Our lives depend on processing the food we eat into substances our cells can take in and use. In a never-ending cycle, our body breaks food down and reconstructs the components to form body structures and burn as energy.

How much you exercise, the food and supplements you eat and how much you sleep influence the efficiency of these processes.

Vitamins and Energy
Certain nutrients are called vitamins because they are crucial for vitality. These nutrients are essential to a productive life, the starting point for all life-giving and life-sustaining processes. Because of vitamins' crucial role in energy production, many people can perk up their stamina simply by consuming an adequate supply of vitamins in their daily diet. Since many vitamins - especially the ones concerned with energy - must be constantly replenished, a decent diet and the right supplements must be consumed every day.

Be Energetic with B Vitamins
Vitamins, especially the B vitamins, play extremely important roles in producing cellular energy. Their most important roles are shown in the illustration on page 48. The chart on page 46 lists the key vitamins and describes their effects as well as the consequences of not getting enough of them. Their effect is felt most profoundly in the energy producing process known as the Krebs cycle (which we'll explain in a moment).

Vitamins B2 and B3, for example, supply the major building blocks for substances called flavin adenine dinucleotide (FAD and FADH) and nicotinamide adenine dinucleotide (NAD and NADH) which are critical elements of producing energy in the Krebs cycle as well as a process called oxidative phosphorylation.

Even though you may never have heard of NAD and NADH, these molecules are found in many places in your body; they play a role in hundreds of biochemical reactions in all kinds of cells. B vitamins also combine with other materials to build coenzymes, chemicals which help form other chemicals necessary for cellular energy. B vitamins are crucial: miss out on one or more and you may break these metabolic chains necessary for peak energy.

Energy to Spend
The main energy currency of every cell is ATP: adenosine triphosphate. This material is used by cells for every imaginable task including reproduction, growth, movement and metabolism. Specialized metabolic cycles within the cell are designed to generate ATP.

Consequently, the more ATP our cells create, the more energy can be generated. The raw materials used to make cellular energy are glucose (blood sugar) and "free" fatty acids. The best way to supply your cells with the sugar they need is to consume complex carbohydrates which also supply fiber and other nutrients. When you eat carbohydrates, they are made into glucose which is stored as a starch called glycogen in muscles and the liver. Your body can rapidly turn glycogen into glucose for extra energy (The process of making energy from glycogen yields carbon dioxide and water as well as ATP.)

Making Energy
The first step in making glucose into energy is called glycolysis. This complicated process requires nine different steps. During these steps, glucose is made into a substance called pyruvate. The process of glycolysis requires ATP, but yields twice as much ATP as is present when it starts.

From here, the process gets a little more complicated as pyruvate enters into a complex chain of events in tiny cellular structures called mitochondria. (Many metabolic events take place in the mitochondria.) The pyruvate molecules are converted to a molecule known as acetyl coenzyme A and eventually made into carbon dioxide, water and more ATP. This process is known as the Krebs cycle or citric acid cycle. It also involves a series of events known as oxidative phosphorylation in which NADH formed during the Krebs cycle is oxidized to form ATP.

Why is fat such a concentrated source of energy? Free fatty acids enter the Krebs cycle to help generate ATP much more efficiently than glucose - producing roughly six times more energy per gram than glucose.

Get Your Vitamins Every Day
While we rely on our diet to supply many of our vitamins, a B complex supplement and multi-vitamins can ensure you consume sufficient amounts of these crucial nutrients.

Many experts agree that a diet rich in raw fruits, nuts and vegetables that minimizes saturated fat can supply adequate a-mounts of these nutrients. Other supplements that may aid energy production:

Alpha Lipoic Acid, an antioxidant that works in the fatty tissues of cell membranes and in cells' watery interiors. CoQ10, a nutrient that protects cell membranes, especially of the heart, against oxidation and toxins. Plus, herbs such as suma, ginseng and licorice root as well as creatine, carnitine and pyruvate.

Of course if you suffer from any long term, intractable fatigue, consult your health practitioner. But for most cases of decreased vim and vigor, adequate vitamins should help your body recover your get up and go.