5 Nutrients That Boost Muscle Strength & Tone


Everyone who engages in a physical fitness program has one thing in common: they wish to improve muscle strength and tone. But what exactly do these terms mean? Strength is the muscle’s ability to produce force against an object. Tone refers to how efficient the muscle is in regards to responding to external stimuli – a weight or other object of force – as well as how the nervous system communicates and responds to stimuli. These two components are of great importance to athletes, weekend warriors and even the couch potato. And, both are required to work properly in order to move our bodies.

Most fitness enthusiasts are aware that protein and amino acids are necessary for muscular strength. So we are going to focus on five nutrients that work indirectly to support and improve your muscles’ ability to function appropriately.

Vitamin D

This fat-soluble prohormone has two main forms: D2 and D3. Upon becoming active in the body, vitamin D is referred to as calcitriol. Calcitriol is extremely important when it comes to utilizing calcium and phosphorus, both of which play an important role in muscular contraction and bone growth. Phosphorus assists with production of ATP, which is the primary source of energy in short bouts of activity such as resistance training. Through vitamin D, absorption of calcium and phosphorus in the intestines improves, blood calcium is increased and calcium reabsorption occurs in the kidneys.

Sunlight triggers the body’s natural production of vitamin D. But most of us, particularly those with limited sun exposure, dark skin and older adults, may need more vitamin D, and supplementation of 1000 IU daily is recommended. Some may require even more vitamin D. If you suspect you are deficient, it might be wise to ask your physician to check your vitamin D levels.

Vitamin D naturally occurs in very few foods. The best food sources are fish, such as salmon, tuna and swordfish, as well as cod liver oil and egg yolks. Many foods are fortified with vitamin D, such as milk, cereals and some brands of orange juice.


Nature’s antibiotics populate the digestive tract and other areas of the body and help establish a healthy immune and digestive system. Two groups of particular importance in regard to muscle strength and tone are bifidobacterium and Escherichia coli (E. coli).

The bifidobacterium group colonizes a large portion of the healthy gut and intestines. The importance of these bacteria being present in the case of muscle strength and tone is to help synthesize and utilize vitamins and amino acids, including vitamin K and the B group. Bifidobacterium also assist with absorption of calcium, iron and vitamin D.

Physiological strains of E. coli, which are necessary for healthy normal functions of the body, offer many of the same benefits as bifidobacterium, assisting with vitamin and amino acid synthesis. None of the nutrients listed in this article will help if they can’t be properly used by the body. Supplementation with probiotics helps populate the body with these healthy bacteria to aid in utilization of nutrients.

A good probiotic supplement will contain strains from at least three different groups: lactobacilli, bifidobacterium and bacillus strains. Adult daily intake can range from 1 billion to 10 billion live organisms split between one to four doses, with 10 billion to 20 billion total units consumed daily. There is no upper limit set for probiotic supplements. Probiotics occur naturally in fermented or cultured foods, such as yogurt, kefir and lacto-fermented sauerkraut and kombucha in addition to quality dietary supplements. Check food labels for the words “lacto-fermented” or “live cultures” to know you are getting a probiotic food, as many modern sources are no longer traditionally fermented.

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This amino acid has long since been linked to muscle energy production via a process called lipolysis, which breaks down triglycerides into free-fatty acids. Dr. Tracey Greenwood, an IFBB fitness pro and associate professor of biokinetics at Eastern University, said, “Because the fatty acid cannot cross the mitochondrial membrane on its own, the amino acid carnitine carries the fatty acid into the mitochondria. Once the fatty acid is in the mitochondria, it can go through beta oxidation and oxidative phosphorylation to make ATP, which the body uses for energy.”

Jamie Free, CPT, refers to carnitine as “the furnace of fat cells.” He also weighs in on how he supplements with L-carnitine to maximize hormone production: “What most people don’t know is that supplementing with carnitine post workout has shown the ability to decrease muscle breakdown and damage as well as opening androgenic receptors for ‘free’ testosterone,” he said. “I personally use a capful of Max LiquiCarn in my Max ARM post workout shake to help burn fat and protect from further muscle breakdown. Couple that with 2TX, Max Muscle Nutrition‘s testosterone amplifier, and you have a lean muscle-making machine.”

Related: The Many Benefits of L-Carnitine


You may not consider caffeine a strength-producing supplement, but it can be just that. Studies have not yet discovered exactly why, but they have shown that caffeine consumption one hour prior to exercise improves endurance, strength and power output. The American College of Sports Medicine reports that consumption of 3-9 mg of caffeine per kg of body weight one hour before exercise in trained individuals increased cycling endurance and running performance. For a 150-pound person, this equates to 200-600 mg caffeine or 1-2 regular size cups of coffee.

Coenzyme-Q10 (CoQ10) 

CoQ10‘s basic function is to provide cellular energy. Dr. Tracey Greenwood, who holds a Ph.D. in exercise physiology, explains the chemical process: “The energy produced from this process … is converted to chemical energy in the form of ATP molecules. CoQ10 plays the role of ‘mobile messenger’ in the electron transport chain. Optimal levels of CoQ10 must be present in the mitochondrial membrane in order for the electron transport chain to generate efficient levels of ATP.” Studies on CoQ10 supplementation indicate no adverse effects with as much as 1200 mg daily intake. The Observed Safe Level, therefore, has been set at this amount. Supplements often occur in doses of 60 mg or 100 mg.

By Alissa Carpio