Lactate is a dynamic substrate with great potential as an energy source in sports drinks. To date, however, the efficacy of adding lactate to these drinks has been sparsely assessed [5,15,16]. Lactate was once considered a metabolic waste but is now recognized as an important energy substrate in the body. Lactate is the main product of carbohydrate metabolism and can be used as a fuel in working muscle cells shuttled to other tissues such as the heart where lactate is fuel [17], or to the liver were lactate serves as a gluconeogenic precursor [18].

A byproduct of our muscles converting carbohydrates to energy, which appears to serve as a secondary energy source.

Lactate

Lactate is a negatively charged molecule formed from a compound called lactic acid. Some bacteria make lactate when they metabolize sugars. Humans also produce lactate as a byproduct of metabolism, though only under certain conditions. Specifically, says Dr. Gary Thibodeau in his book \"Anatomy and Physiology,\" you make lactate when your cells process sugars for energy in the absence of oxygen, such as when you\'re engaging in a hard sprint or power efforts during exercise.

Lactate in Food

Lactate can occur naturally in some foods, and in other cases, it\'s added. Fermented foods like sourdough bread and yogurt contain lactate naturally. This is because these foods are manufactured by allowing bacteria to convert a certain amount of the sugar in the dough or dairy into lactate, yielding a sour flavor and change in texture. Because lactate changes a food\'s acidity, it can make it hard for pathogenic bacteria to grow in the food. As such, lactate is sometimes added to foods as a preservative.

Lactose

Unlike lactate, lactose is a sugar. While it\'s possible for humans, other animals and bacteria to convert lactose to lactate through the process of fermentation, the chemicals have little in common. You take in lactose any time you consume milk or other dairy products. An enzyme called lactase, which occurs in your intestines, digests lactose into smaller molecules that you absorb into your bloodstream and can use for energy, say Drs. Reginald Garrett and Charles Grisham in their book \"Biochemistry.\"

Lactose Intolerance

Some people don\'t produce enough lactase to digest lactose effectively. This is referred to as lactose intolerance. If you\'re lactose intolerant, consuming dairy causes you to experience a variety of uncomfortable gastrointestinal symptoms, including bloating and cramping. If you\'re lactose intolerant, you have to avoid lactose-containing foods. Alternately, you can take a lactase supplement when you consume dairy. You do not, however, need to avoid foods with natural or added lactate.

Lactose and Lactase apparently have no relation to Lactate. Lactose is a sugar in milk, Lactase is an enzyme babies use to digest milk, and Lactate is a byproduct of our muscles expending energy, which is itself a source of energy.