The Effects of Starvation on Blood-Glucose Level

The body can survive for approximately 40 days in a state of starvation before the blood becomes toxic with the buildup of ketone bodies that are being used as the final source of neural energy. The liver and the kidneys, the only tissues able to release glucose into the blood, perform internal processes that regulate blood sugar and brain function.

Glycogen Reserves

• During the first two days of starvation, the liver releases glycogen reserves that it can easily convert to glucose to send to the bloodstream. Glycogen reserves are then depleted.

Hormones

• The body's stress hormones including growth hormone, glucogen and adrenaline, stimulate the liver and kidneys to extract amino acids from muscle fibers.

Gluconeogenesis

• Gluconeogenesis is the process of inhibiting muscle protein synthesis with cortisol released from the liver, enabling the extraction of amino acids from muscle fibers. The liver extracts alanine from skeletal muscles and the kidneys rely on glutamine. Amino acids are broken down into glucose.

Significance

• Gluconeogenesis can supply the body with 100 grams of glucose per day during starvation. The peak conversion of amino acids occurs within the first week. Blood sugars during starvation usually stabilize at 3.5 mmol/l, millimoles per liter. Molecular weight is measured in moles.

Function

• The brain relies on glucose to function, but after two weeks of starvation ketone bodies provide assistance. Ketone bodies accumulate, eventually lowering the pH of the bloodstream, rendering it toxic.