In Study 2 a Student's unequal variance t-test with equal SD was used to compare urine βHB concentrations. Additionally, a linear mixed effects model was constructed to estimate partitions of variance in R, using the lme4 and blme packages (Chung et al., 2013; Bates et al., 2015). Feeding state and visit number were fixed effects in this model, and inter-participant variability was a random effect. Inter-participant variability was calculated according to the adjusted generalized R2 metric (as proposed by Nakagawa and Schielzeth, 2013), to partition variance between the fixed effects of feeding, inter-participant variability, and residual variability. The coefficient of variation for βHB Cmax and AUC were calculated using the method of Vangel (1996).
d-βHB was measured immediately on whole blood using a handheld monitor and enzyme-based reagent strips (Precision Xtra, Abbott Diabetes Care, UK). Samples were stored on ice, centrifuged and duplicate plasma aliquots stored at −80°C. All urine passed during the visit was collected, the total volume recorded, and 1 ml aliquots taken, frozen and retained for analysis.
If you are having a weight loss plateau and you’ve been at the same weight for 3 or more weeks, try changing something to get back to that stable weight loss rate, like a ketone supplement. It would be exciting to lose more than that each week, but our bodies don’t adjust to dramatic changes well, and a slower rate of loss leads to more of the weight staying off in the future.
I had heard horror stories about how bad ketone esters tasted (like “rocket fuel”!) so was prepared for the worst. I followed their instructions and drank the contents of the bottle in one gulp, then chased it with a sip of sparkling mineral water. While not the most pleasant aftertaste, the flavor wasn’t any worse than after a shot of well tequila. Within 15 minutes I was already well into therapeutic ketosis, and after 30 minutes my ketone meter displayed a “HI” error message (meaning my level was greater than 8.0 mmol/L)!
Other ingredients: Many of the supplements contain large amounts of caffeine – the supplement we tested from Prüvit contains the same amount as a 16 oz cup of coffee! Some supplements also contain malic acid, which is “known for its ability to increase energy and tolerance to exercise”. This leaves the nagging doubt: if the experiment shows an increase in energy and physical performance, for example, how do we know it is the (expensive) BHB causing the effect and not the (inexpensive) other ingredients?
In addition to the Weir coefficients being potentially off (which impacts EE), the RQ interpretation may be incorrect in the presence of endogenous or exogenous ketones. As a result, the estimation of fat and glucose oxidation may be off (though it’s directionally correct). That said, the current interpretation seems quite plausible—greater fat oxidation when I had to make my ketones; less when I got my ketones for “free.”
Blood glucose concentrations are decreased during both exogenous and endogenous ketosis, although by different mechanisms. During endogenous ketosis, dietary carbohydrate deficit is the underlying cause of low blood glucose, along with reduced hepatic gluconeogenesis and increased ketone production (Cahill et al., 1966). With exogenous ketosis, carbohydrate stores are plentiful, yet ketones appear to lower blood glucose through limiting hepatic gluconeogenesis and increasing peripheral glucose uptake (Mikkelsen et al., 2015). One clinical use of the ketogenic diet is to improve blood glucose control, yet the elevated blood FFA may increase the risk of heart failure (Holloway et al., 2009). Thus, the ability of exogenous ketones to lower blood glucose without elevating blood FFA concentrations could deliver the desired effect of the diet, whilst also decreasing a potential risk.
The table below shows the same measurements and calculations as the above table, but under the test conditions. You’ll note that BHB is higher at the start and falls more rapidly, as does glucose (for reasons I’ll explain below). HR data are almost identical to the control test, but VO2 and VCO2 are both lower. RQ, however, is slightly higher, implying that the reduction in oxygen consumption was greater than the reduction in carbon dioxide production.
If the color is close to the original beige of the test strip, it means there are few if any ketones in your urine and you’ll need to make some dietary tweaks. This may include eating less fat. That’s because if you have doubled down on the healthy fats your body may be rebelling. One way to tell is if you are constipated. If you think this is the case, ratchet back the fats by 50% and see if it makes a difference.
Hypoglycemia: why not to be concerned – Taking exogenous ketones can drive blood glucose levels quite low, but you are not likely to feel the typical symptoms of hypoglycemia. This is because when ketone levels are high enough, they dominate as fuel in the brain; hence, you will feel just fine despite having low blood glucose. A highly-cited study by George Cahill, found elevated ketone levels could protect fasted participants when they were administered insulin to induce hypoglycemia.
Over four visits, participants (n = 15) consumed 1.6 and 3.2 mmol.kg−1 of βHB as KE (141 mg/kg and 282 mg/kg of R-3-hydroxybutyl-R-1,3-hydroxybutyrate) or as KS (KetoForce, KetoSports, USA) sodium and potassium βHB, containing 1.6–3.2 g of each cation), plus 6 g of sweetener containing 19 kCal (4 g of carbohydrate) (Symrise, Holzminden, Germany), diluted to 300 ml using water. Drink blinding was not possible due to unmaskable differences in taste (bitter vs. salty).
One monk, for example, set out to do a 40 day fast with medical supervision while maintaining his daily activities in the monastery. After 36 days, the medical professionals had to step in due to “profound weakness” and low blood pressure when standing. Although the monk fasted for 15 days longer than Ghandi, the medical professionals were able to stop the fast in time so that he could recover.
Most supplements rely on BHB as the source of their exogenous ketone bodies. BHB is converted to acetoacetic acid with a small quantity converted to acetone through a acetoacetate decarboxylase waste pathway. Some of the acetoacetic acid will enter the energy pathway using beta-ketothialase, which converts acetoacetic acid to two Acetyl-CoA molecules (see diagram below2).
BS, KC, and PC designed the research studies. BS, PC, RE, SM, and PS carried out the studies. SH provided the gas analyser used in the study on behalf of NTT DOCOMO Inc. BS, MS, and SM analyzed the data and performed statistical analysis in collaboration with JM. BS wrote the paper with help from KC, PC, and OF. KC had primary responsibility for final content. All authors read and approved the final manuscript.
Interestingly, poly-BOHB has recently been reported to have important roles in mammalian mitochondrial membranes, cell membrane calcium channels, and in exotic functions like protein folding (Dedkova 2014). It exists in a variety of chain lengths, ranging from short to very long. It is not clear if humans can digest and use poly-BOHB consumed in the diet, but in animals, poly-BOHB appears to have probiotic and bowel protective functions. This is a rapidly evolving topic that we will be watching closely.
To determine the reason for the differences in blood d-βHB concentration, the KE and KS drinks were analyzed for enantiomeric purity. The KE contained >99% of the d-isoform, whereas ~50% of the KS βHB was the l-isoform (Figure (Figure1D).1D). Plasma samples from participants who consumed the high dose KS drink (n = 5) were analyzed to reveal higher l-βHB than d-βHB, the total βHB Cmax being 3.4 ± 0.2 mM (Figure (Figure1E),1E), with a total βHB AUC of 549 ± 19 mmol.min. After 4 h, plasma l-βHB remained elevated at 1.9 ± 0.2 mM; differences in urinary excretion of the two isoforms could not explain this observation as both d- and l-βHB were excreted in proportion to their blood AUCs (Figure (Figure1F).1F). Therefore, in order to determine the time required for l-βHB elimination, a follow-up experiment was undertaken in which subjects (n = 5) consumed 3.2 mmol.kg−1 of βHB as KE and KS with hourly blood and breath sample collection up to 4 h, plus additional samples at 8 h and 24 h post-drink. l-βHB was found to be 1.1 ± 0.1 mM at 4 h, and 0.7 ± 0.2 mM after 8 h, but undetectable after 24 h (Figure 1G). Low amounts of d-βHB (0.3 ± 0.1 mM) were present at 24 h, presumably due to endogenous production. Both ketone drinks significantly increased breath acetone concentration, but at a slower rate than blood d-βHB, reaching a peak after 3 h that was twice as high following the KE (87 ± 9 ppm) than the KS (44 ± 10 ppm), suggesting that d-βHB was readily converted to acetone, but l-βHB was not (p < 0.005, Figure Figure1H1H).
Not everything is perfect with Ketōnd, so there are a few things you should know. One is that it is extremely powerful. The company is pretty adamant about taking the correct dosage - and they are right. This isn't your typical ketone supplement. I'd recommend starting off at half a scoop, even if you are used to taking a different ketone supplement. Odds are if you have your product was underdosed. So, it’s kind of a pain to remember all the time, but once you feel good with the half serving then you can work your way up to a full scoop. If you think it is too strong for you – just take one serving a day, not two, and you will be okay.
Remember how important it is to measure ketone blood levels accurately? Same goes for food tracking. A food tracking app, like MyFitnessPal, provides insight into macronutrient intake and thus the ability to tweak the diet to achieve ketosis. Tracking diet (inputs) and measuring ketones levels (outputs) delivers the best shot at optimizing the keto diet plan.
Let’s briefly discuss some organic chemistry. Two molecules that are “the same” but mirror images of each other (like your hands) are known as enantiomers, a type of spatial isomer. Beta hydroxybutyrate comes in two forms, D-β-hydroxybutyrate (“right-handed”) and L-β-hydroxybutyrate (“left-handed”). D-β-hydroxybutyrate is the form that is naturally produced in the body and is most bioavailable when taken exogenously.
Of course, there may be some people who choose to take these supplements because they genuinely do feel they benefit from them. This is of course your choice and this article in no way aims to shame or criticize anybody. However, I do think that, for most people, eating a low-carb diet based on real foods is a lot more likely to be associated with the benefits that the supplements claim to provide than the supplements themselves.
Background and aims: Currently there is considerable interest in ketone metabolism owing to recently reported benefits of ketosis for human health. Traditionally, ketosis has been achieved by following a high-fat, low-carbohydrate “ketogenic” diet, but adherence to such diets can be difficult. An alternative way to increase blood D-β-hydroxybutyrate (D-βHB) concentrations is ketone drinks, but the metabolic effects of exogenous ketones are relatively unknown. Here, healthy human volunteers took part in three randomized metabolic studies of drinks containing a ketone ester (KE); (R)-3-hydroxybutyl (R)-3-hydroxybutyrate, or ketone salts (KS); sodium plus potassium βHB.
I also concluded that post by discussing the possibility of testing this (theoretical) idea in a real person, with the help of exogenous (i.e., synthetic) ketones. I have seen this effect in (unpublished) data in world class athletes not on a ketogenic diet who have supplemented with exogenous ketones (more on that, below). Case after case showed a small, but significant increase in sub-threshold performance (as an example, efforts longer than about 4 minutes all-out).
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