It’s one of the (many) challenges that inevitably awaits us once we cross the 40-year threshold: maintaining, or better yet, strengthening and building our muscle mass. In fact, keeping muscles strong and resilient is an essential strategy for longevity: it not only helps us avoid the onset of the dreaded sarcopenia (the loss of muscle mass due to aging), but also helps prevent conditions such as cardiovascular disease and diabetes, as an increasing number of studies confirm.
Toned, agile muscles protect bones that become fragile with age, helping to combat osteoporosis as well. That’s why Dr. Stacy Sims, a nutrition scientist and professor at Stanford University, is one of the many experts who recommend strength training. But that’s not all: they also urge people to consume more foods rich in protein and amino acids, which are essential for building athletic-level muscle mass. Among these, one in particular plays a crucial role in muscle maintenance, growth, and recovery: leucine.
What is leucine?
Leucine (or L-leucine) is an essential branched-chain amino acid (like isoleucine and valine) that is not made by the body and must therefore be obtained through diet. This amino acid is particularly important for protein synthesis, muscle growth, and post-workout muscle recovery.
The benefits of leucine
- Helps with muscle growth and development
- Helps maintain muscle mass even in older age, when it tends to decline
- Helps protect muscle mass during weight loss, when the goal is to burn fat rather than muscle
- It aids in the repair of muscle fibres damaged during training and speeds up post-workout recovery
- By playing a role in the formation of immune cells, it supports the immune system
- It supports collagen production and skin regeneration
- It speeds up the wound-healing process
- It may help control body weight by maintaining lean body mass and influencing the production of leptin, the “satiety hormone”
- Some preliminary studies suggest it may also be beneficial for brain health
How much leucine should you get per day?
The generally recommended dose is 4.2 to 4.5 grams per day, but the exact dose for each person is calculated based on body weight (55 milligrams per kilogram of body weight).
10 leucine-rich foods
It’s commonly believed that the foods richest in protein—and consequently in amino acids like leucine—are exclusively those of animal origin. But you don’t have to necessarily have to load up on meat, fish, and poultry, especially if you follow a plant-based diet. Some unexpected foods provide us with abundant amounts of leucine without having to resort to supplements. Plus, they’re easy to digest, versatile and packed with other nutrients that make us feel great. Let’s discover these leucine-rich foods:
Soybeans
Soybeans are an ancient legume with exceptional nutritional value. The protein-rich food contains vitamins, minerals, cholesterol-fighting lecithin, and hormone-balancing phytoestrogens. And they’re among the foods richest in leucine: they contain 3.5 grams per 100 grams, which is more than beef.
Parmesan
The hard cheese contains 3.4 grams per 100 grams (chicken breast provides three grams). However, since this aged cheese is also high in fat, including saturated fat, and fairly high in calories, alternate it with leaner options like ricotta or cottage cheese, which are also good sources of leucine.
Sesame seeds
These tiny seeds are packed with nutrients (minerals such as calcium, magnesium, and zinc; B vitamins, and protein), making them an elixir of health and beauty. Black sesame seeds are believed to even prevent gray hair. The seeds are also rich in leucine: two tablespoons contain 0.25 grams. Sprinkle them on salads, pasta dishes, grains, and legumes or add them to your favorite smoothie.
Eggs
Universally beloved, eggs are packed with nutrients such as protein, minerals, and choline, which are good for the brain, as well as antioxidants like lutein and zeaxanthin, which are beneficial for eye health. In addition, one egg contains 0.6 grams of leucine. Eat a couple in the morning before your workout, for lunch or dinner after your workout, or munch on a hard-boiled egg as a snack, even at the gym or while travelling.
Pumpkin seeds
Pumpkin seeds are a superfood that’s easy to enjoy at any time of day. In addition to vitamin E, which promotes healthy skin, they contain healthy, anti-inflammatory fats, protein, fibre and minerals such as magnesium, zinc, iron and manganese. Three tablespoons of these crunchy seeds also provide 0.65 grams of leucine. Add them to your smoothie, sprinkle them on your muesli and enhance soups and salads with an extra dose of flavour and nutrients.
Lentils
These tasty legumes, rich in antioxidants, fiber, and protein, are the perfect addition to almost any meal. One cup of lentils provides 1.3 grams of leucine.
Hemp seeds
Hemp seeds are a phenomenal source of plant-based protein and amino acids like leucine. Three tablespoons of these seeds contain 0.25 grams of the amino acid.
Peanuts
A staple of the aperitif, peanuts aren’t just a delicious salty snack. These nuts are among the best plant-based sources of leucine, containing 1.5 grams per 100 grams. They’re also rich in vitamin E, which is good for your skin, as well as plant-based protein, fiber, healthy fats, and minerals like magnesium, potassium, zinc, and copper.
Spirulina
This anti-inflammatory algae is a true superfood: it provides minerals such as calcium, potassium, and magnesium, B vitamins, and antioxidants. In addition to all the essential amino acids, two tablespoons of this blue-green microalgae provide 0.69 grams of leucine.
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