Science buffs and medical staff help me figure this out please!
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Cheesy567
Posts: 1,186 Member
What happens in terms of metabolic acidosis/ alkalosis with LCHF? Ketosis is a metabolic acidosis, right? A respiratory compensation is expected?
(I hated this aspect of medicine, I might have it completely backwards and would appreciate correction if needed!)
(I hated this aspect of medicine, I might have it completely backwards and would appreciate correction if needed!)
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Sorry, I'm not the best to answer your question (lurker with limited knowledge, but no one answered yet!), however I do know a little about metabolic acidosis, and ketosis is definitely NOT metabolic acidosis. You get to acidosis when your acid-base buffering system is overwhelmed, a medical emergency most often seen in diabetics with prolonged hyperglycemia.
You would expect a respiratory compensation if you were in acidosis (increased breath rate to blow off CO2...I think!).
Acid-base balance is a tricky concept, I'm still shaky on it after 24 years of nursing!1 -
Ditto on the limited knowledge aspect. I'm a nurse too, not a doc or a scientist. Respiratory acidosis or alkalosis occurs when the body isn't exchanging enough or too much O2 and/or CO2. It has nothing to do with ketosis. People with COPD can't exchange gasses properly and retain CO2 for example.
and everything @macybean said0 -
Ketoacids do get buffered in an effort to maintain blood pH. The degree of acidosis depends on the level of ketones and the degree of buffer exhaustion.
Levels are defined here:
http://emedicine.medscape.com/article/118361-workup
While definitions vary, mild DKA can be categorized by a pH level of 7.25-7.3 and a serum bicarbonate level between 15-18 mEq/L; moderate DKA can be categorized by a pH between 7.0-7.24 and a serum bicarbonate level of 10 to less than 15 mEq/L; and severe DKA has a pH less than 7.0 and bicarbonate less than 10 mEq/L.[12] In mild DKA, anion gap is greater than 10 and in moderate or severe DKA the anion gap is greater than 12.
I don't know at what point respiratory compensation would kick in, but @Sunny_Bunny_ has experience with T1D and DKA.0 -
I think this is where it gets so confusing @wabmester. You're posting levels of blood pH for DKA. Ketosis is not DKA. Yes, ketones are acidic and are buffered, but buffered means that your blood pH is stable, not acidotic. In ketosis your blood pH should be normal, right? Hence, the answer to the original question (ketosis is metabolic acidosis?) is no, right?
Not trying to be argumentative, just curious as I think DKA and ketosis are confused with each other! And in my experience in the ER is that metabolic acidosis is life threatening (and respiratory compensation is immediate once blood pH starts to drop). Ketosis is beneficial. Hard to wrap my head around all of this...0 -
It's a spectrum, as that definition I referenced shows. As you say, ketones are acids, and your body has to respond to the acid load, even at lower concentrations typical of nutritional ketosis.
But I would think respiratory compensation would mostly kick in during alkalosis, not acidosis. Increased respiration would decrease CO2, and we'd want increased CO2 for acidosis. Holding your breath might help.
Edit:
FWIW, here's a case report of ketoacidosis caused by low-carb:
https://www.ncbi.nlm.nih.gov/pubmed/264280830 -
CO2 is acidotic, so we increase respirations to bring pH back to normal (which is what we'll do if you're on a ventilator, increase your respiratory rate). Holding your breath would increase CO2, increasing acidosis.
Respiratory compensation in alkalosis would slow down the rate of breathing.
Again, ketones are acidic, but acidosis is a state of decompensation. How can ketosis be a state of decompensation? Blood pH is normal in ketosis, correct? Now I'm more confused than ever!! I knew I shouldn't have tried to figure it out.0 -
Oops, you're right on CO2. I was thinking it would be conserved to build bicarbonate buffer.
https://en.wikipedia.org/wiki/Bicarbonate
70–75% of CO2 in the body is converted into carbonic acid (H2CO3), which can quickly turn into bicarbonate.
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Thanks...I thought my brain was failing me!! It does often enough...0
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It's a spectrum, as that definition I referenced shows. As you say, ketones are acids, and your body has to respond to the acid load, even at lower concentrations typical of nutritional ketosis.
But I would think respiratory compensation would mostly kick in during alkalosis, not acidosis. Increased respiration would decrease CO2, and we'd want increased CO2 for acidosis. Holding your breath might help.
Edit:
FWIW, here's a case report of ketoacidosis caused by low-carb:
https://www.ncbi.nlm.nih.gov/pubmed/26428083
It's my opinion that the referenced patients' acidotic state was a result of blood concentration of the acids due to severe dehydration.
"However, to the best of our knowledge this is the first reported case in the literature of ketoacidosis, in a non-diabetic patient, associated with a combination of low carbohydrate, high fat diet and lactation.
CASE PRESENTATION: A healthy non-diabetic, 32-year old white woman started a low carbohydrate, high fat diet when she was breastfeeding her son of 10 months of age. After 10 days she was admitted to our hospital with nausea and vomiting and a serum pH of 7.20 and base excess of -19"
She was only 10 days in, breast feeding a baby and what do you want to bet she wasn't drinking enough water or getting enough salt?!?!
DKA like what happens in T1D is only possible when there is no insulin. This lady had insulin. What she didn't have was any fluid by which she could rid her body of the excess ketones so they built up and created acidic blood. I have no idea how she even allowed that to happen because in my experience with my daughter, she can't get enough water! It's like she can't get enough water fast enough. If I stuck a garden hose in her mouth she wouldn't think it was enough! I don't understand how this person didn't feel insanely thirsty! It makes absolutely no sense to me.
As far as respiratory rate in DKA, have you seen a dog panting on a hot day after a run? That's how it looks. This happens fairly early on too. I could always tell when my daughter had progressed so far into DKA that I couldn't bring her back without a stay in ICU by the severity of her panting. It starts out with heavy, labored breathing and the telltale fruity smell. If we can't blood sugar down then it just progresses until she's panting at a fast rate and then the pain all through the body starts. At that point I know it's progressed too far and sodium and potassium levels are too low for us to wait any longer and a trip to the ER is unavoidable. You get quick service when you walk in and say you're a T1D in DKA though!
Here are the first tests upon her last hospitalization for DKA if you're curious about numbers.
This one was done since going low carb and starting insulin pump, but she was only about 8 days in when this was done.
I see the CO2 is 25 but, a test from last September showed it was 25 also so it seems that low carb had no effect on that 8 days in.
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CO2 is acidotic, so we increase respirations to bring pH back to normal (which is what we'll do if you're on a ventilator, increase your respiratory rate). Holding your breath would increase CO2, increasing acidosis.
Respiratory compensation in alkalosis would slow down the rate of breathing.
Again, ketones are acidic, but acidosis is a state of decompensation. How can ketosis be a state of decompensation? Blood pH is normal in ketosis, correct? Now I'm more confused than ever!! I knew I shouldn't have tried to figure it out.
The pH would stay normal as long as your body is compensating well, right? You wouldn't cross-over into acidosis until your compensatory mechanisms are over-burdened, such as in a severe dietetic keto-acidosis.
My original question was more of the compensating type, not as severe as DKA.
I have a muscle disease (MG) that causes weakness with repeated muscle use, including the diaphragm and rib muscles. Back in Feb, when I was admitted with respiratory weakness (in this disease it causes "panting" because the muscles are too weak to take a deep breath), I had high ketones in the urine, and a mild shift in pH. Probably due to a combination of LCHF, and maybe dehydration due to swallowing weakness.
Last week I had more breathing issues, but the muscle strength was adequate to avoid respiratory support and didn't explain it all. I was in deeper ketosis than usual because of swallowing issues again. I was hypothesizing that the increased respiratory rate from ketosis (which you guys probably don't notice because your body just does it) was causing some respiratory weakness/ fatigue. I.e. let's say that ketosis causes us to breathe 2-4 extra breaths a minute to blow-off the ketones. Well, was that too taxing for the MG and causing my rib cage to feel fatigued and overworked, like the week before the crisis in Feb? Didn't check a blood gas this time, though, since my breathing strength tests were adequate at avoid needing respiratory support, so I don't know what the pH or base excess was. The bicarbonate was slightly low, and the anion gap was high normal range. So, unlikely I had crossed over into true acidosis.
After two days of feeling breathless and uncomfortable, unable to relax enough to sleep, I decided to do an n-of-one study and break ketosis. About an hour later my respiratory rate had calmed down, and I was able to sleep. Seemed to help. Since then I increased my daily carbs and I've been toying with the timing of them to avoid dips into a deep ketosis.
Oh yeah, and ramping up the treatment of the MG, too
. Always best to treat the source. 0
