Fatigue may also be caused by impaired energy processing through cells. This may result from a number of causes, but they all have a common mechanism. This mechanism is inhibition of the cell mitochondria. The mitochondria are small “engines” within the cell that generate the molecule responsible for energy, ATP.
 
The generation of ATP is done taking potential energy molecules that the cell has processed such as sugar and fats and transitioning them through several enzymes that result in the final production of ATP. Nutrient deficiencies, inflammation, oxidative stress, and genetic mediated enzyme variations can all slow these enzymes making it difficult to produce adequate ATP to keep up with energy demand. This results in generalized fatigue often accompanied by low grade aches and pains.
 
Each enzyme is produced by a specific gene each time it is needed. However, when it is produced, it is inactive and has to be combined with “cofactor” to be fully active. Cofactors are typically micronutrients such as vitamins and minerals with each enzyme requiring a different combination.
 
Each human gene can have multiple variations called polymorphisms. These gene variations tend to cause the resulting enzyme to be underactive. One of the interesting findings has been that in these genetically underactive enzymes, their activity can often be raised to normal with much higher amounts of the nutrients that are co-factor for that enzyme normalizing energy production.
 
There are hundreds of different enzymes in humans, and the unique ones that are underactive in each person is unique. Testing is now available looking at the gene polymorphism in the common enzymes in the energy production process. This allows for individualized nutritional recommendations to correct energy deficits.
 
Another type of testing called metabolomic analysis is also available. This testing looks at intermediates called organic acids in the enzyme pathways in the urine. For example if a metabolic pathway converts “A” with enzyme A into “B” and then enzyme B converts “B” into ATP and enzyme A does not work very well because of genetic variation; or if it is being suppressed by inflammation, “A” will build up and spill excessively in the urine.

While each individual may have a unique group of factors producing their cell energy deficits, identification of these factors, correction of modifiable factors (inflammation, oxidative stress, etc) and an individualized nutritional program will often produce pronounced symptomatic relief.
 
Currently, relatively cost effective genetic testing is available for some of the common gene variations that cause imbalances in energy metabolism and ultimately, fatigue. In appropriate patients it can allow specifically tailored treatment.
 
As you can see, fatigue can be from several factors. It is one of the most important symptoms to approach with this understanding. The solution always revolves around knowing the cause in the first place.