The Effects of a Low Carbohydrate Diet on ATP Production

cues (58)in #blog • 5 years ago

Adenosine triphosphate, or ATP, is the body's basic form of chemical energy and the only energy the muscles can use to contract. A human body must be able to produce ATP to survive because every major organ in the body, including the brain, depends on it. Glucose, which comes from dietary carbohydrate intake, is the default fuel supply of the body and the the major substrate of ATP production. When carbohydrate intake is less than 50 grams per day, the body is still able to produce ATP but is forced to use alternative pathways.

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NORMAL METABOLISM

Under normal dietary conditions, carbohydrates from the diet are absorbed and broken down to glucose. Glucose then undergoes glycolysis to produce energy in the form of ATP. The end product of glycolysis is pyruvate, which can be decarboxylated to Acetyl CoA, which goes through the Krebs Cycle to generate more ATP. This entire process depends on an adequate supply of glucose from the diet.

GLUCONEOGENESIS

The metabolic effects of a low-carbohydrate diet resemble those of starvation. When the supply of glucose from the diet is low, the body is able to generate its own supply of glucose through a process called gluconeogenesis. Gluconeogenesis is synthesis of glucose from amino acids, glycerol and lactate. The synthesized glucose can then undergo glycolysis, and the body is able to continue ATP production without a supply of carbohydrates.

KETOSIS

Ketone bodies are a very important source of energy when carbohydrate supply is inadequate. The liver can convert free fatty acids to either acetone, acetylacetate or b-hydroxybutyrate, which are all ketone bodies. Ketone bodies are converted to Acetyl CoA to enter the Krebs Cycle to produce ATP. Most tissues in the body actually prefer to use ketones for energy over glucose or fatty acids, so the limited available glucose can be preserved. Unlike fatty acids, ketone bodies are able to cross the blood-brain barrier to supply energy to the central nervous system and the brain, making them essential during periods of starvation or low carbohydrate intake. The Institute of Medicine has recommended an intake of 130 grams or carbohydrate per day to prevent ketosis, which is the presence of ketone bodies in the blood.

CONSIDERATIONS

While ketone bodies are an important source of fuel, they cannot completely replace glucose in the body. Some areas of the brain can only be fueled by glucose. The long-term effects of low-carbohydrate diets are unknown. The potential side effects are kidney stones, electrolyte imbalances, elevated fatty acids and gout.