The Official Aminogen Blog

Protein and Testosterone: What's the Connection?

A surprising new study  reports that in men, the skeletal system is involved in testosterone production.

Osteocalcin

It turns out that osteoblasts, bone cells that generate new bone tissue, also produce a hormone called osteocalcin. And osteocalcin, the researchers found, seems to promote testosterone production. The surface of testosterone-producing Leydig cells of the testicle have osteocalcin receptors, and testosterone production in these cells seems to be upregulated or enhanced by the presence of osteocalcin (see diagram).

When scientists injected osteocalcin into mice, testosterone levels increased accordingly.  Mice with low levels of osteocalcin were found to have low levels of testosterone, low sperm counts, and poor rates of reproduction.

While it's been known for some time that sex hormones like estrogen and testosterone can affect bone growth, there wasn't any research on the influence of bone on sex hormone levels. Bones were thought to be the product of metabolism (growth, calcification, etc) rather than producers.

Bone hormone osteocalcin was discovered in 1975 (Hauschka Laboratory of Boston's Children's Hospital). Just a few years ago, in 2007, osteocalcin was found to increase insulin sensitivity and secretion, help to control glucose levels and bodyweight.

Protein, Bone Health and Testosterone

So how does protein fit into the osteocalcin-testosterone equation?

A high protein diet has been shown, in animals, to increase bone mineral content. Human studies have shown that a high protein diet improved recovery from hip fractures. Researchers explain that protein stimulates human growth factor, which in turn promotes bone growth. A 2004 study in the Journal of Endocrinology and Metabolism confirmed that a diet high in protein and low in carbohydrates increased bone growth factor IGF-1in both men and women.*

So what is good for the bones - like protein seems to be- may be good for men's testosterone levels too.

*Interestingly, although the lower estrogen levels women experience after menopause is associated with bone loss, researchers have not yet found evidence of the reverse.  There is no documented effect at this time of osteocalcin on women's estrogen levels or fertility, although future research may prove otherwise. It would make sense, given that low estrogen-osteoporosis connection, but remains to be proven.  

The Scoop: Single-Serve Protein Facts

Think Fast. Danish researchers publishing in the journal Clinical Nutrition report that a high-protein diet increased reaction time when compared to an average-protein diet.

They postulate that increases in plasma levels of branched-chain amino acids and phenylalanine in the high protein group may account for the improved reaction times, since these amino acids are known to play a role in neurotransmitter metabolism, cognitive function and brain cell repair.

Want to test your own?  Take this reaction-time test next time you whip up your favorite protein drink.

[Note: No sheep were harmed in the making of this reaction-time test.]

Trends In Dairy Research

The Dairy Research Institute announced some of the most promising research on dairy over the last year and talks about what the organization plans to focus on in 2011.

Their statement highlights several studies that point to the benefits of whole-fat dairy. 

For example, this study, published in the Annals of Internal Medicine found that intake of whole-fat dairy may help to reduce incidence of type 2 diabetes as it was strongly associated with:

 

Lower body mass index

Smaller waist circumference

Higher levels of HDL cholesterol

Lower triglycerides

Lower total cholesterol

Lower C-reactive protein*

Lower fasting insulin levels

 

The study measured blood levels of trans-palmitoleic acid in subjects and found that the higher the level, the less likely the subject was to develop diabetes.

 

Lead investigator Dr. Dariush Mozaffarian was quoted at heartWire saying, "Trans-palmitoleic acid is a fatty acid relatively unique to dairy foods. We don't make it in our bodies, so consuming it is the only way for it to enter the bloodstream."

 

Another study from the American Journal of Clinical Nutrition found certain constituents of milk fat to lower the risk of heart attacks in men and especially in women. Researchers in this study looked specifically at the effects of pentadecanoic acid and heptadecanoic acid, saturated fatty acids found in milk fat.

In 2011, the Dairy Research Institute says it plans to focus on the effects of three dairy servings per day, how these may improve metabolic health, milk's role in muscle recovery, and translating research findings into practical advice that people can use in their own quest for health.

For more on dairy protein like whey, dairy fat, and all the latest research on the benefits of dairy, you can check the Institute's news site.

*You will probably remember that c-reactive protein levels were lowered in healthy males taking Aminogen with their whey protein more than healty males taking whey protein without Aminongen.

 

If You Have Muscles, Or Know Someone Who Does

The BBC has a 30 minute report on muscle loss that you don't want to miss. It includes interviews with several of the foremost researchers on the subject, which you may also be familiar with as sarcopenia. So pull a chair up next to your computer speakers and get comfortable, your muscles will thank you for it.

 

[BTW-I couldn't track down a transcript of this broadcast, but if you are unable to access this program from your computer, this older BBC article provides some of the same information, minus the most recent research. The bottom of this page also provides links to the researchers mentioned in the audio program.]

 

One of the featured scientists, Professor of Clinical Physiology, Faculty of Medicine & Health Sciences at the Univerisity of Nottingham Medical School Mike Rennie, said he was surprised by one of the conclusions from recent research:

 

Loss of lean muscle (lean muscle is crucial for good health ) is primarily a problem of inadequate protein synthesis.

 

Why is this surprising? 

 

How Muscle Is Made

Because muscle is constantly being regenerated through a process of tearing down and rebuilding of tissue.  Muscles are broken down by the body to harvest amino acids, which are then used, in part, to rebuild these muscles. 

The amino acids from muscle may also be used to build hormones, neurotransmitters and other tissues.  They perform a host of other functions within the body. When amino acids are adequately supplied through the diet, the carefully balanced give-and-take of protein supports the healthy functioning of all of these systems, as well as the maintenance of muscle. 

Exercise can cause muscle tissue breakdown, but this breakdown then signals the body to rebuild muscle and store more amino acids there, resulting in muscle growth.

 

How Muscle Is Lost

Both aging and illness can make it difficult for the body to maintain this process; muscles grow weaker and smaller as they are depleted of amino acids.  Rebuilding muscle tissue slows or stops as the body becomes overwhelmed by the demand.

Exactly how this happens is still a hot research topic - getting hotter, in fact, as the US population ages, because loss of muscle mass affects the immune system, bone health, the ability to fight off and recover from major illness, and can lead to injury and disability.

Scientists simply don't have all of the answers yet. But what they have learned is that it's not so much the breakdown of muscle (sometimes called catabolism) that's the problem.  It's when this breakdown is not followed by rebuilding (anabolism).

 

Headed for a Breakdown

Muscle breakdown in and of itself is not the problem, scientists like Rennie and others have concluded, because this breakdown is normal part of muscle regeneration.

For example, as I mentioned earlier, exercise actually induces muscle breakdown. Findings published in the 2004 Journal of Nutrition even show that exercise specifically induces the breakdown of the branched-chain amino acids (BCAA) in muscle.

When everything is functioning properly, this then triggers repair and rebuilding of muscle.  If this doesn't happen, however, muscle is lost. 

Over time, this can add up to some serious lean muscle loss, up to one pound each year, and 80 percent over a lifetime.

 

Why Do You Build Me Up, Buttercup

Branched chain amino acids, it turns out, are really important for muscle building. After exercise, these amino acids have been shown to activate key enzymes that stimulate protein synthesis.

 

The authors of the 2004 Journal of Nutrition study on exercise-induced BCAA catabolism concluded that "....that the BCAA requirement [may be]increased by exercise. BCAA supplementation before and after exercise has beneficial effects for decreasing exercise-induced muscle damage and promoting muscle-protein synthesis."

 

So muscle breakdown during exercise can teach us something about how muscles deteriorate, and what may protect them. 

But what about age-related muscle loss? Does it happen the same way? Can BCAAs  - or anything else, for that matter - help preserve muscle, the way they do after exercise? (pssst...they help when taken before exercise, too, but that's for another post.)

 

 

BCAAs and Age-Related Muscle Loss

For one thing, we know that the BCAAs leucine and isoleucine are known to help preserve lean muscle. Moreover, scientists have recently found that BCAAs leucine, isoleucine and valine increased the lifespan of mice by 12 percent, and improved age-related muscle deficits and mitrochondrial biogenisis (think energy) too.

Their study, "Branched-chain amino acid supplementation promotes survival and supports cardiac and skeletal muscle mitochondrial biogenesis in middle-aged mice," is published in Cellular Metabolism. (quiz: what kind of car does a middle-age mouse drive?)

But older adults may have difficulty taking in adequate BCAAs, since they may have difficulty chewing, produce fewer endogenous digestive enzymes and may be less inclined to choose protein foods. In fact, between 15 and 38 percent of adult men and 27 to 41 percent of adult women may not be getting the RDA for protein on a daily basis. Unfortunately, we know that protein intake is directly correlated to how much lean mass is lost with age.

This does mean though, that older adults can take help support their own muscle health by making sure their diet contains enough quality protein.  Remember, changes to the diet should never be made without consulting a physician.

  

 

Exercise and Aging Muscle

The other good news is that resistance exercise seems to do a good job of maintaining and building muscle, even with age. In fact, Rennie calls the growth response of older adults' muscles to weight bearing exercise "a much bigger response than expected."

While older muscles may respond to exercise more slowly- and perhaps less efficiently- than younger muscles do, they do respond. 

 

 Many say muscle wasting is more a disease of inactivity rather than of age. 

It may be a combination of both.  Scientists are still sorting out the roles of hormones, diet, activity and genes in this puzzle. But the role of exercise is undeniable.

Take a look at this MRI of an 70 year old woman's quadriceps, before and after resistance training, from this study in the Journal of Applied Physiology. Her muscle increased in size by 32 percent over 8 - 12 weeks of daily resistance exercise. Improvements in muscle strength, not just size, were also seen.

Organizations like the National Strength and Conditioning Association provide guidelines for weight-bearing exercise for seniors, but this should only be done under the supervision of a physician or health care provider.

And so, to summarize what we now know about preserving and building lean muscle, the two factors that can make a difference are:

1. Eating and absorbing adequate amounts of high quality protein

2. Stimulating muscles with resistance exercise

Both of these steps should only be done with the guidance of a physician, of course. But science is showing that they may go a long way when it comes to supporting healthy lean muscle.

 

Why Timing Is Everything: Pre Exercise Protein Boosts Metabolism All Day Long

A study published in Medicine and Science in Sports and Exercise found that protein taken 30 minutes before resistance training gave the metabolism a boost that lasted long after the exercise was over- up to 24 hours later, in fact!

The study was small (eight subjects) but I like that it included both men and women in a double-blind two-trial crossover design. Compared with pre-exercise carbohydrate supplementation and heavy resistance training without supplementation, 20 grams of pre-exercise protein supplementation significantly increased metabolism, as measured by resting energy expenditure (REE).

Protein vs Carbs

Here's the difference: while pre-exercise carbohydrate supplementation raised metabolism as well, pre-exercise protein supplementation outperformed carbs at the 24 hour mark and continued to keep REE elevated.

So taking at least 20 grams of protein, 30 minutes before resistance training, just might keep keep you revved up all day long. 

And while we're talking about timing, make sure you are absorbing that supplemental protein properly. 

Read how gastrointestinal transit time (GTT) and the rate of protein digestion can affect absorption (hint: so does Aminogen) here. Don't let incomplete protein absorption slow you down!

 

The Scoop: Single Serve Protein Facts

"Both quality protein intake and frequency are positively associated with favorable body composition and bone health."

That's the conclusion from this study published in the December Annals of Nutrition and Metabolism. Researchers found that the number of times each day subjects took in at least 10 grams of essential amino acids from quality protein directly correlated with improvements in lean mass, bone mineral density and bone mineral content.

The link between lean muscle and bone health is clear. For Aminogen fans who know that the enzyme was shown to increase levels of amino acids by 100 percent, and branched-chain amino acids by 250 percent, this is good news!

Study Confirms More Protein, Fewer Carbs to Keep Weight Off

A large-scale study reported in The New England Journal of Medicine concludes that a "modest increase in protein content and a modest reduction in the glycemic index led to an improvement in study completion and maintenance of weight loss."

Researchers studied 773 European families during an eight week period of calorie constriction and found that people consuming slightly more protein, and fewer refined (high GI) carbs were more successful at maintaining their weight loss after the eighth week.

 

 Surprising?

 

It's not the first time we've heard bad news about refined carbs.

And it makes sense, since we know that amino acids found in protein like leucine and isoleucine help to inhibit fat accumulation , promote fat loss and lean muscle maintainence.

Protein also lowers levels of ghrelin (the hunger hormone) longer than fat or carbohydrates do.

Protein is so key to maintaining weight, in fact, that a lack of of it will drive you to overeat.

 

And Aminogen?

 

Adding Aminogen to protein increases the levels of fat-fighting branched-chain amino acids like leucine and isoleucine by 250 percent, so it makes sense for weight maintenance solutions.

You'd think the number would be lower, given that wild turkeys can run up to 20 miles per hour...

But Americans will eat 45 million turkeys this Thanksgiving - that's some 675 million pounds of high quality protein. 

And pound for pound, in fact, turkey has less fat and more protein than beef or chicken.

Contrary to popular myth, the tryptophan in turkey will NOT make you sleepy.

For one thing, turkey doesn't contain an unusually high amount of tryptophan.  Chicken and beef contain about the same; soybeans, cheese and pork have more.  

Second, a good share of the tryptophan you eat never makes it through the brain's protective barrier (a sort of neurological red velvet rope, no one gets in without being on the list.  And while tryptophan does have an invite, it is easily crowded out by the throngs of competing amino acids waiting in line after a protein meal.)

Likely it's the consumption of lots of fat, lots of carbohydrates (hello insulin!) and lots of extra calories that makes you sleepy. Scientific American has a good explanation here.

[A note on tryptophan: It's an important amino acid and a prescursor to serotonin.  While research does suggest that tryptophan levels in the brain can affect serotonin production and circulation, it is important to emphasize tryptophan levels correlating with serotonin were measured in the brain. Levels outside of the brain can be substantially different. Breaking down the protein you eat, and getting enough tryptophan successfully across the brain's barrier in order to increase brain tissue levels of the amino acid - that's probably not happening during a typical meal, although it can be done. More on this amino acid in future posts...]

But getting back to turkey...

Check out the country's only turkey museum, brought to you by the National Wild Turkey Federation (who knew?)

Be thankful for turkey, and enjoy a safe and happy Thanksgiving holiday!

 

The Scoop: Single Serve Protein Facts

We already know that that muscles are an important part of the immune system, and that branched-chain amino acid arginine is a precursor of nitric oxide (which is antimicrobial).  Now researchers are figuring out just how arginine works as part of the immune system, above and beyond nitric oxide production.  

Turns out, this amino acid signals immune system cells called macrophages to start doing their thing.  (Think of a macrophage as a cellular-sized, disease-chomping pac-man).  These guys help to get rid of invading cells and bacteria - and arginine seems to really get macrophages moving.  In fact, scientists reported in the August 17th issue of Science Signaling that adding arginine to the diet of malnourished mice improved their immune response. They theorize arginine does this through three different mechanisms: nitric oxide production, cytokine stimulation and macrophage signaling. 

Increasing Need for Sarcopenia Solutions

Sarcopenia was named by the CDC as one of the top five health risks for older adults over a decade ago.  And yet awareness of the condition has been slow-growing, until now.

 

Boom!

Enter the baby boomers.This generation is 40 million strong, and expected to live longer than any previous generation.  Many have watched their parents age, become frail, or lose their independence due to a chronic disease or broken hip. Boomers are looking for ways to help aging parents and safeguard their own healthy futures.

Their needs, and ongoing research into the physiological mechanisms behind sarcopenia, have finally driven the issue of age-related muscle loss into the spotlight. It couldn't be more timely.

Muscle loss can begin as young as age 30, when men and women can lose much as a half-pound of muscle each year.  And for every half-pound of lean muscle lost, most are gaining twice as much fat.  This can make muscle loss an insidious process because this additional fat means that the lost lean tissue may not register on the scale. A person's weight may not change drastically even when their ratio of muscle to fat does. (See a New York Times illustration of what this looks like).

Research shows that after age 50, this process significantly accelerates. A 20 to 40 percent loss of lean muscle mass is possible by the time a person has reached 70.

Most baby boomers have already turned 65 as of this year.

 

So why is this muscle loss such a big deal?

Turns out that our muscles do more than just help us move. Our muscles are an integral part of a healthy immune system and metabolism. Lack of lean muscle is even associated with higher mortality rates in men.

Muscles secrete hormones that fight inflammation. They play an important role in the immune system, and serve as a reserve of amino acids needed for tissue repair during illness and injury. Lack of muscle is a known risk factor for those debilitating hip fractures we so want to avoid. A lack of healthy lean muscle can also affect insulin functioning and mineral metabolism, and therefore influences several chronic diseases.

 

In fact, inadequate muscle mass can impact:

Immune response

Chronic diseases such as diabetes and osteoporosis

Survival rates from critical illness such as cardiovascular disease and cancer

Ability to recover from injury and surgery.

 

Given the importance of lean muscle mass, older adults need solutions for muscle health now.

The logical place to begin is by understanding why muscle loss happens in the first place.

 

Motor Neurons

One obvious culprit is lack of use.  Take a look at a neuromuscular junction, the place in the body where muscle fibers connect with the nerve cells that stimulate them.  Moving muscles - walking, gardening, running the elliptical, aka exercise-  gets these nerves firing (a good thing).  This, in turn, signals more nutrients to be sent into the muscle, and encourages muscle cells to make repairs and reproduce. 

When all is quiet on the western front -  aka sitting on the couch watching House marathons - aka inactivity- this process slows dramatically. Atrophy occurs.  A classic case of use it or lose it.

...Easy enough to remedy if you are forty and can schedule some exercise into your day.  Not so easy as you get older, deal with injuries and disabilities, or struggle with painful diseases like osteoarthritis. And making things even more difficult - even when older adults can exercise, it seems that the motor nerve endings weaken and fray, their ability to relay messages to muscle fibers decreases considerably.

 

Molecular Changes

Other contributors to the problem of muscle loss include hormonal and molecular changes that occur with age.  Hormone levels may decrease.  Hormone receptors and uptake of hormones may be diminished, which can alter metabolic processes such as insulin sensitivity and fat distribution.  Expression of microRNA in skeletal muscle (a topic I will explore further in an upcoming post) slows and becomes disregulated. MicroRNA helps to instruct muscle cells on how to grow and function, so when it goes awry, the growth cycle of muscle cells, and consequently protein synthesis, can be affected.

 

Dietary Protein

Finally, scientists have shown that dietary protein plays a role in lean muscle maintenance.

 

Many older adults do not take in Recommended Daily Allowance for protein - between 15 and 38 percent of adult men and 27 to 41 percent of adult women, according to an analysis reported in the American Journal of Clinical Nutrition.

 

What's more, not all of the protein older adults do get is necessarily utilized by the body. Protein can only be absorbed by the body for a certain amount of time after ingestion. And as we age our bodies produce fewer digestive enzymes, making it more difficult to break down and absorb protein. The undigested protein can create uncomfortable gastrointestinal symptoms like gas, bloating, and constipation, and people may decrease the protein in their diet in order to avoid this discomfort.

The body also becomes less efficient at using the amino acids it does get from protein.  Since these amino acids are important in such a wide range of physiological functions, from building hormones and neurotransmitters to tissue repair and immune response, the lack of protein can have far-reaching consequences.

 

 Solutions

As the population ages, scientists are looking for ways to combat sarcopenic muscle loss on all three of these fronts.

Physical activity is thought to improve and help preserve motor neuron function, although the ability of some older adults to remain active may be limited, as discussed above. Generally speaking, exercise (under the supervision of a health care provider) is encouraged,  and shown to be beneficial at almost every age.

Researchers are working on ways to affect change through hormonal, molecular and genetic pathways, although it may be a long time before this research translates into available treatments. (Interesting to note, however, is the discovery that one way genes may be turned on, off, or modified, is through good old-fashioned diet and exercise!)

Improving dietary protein intake and utilization is one part of the solution that is practical and obtainable for many people. Simply becoming aware of protein intake, choosing quality digestible proteins, and addressing digestion issues with a health care provider may all be important steps that can make a difference.