Dietary Fat Preserves Muscle?

Preservation of lean muscle mass matters for long term health and function.  It is also important to those who want to gain muscle mass so they can look hot and/or awesome.   it is also important for strength and for athletic performance. Whatever your interests, here is a report of a recent study on dietary fats and muscle mass.

Sprinting and Jumping help you stay strong so you can beat up young people.
Dietary fat may help you stay strong so you can beat up young people.

Dietary Fat and Protein Turnover

Dietary fat may regulate protein turnover.  The thought is that dietary fats influence both inflammation and insulin.  This study was published in this month’s issue of the Journal of Nutrition.   Study subjects were 2,689 women who are part of a study of twins in the UK.  Data was collected on:

  • Percent of Calories obtained from Fat
  • Fatty acid profile
  • Fat -free mass in kilograms (an indicator of muscle mass)
  • Fat-free mass measured by X-Ray absorptiometry

Results of the Dietary Fat and Muscle Study

  • Women whose diets were higher in polyunsaturated fatty acids had higher fat-free mass (more muscle).
  • Women who got more of their calories from fat had less fat free mass (less muscle)
  • Women who ate more saturated fat had less fat free mass (less muscle)
  • Women who ate more unsaturated fatty acids had less fat free mass (less muscle)
  • Women who are more transfats had less fat free mass (less muscle)

Women who were in the top 20% for energy intake from polyunsaturated fatty acids had about a pound more muscle mass than women who were at the bottom 20% for polyunsaturated fatty acid.  This is about the same difference in muscle mass that would be seen in a 10 year aging period.  You could look at this and say that a diet high in polyunsaturated fatty acids saves 10 years of muscle aging.  And you might be right.  Polyunsaturated fatty acids reduce inflammation and seem to protect against cardiovascular disease and cancer as well.  We don’t know what drives age-related muscle loss.  It might be related to the same factors that drive cell-aging in general.  

The Simple Takeaway for Dietary Fat and Muscle Mass

ResearchBlogging.orgThis is the first study of its kind and more research is needed to figure out what is going on.  However, this study supports the idea that a diet higher in polyunsaturated fatty acids is protective against loss of muscle mass.  As many are sure to proclaim: correlation is not causation.  That claim does not end arguments, although it is often used that way.  It simply means that we need to know more.   This is an interesting study that should lead to further investigation.  Thanks to the team (Alisa Welch, Alex MacGregor, Anne-Marie Minihane, Jane Skinner, Anna Valdes, Tim Spector and Aedin Cassidy) for your hard work.

 

Welch AA, Macgregor AJ, Minihane AM, Skinner J, Valdes AA, Spector TD, & Cassidy A (2014). Dietary fat and Fatty Acid profile are associated with indices of skeletal muscle mass in women aged 18-79 years. The Journal of nutrition, 144 (3), 327-34 PMID: 24401817

New Evidence on the Benefits of Sprinting for Long-Term Health and Fitness

ResearchBlogging.orgBenefits Sprinting and Jumping: New Evidence

I began distance running at the age of 12 and have kept with it for decades now. Running at a mellow pace has helped me unwind, de-stress and keep my sanity through turbulent times. Until I started CrossFit about five years ago. While I miss the runners high there are some great benefits to including weights, varied movement and group training. There is plenty of research on the benefits of running and aerobic exercise. Research on the benefits of resistance training and high intensity interval training (which resembles CrossFit in some respects) is showing that these forms of exercise are important. They may, in fact, be more effective and provide greater benefits for long-term health.  Here is an outline of some possible benefits or sprinting.  Or being a sprinter.

Sprinting and Jumping help you stay strong so you can beat up young people.
Sprinting and Jumping help you stay strong so you can beat up young people.

Today’s Study: Benefits of Sprinting (or being a Sprinter) vs. Other Types of Runners

Today’s study was published last year (2013) in the journal Osteoporosis International.  Subjects were Experienced Masters Runners between 35 and 90 years of age.   Runners were asked to identify their strongest running distance:

  1. Short Distance (400 meters, triple jump and/or long jump
  2. Middle Distance (800 meters to to 1500 meters
  3. Long Distance (2000 meters to marathon)

Information on numbers of years of training, age, gender, age of menarche, and age of menopause (when appropriate) were collected.  Subjects then completed a series of tests:

  1. Bone Mineral Density
  2. Lean Body Mass Evaluation
  3. Grip Strength (this is a marker of general strength and a predictor of strength in old age).
  4. Neuromuscular Function (evaluated by counter movement jumps and hopping)

Findings (aka Results)

Short distance runners and jumpers did better on all measures with the exception of arm bone mineral density.  There were no significant differences in arm bone density among the athletes tested.  While there are a number of limits to the study the sprinters have better grip strength, higher lean muscle mass, stronger bones, and better neurouscular function than middle or long-distance runners.  An unfortunate finding was that all types of athletes experienced a similar rate of decline in strength and coordination with age. Still, it seems better to start high and land in the middle than to start in the middle and face plant during one’s senior years.

Study Limits:  More research is needed on the long-term benefits of sprinting

The study has a number of limits.  Here they are a few that were apparent to me.  There may be more.  Take a look at the article.  There is a link below.

  1. It was not clear if people who identified as sprinters, middle distance runners or long distance runners trained for these events or if they preferred them.
  2. Subjects may have simply had the body and neurological types to be sprinters, jumpers, middle distance or long distance runners and would have showed similar results whether they had been Masters Runners or not.  Are there benefits or sprinting?  Or benefits from being someone with a sprinters body type?  It would also be good to know what differences are seen between runners and jumpers.

Takeaway:

This study supports growing evidence that sprinting may provide benefits not found in jogging or long distance running. Check out this 61 year old Masters Athlete racing against a 16 year old soccer star.
)

 
Gast U, Belavý DL, Armbrecht G, Kusy K, Lexy H, Rawer R, Rittweger J, Winwood K, Zieliński J, & Felsenberg D (2013). Bone density and neuromuscular function in older competitive athletes depend on running distance. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 24 (7), 2033-42 PMID: 23242430

High protein diet is protective for older people, but may be unhealthy for others

We’ve written several articles on the apparent benefits of a higher protein diet for the older athlete.  Loss of muscle mass starts fairly early and loss of strength is often apparent by middle age.  We do not know how much protein intake is ideal for humans.  High protein diets for older people have been geared towards controlling sarcopenia.  Sarcopenia is the term used to describe the muscle loss that happens as people age.  Sarcopenia is a major cause of frailty.  Osteoporosis, where loss of calcium from bones leads to brittleness and fractures, is the other big problem.   Sarcopenia and osteoporosis can be worse for women who have less bone mass and less muscle mass to start with.  A number of studies have shown that older people preserve more muscle if their protein intake is increased.  If older people can preserve more muscle that should mean fewer people needing assisted-living.  Exercise, including resistance exercise also helps preserve muscle.  Exercise also strengthens bone and protects against osteoporosis.  As for the older athlete, preservation of muscle mass may provide a competitive edge.  For more easy-going people, preservation of muscle mass may mean:

  • less of the sinking feeling you get when you realize you know exactly where your body should have been when you took that flying leap for a frisbee.
  • fewer pained expressions on the faces of children when you fail a back flip
  • less aggravation opening jars
woman masters crossfit athlete high protein diet
Masters Crossfit Athlete competes in the Crossfit Games Open 14.1 in the 50-54 age category.

A new study by a team of researchers from the US and Italy examined protein intake in adults over age 50 compared with rates of Cancer, Diabetes, Mortality in general and IGF-1 (a growth hormone) levels.  Study subjects were divided into two groups: ages 50 to 65 and those over 65.  For people ages 50 to 65 a high protein diet increased risk of cancer, diabetes and death in general.  IGF-1 levels were also higher in these adults.  IGF-1is a growth hormone that may preserve muscle mass, but may also increase risk of cancer.  Middle-age users of deer antler velvet, which contains IGF-1, beware.  Researchers also found that people who ate more plant protein had lower death rates than people who ate more animal protein.  In bullet points:

High protein diet for people age 50 to 65

  • High animal protein diet increased risk of cancer by 400% in adults 50-65
  • High animal protein diet Increased risk of death by 75%
  • High animal protein diet increased risk of death from diabetes-related causes by 500%
  • High plant-based protein diet showed little to no increase in death or cancer risk

High protein diet for people over age 65

  • high protein diet reduced risk of cancer and death in people over age 65
  • Risk of death from diabetes-related causes was the same as it was for adults 50-65

Conclusions for dietary protein intake:

The researchers in this case also compared epidemiological findings with data derived from mice, which is unusual.  One of their conclusions was that a low protein intake diet during middle age followed by a high protein intake in later age may “optimize healthspan and longevity.”  I would add some considerations to that:

  1. It didn’t seem to be protein in itself thatwas the main culprit in the study, although there was some interesting data on ifg-1 levels and protein intake.  One of the problems with some forms of animal protein (meat) is that carcinogents (cancer causers) may form during high heat cooking. 
  2. Animal fat will contain more lipophilic chemicals than vegetable fats.  Some lipophilic chemicals build up in humans over time. 
  3. It seems likely that something besides protein is causing the problem. 
  4. There may be other considerations for post-menopausal women, who seem to weather aging (functionally) better when protein intake is higher.
  5. People age 50-65 are different than people 65 and older.  The 65 and older group may already have weeded out people who were vulnerable to heart disease.  (This would probably not hold for cancer).

High protein diets have been popular for a number of years now.  High protein diets, especially meat based high protein diets, have been especially popular in the Crossfit Community.  Unless you are a middle aged adult, a high animal protein diet may be bad for your long-term health.    It would be nice to know what the results would be if high-fat/high protein/poor lifestyle/obesity was separated from high protein/healthy lifestyle/healthy weight.  Hopefully the researchers will continue this line of inquiry. 

 

Levine, M., Suarez, J., Brandhorst, S., Balasubramanian, P., Cheng, C., Madia, F., Fontana, L., Mirisola, M., Guevara-Aguirre, J., Wan, J., Passarino, G., Kennedy, B., Wei, M., Cohen, P., Crimmins, E., & Longo, V. (2014). Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population Cell Metabolism, 19 (3), 407-417 DOI: 10.1016/j.cmet.2014.02.006

Gregorio L, Brindisi J, Kleppinger A, Sullivan R, Mangano KM, Bihuniak JD, Kenny AM, Kerstetter JE, & Insogna KL (2014). Adequate Dietary Protein is Associated with Better Physical Performance among Post-Menopausal Women 60-90 Years. The journal of nutrition, health & aging, 18 (2), 155-60 PMID: 24522467

Beasley JM, Wertheim BC, LaCroix AZ, Prentice RL, Neuhouser ML, Tinker LF, Kritchevsky S, Shikany JM, Eaton C, Chen Z, & Thomson CA (2013). Biomarker-calibrated protein intake and physical function in the Women’s Health Initiative. Journal of the American Geriatrics Society, 61 (11), 1863-71 PMID: 24219187

Protein intake throughout the day increases muscle protein synthesis by 25%

New research on protein intake: protein each meal results in more muscle protein synthesis than the same amount of protein eaten in one meal

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Protein synthesis is a high-interest topic of athletes and many male recreational athletes. Well-developed muscles are signs of health, strength and virility in men. Well-developed muscles are also important for women. Muscles as well as bone are lost as we get older. Much attention has been given to avoiding osteoporosis. Osteoporosis can lead to fractures, spine malformation, pain and loss of independence. Sarcopenia is the muscle equivalent of osteoporosis. Muscle mass is lost a bit each year. That can accelerate in menopausal women. Loss of muscle can lead to weakness, frailty and loss of independence too. Sarcopenia also happens to men. It is important to take care of “muscle health,” even if you’re not interested in looking jacked.

Timing of protein intake

There are some advantages to late protein intake. Protein intake before bed increases muscle synthesis. But what about the rest of the day? Many people get most of their protein at dinner. Many get most of their carbs at breakfast. Is there an advantage to spreading protein intake out over the course of your day? It looks like the answer is Yes.

The Research:

Researchers looked at 24 hour muscle protein synthesis in a group of healthy adults (men and women). The subjects were first given a diet with most of the protein consumed at night (about 10 grams at breakfast, 16 grams at lunch and 63 grams at dinner). This was followed by a second diet where protein was consumed evenly at three meals (average about 31 grams per meal). Subjects stayed on each diet for seven days.

The results:

Protein synthesis was 25% higher when subjects consumed protein evenly at each meal.

Take away:

Its better to have protein with breakfast, lunch and dinner than having a big high protein meal at night. This runs counter to some current diet practices among the health conscious such as intermittent fasting or eating one meal a day. For more information on intermittent fasting see this article by Dr. Jose Antonio of the International Society of Sports Nutrition.  Those practices may not be beneficial for prevention of muscle loss although they may be beneficial for other reasons.  The paper is written more with an eye towards preventing sarcopenia in the ill and the elderly. The authors do suggest that the amount of protein in the RDA is low for optimal health.  I don’t know of any research that’s been done on protein timing and performance for athletes.  If anyone does, please send a link.

“There is broad agreement among many protein researchers
that the RDA for protein [0.8 g protein/(kgd)], although
sufficient to prevent deficiency, is insufficient to promote optimal
health, particularly in populations exposed to catabolic stressors
such as illness, physical inactivity, injury, or advanced age (4,22–
25). Several recent consensus statements have suggested that a
protein intake between 1.0 and 1.5 g/(kgd) may confer health
benefits beyond those afforded by simply meeting the current
RDA (4,26,27). In the current study we provided diets that
exceeded the RDA for protein by 50% but were consistent with
the average daily protein intake of the U.S. adult population [i.e.,
1.2 g protein/(kgd)]”

 Dietary Protein Distribution Positively Influences 24-h Muscle Protein Synthesis in Healthy Adults J. Nutr. jn.113.185280;

 

Resistance and Aerobic Training: New research says both together is better for heart health

Heart disease is the most common cause of death in older adults.  Heart disease kills about 600,000 Americans annually.  Heart disease is the most common cause of death for women.  It is more common than breast cancer, which tends to get more attention.  Many women who suffer heart attacks do not have previous signs of symptoms (approximately 2/3rds will have a sudden heart attack).  Major risk factors for heart disease are:

  1. High blood pressure
  2. Obesity
  3. Poor blood lipid profile (dyslipidemia)
  4. Inactivity
Coconut oil and CrossFit Masters
CrossFit Masters Athletes combine aerobic and resistance training all the time.

An obese individual can expect to lose 6-7 years of life.  This can matter a lot to the individual, but also to his or her family, who may lose that person’s love, support and companionship.  Exercise reduces all four of the major risk factors for heart disease.  The Centers for Disease Control (CDC), The American College of Sports Medicine and the American Heart Association all recommend 20-30 minutes of moderate-to-vigorous exercise every day for adults.

Resistance training is also recommended, but with an eye to improving functional fitness into old age.   Little research has been done on the benefits of resistance training as a means of improving cardiovascular health.

Exercise:  resistance training and aerobic training reduced risk of heart disease

A new study from the Research Center in Sports Science, Health Sciences and Human Development and the Research Center in Physical Activity, Health and Leisure, Faculty of Sport and the University Porto, in Porto, Portugal examined the effects of aerobic training alone vs. aerobic and resistance training together and got some interesting results.  Here are some of the study details:

  • Subjects were 59 older men
  • Men were divided into three groups: Aerobic training, aerobic and resistance training or no training.
  • None of the men had cardiovascular disease, high blood pressure or was severely overweight
  • Men had no previous history of exercise training or recreational sports

The Training Programs lasted 32 weeks:

  • Aerobic Training Group: ran or did brisk walks two days a week and swimming training 1 day a week at levels that were perceived by participants as “moderate intensity”.  Each training session included a 10 minute warm up, 3 sets of 15-20 rep body weight exercises and a five minute cool down with stretching.  Subjects did agility exercises in the pool for 10 minutes each session.  Agility exercises included water volley-ball and water polo.  Sounds like a fun program.
  • Resistance and Aerobic Training Group:  did the same exercises as the Aerobic Training group except that one of the dry-land aerobic sessions was replaced with resistance training.  Resistance training consisted of 65% of one rep max with three sets of 8-10 reps of bench press, leg press, lateral pull-down, leg exension, military press, leg curl and arm curl.  Subjects also worked on their abs and backs.
  • Control Group: carried on with normal life

Results:

No improvements in hypertension , obesity or dyslipidemia were seen in the Aerobic Training Group.  Disappointing.   Maybe a longer training period was needed.  Hard to say.  Improvements were observed in the Resistance and Aerobic Training Group.  Improvements were seen in:

  • Hypertension
  • Dyslipidemia

Discussion:

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Eye Pood Kettlebell Shirt by WODMASTERS

Why didn’t the aerobic training group show improvements?  Perhaps the exercise program wasn’t intense enough.  Maybe improvements would have been seen if the exercise program had lasted longer.  Maybe it is important to increase the intensity beyond moderate, especially over time.   Perhaps the resistance training program provided more aerobic training.  8-10 reps may be like short sprints for the cardio-vascular system. Short bouts of intense exercise can be very effective (See High Intensity Impact Training).  More research is needed, but for what we have so far it looks like combining both is better than just aerobic training alone.  If you do crossfit you are doing this already.

 

Sousa N, Mendes R, Abrantes C, Sampaio J, & Oliveira J (2013). Long-term effects of aerobic training versus combined aerobic and resistance training in modifying cardiovascular disease risk factors in healthy elderly men. Geriatrics & gerontology international, 13 (4), 928-35 PMID: 23441809

Polyunsaturated fats may protect against loss of muscle mass

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Our previous post (see below or click here) discussed the impact exercise on long-term strength.  In a nutshell, exercise has long term effects, even after the program has been halted.  This week we will talk about new research that shows that dietary fats may also be important for muscle mass.  Who’d have thought?  Researchers are unsure how it works, but . . . dietary fat may influence protein turnover through its effects on inflammation and insulin.  This may be important for long term health.   Preserving muscle mass may be important for athletes and for maintaining a competitive edge.  Loss of muscle mass occurs with age and is one of the leading contributors to frailty in the elderly.  Preserving muscle mass may also allow people to enjoy active lives longer.

A study just published in the Journal of Nutrition  looked at what types of fats were eaten by 2,689 women who are part of the UK study of twins.  The women were between the ages of 18 and 79.  Researchers also looked at ratios of the different types of fats (polyunsaturated /saturated fats), the percent of calories obtained from fat and the womens’ fat free mass.   “Fat Free Mass” is used as an indicator for muscle mass.  Its imperfect.  Bone, of course, has mass.  But people with higher fat free mass usually have more muscle mass.

Women who ate more polyunsaturated fats had the most fat free mass.  Women who ate more transfats, saturated fats and monounsaturated fats had less fat free mass.  The researchers also noted that the difference in fat free mass between women who ate mostly unsaturated fatty acids and those who ate mostly saturated fatty acids was about the same amount of fat free mass loss that occurs over the course of a decade.  Interesting.   These are, of course, correlations.  More research will be needed to find out if it is certain that unsaturated fats can protect people from age-related loss of muscle mass.

Good sources of unsaturated fatty acids include:

Olive oil
Avocado
Flax
Nuts
Etc.

Welch AA, Macgregor AJ, Minihane AM, Skinner J, Valdes AA, Spector TD, & Cassidy A (2014). Dietary Fat and Fatty Acid Profile Are Associated with Indices of Skeletal Muscle Mass in Women Aged 18-79 Years. The Journal of nutrition PMID: 24401817

Masters Athletes: Long-Term Impact of Strength Training on Muscle Strength

A Crossfit Masters Athlete shares his outlook with a young Crossfit trainer
A Crossfit Masters Athlete shares his outlook with a young Crossfit trainer at CrossFit Seven in Fort Worth, TX

We can expect to lose about 1% of our muscle strength each year after age 50. By age 65 that rate of loss increases. There are some interesting differences in the how and why of strength loss. When researchers look at strength they tend to look at static muscle strength and dynamic muscle strength. Basically static muscle strength refers to the ability to generate a force. Dynamic muscle strength basically refers to strength in which bones and tendons actually move. As people get older dynamic muscle strength suffers more than static muscle strength. Muscle power (the ability to do a strength movement quickly) also suffers. Muscle power declines faster than strict strength. This is one of the reasons why Masters Athletes, particularly Crossfit Masters Athletes, do not perform as well as younger athletes. You can tell a Masters Athlete over and over that he/she needs to move quickly in order “to get under the bar.” But, simply put, Masters Athletes are physiologically different than younger athletes. As stubborn and strong as they are, they may not be able to move their elbows any faster. At least not yet.

Don’t give up on Masters Athletes. Don’t give up in general.

Strength training can improve muscle strength and muscle power in Masters Athletes. This has been documented in short-term studies. But what about over the long haul? A recently published study sheds some light. A fairly large group of older adults (233) participated in a 1-year strength training program. Measurements were taken before and after. Researchers also evaluated the condition of 83 former participants some 7 years later. Strength and power improved in adults who completed the training. (This is hopefully no surprise). What is surprising and good news is that the adults who completed the training had better measures of strength, power and speed seven years after completing the program. Measures for everyone (trained and untrained) were lower than they had been though.

This study has its limits. It was not clear (or unknown) if subjects kept working out or not. Nor was it known how much more or less active subjects in the control group might have been. Still, it is nice to know that positive effects were seen seven years after an exercise program was completed.

Take away message:

So far research (and anecdotal evidence) indicate you should not stop working out. Trainers: keep encouraging your masters athletes.

Kennis E, Verschueren SM, Bogaerts A, Van Roie E, Boonen S, & Delecluse C (2013). Long-term impact of strength training on muscle strength characteristics in older adults. Archives of physical medicine and rehabilitation, 94 (11), 2054-60 PMID: 23831385

Running and Arthritis? It looks like running protects joints instead.

running and arthritis?  Doesn't look like it.
Running and arthritis? Neither of these turds has needed a hip or knee replacement yet. Shoulders are a completely different matter. At Crossfit Seven in Fort Worth, TX.

Arthritis can be crippling and painful.  We can safely say that no one wants arthritis, however, many of us will get it anyway.   Research in this area has been confusing.  There has been a fair amount of research on exercise and arthritis with many finding an increased risk with exercise and other finding decreased risk.  There are probably many factors involved and many reasons why one study produces on result and similar study does not.  The type of exercise may be key.  Common belief has been that running would lead to arthritis in the knees or hips. That particular belief seems to be incorrect.  Running may in fact protect the knees and hips and prevent arthritis in these areas.  There are a number of ways be which exercise may protect joints:

  • Strengthening of cartilage and connective tissue
  • Increased production of elasticity protective factors like cartilage proteoglycans
  • Helping people maintain a healthy weight so that joints are less stressed on a daily basis.

The first two factors are important because thinned, inelastic tendons go hand in hand with osteoarthritis.  Osteoarthritis is usually caused by injury or wear and tear rather and not an auto-immune process.

The National Runners Health Study Results

The National Runners Health Study is a study of about 60,000 runners and 40,000 walkers that began in 1998.  50,000 or these original volunteers completed a survey in 2006.  A recent report using data from the National Runners Health Study found no increased risk of osteoarthritis or hip replacement among recreational runners.  This included runners who completed multiple marathons and regularly exceeded recommended guidelines for exercise.   In fact, the number of marathons run did not seem to have much to do with arthritis risk.   Risk of arthritis and hip replacement was lowest in subjects that ran more than 8 miles a week.

People who walked also had less arthritis and hip replacements, but the benefit seemed to be greater for runners.  The researchers calculated that about 1/3 to 1/2 of the decreased risk of arthritis was simply reduced body mass index (BMI) in people who run or walk.
Williams PT (2013). Effects of running and walking on osteoarthritis and hip replacement risk. Medicine and science in sports and exercise, 45 (7), 1292-7 PMID: 23377837

Timing of protein intake: 20 grams of protein within 2 hours of exercise builds muscle with max efficiency

Timing of Protein intake builds muscles after resistance training.

Timing of protein intake matters.
Timing of protein intake can matter. Before or shortly after exercise seems to work best.

Today’s topic is an overview of dietary protein and amino acids and how these help build muscle and prevent muscle loss.  First, just a tiny bit about proteins and amino acids.  Proteins are made of amino acids.  Proteins are (for the most part) broken down into amino acids during digestion.  Once that happens they can be reassembled into whatever proteins your body needs.  Amino acids are hugely important to physiology.  They are needed for enzymes, hormones, hair and other things.  For most people, the first thoughts of protein and amino acids are muscle.

There is good evidence that consuming protein directly before or after resistance training reduces muscle breakdown and increases muscle mass accumulation.  The fine points of how much, which amino acids and exactly when they should be taken are under investigation.  Here are a few highlights.  Bear in mind that these may change as research continues:

  • Timing of intake: so far it looks like protein has its best protective effect when taken just before or soon after resistance training.  Consuming protein as late as two hours after exercise doesn’t seem to work as well as consuming proteins within five minutes of an exercise session.  Keep in mind that this timing difference may not matter functionally.  Even without extra protein, muscles are in active building mode for about 48 hours after exercise.
  • Which amino acids: How different amino acids stack up against each other is unknown to date.  Studies conflict.  One study is not necessarily wrong.  Two studies can conflict and still provide valuable information.  Results that seem to contradict one another may be caused by differences in how the study was done.  How old were the subjects; were they all men, or men and women?  What was the timing?  What training protocol was followed?   How much protein was given?  What else were the subjects eating or doing in their real lives?
  • How much: 20 grams of amino acids (or protein in a meal) seems to induce maximal results for young adults.  Older adults and elderly people may need more to get the same benefit.  This is probably because they (we) aren’t as efficient as we used to be.  Bummer.  But there you go.  Elderly people taking 35 grams of amino acids after exercise have had better results than elderly people taking 20 grams of amino acids. Elderly people in one study needed 40 grams of protein to reach maximal rate of muscle protein synthesis.

Timing of Protein Intake and Amino Acids can help prevent muscle loss during dieting.

Protein intake is important body builders and hyper-jacked crossfit nuts.  But it is also important to people on weight loss programs.  Increasing protein while dieting can help preserve muscle mass.  Preserving muscle mass matters to many people for aesthetic reasons.  Muscle gives form and definition.  Having well-developed muscle may also help people keep weight off.  That is pretty well accepted.  Less attention is given to the importance of preserving muscle mass during aging.  People who are constantly dieting and losing muscle mass may end up with even less when they are older.  Loss of muscle with aging is a major cause of frailty and loss of independence.   People with no interest in sporting huge muscles should still pay attention to this aspect of health.

Protein after exercise

If you are a young adult you can get your 20 grams of protein by using a protein bar or shake.  Powerbar makes a bar containing 20 grams of protein at a cost of about $2.00.  You could also have a glass of milk and a whole wheat peanut butter sandwich at a cost of about $0.60.  The milk and peanut butter sandwich would have about 23 grams of protein.  You could save $1.40 each time.  Please consider donating that money to research.  Many of our Paleo Diet readers will consider milk, bread and peanuts as horrors of the dark.  Its OK to eat these things.  Especially if the alternative is refined snacks, processed food or junk food.

If you are a masters athlete or older adult you may need to think about the extra calories you might get from two glasses of milk and two peanut butter sandwiches.  Timing meals with exercise may help.

Take away:

Twenty grams of protein within 2 hours of exercise helps build muscles with maximal efficiency.  Older adults may need 35 to 40 grams to get the same effect.

ResearchBlogging.org

Churchward-Venne TA, Murphy CH, Longland TM, & Phillips SM (2013). Role of protein and amino acids in promoting lean mass accretion with resistance exercise and attenuating lean mass loss during energy deficit in humans. Amino acids, 45 (2), 231-40 PMID: 23645387

Children's outdoor play may protect them from nearsightedness

250x400 Birth of Venus BannerToo much time spent indoors may make children nearsighted.  Not long ago people thought that reading too much was bad for the eyes, or that other forms of “close work” would lead to poor vision.  Maybe there is something to that.  Research over the last few years has revealed increasing rates of nearsightedness.  In the US, about 30% of the population is nearsighted (Vitale et al. 2008).   The incidence of nearsightedness has nearly tripled among African Americans.  Much of the research on increasing rates of myopia has been done in Asia, where rates of nearsightedness, especially in children are particularly high and seem be rising.

Nearsightedness: too much time in front of a screen?

Is it too much time spent doing “close work” such as reading, video games, internet activity and/or homework?  An alternative factor might be lack of sunlight.  People (including children) who spend a lot of time on the computer, reading and doing homework are probably getting a lot less exposure to natural light.  Of course there may be other factors in play, for example:

  • less shifting of focus from near to far (which would happen during outdoor activity).

Or not enough sunlight?

Time outdoors is looking like the major factor.   A recent study found that elementary school children who played outdoors during recess had better vision than those who spent recess time indoors.  Students were ages 7 to 11 attending similar schools only a few miles apart.  Students in both schools got 2 hours of outdoor physical education a week and 80 minutes of recess every day.  Children had visual exams at the start of the study and an additional exam a year later.   There were significantly fewer new cases of myopia in the children who got the extra 80 minutes of daily outdoor recess.   This is a very exciting finding and an exciting area of research.  How many of us have just assumed the need for glasses was genetic?

You can read more about environmental factors and nearsightedness in this excellent article by Tim Lougheed in  Environmental Health Perspectives.

Vitale S, et al. Prevalence of refractive error in the United States, 1999–2004. Arch Ophthalmol 126(8):1111–1119 (2008); http://dx.doi.org/10.1001/archopht.126.8​.1111.

Jones LA, Sinnott LT, Mutti DO, Mitchell GL, Moeschberger ML, & Zadnik K (2007). Parental history of myopia, sports and outdoor activities, and future myopia. Investigative ophthalmology & visual science, 48 (8), 3524-32 PMID: 17652719

Vitale S, Sperduto RD, & Ferris FL 3rd (2009). Increased prevalence of myopia in the United States between 1971-1972 and 1999-2004. Archives of ophthalmology, 127 (12), 1632-9 PMID: 20008719

Wu PC, Tsai CL, Wu HL, Yang YH, & Kuo HK (2013). Outdoor activity during class recess reduces myopia onset and progression in school children. Ophthalmology, 120 (5), 1080-5 PMID: 23462271

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