Press "Enter" to skip to content

The Science Behind Sports and Fitness Nutrition Supplements

Sports and fitness nutrition supplements are designed to achieve several objectives once in the body – (1) to supply rapidly accessible forms of energy, (2) to replenish electrolytes to the muscle cells, (3) to replenish neurotransmitters, and (4) to supply high levels of antioxidant nutrients into the system to prevent damage to the cells in the muscles and in other parts of the body.

Most of us can recall running out of breath after a sprint – and feeling aches in our lower leg muscles, and probably breaking a sweat as your body heats up. Physical activity or exertion does that to our bodies, and this is normal and natural. These reactions to intense activity and physical exertion in fact are the reasons most of us can’t stick to a regular exercise routine.

Fitness enthusiasts however, as well as amateur and professional athletes have to endure this “punishment” on a daily basis and to put up with the discomfort.  Their bodies also have to recover quickly from the exertion and fatigue so that they are in shape to do it all over again in hours, not days.

This is where sports and fitness nutrition supplements can really help. They can increase endurance, performance, and greatly help to speed up post-workout recovery.

Supplements ideally should achieve these goals without filling the digestive tract with food or other bulk, because that would start the process of digestion, which takes energy and draws more blood into the digestive tract – blood and energy that would be better used elsewhere for the sports or fitness activity.

How our bodies generate energy for exercise and physical exertion

When we engage in physical activity such as running or weight training we start a process that invokes an incredibly complex and vigorous interaction between all our body’s systems. The basis of any exercise or exertion of course is the burning of fuel.

Food supplies fuel to our muscles in the form of nutrients. Inside of our cells, mitochondria are the basic engines that consume food molecules. They also release heat and store energy for the other functions of the cell.

Muscle cells use the energy to contract. Muscular contraction and release (or relaxation) is the basis of all human activity. During exertion the body loses water as well as electrolytes through sweat and through the lungs as you breathe out.

These electrolytes and the water must be replaced – the faster the better, for peak performance. While we exert our muscles, neurotransmitters are consumed at a prodigious rate and they too must be re-synthesized out of nutrient substrates (building blocks) that are rapidly consumed in the muscle cells. Again, the faster that this happens, the better, to maintain peak performance.

A Theory of Human Energy

Living cells are glucose-burning machines. In nature glucose comes from plants, which have this awesome ability to produce it from solar energy and the minerals they get from the soil, along with the carbon dioxide and oxygen they get from the air.

The energy that supports us human beings is stored in the molecular bonds of a few basic fuel molecules… you have glucose, you have fructose, fatty acids, and the amino acids.

This energy is released when these energy-supplying molecules are broken down. This chemical reaction that breaks down the energy molecules can be called “oxidation.” An “oxidant” is a chemical that aids or speeds up the process of oxidation; an “anti-oxidant” is one that prevents the oxidation reaction or slows it down.

Food-derived energy allows us to move, to do work by muscle contraction – and to keep us warm. All the cells in our bodies generate heat through the metabolic processes that go on quietly in the background. This is what becomes our body heat.

Carbohydrates and fats are the principle sources of energy, although the body can extract energy from amino acids also. When the muscles burn amino acids for energy, this process gives off nitrogen, which is first converted to ammonia.

Glutamine is the vehicle that transports ammonia from the rapidly-metabolizing muscle tissue to the liver. The liver converts this ammonia to urea, which is delivered to the kidneys, from where it is eliminated in the urine.

Our physical activity determines how much energy our bodies need to perform and to function. This means that your energy balances shift depending on how much food you take in, as well as how active you are.

A healthy adult who is moderately active usually spends between one thousand (1,000) and three thousand (3000 Kcal) per day of food energy. This is equal to approximately 33Kcal/Kg.

Exercising daily is recommended for everybody because it promotes normal body weight as long as your energy intake matches your output or physical activity.

To enhance endurance and/or to improve performance, fitness enthusiasts and sportsmen and women sometimes go on a restricted diet. The problem with this is that when the body senses that it’s getting underfed, it responds by increasing your metabolic efficiency – meaning that the brain instructs the body to do better with less.

This increased efficiency, induced by caloric restriction, is what frustrates people seeking to lose weight by going on a diet that eliminates carbohydrates and sugars and fats.

So you can imagine how the body could quickly burn up the nutrients when you’re dieting and exercising for weight loss, or engaging in sports or workouts for fitness – and how this could throttle down your endurance, and speed up the damage to your muscle cells, as we’ll see shortly.

Antioxidants and post-workout supplements

Antioxidants have many potential health benefits for people who exercise and work out regularly. Some of the most potent antioxidant nutrients include Vitamin C, beta carotene, vitamin E and selenium. These can scavenge oxygen “free radicals” [explained below] from the bloodstream and the inside of cells in the muscles.

Someone has compared the process by which cells burn energy-carrying nutrients to a wood stove. A wood stove needs adequate protection (or shielding) to do its job without burning the house down.

As we burn fuel in our muscle cells, some oxygen atoms end up with an extra electron from the reaction and these become the free radical, O2– (two oxygen atoms bonded together and carrying a negative charge).

Some of these free radicals escape the confines of the cell membranes, the energy engines. The “floating” free radical can interact with and damage other molecules whenever it gets the chance.

Cell membranes in particular are vulnerable to oxygen free-radical injury. Also, a damaged cell membrane disturbs the function of the entire cell. Additionally, extra O2– radicals can react with DNA, the structures in cells that carry the genetic code. When this happens, the DNA code becomes “sticky” and this can cause mistakes in code-reading or code-replication, which can result in cell mutation.

Scientists believe that it is the cumulative damage to cells from billions or trillions of random encounters between cells and these oxygen free radicals over a period of many years that contributes to accelerated aging and the death and mutation or dysfunction of cells.

Our bodies, fortunately, produce natural oxygen detoxification enzymes called peroxidases, and superoxide dismutase, and others are catalases. These nutrients combine harmlessly with the O2– free radical and are therefore called “antioxidants”.

Among the vitamins, Vitamin C is the cheapest, the safest, and the best antioxidant you can find. If you raise the levels of Vitamin C in the muscle cells, this can remove enough oxygen free radicals to make a long-term difference.

For this purpose, the effect of Vitamin C is enhanced if three other nutrient antioxidants are available at the same time – Vitamin E, beta carotene, and selenium.

You can’t take superoxide dismutase (or other enzymes) by mouth and expect to benefit from them – since it will be digested and will not arrive in a form that helps when it gets to the intra-cellular locations where it is designed to work.

Amino Acids, Endurance, and Sports Performance Enhancement

There are two ways to provide the muscles with rapidly accessible energy reserves for growth and performance – you can give them proteins or you can give them the real nutrients derived from proteins by digestion of food, namely, amino acids!

Amino acids designed for sports and fitness nutrition typically contain branch-chain amino acids at a high concentration to enhance muscle action as well as muscle growth. A good supplement should ideally have the 9 essential amino acids as well as some non-essential amino acids that enhance the utilization of the essential amino acids.

Some of the common non-essential amino acids include:

Leucine: It seems to promote muscle growth, acting in concert with insulin.

Isoleucine and valine: These branched-chain amino acids supply muscle fuel if the muscles for some reason have trouble metabolizing glucose to convert it into energy.

Arginine is effective in improving tissue repair and can be considered growth-promoting. This makes it a good ingredient to include in a post-workout supplement for example.

With these points in mind, you can hopefully see why “amino acid proportioning” is something of a science – the science of nutritional programming for athletic performance.

A great sports and fitness nutrition supplement must help the body by supplying rapidly available energy; it must help the body remove the oxygen free radicals as soon as they escape the energy engines within the muscles, and it must speed up repair to the damaged cells, as well as promoting muscle growth.

Protein powder or amino acids – what’s best for endurance or performance enhancement?

The body can use proteins or it can use amino acids. But as we’ve seen above, amino acids are a pure form of nutrient, what you get after breaking down the protein molecules.

This means the muscles can convert amino acids into energy a lot faster.

The other thing is with protein powder is that these are prepared from staple foods, including milk, eggs, wheat, and meat – the kinds of proteins exactly that frequently cause immune responses in some people. The peptides in these proteins are behind what’s called delayed patterns of food allergy.

The quality of the protein powder supplement too matters a lot. Some protein powders are often made from cheap proteins such as milk protein (casein, whey), egg white (albumin), soya proteins, or hydrolyzed vegetable proteins.

So, for people who suspect that they could have an allergy to milk or meat or eggs, etc, protein powders may be a risky choice. Proteins are the most reactive molecules in food allergic disease. Amino acids on the other hand have none of these issues.

Weighing the cost versus the benefits

Amino acids do not trigger immune responses. Free amino acids are much more expensive than protein powders, but freeing the immune system from protein challenge is well-worth the extra cost of these supplements.

So, if cost is an issue, protein powders are not all that bad a choice if you have no food allergies to milk, eggs or meat. If you’re a vegan, be sure to check the ingredients. Vegan sports or fitness nutrition supplements should be based exclusively around hydrolyzed vegetable proteins and such.

A Note on Neurotransmitters in Supplement formulations

A good sports/fitness nutrition supplement should include some amino acids that are not destined to be used inside the cells for growth and energy, but those that are used as neurotransmitters in the system.

Tyrosine and phenylalanine, for example, are converted to the hormone dopamine, and the hormones noradrenalin and adrenalin.

Trytophan is another of these “neurotransmitters.” Inside the body it is a building block, and is converted into serotonin.

Other neurotransmitter substrates or building blocks are not amino acids. These include choline, which becomes acetylcholine.

Acetylcholine is the transmitter that facilitates the communication of the millions of messages per second which translate “brain movement maps” via the “skill circuits” in the brain (as Daniel Coyle describes them in The Talent Code) into coordinated muscle movement.

If the supply of acetylcholine is low or limited, no amount of training or good intention will avoid performance failure – from things like poor timing, lapses in concentration, or power-down effects, etc.

Choline is the building block for this transmitter. A study of blood choline levels in runners demonstrated a 40% drop in choline levels following the Boston marathon. Thiamin is the cofactor for the production of acetylcholine from choline.

Glycine is another major neurotransmitter in the spinal cord.

Glutamate is another important amino acid – neurotransmitter.

A good supplement should have some of these neurotransmitters in its formulation for the obvious benefits for performance and endurance enhancement.

Sports/Fitness Nutrition Supplements for Women

Women have a larger surface area to mass ratio, meaning that for each pound or kilogram of weight a woman has more skin area compared with a man. Women also have lower bone mass compared to men, as well as a wider, shallower pelvis compared with men.

Women in addition have more body fat, less lean muscle mass, they have a “gynoidal” fat distribution, a lower metabolic rate when not active (resting), and a lower red blood cell mass compared with men.

What all this means is that women have an advantage in dry heat, but they’re also more at risk of developing osteoporosis. They also experience more knee problems as result of physical exertion. The difference in muscle strength between a trained woman and a man is a difference in muscle mass size.

One of the major problems that occur among female athletes is the misuse of restrictive diets to lower body fat aimed at improving their appearance and their athletics performance. The outcome is an athlete who may be deficient in many of the essential nutrients we’ve seen above.

This can result in eating disorders, anemia, amenorrhea, premature osteoporosis, and increased risk of injuries that take longer than usual to heal.  A good solution is to use sports and fitness nutrition supplements to assist the excessive caloric reduction without compromising nutritional intake.

Take these considerations into account when deciding on a supplement to buy.


Sports and fitness nutrition supplements are not just a fad being pushed by Big Pharma, although there is no denying that the big pharmaceutical companies are raking it in with these products! The fact is though, as humans we have evolved to a point where we really need a few perks here and there to sustain a lifestyle that requires us to exercise and exert ourselves both for fan and to stay healthy.

You don’t have to be an athlete or a sports star to enjoy this particular perk though… A good performance enhancing fitness supplement could be all the help you need to sustain the motivation and to build up the endurance required to stick to a regular exercise regimen. Failing to stick to an exercise or workout routine is probably the biggest reason why people fail with their resolutions to lose weight, or belly fat, or to combat diabetes or heart disease, or to build muscle, to get six-pack abs, to jump higher, to participate in a marathon and so on.


Comments are closed.