How does the brain use food as energy? (2024)

FAQs

How does the brain use food as energy? ›

Just like other cells in the body, brain cells use a form of sugar called glucose to fuel cellular activities. This energy comes from the foods we consume daily and is regularly delivered to brain cells (called neurons) through the blood.

The main energy currency of our brain cells is a molecule called adenosine triphosphate (or ATP), which our body makes from sugar and oxygen. Tracing brain energy consumption can be done using both sugar and oxygen, but oxygen is the more accessible option.

Foods contain a lot of stored chemical energy; when you eat, your body breaks down these foods into smaller components and absorbs them to use as fuel. Energy comes from the three main nutrients carbohydrates, protein, and fats, with carbohydrates being the most important energy source.

Glucose is the essential metabolic fuel for the brain. Acute and severe reduction of brain glucose leads quickly to impairment of cognitive and reflex function, autonomic failure, seizures, loss of consciousness, and permanent and irreversible brain damage and, if not rapidly corrected, can be lethal.

The brain is dependent on glucose as a primary energy substrate, but is capable of utilizing ketones such as β-hydroxybutyrate (βHB) and acetoacetate (AcAc), as occurs with fasting, prolonged starvation or chronic feeding of a high fat/low carbohydrate diet (ketogenic diet).

Your brain, unlike your muscles, can't use fat as a fuel source. However, the brain can use ketones. When glucose and insulin levels are low, your liver produces ketones from fatty acids. Ketones are actually produced in small amounts whenever you go for many hours without eating, such as after a full night's sleep.

Your brain is arguably the hungriest organ in the body, consuming roughly 20 per cent of your energy each day. Most of that energy is produced by tiny structures inside cells called mitochondria, which break down complex carbohydrates from our food into simple sugars.

Because the brain demands such high amounts of energy, the foods we consume greatly affect brain function, including everything from learning and memory to emotions. Just like other cells in the body, brain cells use a form of sugar called glucose to fuel cellular activities.

Your brain also needs special materials to run properly: glucose, vitamins, minerals and other essential chemicals. For example, the fuel (energy) for your brain is glucose.

What organ uses the most energy? ›

Because the brain is so rich in nerve cells, or neurons, it is the most energy-demanding organ, using one-half of all the sugar energy in the body. Brain functions such as thinking, memory, and learning are closely linked to glucose levels and how efficiently the brain uses this fuel source.

After 2 or 3 days of fasting, the liver begins to synthesize ketone bodies from precursors obtained from fatty acid breakdown. The brain uses these ketone bodies as fuel, thus cutting its requirement for glucose. After fasting for 3 days, the brain gets 30% of its energy from ketone bodies.

The hypothalamus is one of the best-studied and most important brain regions involved in the central control of feeding and energy expenditure. In particular, the arcuate nucleus (ARC) within the hypothalamus is critical for the regulation of feeding and metabolism (Myers and Olson, 2012).

The brain does indeed convey its signals by means of electricity and chemical compounds; so much is well known.

The major flow of energy in the brain passes through ATP and very likely is directed toward re-establishing the ionic changes resulting from nervous activity, Na⁺–K⁺ stimulated Mg⁺⁺ dependent ATPase system.

During normal conditions, the primary energy substrate in the brain for neurons is blood-derived glucose; however, when at elevated levels in the blood, ketone bodies and lactate can be used as energy sources as well (Magistretti and Allaman, 2018).