Stem cell research is expanding beyond earthly confines. Scientists from Cedars-Sinai in California have partnered with the private company Axiom Space to help them produce stem cells aboard the International Space Station—an apparent first that will test whether these cells can be manufactured more efficiently in a microgravity environment.
The initial cargo needed for the two-year-long experiments will be delivered via the Axiom Mission 2 spaceflight, set to launch early next month. Stem cells are often considered the building blocks of life. Soon after the embryo forms, these cells will start to divide and then mature, or differentiate, into every other cell and organ of the human body.
As we age, they continue to replenish various types of cells, helping us heal from injury and illness. We’ve already learned how to extract and transplant certain stem cells to help people recover from conditions such as leukemia. But scientists hope that the rejuvenating potential of stem cells will one day allow us to treat a large variety of health issues.
For now, though, we’re still in the early stages of stem cell therapy, and there remain many hurdles toward making them a practical medical treatment. One of these hurdles is the resources it typically takes to grow a healthy and sizable batch of stem cells in the lab. But in recent years, some scientists have argued that space could help ease that particular problem.
Some research has suggested that the microgravity environment found in space is a better match for the conditions that stem cells naturally grow in than those found in a standard lab. One hope is that space-grown stem cells will be easier to produce and possibly even healthier than the Earth-grown version. Simply seeing how they grow in space might help us better understand their inner workings, including how they can become cancerous.
Among the many researchers studying stem cells in space is a team at Cedars-Sinai in California. They and others have previously sent samples of stem cells to the International Space Station for brief periods of time, including induced pluripotent stem cells (iPSCs), which are derived from adult cells that can then turn into any other cell.
But now, they appear to be broadening their ambitions with an attempt at a novel feat: creating iPSCs from scratch aboard the ISS. “This is the first time that induced pluripotent stem cells will be made entirely in space,” Arun Sharma, one of the project’s principal investigators and a stem cell biologist at the Cedars-Sinai Board of Governors Regenerative Medicine Institute, told Gizmodo in an email.
“These cells are very powerful because they can be made from a small sample of skin or blood from a process called ‘reprogramming’ which takes a few weeks.”The team’s research is funded by a NASA grant. But their materials will be ferried by the Axiom Mission 2 (Ax-2), the second flight to the ISS made by the Texas-based company, which is scheduled to launch May 9.
Axiom has become a major presence in space travel as of late. Last April, the Axiom Mission 1 became the first fully privately crewed spaceflight to the ISS. NASA has also chosen the company as one of its partners in creating the next generation of space suits intended for humanity’s return to the Moon, which were previewed last month. And the company plans to use Ax-2 and future missions as stepping stones to its ultimate goal: the creation of the first truly commercialized space station, intended as a successor to the ISS.
As for the Cedars-Sinai team, this will be the first of three missions planned over the next two years. Along the way, the scientists will examine if spaceflight changes or enhances the reprogramming production of iPSCs, as well as their ability to divide and differentiate once made. And if these and other stem cell-related experiments prove fruitful, then space could very well become a crucial part of this burgeoning research field.
“If successful in showing that stem cells can be grown or produced better in orbit, we may be able to scale up our production for further academic and commercial/industrial applications,” Sharma said.
Every single morning for the past 11 years, Libby DeLana has walked out her back door at 5:30 no matter the weather, how tired she may be, or even how sick. “It’s not about the miles or the number of steps,” says DeLana, author of the book Do Walk: Navigate earth, mind, and body.
Step by step. and co-host of the podcast The Morning Walk. “This practice is about fidelity to myself and knowing what it is that creates a sense of well-being in my body, and that includes significant time in the outdoors and putting my eyes to the sun and feeling the breeze on my face.”
DeLana, who lives just north of Boston, Massachusetts, walks through all four seasons and regularly covers eight to ten miles per day. Even when she’s sick, she says, she’ll get out for a slow, gentle walk around the block just to move and put one foot in front of the other.
“For me, the walk is like a seated practice of meditation,” says DeLana. “The quiet is revealing. Obviously, there’s the sound of the natural world—the sound of the waves or the wind or the birds, but there are a lot of messages from the quiet.”
Daily movement has been part of human evolution for thousands of years, and DeLana has found that making movement a nonnegotiable part of her own daily routine is good for mind, body, and spirit. But keeping up that consistency, day after day, in all kinds of weather and trail conditions, requires good gear—especially shoes…..
HIIT workouts and heavy lifts tend to steal the workout limelight, but good, old-fashioned walking is actually having a moment. In fact, more people are taking recreational jaunts now than before the pandemic, according to a June 2021 study in Nature. That’s because in as little as 10 minutes a day, you can reap the health benefits of walking.
“Studies show that people who walk for 10 minutes a day have noticeable improvements in cardiovascular health, decreased mortality and increased longevity and better overall fitness,” says R. Kannan Mutharasan, MD, co-program director of sports cardiology at the Northwestern Medicine Bluhm Cardiovascular Institute. “The benefits of walking keep going up until you hit about 30 minutes a day.”
According to a June 2013 study in the Journal of Medical Internet Research, doing daily 10-minute stair walks improved the heart health of adults with sedentary jobs. A January 2022 study in JAMA Internal Medicine also found 10 minutes of moderate-to-vigorous physical activity daily, such as walking, is associated with a 6.9 percent decrease in the number of deaths per year.
Bonus: There are no bells or whistles required when getting your steps in. “Simply put on a pair of comfortable sneakers and head outside,” Dr. Mutharasan says. (Or hop on the treadmill!)
While sauntering has a lot going for it, should you make it an everyday form of exercise — or is it better to mix things up with your fitness routine? Here, we break down what really happens to your body if you lace up for a daily walk.
Your Heart Gets Stronger
If you want to show your heart some love, hit the pavement every day. “Walking gets your heart rate up, which improves its pumping function,” Dr. Mutharasan says.Your heart is a muscle, after all. Giving it a workout — say, by forcing it to pump rapidly during a moderate-intensity walk — will strengthen it.
Stick with daily walks, and over time your heart will be able to move blood through your system more easily and efficiently. Walking every day also increases your cardiovascular endurance, allowing you to exercise longer and harder.
“Putting your cardiovascular system under a bit of stress by walking improves blood flow, which increases oxygenation to your bones, organs and muscles,” says Farah Hameed, MD, assistant professor of Rehabilitation and Regenerative Medicine at Columbia University Medical Center.”This, in turn, normalizes blood pressure and cholesterol and blood sugar levels, which lowers the risk of diabetes and heart disease.”
Your Bones and Joints Stay Healthy
Because walking is a weight-bearing activity, making time for it every day keeps your bones healthy, boosting bone density and decreasing your risk of osteoporosis and fractures. “Walking puts stress on your bones, which helps them maintain their strength,” Dr. Hameed says. She notes you don’t get the same bone benefits when you do non-weight-bearing exercise, like biking or swimming.
And although resistance training is hailed as the most powerful antidote for brittle bones, particularly as you age, walking every day targets areas that weightlifting might miss. “For example, squats and lunges pull on the bone,” Dr. Hameed says, “but walking stimulates bones throughout the entirety of the foot and leg.”
The movement in your hips, knees and ankles also helps pump nutrient-rich synovial fluid into the cartilage in your joints. “This helps maintain the lifespan of your joints,” says Natasha Trentacosta, MD, pediatric and adult sports medicine specialist and orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles.
A daily walk also strengthens the muscles, tendons and ligaments surrounding your joints so they are better able to support the weight of your body, instead of the whole load landing on your joints. This reduces your risk of pain and injury……
Even before the pandemic, more than a third of Americans weren’t getting the recommended seven plus hours of nightly sleep that industry professionals recommend. Add the stress of everyone’s new reality, and, by certain estimates, 68% of Americans say they just aren’t getting enough rest.
While you’re probably aware of some of the issues, like mental fog, that can arise when you don’t get enough rest, you may not be aware that your snoozing habits may impact all sorts of unexpected things—think: how well your heart pumps blood, and even your sex drive.
“Most of the systems in our body are predicated on some process of renewal or need for sleep,” explains board-certified sleep medicine researcher W. Christopher Winter, MD, the author of The Sleep Solution: Why Your Sleep Is Broken and How to Fix It. “Sleep is a fundamental aspect of our thinking, our ability to function, and our immune system. It impacts pretty much everything we need to survive.”
So turn off your phone, close the shades, and hop into bed early tonight. If you don’t, here’s how a lack of sleep may impact your body.
1. It can hurt your immune system.
“There’s a very strong link between sleep and the immune system in general,” says Michael Awad, MD, chief of sleep surgery at Northwestern Medicine and chief medical officer of Peak Sleep. “The body repairs just about every cell in the body when it comes to sleep. Sleep deprivation lowers the body’s ability to mount an immune response.”
Sleep loss is linked to a higher risk of infection, according to the Centers for Disease Control and Prevention (CDC). One study published in JAMA found that restricting a person’s sleep for four hours a night for six days, followed by sleeping 12 hours a night for seven days, can lead to a greater than 50% decrease in the production of antibodies to a flu vaccine. Basically, your body just can’t mount the usual immune response when you’re wiped out.
Lack of sleep can also lower your immune system’s ability to fight tumor cells and lead to the generation of inflammatory cytokines. These proteins are secreted by the immune system and can cause the development of metabolic and cardiovascular disorders.
2. It can raise your risk of heart disease.
One study of nearly 117,000 people published in the European Heart Journal found that people who slept less than six hours a night were at a greater risk of developing heart disease than their well-rested counterparts. And getting irregular sleep—that is, having no consistent bedtime and wake time—can raise your risk of having some kind of cardiovascular event, including stroke, congestive heart failure, and coronary heart disease, according to a study published in the Journal of the American College of Cardiology.
There are a “tremendous number of mechanisms” at play here, Dr. Winter says. “When you are sleep deprived or have fragmented sleep, your blood vessels lose, to some extent, the ability to expand and contract to regulate things,” he says. People also tend to be at a higher risk of developing high blood pressure when they don’t get enough sleep, Winter says, which can be tough on your heart.
Sleep deprivation can also increase cholesterol levels and general inflammation throughout your body, leading to the formation of plaque in the blood vessels, Dr. Awad says. “When blood vessels start to form plaque, the heart has to work harder,” he explains.
3. It can lower your sex drive.
There are a lot of reasons for this, Dr. Winter says. “When you’re fatigued, your brain prioritizes getting sleep over other things,” he says. But Dr. Winters says other chemicals that are important for sexual performance and arousal, such as oxytocin, can be lowered by sleep deprivation.
One study in JAMA restricted 10 men’s sleep for a week and found that the levels of the sex hormone testosterone in their bodies decreased by up to 15%. (Testosterone is a hormone that can fuel a person’s sex drive.) The reverse is also true: Another study published in JAMA found that people who got more sleep than usual were more likely to have sex the next day. Meaning, if you hit the hay earlier, you just might be up for a little something extra.
4. It can raise your risk of weight gain.
There are a few reasons for this. One is that people “tend to make bad eating decisions when they’re tired,” Dr. Winter says. People are also typically more sedentary and less likely to work out when they’re tired, which also can lead to weight gain, he says.
Research published in the journal Sleep found that people with restricted sleep had altered levels of endocannabinoids, one of the chemical signals that affect appetite, and the brain’s reward system. The researchers also discovered that when people were sleep-deprived, they ate more and unhealthier snacks between meals, at the same time that endocannabinoid levels were at their highest.
Older research has also found that women who get less sleep tend to weigh more than their better-rested counterparts, likely for the reasons above, Dr. Winter says.
5. It can increase your risk for developing diabetes.
There’s a direct correlation between lack of sleep and diabetes, Dr. Awad says. It’s due to your body’s ability to regulate insulin, a hormone produced in the pancreas that controls your blood sugar, he says. “Lack of sleep reduces the production of insulin from the pancreas and decreases gluten tolerance,” Dr. Awad says. “Cells are then less effective at using insulin, and that can lead to the development of diabetes.”
If you’re struggling with sleep, Dr. Winter recommends first trying to prioritize rest and practicing good sleep hygiene. That includes the following, per the CDC:
Go to bed at the same time each night and get up at the same time each morning, including on weekends.
Make sure your bedroom is quiet, dark, relaxing, and at a comfortable temperature.
Remove electronic devices, such as TVs, computers, and smartphones, from your bedroom.
Avoid large meals, caffeine, and alcohol before bed.
Exercise regularly. Being physically active during the day can help you fall asleep more easily at night.
If these tried-and-tested tips don’t help, Dr. Awad says it’s a good idea to talk to your doctor about what else you can do to get the rest your body needs.
Nutritionists will tell you to eat a rainbow of fruit and vegetables. This isn’t just because it looks nice on the plate. Each colour signifies different nutrients our body needs. The nutrients found in plant foods are broadly referred to as phytonutrients. There are at least 5,000 known phytonutrients, and probably many more. So what does each colour do for our body and our overall health?
Red
Red fruits and vegetables are coloured by a type of phytonutrient called “carotenoids” (including ones named lycopene, flavones and quercetin – but the names aren’t as important as what they do). These carotenoids are found in tomatoes, apples, cherries, watermelon, red grapes, strawberries and capsicum.
These carotenoids are known as antioxidants. You will have heard this name before, but you might not remember what it means. It has something to do with “free radicals”, which you’ve also probably heard of before.
Free radicals are formed naturally in our body as a byproduct of all our usual bodily processes such as breathing and moving, but they also come from UV light exposure, smoking, air-pollutants and industrial chemicals.Free radicals are unstable molecules that can damage proteins, cell membranes and DNA in our body. This natural but damaging process is known as oxidation or oxidative stress.
This contributes to ageing, inflammation and diseases including cancer and heart disease.Importantly, antioxidants “mop up” the free radicals that form in our body. They stabilise the free radicals so they no longer cause damage.Increasing antioxidants in your diet lowers oxidative stress and reduces the risk of many diseases including arthritis, type 2 diabetes, heart disease, stroke and cancer.
Orange
Orange fruits and vegetables also contain carotenoids, but slightly different ones to red veggies (including alpha and beta-carotene, curcuminoids, and others). These are found in carrots, pumpkins, apricots, mandarins, oranges and turmeric.Alpha and beta-carotene are converted to vitamin A in our bodies, which is important for healthy eyes and good eyesight.
Vitamin A is also an antioxidant that can target the parts of your body made of lipids (or fats) such as cell membranes.The vitamin A targets the free radicals building up around our cell membranes and other areas made of lipids, reducing the risk of cancers and heart disease.
Yellow
Yellow fruit and vegetables also contain carotenoids, but they also contain other phytonutrients including lutein, zeaxanthin, meso-zeaxanthin, viola-xanthin and others. These are found in apples, pears, bananas, lemons and pineapple.
Lutein, meso-zeaxanthin and zeaxanthin have been shown to be particularly important for eye health and can reduce the risk of age-related macular degeneration, which leads to blurring of your central vision.These phytonutrients can also absorb UV light in your eyes, acting like a sunscreen for the eyes and protecting them from sun damage.
Green
Green fruits and vegetables contain many phytonutrients including chlorophyll (which you probably remember from high school biology), catechins, epigallocatechin gallate, phytosterols, nitrates and also an important nutrient known as folate (or vitamin B9). These are found in avocados, Brussels sprouts, apples, pears, green tea and leafy vegetables.
These also act as antioxidants and therefore have the benefits as described above for red veggies. But this group also provides important benefits in keeping your blood vessels healthy, by promoting something called “vasodilation”. These phytonutrients help make our blood vessels more elastic and flexible allowing them to widen or dilate. This improves blood circulation and reduces blood pressure, reducing our risk of heart and other vessel complications and disease.
Folate is recommended before pregnancy because it helps reduce the risk of neural tube defects (such as spina bifida) in babies. Folate helps the development of the foetal nervous system during the first few weeks of pregnancy, as it has been shown to promote healthy cell division and DNA synthesis.
Blue and purple
Blue and purple produce contain other types of phytonutrients including anthocyanins, resveratrol, tannins and others. They are found in blackberries, blueberries, figs, prunes and purple grapes.Anthocyanins also have antioxidant properties and so provide benefits in reducing the risk of cancer, heart disease and stroke, as explained under red fruit and veg.
More recent evidence has indicated they may also provide improvements in memory. It is thought this occurs by improving signalling between brain cells and making it easier for the brain to change and adapt to new information (known as brain plasticity).
Brown and white
Brown and white fruits and vegetables are coloured by a group of phytonutrients known as “flavones”, this includes apigenin, luteolin, isoetin and others. These are found in foods such as garlic, potatoes and bananas.
Another phytonutrient found in this colour of vegetables, particularly in garlic, is allicin.
Allicin has been shown to have anti-bacterial and anti-viral properties.Most of this research is still at the lab-bench and not many clinical trials have been done in humans, but lab-based studies have found it reduces microorganisms when grown under laboratory conditions. Allicin has also been found in systematic reviews to normalise high blood pressure by promoting dilation of the blood vessels.
How can I get more veggies in my diet?
Coloured fruit and vegetables, and also herbs, spices, legumes and nuts provide us with a plethora of phytonutrients. Promoting a rainbow of fruit and vegetables is a simple strategy to maximise health benefits across all age groups. However most of us don’t get the recommended amount of fruit and vegetables each day. Here are some tips to improve your intake:
1. when doing your fruit and vegetable shopping, include a rainbow of colours in your shopping basket (frozen varieties are absolutely fine)
2. try some new fruit and vegetables you haven’t had before. The internet has tips on many different ways to cook veggies
3. buy different colours of the fruit and vegetables you normally eat like apples, grapes, onions and lettuces
4. eat the skins, as the phytonutrients may be present in the skin in higher amounts
5. don’t forget herbs and spices also contain phytonutrients, add them to your cooking as well (they also make vegetables more appealing!)
A lot of creatine experts are sick of the way we talk about creatine. Some are tired of cotton candy-flavored energy drinks hawking “super creatine” on neon cans, protein bars infused with the supplement, social media posts confusing creatine with steroids. Others are tired of the slew of “before and after” TikToks in which trim young men show off bulging muscles after a handful of weeks taking the supplement, or women display rippling abs they attribute only to the powder.
“I don’t know why people make up things about this particular supplement,” said Jose Antonio, an associate professor of health and human performance at Nova Southeastern University in Florida who has studied creatine. The world of creatine is rife with misinformation, he said, in spite of the large — and growing — body of evidence that the supplement can improve short bursts of athletic performance and enhance muscle mass.
Is the powder a miracle workout supplement, or is the hype overblown? Here’s what to know.
What even is creatine?
Creatine is formed in the body from compounds similar to amino acids, the building blocks of proteins. It serves as a type of fuel for your skeletal muscles, and can promote muscle growth when paired with exercise. It’s produced in the liver and kidneys, but you likely get creatine through your diet, too — red meat, fish and chicken contain it.
Throughout the day, your body naturally replenishes creatine in your muscles, but supplements can help “top up the tank,” said Eric Rawson, a health, nutrition and exercise science professor at Messiah University in Pennsylvania.
Creatine monohydrate — the form of creatine typically found in commercial powders — has been rigorously studied. “There’s probably more data on creatine monohydrate than any other supplement in existence,” Dr. Antonio said.
The Facts Behind 5 Supplements
Card 1 of 5
Collagen. Collagen, is one of the most abundant proteins in the body and helps form our skin, bones, muscles, tendons and ligaments. As we age, we naturally start reducing its production. Some studies show that taking collagen supplements can reduce signs of aging, increase bone density and improve joint, back and knee pain. But many of these studies are small and funded by the companies behind such products, increasing the opportunity for bias. Certain products also have flaws that reduce the likelihood of their efficacy: Topical creams, for example, are unlikely to make it into the deeper level of the skin where collagen is produced.
Vitamin B6. This essential nutrient is involved in a number of chemical reactions that are important for the proper functioning of the immune and nervous systems. As with the other essential vitamins, the body cannot produce B6 on its own, so you can only get it from foods (such as tuna, salmon, chickpeas, poultry, dark leafy greens, bananas, oranges, cantaloupe and nuts) or supplements. Most healthy adults get more than enough vitamin B6 from their diets alone, so B6 supplements are generally not needed.
Melatonin. The hormone is released by our brains as it starts to get dark outside, making us sleepy. Taking it in supplement form tricks your body into feeling like it’s nighttime. Experts urge people to consult their doctor before taking melatonin, as the supplement does not address underlying health problems, like anxiety and sleep apnea, that may disrupt sleep and require treatment. Lifestyle changes that experts say help us sleep better, from limiting alcohol consumption to exercising regularly, should also be considered first.
Vitamin D. Our bodies need this vitamin for the gut to absorb calcium, which bones need to grow and stay healthy. But a large study in the United States reported that vitamin D pills taken with or without calcium have no effect on bone fracture rates and a host of other ailments like cancer and cardiovascular disease. Even so, some people, including those with conditions like celiac and those who are deprived of sunshine, however, may find the supplements useful.
There are more than twenty different formulations of creatine, Dr. Rawson said, including creatine hydrochloride and creatyl-l-leucine, but only creatine monohydrate has strong evidence behind it, so he would recommend against consuming another form of the compound.
What are the benefits of creatine?
Creatine has specific, focused benefits for exercisers. The supplement can power you through short bursts of activity, like lifting a weight or dashing through a short race. If you’re in the middle of a Peloton workout, for instance, you might be able to increase your speed for a sprint, said David Creel, an exercise physiologist and a psychologist and dietitian in the Bariatric and Metabolic Institute at the Cleveland Clinic.
But the effect is usually small. Creatine makes the most sense for certain competitive athletes eager for a split-second advantage, said Samantha Heller, a senior clinical nutritionist at N.Y.U. Langone Health. “For your average gym-goer, someone who’s a cyclist, someone who plays soccer on the weekends — they don’t need this,” she said.
Scientists have studied creatine and exercise performance since the early ‘90s. A recent review of 35 studies found that creatine supplementation, combined with resistance training, increased lean body mass — the body’s weight, minus fat — by more than two pounds in adults, regardless of age. The difference is small, but significant, although men reported higher gains than women. Vegetarians and vegans are more likely to have a larger response to the supplements, since they don’t get as much creatine in their diets, Dr. Rawson said.
Creatine may provide a small boost in muscle mass, but “whether it’s a 2 or 3 or 4 percent gain, no dietary supplements compare to proper training and sleep and nutrition habits,” Dr. Rawson said. Still, the increase could have a notable effect on older adults in particular, he said. “A very, very small improvement in strength could be the difference between a fall and not a fall.”
And emerging research suggests that creatine could have cognitive benefits, potentially enhancing memory and attenuating symptoms of concussions or traumatic brain injuries, although that data is much more limited than studies on creatine and muscular fitness.
Are there side effects to creatine?
“There really doesn’t appear to be any major hazards to it, which is kind of unique for a supplement,” said Dr. Creel. People who take the supplement, especially in large quantities, might experience some gastrointestinal distress, said Ms. Heller. People may also bloat or experience weight gain.
There are some claims floating around social media that creatine causes hair loss, but doctors said there was not significant research to verify that. And you won’t get any kind of high from creatine — it’s not like the jolt of energy you get from downing an espresso, Dr. Creel said.
The supplement is popular with teenagers, but there isn’t data on prolonged long-term use, especially in people who are still growing, said Dr. Pieter Cohen, an associate professor of medicine at the Cambridge Health Alliance, who studies supplements. Out of an abundance of caution, he suggested that teens refrain from using the supplement.
What to keep in mind before taking creatine
As with any supplement, you should talk to your primary care doctor before you start taking creatine. And just like other dietary supplements you can pull off the shelves, creatine is not tested by the Food and Drug Administration, said Dr. Cohen. That means there’s no guarantee that a powder you’re buying actually contains the amount of creatine it claims, or even any at all. The Department of Defense’s Operation Supplement Safety program recommends four third-party companies that test and evaluate dietary supplements, which you can use to ensure you’re really getting creatine.
You should also stick with the recommended dose, which is usually around three to five grams per day. There isn’t substantial data for how long people can safely take the supplement beyond five years.It’s also important to come up with specific goals before taking the supplement, Dr. Cohen said, and to determine what the pill or powder could actually help you achieve — keeping in mind that it’s not a guaranteed ticket to building muscle. “People think creatine’s a steroid,” Dr. Antonio said. “That’s like saying water is fire.”
Creatine was first identified in 1832 when Michel Eugène Chevreul isolated it from the basified water-extract of skeletal muscle. He later named the crystallized precipitate after the Greek word for meat, κρέας (kreas). In 1928, creatine was shown to exist in equilibrium with creatinine.[3] Studies in the 1920s showed that consumption of large amounts of creatine did not result in its excretion. This result pointed to the ability of the body to store creatine, which in turn suggested its use as a dietary supplement.[4]
In 1912, Harvard University researchers Otto Folin and Willey Glover Denis found evidence that ingesting creatine can dramatically boost the creatine content of the muscle.[5][non-primary source needed] In the late 1920s, after finding that the intramuscular stores of creatine can be increased by ingesting creatine in larger than normal amounts, scientists discovered phosphocreatine (creatine phosphate), and determined that creatine is a key player in the metabolism of skeletal muscle. The substance creatine is naturally formed in vertebrates.[6]
The discovery of phosphocreatine[7][8] was reported in 1927.[9][10][8] In the 1960s, creatine kinase (CK) was shown to phosphorylate ADP using phosphocreatine (PCr) to generate ATP. It follows that ATP, not PCr is directly consumed in muscle contraction. CK uses creatine to “buffer” the ATP/ADP ratio.[11]
While creatine’s influence on physical performance has been well documented since the early twentieth century, it came into public view following the 1992 Olympics in Barcelona. An August 7, 1992 article in The Times reported that Linford Christie, the gold medal winner at 100 meters, had used creatine before the Olympics. An article in Bodybuilding Monthly named Sally Gunnell, who was the gold medalist in the 400-meter hurdles, as another creatine user. In addition, The Times also noted that 100 meter hurdler Colin Jackson began taking creatine before the Olympics.
At the time, low-potency creatine supplements were available in Britain, but creatine supplements designed for strength enhancement were not commercially available until 1993 when a company called Experimental and Applied Sciences (EAS) introduced the compound to the sports nutrition market under the name Phosphagen.[14] Research performed thereafter demonstrated that the consumption of high glycemic carbohydrates in conjunction with creatine increases creatine muscle stores.
Creatine is a naturally occurring non-protein compound and the primary constituent of phosphocreatine, which is used to regenerate ATP within the cell. 95% of the human body’s total creatine and phosphocreatine stores are found in skeletal muscle, while the remainder is distributed in the blood, brain, testes, and other tissues. The typical creatine content of skeletal muscle (as both creatine and phosphocreatine) is 120 mmol per kilogram of dry muscle mass, but can reach up to 160 mmol/kg through supplementation.
Approximately 1–2% of intramuscular creatine is degraded per day and an individual would need about 1–3 grams of creatine per day to maintain average (unsupplemented) creatine storage.[18][19][20] An omnivorous diet provides roughly half of this value, with the remainder synthesized in the liver and kidneys.
Journal of the International Society of Sports Nutrition. 9 (1): 33. doi:10.1186/1550-2783-9-33. PMC3407788. PMID22817979. Creatine is produced endogenously at an amount of about 1 g/d. Synthesis predominately occurs in the liver, kidneys, and to a lesser extent in the pancreas. The remainder of the creatine available to the body is obtained through the diet at about 1 g/d for an omnivorous diet.
“The role of dietary creatine”. Amino Acids. 48 (8): 1785–91. doi:10.1007/s00726-016-2188-1. PMID26874700. S2CID3700484. The daily requirement of a 70-kg male for creatine is about 2 g; up to half of this may be obtained from a typical omnivorous diet, with the remainder being synthesized in the body … More than 90% of the body’s creatine and phosphocreatine is present in muscle
Hultman E, Söderlund K, Timmons JA, Cederblad G, Greenhaff PL (July 1996). “Muscle creatine loading in men”. Journal of Applied Physiology. 81 (1): 232–7. doi:10.1152/jappl.1996.81.1.232. PMID8828669.Balsom PD, Söderlund K, Ekblom B (October 1994). “Creatine in humans with special reference to creatine supplementation”. Sports Medicine. 18 (4): 268–80. doi:10.2165/00007256-199418040-00005. PMID7817065. S2CID23929060.
Harris RC, Söderlund K, Hultman E (September 1992). “Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation”. Clinical Science. 83 (3): 367–74. doi:10.1042/cs0830367. PMID1327657.Brosnan JT, da Silva RP, Brosnan ME (May 2011). “The metabolic burden of creatine synthesis”. Amino Acids. 40 (5): 1325–31. doi:10.1007/s00726-011-0853-y. PMID21387089. S2CID8293857. Creatinine loss averages approximately 2 g (14.6 mmol) for 70 kg males in the 20- to 39-year age group. …\
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