Those of you familiar with my writings are well aware of the fact that I am strongly in support of intelligent training methods. In this article, I give this advocacy a unique twist and discuss whether it is possible to train for intelligence. Research has shown that a person's cognitive capacity may remain acute far into advanced age, if practiced throughout life. In a sense, this result suggests that a person’s “mental fitness” improves with training. And since, nutritional supplements plays a big role in modern athletics, this issue also begs the question whether nutritional supplementation may also help maintain mental fitness. In this respect, a pivotal study recently appeared in the scientific press that examined the effects of creatine supplementation on human intelligence (1). This study might change the way you think...

Brain Energetics

As for any activity we undertake, thought requires energy-or should, in any case. In fact, thinking takes lots of energy. On a per weight basis, the brain is one of the body's highest energy consumers. Although representing only 2% of our total body mass, the brain consumes nearly one quarter of our entire energy resources. The disproportionate amount of energy consumed by our brains is reflected by the fact that the head is generally warmer than the body core temperature; this gives an entire new meaning to the phrase “hot head”, doesn’t it.

Any thought we abstract, any sensation we perceive, or any action we initiate, is encoded by electrical impulses that literally flow throughout our nervous systems. However, unlike the electrical currents that flow through the wires in our homes and that are carried by negatively charged electrons (a part of an atom), the electrical impulses that propagate through our nerve cells, or neurons, are largely mediated by positively charged atoms that, interestingly enough, lack electrons. Such charged atoms are known as ions, nothing more than atoms with an incomplete number of electrons in their outer shell. Electrical currents (carried by positive ions) literally flow through our neurons relaying information from brain to target, and back again.

A neuronal impulse is initiated with the flow of positively charged sodium ions into a neuron. This influx of sodium ions causes a localized accumulation of positive charges near their point of entry at the neuronal membrane. To relieve this buildup of positive charges, potassium ions (also positively charged) respond by flowing outward, since like charges repel each other. This instantaneous switch in ionic polarity can be likened to a spark that rapidly spreads along the entire length of the nerve cell. Obviously, this situation cannot continue forever, otherwise all of the sodium ions would end up on the inside the neuron and all the potassium ions on the outside. Indeed, after a flurry of electrical activity the relative distribution of sodium and potassium (near the membrane) nearly reverses. In order for brain activity to continue, therefore, these ions need to be actively placed back onto their appropriate sides of the membrane. This process is energetically very expensive.

The molecular pumps that are responsible for situating sodium and potassium back to their respective sides of the neuronal membrane are called ATPases; obviously, since they rely on ATP to function. In fact, maintaining these pumps active is the greatest sink of energy in the brain. As in muscle, however, ATP is often limiting. Also analogous to the muscular situation is the fact that phosphocreatine (PCr) is what assures a steady supply of ATP to the cell. PCr thus keeps these ATPases pumping sodium and potassium back into their respective compartments, thereby allowing continual neuronal activity. Figuratively speaking, phosphocreatine keeps us thinking.

So, what does this have to do with creatine?

Recall that PCr is the energized form of creatine that is present within the cell. When we supplement with creatine, what we are in actuality doing is increasing the PCr content of the cell. Therefore, at least in theory, creatine supplementation should influence how well we think under pressure. Food for thought, so to speak. One recent study, furthermore, showed that mice deficient in the enzyme that creates PCr from creatine, creatine kinase, are slower at learning a water maze (2). In other words, the mice with lower levels of PCr erred more often and generally spent more time in the water. The stage was thus set for human studies...

Does creatine supplementation influence mental acuity in humans?

This was the question asked by a recent study conducted at the Universities of Sydney and Macquarie, Australia.