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Ketosis During Hibernation

My Thoughts On Low Carb And Paleo Episode 3: A New Hope

My Thoughts On Low Carb And Paleo Episode 3: A New Hope

Really clear, concise and informative post! If people still insist on not “getting” it, know that you have been as pedagogical as is humanly possible and that people, at the end of the day, will have to be responsible for their own reactions. Some reflections based on my own “tinkering”: My first foray into paleo was in 2005. I jumped on board to lose a few vanity lbs (I’ve never been in horrible shape) and for overall health. Unlike many paleo adherents, I’m neither a reformed vegan nor someone who’s had a lot of health issues. My introduction to paleo came as a result of being the co-translator for the Swedish version of Loren Cordain’s The Paleo Diet. The whole thing just made sense to me, and coming from a science background I found the whole premise intriguing. However, when I first discovered paleo, it had yet (at least as far as I was aware) to start overlapping with the whole LC philosophy. As a result, I focused entirely on nutrient density and eliminating the bad stuff. So, I ended up eating starchy tubers more or less freely (no potatoes though) and quite a bit of fruit on top of that. I lost 25 lbs over a four-month period with little effort (I was tiny by the end of it). When I actually bothered to add up the calories I was eating it was never over 1600-1800 kcal (I’m 5’7” and naturally muscular). I almost started worrying that I wasn’t eating enough. The things was, though, that I was hardly ever hungry. The increased satiety, weight loss and stable blood sugar came despite not specifically aiming to reduce carbohydrates. However, I think it’s important to note is that even a so-called high carb paleo diet will usually be lower in carbs than the standard Western diet. Just eliminating refined sugars and grains might be enough to c Continue reading >>

Hibernating Bears 'a Metabolic Marvel'

Hibernating Bears 'a Metabolic Marvel'

For the first time, scientists say they have been able to monitor a bear's vital signs continuously during a six-month period of hibernation. To their surprise, the researchers discovered that despite lowering its metabolism by 75 percent, a hibernating bear's internal temperature barely drops at all. The bear study took place at the University of Alaska, Fairbanks. The bears spent the winter in a hibernaculum — basically a big box. The researchers weren't sure whether the bears would be willing to spend the winter in this small, artificial cave. "We anticipated they might just tear the place up or go on strike or something," says Brian Barnes, one of the authors of the new study. "But they actually showed very natural behavior of getting ready to hibernate. They curl up, they go to sleep. They begin to quiet their heart rate, slow their breathing and their metabolic rate plunges." The fact that a bear could reduce its metabolism so much with such a small drop in temperature was a surprise. Barnes says two factors appear to be responsible. First, a bear has a lot of fat and thick fur, so it is well-insulated. Second, when a bear's internal temperature drops below about 90 degrees Fahrenheit (99 degrees is normal for a bear), it starts to shiver. The shivering produces heat, and the bear's temperature rises a few degrees. This periodic shivering occurs throughout the winter. 'A Closed System' Barnes says just about everything a bear does while hibernating is remarkable. "Bears don't eat, drink, urinate or defecate for six or seven months," he says. They make their own water, probably by metabolizing fat, and they get rid of wastes by breaking them down internally. "They're a closed system. All they need is air, and they can do just fine. They're a metabolic marvel," he Continue reading >>

Ketone Body Metabolism In A Ground Squirrel During Hibernation And Fasting

Ketone Body Metabolism In A Ground Squirrel During Hibernation And Fasting

Hibernating Belding's ground squirrels (Spermophilus beldingi) are ketotic relative to fed nonhibernators. Muscles from torpid individuals, when incubated in media containing physiological concentrations of glucose and ketone, show reduced uptake of glucose in the presence of ketone. The magnitude of the reduction is dependent on ketone concentration and reaches 60% in heart and 100% in pectoralis at 1.4 mM ketone. Fasted squirrels are also ketotic. However, ketone does not reduce glucose uptake in muscles from fed or fasted animals. Glucose utilization by muscles decreases during a long-term fast, but the reduction is independent of ketone. Thus both a long-term fast and hibernation lead to changes in muscle tissues that decrease their reliance on glucose as an energy source. Ketosis leads to glucose sparing during hibernation, whereas muscle glucose utilization is decreased independently of ketone during a fast. The glucose sparing achieved in both hibernation and fasting leads to conservation of body protein, the major source of gluconeogenic precursors in fasting mammals. Grey seal pups (Halichoerus grypus) were collected at the time of weaning (early November) and starved for 31 days at thermoneutrality. During starvation body weight decreased linearly, whereas metabolic rate was stable at 1.58 +/- 0.13 (SD) W X kg-1. Metabolic rate as related to body weight was significantly higher (P less than 0.01) than predicted by Kleiber (The Fire of Life, New York: Kreiger, 1975). Respiratory quotient averaged 0.67 +/- 0.03 during the 1st wk but increased to an average of 0.76 +/- 0.04 during the final week of fasting. Body composition was evaluated three times during starvation by use of computed tomography. The area of blubber and skeletal muscle in three transverse (thora Continue reading >>

Hibernation – How Bears Can Go Without Food And Water For Months

Hibernation – How Bears Can Go Without Food And Water For Months

I was reading on lipid metabolism the other day when I got to a very interesting “fact box” in Lehninger Principles of Biochemistry. The title was “Fat Bears Carry out Beta Oxidation in Their Sleep”. It describes that many animals depend on their fat storage for energy production when they are in hibernation and it says that one of the most pronounced adjustments of fat metabolism occurs in hibernating grizzly bears. Did you know that grizzly bears are in hibernation for as long as 7 months per year? Bears, Hibernation and Beta Oxidation Besides, unlike many hibernating animals, bears are able to keep their body temperature between 32 and 35 degrees Celsius (which is very close to the normal body temperature of 37 degrees Celsius). The caloric daily consumption during hibernation in bears is approximately ~6,000 kcals. Keep in mind that they don’t eat, drink, urinate, and defecate for months at a time. Humans are able to go without food for very long periods of time. However, it would not be wise to do so. According to Lehninger, the sole fuel for grizzly bears in hibernation is their body fat. Through beta-oxidation they are able to yield enough energy for homeostasis, for protein synthesis, as well as for membrane transport (among other processes). The oxidation of fat yields consistent amounts of water that keeps the animal hydrated and it makes up for the loss of water through breathing. They also use the glycerol that is released from degrading TAG (triglycerides) to convert it in glucose through the process called gluconeogenesis (synthesis of glucose). It is very interesting how these bears evolved to reabsorb the urea which results from amino-acid breakdown and use it to make new amino-acids. This helps them to minimize the loss of lean muscle during t Continue reading >>

How Do Bears Hibernate?

How Do Bears Hibernate?

Somewhere near Portsmouth there is probably a bear hibernating. How do bears do that? The first thing to clarify is that hibernating is not sleeping. The brain activity of hibernating animals is like awake brain activity. In fact when they “wake up” from hibernating many mammals show signs of sleep deprivation and may have to sleep more for a few days. These are some things that are known about hibernation in bears.(1) – For as many as 7 months of hibernation bears go without eating, drinking, defecating or urinating, in contrast to chipmunks and other small mammals that get up to do that stuff every week or so. – Bears hibernate at or near normal body temperature, in contrast to the those other small mammals who hibernate with a body temperature near ambient, approaching but not falling below 0°C. – Weight loss in hibernating bears ranges from 16% to 37% of body weight at the start of hibernation. So they will need to put that weight back on before the next hibernation. – Bears conserve lean body mass during hibernation using almost only fat combustion for energy needs. – So fat content at the start of hibernation is 36% to 38% of total weight in black bears and 49% in polar bears and declines proportionate to the decline in body weight. – Blood lipids (cholesterol, triglycerides, and free fatty acids) increase during hibernation, a result of increased combustion and decreased production of fat. – Ketosis which is a sign of fat burning in starving humans does not occur in hibernating bears. – Total body water, blood volume, and water content of plasma and red blood cells do not change during hibernation in black bears. – During hibernation, black bears maintain bone mass and measures of bone formation. In other species undergoing long periods of Continue reading >>

Hibernation Impact On The Catalytic Activities Of The Mitochondrial D-3-hydroxybutyrate Dehydrogenase In Liver And Brain Tissues Of Jerboa (jaculus Orientalis)

Hibernation Impact On The Catalytic Activities Of The Mitochondrial D-3-hydroxybutyrate Dehydrogenase In Liver And Brain Tissues Of Jerboa (jaculus Orientalis)

Abstract Jerboa (Jaculus orientalis) is a deep hibernating rodent native to subdesert highlands. During hibernation, a high level of ketone bodies i.e. acetoacetate (AcAc) and D-3-hydroxybutyrate (BOH) are produced in liver, which are used in brain as energetic fuel. These compounds are bioconverted by mitochondrial D-3-hydroxybutyrate dehydrogenase (BDH) E.C. 1.1.1.30. Here we report, the function and the expression of BDH in terms of catalytic activities, kinetic parameters, levels of protein and mRNA in both tissues i.e brain and liver, in relation to the hibernating process. We found that: 1/ In euthemic jerboa the specific activity in liver is 2.4- and 6.4- fold higher than in brain, respectively for AcAc reduction and for BOH oxidation. The same differences were found in the hibernation state. 2/ In euthermic jerboa, the Michaelis constants, KM BOH and KM NAD+ are different in liver and in brain while KM AcAc, KM NADH and the dissociation constants, KD NAD+and KD NADH are similar. 3/ During prehibernating state, as compared to euthermic state, the liver BDH activity is reduced by half, while kinetic constants are strongly increased except KD NAD+. 4/ During hibernating state, BDH activity is significantly enhanced, moreover, kinetic constants (KM and KD) are strongly modified as compared to the euthermic state; i.e. KD NAD+ in liver and KM AcAc in brain decrease 5 and 3 times respectively, while KD NADH in brain strongly increases up to 5.6 fold. 5/ Both protein content and mRNA level of BDH remain unchanged during the cold adaptation process. These results cumulatively explained and are consistent with the existence of two BDH enzymatic forms in the liver and the brain. The apoenzyme would be subjected to differential conformational folding depending on the hiber Continue reading >>

Best Ketogenic Diet Book For Cancer

Best Ketogenic Diet Book For Cancer

The best Ketogenic Diet Book for Cancer will be available to the public soon. I’m currently completing what will be once published the best ketogenic diet book for cancer available on the market. This book will be a raw vegan ketogenic diet book which comes from decades of firsthand experience helping people heal from cancer. I’m asked often if this vegan keto diet is science based? The answer is yes, it is backed by science big time! My book will be drawn from years of helping people restore their health and go on to thrive. We use this healing diet at An Oasis of Healing, the healing center I founded over a decade ago. A raw vegan ketogenic diet works in harmony with our comprehensive cancer care program. Raw plant based nutrition is key to healing from cancer and works in harmony with the laws of nature. Let’s look at what the word Keto means? Keto also means ketosis or ketones. What is the function of ketosis? Fatty acids allow human beings to store energy. As these fatty acids are separated into different pieces they become fuel for the body. When they are separated even further, they become ketone bodies which consist of three molecules. The ketone bodies are carried into cells and then split apart even more to become pure fuel for the body. This fuel provides the necessary energy for the body. These fatty acids produce twice the amount of energy versus carbs and protein. Fat is nature’s gift to humanity as a result of its capacity for energy storage. Why do you think bears are able to hibernate all winter? They eat a lot and as a result store fat. They then go into hibernation and live off their stored fat. While they hibernate, the bears are in ketosis. The Best Ketogenic Diet Book For Cancer Can Help Reverse This Pandemic There’s a right way and a wro Continue reading >>

Protein And Fat Metabolism In Hibernating Bears.

Protein And Fat Metabolism In Hibernating Bears.

Abstract Hibernation in the bear (Ursus americanus) is unique in that it is continuous for 3 to 7 months and occurs at near normal body temperature, yet the bear does not eat, drink, urinate, or defecate. During hibernation there is no loss of lean body mass because amino acids enter protein synthetic pathways at increased rates producing reciprocal decreases in entry into the urea cycle. The urea that is formed is hydrolyzed and the nitrogen released is combined with glycerol to form amino acids, which reenter protein synthetic pathways. Body fat supplies the substrate for metabolism (400 kilocalories/day). Ketosis does not occur. Metabolic water is sufficient to maintain normal hydration. About 100 ml of urine is filtered daily by the kidneys but the baldder wall transports water and solute back into blood at a rate about equal to their entry into the bladder. The bear cannot duplicate its winter adaptation in summer when housed in the cold and dark. During hibernation the bear shows hypothalamic hypothyroidism and increased testosterone production. These changes appear necessary for developing the selective states of anabolism and catabolism found in the hibernating bear. Continue reading >>

The Biochemistry Of Mammalian Hibernation As A Possible Basis For Therapies

The Biochemistry Of Mammalian Hibernation As A Possible Basis For Therapies

Hi there ! Interesting ! This could turn out helpful, especially the limb/organ regeneration (like geckos/salamanders/lizards cell transdifferentiation to regrow their cut-off limbs/tails...regrow a human arm or leg after losing it. But 'don't lose your head' (pun!) over losing your other limbs (joke)). Regrowing your head would still not stop you from dying from losing it in the first place. It's the regrowing of organs that has me more interested, limbs ok, but organs...that's a whole different thing. If we could regrow/regenerate our organs, except perhaps brain, to the exact same state during youth; that would be a form of rejuvenation. Exceptional cancer resistance by (NMRs) naked mole rats (large hyaluronan molecules, plump skin for hypoxic environment, altered p53-p16-p21 levels and stronger stromal cell barriers that inhibit tumor propagation to other organs) is definitely something we can do with; although, this is mixed stuff. Certain studies showed an actual increase in hyaluronic acid (HA) during human cancers (neoplastic remodelling is what is happening). Inflammation is characterized by higher amount of short-chain/fractured hyaluronan while anti-inflammation in ECM has more long-chained hyaluronan. Still, this is inconclusive, an small and large chain HA have been found during pathological remodelling (like fibrosis). ECM remodelling is complex and cancer neoplasticity ECM remodelling is too; it messes up HA, not like in naked mole rats. I'm not so sure increasing long-chain HA would amount to all that much, in humans, plumper youthful skin, like a naked mole rat, such as in little children or babies would not stop cancer (kigs gets cancers...anyways and have higher HA and plumper skin/tougher organ stromal barriers). Our cell density/organ complexity/siz Continue reading >>

The Ketogenic Diet As The Default Human Diet: An Energy Perspective

The Ketogenic Diet As The Default Human Diet: An Energy Perspective

The conditions under which the liver delivers optimal fuel on demand may be the conditions under which it evolved. When you are on a ketogenic diet, the mitochondria in your cells — the parts of the cells that produce energy — actually switch from primarily using sugar for fuel to primarily using fat for fuel. They use fat mostly in a form called ketone bodies (or, commonly, ketones), thus a ketogenic diet. (See Keto-adaptation: what it is and how to adjust for more on this process of switching fuels.) Sugar-based living (from a diet with more than about 5% calories from carbohydrate) When you are using the sugar-based system, all of the cells in your body constantly take sugar out of your bloodstream. It's hard for your body to keep up, and you need to frequently refuel by eating carbohydrate-containing food. Getting sugar out of the carbohydrates that you eat is a blunt tool. Unless you eat in a trickling stream, you will consume more sugar than is safe to hold in the bloodstream at once. That sugar has to be quickly removed, because high blood sugar damages your cells. So a flood of insulin comes in to initiate the process of sugar removal. There is some limited storage space in the liver, but when that is full, the rest basically gets stored as fat. Soon however, the job is done. Your blood sugar is back in a safe range. Your body cells are still demanding sugar, though, and your blood sugar starts to drop too low. Your liver can release some sugar back into the bloodstream, but not fast enough to keep up with demand, so you get tired and hungry, and the process starts all over. People on carbohydrate-based diets typically have to "snack" every couple of hours. Endurance athletes have to stop and eat sugar just to get through their events. On a sugar-based metab Continue reading >>

In Silico Evidence For Gluconeogenesis From Fatty Acids In Humans

In Silico Evidence For Gluconeogenesis From Fatty Acids In Humans

Abstract The question whether fatty acids can be converted into glucose in humans has a long standing tradition in biochemistry, and the expected answer is “No”. Using recent advances in Systems Biology in the form of large-scale metabolic reconstructions, we reassessed this question by performing a global investigation of a genome-scale human metabolic network, which had been reconstructed on the basis of experimental results. By elementary flux pattern analysis, we found numerous pathways on which gluconeogenesis from fatty acids is feasible in humans. On these pathways, four moles of acetyl-CoA are converted into one mole of glucose and two moles of CO2. Analyzing the detected pathways in detail we found that their energetic requirements potentially limit their capacity. This study has many other biochemical implications: effect of starvation, sports physiology, practically carbohydrate-free diets of inuit, as well as survival of hibernating animals and embryos of egg-laying animals. Moreover, the energetic loss associated to the usage of gluconeogenesis from fatty acids can help explain the efficiency of carbohydrate reduced and ketogenic diets such as the Atkins diet. Author Summary That sugar can be converted into fatty acids in humans is a well-known fact. The question whether the reverse direction, i.e., gluconeogenesis from fatty acids, is also feasible has been a topic of intense debate since the end of the 19th century. With the discovery of the glyoxylate shunt that allows this conversion in some bacteria, plants, fungi and nematodes it has been considered infeasible in humans since the corresponding enzymes could not be detected. However, by this finding only a single route for gluconeogenesis from fatty acids has been ruled out. To address the question Continue reading >>

The Bears Take On Hibernation Biology Essay

The Bears Take On Hibernation Biology Essay

Disclaimer: This essay has been submitted by a student. This is not an example of the work written by our professional essay writers. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of UK Essays. Bears are members of the family Ursidae, there are eight species alive today, with a large geographical range. They are found in North America, South America, Asia and Europe; they occupy a large range of habitats, from the Arctic tundra to temperate forests (Craighead Institute 2010). During winter, bears enter a state of dormancy. Most animal species become dormant to some extent during their lives, as an energy saving mechanism. Sleep is the archetypal form of dormancy, with animals retiring to a nest, assuming a sleep posture, remaining behaviourally quiescent and exhibiting elevated arousal thresholds (Heller et al 2004). A more extreme form of dormancy is torpor. Torpor is characterised by a controlled reduction of body temperature (Tb), metabolic rate, and other physiological functions (Geiser 2004). Torpor has the superficial appearance of sleep, indeed torpor and sleep are believed to be homologous. This has been supported by numerous electroencephalographic (EEG) studies (Heller et al. 2004). There are two basic forms of torpor used by heterothermic animals, hibernation (or prolonged torpor) and daily torpor. Daily torpor is usually not as deep as hibernation, lasts only for hours rather than days or weeks, and is usually interrupted by daily foraging and feeding (Geiser 2004). There is a lack of agreement over whether the winter dormancy of bears constitutes "true" hibernation. Hibernation is defined as "the dormant condition into which many animals and plants pass whe Continue reading >>

Denning And Hibernation Behavior

Denning And Hibernation Behavior

blockquote {border-left: 5px solid #fff;} Hibernation is an adaptation to a seasonal shortage of food, low environmental temperatures, and snow cover on the ground (Craighead and Craighead 1972; Tietje and Ruff 1980). Bears hibernate during the winter months in most areas of the world. Duration of winter denning is dependent upon latitude and varies from a few days or weeks for black bears in Mexico to 6 months or more for bears in Alaska (Kolenosky and Strathearn 1987, Haroldson et al. 2002). The denning period in Yellowstone National Park is approximately 5 months. For many years some people did not consider bears to be true hibernators. Mammals considered true, or deep hibernators, such as chipmunks and ground squirrels, experience a drastic decrease in body temperature during hibernation. Body temperature for hibernating bears remains above 88°F (31°C) which is within 12°F (11°C) of their normal body temperature of 100°–101°F (37.7°–38.3°C) (Bagget 1984). This allows bears to react to danger quicker than hibernators whose body temperature may be less than 40° F (4° C) and who have to warm up before they can move quickly (Bagget 1984). Many scientists now consider bears to be super hibernators. Due to the highly insulating pelts of bears and their lower surface area to mass ratio than smaller hibernators, body heat is lost slowly which enables bears to cut their metabolic rate by 50-60% (Craighead and Craighead 1972; Rogers 1981). Respirations in bears decrease from 6-10 breaths per minute normally, to 1 breath every 45 seconds during hibernation. They experience a drop in heart rate from 40-50 beats per minute during the summer to 8-19 beats per minute during hibernation. Mammals that experience lower body temperatures during hibernation, such as chipm Continue reading >>

Going Low-carb Too Fast May Trigger Thyroid Troubles And Hormone Imbalance

Going Low-carb Too Fast May Trigger Thyroid Troubles And Hormone Imbalance

If you’ve been turned on to the low-carb Paleo diet craze, you may have noticed increased energy, better digestion and happier mood, and a shrinking waist line. Good for you. But some folks who’ve taken the Primal leap—particularly those who were previously on a high-carb diet—have been faced with unexpected side effects waving them back to the world of bread, sugary fruits and sweet potato casserole. Interestingly, these side effects include a wide range of symptoms that are nearly identical to symptoms of severe thyroid hormone deficiency. More interestingly, lab tests often show normal or near normal thyroid function. More interesting still is that these symptoms seem to only be relieved by adding back carbs into the diet, sometimes upward of 300 grams—a level I consider to be very likely to harm. Why is this happening? Is it that low-carb simply doesn’t work for everyone, or is something else going on? In an effort to get to the bottom of this, low-carb blogger Jimmy Moore is asking his cadre of low-carb literate practitioners to weigh in on the issue with our opinions. This so happens to be an issue I’ve been pondering since reading about the controversy over safe starches, and a couple pieces of the puzzle recently fell into place that I think I add up to at least one explanation for the debilitating symptoms some people develop on going low-carb, and offer a method for anyone going low-carb to do so without problems. Here’s what I discovered about those with thyroid problems. Abrupt Change May Be too Much For the Thyroid People who run into trouble going low-carb seem to follow a pattern. They follow any number of diets from SAD to vegan before making a relatively abrupt switch to a low carb (often less than 50 gm) diet. At first they lose weight Continue reading >>

Reactions To Arguments About Ketosis

Reactions To Arguments About Ketosis

So far I’ve only read about 2/3 of Keto Clarity, Jimmy Moore’s recent book. (As usual, I’m behind on my reading. The book was released three weeks ago.) Since the book is about nutritional ketosis, naturally I’ve been replaying the debates about ketosis in my mind as I read. I don’t want to clutter up my soon-to-appear review of the book with those debates (the book, after all, is mostly a how-to guide for people who have already decided to try a ketogenic diet) so I thought I’d chime in with some thoughts on ketosis now and review the book on its own merits. I’m not a fan of caustic debates among bloggers and authors who all advocate a more-or-less paleo, whole-foods diet but disagree on safe starches or ketosis. I explained why in my post about Differences, Commonalities and the Judean People’s Front. We agree far more than we disagree, but when the topic of ketosis comes up, you can almost sense some people wanting to yell “Splitters!” across the coliseum. Depending on which splitter has the floor, nutritional ketosis is either the natural human metabolic condition and should be sought by everyone who wants to be lean and healthy, or it’s an emergency-only condition that will ruin your metabolism and possibly kill you. I don’t buy either argument, at least not as a blanket statement for everyone. I believe achieving ketosis could be beneficial or not, depending on the individual. So I’ll just toss out some of the arguments I’ve come across recently in books, blogs and podcasts and respond with what went through my head when I heard them – and that’s all these are: my personal reactions to those arguments. Ketosis was the natural metabolic state of our Paleolithic ancestors. I used to believe that, but I don’t anymore. I think paleo p Continue reading >>

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