Leucine for muscle mass

Leucine is one of the most potent amino acids for the stimulation of muscle protein synthesis and growth in men over 50.

Leucine is an "essential" amino acid.

Leucine benefits include the production of growth hormone, energy, and regulating blood sugar.

Our primary interest here is in the role it plays in our body's muscular system. This might just be the best amino acid for men over 50 who want to retain muscle. And who over 50 doesn't?

Five benefits of leucine.

1. Muscle building.
2. Muscle maintenance.
3. Muscle recovery & performance.
4. Weight control.
5. Your body can't produce it.

We need leucine in our diets, either from foods or supplements. The link below provides more information on essential amino acid profiles, including leucine and why it is important, as well as how amino acids benefit a healthy functioning 50-year-old plus body.

Read more on leucine, and the benefits of leucine for muscle health below.  

Why is leucine important?

Leucine is one of the three branched-chain amino acids (BCAAs) alongside valine and isoleucine.

It is also a favourite amongst athletes due to its ability to boost muscle mass and improve performance.

Compared to the other BCAA's, leucine is broken down and absorbed more rapidly.

Nitrogen balance.

A negative nitrogen balance occurs when urinary nitrogen losses exceed oral intakes. A negative nitrogen balance suggests a loss of nitrogen, which in turn is associated with a loss of muscle protein.

Training

Resistance training, for example, has occurred, and no subsequent feeding has occurred. Where feeding occurs, a positive nitrogen balance occurs. This reflects the process of gain or loss of total body protein.

The greater the balance, the faster the recovery post-exercise or work-out. If negative, nitrogen is drawn away from the muscle where it is needed for growth and can also destroy muscle.

Over-training generally means a breakdown of muscle tissue.

Rest and protein are thus required. Too much training and too little protein means a negative nitrogen balance. 

In a test of men and women aged 56 - 80 years old, those consuming higher levels of protein avoided a negative nitrogen balance and the associated impact on their muscles. You can read the research here. Leucine results in a net loss of nitrogen from the muscle. (PubMed)

Leucine levels.

As you age, you are likely to lose muscle as your physiology resists building new muscle.

Muscle loss starts from around 30 years old and in certain cases earlier. From 0.5% to 2% of total muscle mass can be lost each year. The good news is protein, and exercise can help avoid this, and in fact, show muscle gains.

Higher leucine levels in the blood not only support muscle maintenance and repair, but can also benefit endurance, and enhance the immune system.

Protein helps buffer the aging process, according to Layman (See above),

Leucine is the amino acid that is the key threshold to the synthesis of muscle tissue.

Pass this threshold which will be higher as you get older and muscle synthesis triggers. Longer-term essential amino acid supplementation can be useful for the prevention of Sarcopenia, especially if excess leucine is provided.

Whey protein is a great source of leucine.

Having too much leucine, however, can interfere with the production of Niacin and impact mood. High doses can be toxic. 

Leucine studies.

#1. 48 health subjects aged 55 years to 75 years old with BMI ranges of 19 to 30 were evaluated over a 12-week period with leucine-rich supplementation and placebo approach and moderate exercise.

The supplementation of leucine resulted in reduced loss of strength and improved recovery.

Findings included the fact that leucine counteracted the negative effects of eccentric exercise and a reduction in exercise-induced strength loss. You can read more on this research from the BMJ Open Sport & Exercise Medicine Journal here. 

#2. Leucine supplementation was given to 13 men new to resistance training and a further 13 received placebo lactose. The average BMI was 24.9 and the average age was 28 years old. All did supervised training twice a week using 8 standard machines. Testing was done as a baseline and at the end of the period and was assessed with repetition maximum and dual-energy X-ray absorptiometry.

The group receiving leucine demonstrated significantly higher gains in strength in 5 of the 8 exercises.

This was done over a 12-week period. You can read the detailed research at the National Library of Medicine here.

#3.  More on leucine and muscle synthesis in the research from Today's Dietician. Evidence-based recommendations for optimal protein intake in older people.

There are several other studies around leucine to support this as well as those included in the section, The Benefits of leucine.

Leucine sources.

There are a number of leucine-rich foods available. Common foods you can include in your daily diet are:

• Eggs
• Chicken
• Cottage cheese
• Peanuts
• Grass-fed beef
• Oats
• Tuna fish
• Supplementation

Also, included in Old Bull Health protein powder.

Summary

Leucine is an essential amino acid found in protein that your body cannot produce.

Leucine can help gain and retain muscle mass and improve performance. You can get it from supplements or a well-balanced and healthy diet. 

Read more about Protein in our Protein Guide.