase in cells ATP reserves would require the uptake of one part adenosine (Ad) molecule for three parts Pi molecules which are the constituents of ATP. Furthermore, it would also require the Pis to attach to adenosinediphosphate (ADP) somewhere along the way. I will try to identify certain mechanism that would enable the transport of Ad and Pi into cells and ones that would facilitate their conversion to ATP. The real world relevance of this to fitness is that the current methods of metabolic enhancement for weight loss rely on uncoupling. This poses significant health risks due to overheating. However, if there were enough ADPs and Pi to generate a high metabolic demand for ATP synthesis (coupled oxidative respiration), then coupled metabolic enhancement could burn enough calories to make a substantial difference. Furthermore, increased ATP reserves might mitigate some of the negative effects of uncouplers, which presumably stem from their ATP depletion, like lethargy and water retention.

            

         Before really delving into the technical details (that I myself have a tentative understanding of), I want to explicate some assumptions and give a basic primer on ATP. ATP is used to “give” energy to intracellular enzymes by donating them a Pi. Once it does this, it turns into ADP. Most of this happens outside of the mitochondria. Later, both the ADP and the Pi (which is recovered from the enzyme that it is attached to, by other enzymes) return to the mitochondria to make ATP again. The formation of ATP from Pi and ADP is what requires energy from food. I think that people can vary on the amount of ATP that they have in their body. Throughout this text, I will refer to this as ATP reserves. Another assumption is that ATP reserves can be increased. Thirdly, increased ATP reserves, up to the point where they would lead to the fastest intracellular ADP and Pi formation rate, would be a metabolism increasing factor. This is because intramitochondrial ADP stimulates the oxidative respiration, by increasing the activity of the Isocitrate dehydrogenase enzyme¹³. Essentially, ADP signals the mitochondria to generate ATP, which is equivalent to the mitochondria “burning” calories from food.

            

          The first constituent factor that I will address is adenosine. Ad, uptake seems to be triggered by activity of the adenosine receptor and the relationship between the two seems to be mediated by potassium channels^1, at least in rat liver cells.  In their experiment, Duflot et al. saw that an adenosine receptor agonist increased the rate at which the adenosine transporter transferred adenosine to the interior of the cell¹. This suggest that there is a signaling mechanism between the receptor and the transporter which enables the cell to “know” that there is “adenosine to be gathered” from the surroundings. Interestingly, they also found that the signaling between the receptor and the transporter was mediated by ATP dependent potassium channels. Chemicals that increased the potassium channel activity increased the activity of the transporter even when the receptor was not activated by adenosine, and furthermore, further activating the receptor did not increase the activity of the transporter when an independent chemical already opened the potassium channel.  This implies that the direct regulator of adenosine transport is the potassium channel. But the channel is conveniently linked to the adenosine receptor so that the transporter can be activated when adenosine is around. Another interesting part of the experiments was that excess glucose inhibited adenosine transport. This is a very important point that I will come back to later. So based on the above, if the adenosine uptake mechanisms of most human tissues is similar to that of rat liver cells (which I know is a big assumption) than consuming foods that have the raw materials to synthesize adenosine and making sure that our potassium channels are not blocked would increase our likelihood of increasing intracellular adenosine. Adenosine receptor agonists would help as well. Lestan and collogues did a study supporting the underlying rationale that increasing Ad would improve ATP reserves.  He and his colleagues noted that the introduction of betahyroxybutrate (BHOB, a type of ketone body) diminished the amount of ATP degradation products measured from plasma under the effect of ATP degradation agents. They interpreted this as BHOB increasing the rate of ATP resynthesis.

            

          Adenosine is a purine and the liver is the primary site of purine synthesis².  The cofactors necessary for purine synthesis are, glutamine, cysteine, CO₂ aspartate and formyltetrahydrofolate³. Glutamine, cysteine and aspartate are amino acids that can be obtained from animal protein consumption and CO₂ is a byproduct of mitochondrial respiration, which can be obtained from uncoupled mitochondrial activity as well. Formyltetrahydorfolate is a dihydrofolic acid (vitamin B9) derivative from what I understand is itself a folic acid derivative.

          

           Given all of this, a tentative course of action presents itself regarding how to increase adenosine production.  Eat protein and supplement with protein sources that would supply the necessary amino acids, get adequate folate and find a way of increasing CO₂.

            

           The last bit is a little less straightforward. Respiration itself increases CO₂ but any factor preventing ATP formation as a result of respiration has an inhibitory effect on the whole (coupled respiration) process⁴. Therefore, as long as respiration is coupled to ATP synthesis, the creation of CO₂ depends on the existence of the very substrates we are tying to increase. A way around this might be using respiratory uncouplers in order to free CO₂ formation from the restraints of ATP formation. Ray Peat claims that CO₂ production increases when respiration is uncoupled⁴. Carbonic anhydrase inhibitors, bicarbonate supplementation and regular bag breathing and breath holding exercises may help as well. Here, the point is not to use uncouplers to the point where one is feeling a discomfort from the increased heat production but is rather comfortably warm.

            

             To make sure that the adenosine enters cells, consuming MCT oil might be particularly effective on the account that it gets metabolized to ketone bodies more efficiently than any other food substance, and there is evidence to suggest that ketone bodies stimulate adenosine receptors⁶.

            

              But adenine nucleotides consist of phosphate as well so in order to increase the total adenine nucleotide and particularly ATP reserves, we have to increase the amount of intracellular Pi alongside adenosine as well. There is evidence to suggest that Pi transport into cells is at least partially dependent on insulin⁷. Poglreen et al. showed that insulin stimulated Na dependent Pi influx into rat muscle cells and myoblasts in vitro. Petersen and colleagues’ finding that the children of insulin resistant parents had lower insulin stimulated ATP synthesis and a concomitant lower phosphate transport into cells⁸ supports Polgreen’s findings.  The study done by Nishi et al. impaired the phosphate transport capacity of rat insulinoma mitochondria and found that doing so reduced their glucose induced ATP production⁸. Thus, it seems that insulin promotes phosphate transport into cells and phosphate is one of the regulatory factors in the formation of ATP. A stronger support to this notion comes from Johnson et al. who has found that ATP degradation agents increase ATP degradation products in the blood of Pi depleted people but not in Pi repleted people¹⁴. This suggests that the higher blood Pi stimulated the reformation of ATP from the breakdown products of the degradation agent.

            

               The most significant practical implication of this is that having some form of insulinogenic food would aid in the formation of ATP by driving phosphate into cells.  Thus, despite the adenosine promoting effects of ketones, reaching ketosis through carb and protein starvation could oppose the effects of increased adenosine into cells.  This is another support for producing ketone bodies through MTC oil instead of severe carb restriction. Furthermore, either MCTs, ketone bodies or both are insulinogenic so carbs can still be restricted if it is desired. It seems that phosphate is ubiquitous in food so getting enough of it does not seem to be a problem but just as a note, animal foods seem to be particularly rich in it. Supplementation might be beneficial for some as well.

          

                I want to come back to MCT oil and ketone bodies for a minute. First of all burning ketones and burning fats are not the same thing. Ketones are produced when fats are incompletely oxidized by the liver and ketone burning by peripheral tissues occurs when the said ketones are used by peripheral tissues as fuel. Since insulin drives blood lipids into fat or muscle cells (depending on the rate of muscular activity) and prevents the liberation of fatty acids from fat cells, carbohydrates tend to counteract ketone production. What is useful about MCT oil in this case is that it gets shuttled directly to the liver through the portal vein instead of going into the blood stream through chylomicrons first^10,12. This means that they reach the liver before they enter general circulation. So insulin is bound to have less of an effect on them, if any. The fact that MCTs hit the liver first might allow for more carbohydrates while still producing ketones at a beneficial amount. According to Peter Attia MD. , ketone bodies also produce more ATP per carbon in their backbone and per oxygen consumed¹¹. He does not give an explicit reference for this claim but he seems to be very knowledgeable about ketones so I trust his claim. This maybe another reason why they might be particularly useful fuel sources for people who are metabolically compromised. People who have low metabolisms most likely have low tissue CO₂ concentrations. Since CO₂ is a potent oxygen releaser, people with low metabolisms might be hypoxic as well. The use of ketone bodies for fuel might side step the hypoxia induced barrier to ATP production. An additional reason that this is useful is that once adenosine is inside the cell, it gets phosphorylated by ATP into AMP to be added to the adenine nucleotide pool. Also, the ADP and Pi that is outside the mitochondria is transferred into the mitochondria by being exchanged with intramitochondrial ATP, so having as much ATP at hand as you can is conducive to increasing total ATP reserves.

            

               Before giving a complete practical summary, I want to draw attention to a few things. Firstly, I don’t believe that Pi transport into cells can be entirely dependent on insulin. This would not make sense since fat ultimately ends up becoming ATP as well, which means that it would have to correlate with plasma to cell Pi transport as well since it creates a demand for intramitochondrial Pi.  If Pi transport were entirely insulin dependent extremely low carb diets would not be feasible. Another thing to note is that the excess sugar seemed to prevent adenosine transport in Duflot’s experiment. This suggests that carbohydrate limitation may be conducive to increasing intracellular adenosine reserves. Another point to consider is that the cells in this experiment were isolated and in vitro. Therefore the effects of glucose were not mediated by insulin. Thus the experiment does not make the suggestion that insulin is an inhibitor of adenosine uptake. This means that the insulinogenic foods that would help with Pi transport would not necessarily limit adenosine transport.

           

                 With all that has been said, application is relatively straightforward. Get some urine ketone measurement sticks and consume enough MCT to give you a reading of moderate to large. Up your carb and protein intake to the greatest amount that will still allow you to stay in ketosis. Eat or supplement with proteins that give you the Ad forming amino acids, get some folate and try to increase CO₂. Try to eat phosphate rich food sources or experiment with supplementation and aim to consume them at the same time with insulinogenic foods. At this point some of the more avid Peat followers might have noticed that I am suggesting limiting carb intake, which is sacrilege for some. Yet given how differently people can respond to carbohydrates, the fact that a lot tend to gain weight on Peat, and some actually get worse and that ketone bodies have such a wide variety of benefits, some of which seems to be washed away by excess blood glucose, makes that (tentative) suggestion sensible. And keep in mind, the point is not to induce ketosis through carb starving but to lower carbs to the point where they don’t prevent MCT’s converting to ketone bodies.

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9.Nishi Y, Fujimoto S, Sasaki M et al. Role of mitochondrial phosphate carrier in metabolism–secretion coupling in rat insulinoma cell line INS-1. Biochem J. 2011;435(2):421-430. doi:10.1042/bj20101708.

10.You Y, Ling P, Qu J, Bistrian B. Effects of Medium-Chain Triglycerides, Long-Chain Triglycerides, or 2-Monododecanoin on Fatty Acid Composition in the Portal Vein, Intestinal Lymph, and Systemic Circulation in Rats. Journal of Parenteral and Enteral Nutrition. 2008;32(2):169-175. doi:10.1177/0148607108314758.

11. Attia P. Ketosis – advantaged or misunderstood state? (Part II) - The Eating Academy | Peter Attia, M.D. The Eating Academy | Peter Attia, MD. 2013. Available at: http://eatingacademy.com/nutrition/ketosis-advantaged-or-misunderstood-state-part-ii. Accessed July 16, 2015.

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15. Lestan B, Walden K, Schmaltz S, Spychala J, Fox I. beta-Hydroxybutyrate decreases adenosine triphosphate degradation products in human subjects. - PubMed - NCBI. Ncbinlmnihgov. 2015. Available at: http://www.ncbi.nlm.nih.gov/pubmed/8051483. Accessed July 18, 2015.