What Is the Function of Ubiquinone in the Body?

Ubiquinone, also known as Coenzyme Q10 (CoQ10), is a vitamin-like substance synthesized naturally within the human body and present in every cell. This compound is fundamental to cellular operations. Its presence is highest in organs with significant energy needs, such as the heart, liver, and kidneys.

The Function of Ubiquinone in Cellular Respiration

Ubiquinone has a primary function in producing energy within the mitochondria, the powerhouses of the cell. It is a component of the electron transport chain, a series of protein complexes embedded in the inner mitochondrial membrane. This chain is the final stage of cellular respiration, the process by which cells convert nutrients into adenosine triphosphate (ATP), the body’s main energy molecule.

The structure of ubiquinone, consisting of a quinone head and a long, lipid-soluble tail, allows it to move freely within the mitochondrial membrane. This mobility is necessary for its role as a shuttle. Ubiquinone accepts electrons from the first two protein complexes in the chain (Complex I and Complex II) and transports them to the third complex (Complex III).

This transfer of electrons is a step in a process called oxidative phosphorylation. As electrons move down the chain, they power the pumping of protons from the mitochondrial matrix into the intermembrane space. This action creates an electrochemical gradient. The energy stored in this gradient is then used by ATP synthase to generate large quantities of ATP, which fuels nearly all cellular activities.

Ubiquinone’s Protective Antioxidant Actions

Beyond its role in energy metabolism, ubiquinone functions as an antioxidant, primarily in its reduced form, ubiquinol. As a lipid-soluble antioxidant, it is positioned within cell membranes, where it helps protect fatty acids, proteins, and DNA from oxidative damage caused by free radicals. This action helps prevent lipid peroxidation, a process that can damage cell membranes.

Ubiquinol directly scavenges harmful free radicals, neutralizing them and halting damaging chain reactions. Its effectiveness is comparable to that of vitamin E, another lipid-soluble antioxidant. The body has enzymatic pathways to recycle ubiquinol from its oxidized state, allowing it to perform its antioxidant duties repeatedly.

Ubiquinone also contributes to the body’s broader antioxidant network. It can regenerate other antioxidants, most notably vitamin E. When vitamin E neutralizes a free radical, it becomes a radical itself; ubiquinol can donate an electron to the vitamin E radical, restoring its antioxidant capacity. This enhances the body’s overall defense against oxidative stress.

Natural Ubiquinone Sources and Endogenous Production

The body acquires ubiquinone through dietary intake and its own internal synthesis. While many foods contain this compound, the concentrations are low. The richest dietary sources include:

• Organ meats like heart and liver
• Oily fish such as salmon and mackerel
• Beef
• Soybeans
• Nuts like peanuts and walnuts

Daily dietary intake is estimated to be only around 3 to 6 milligrams, which contributes a small fraction to the body’s total pool.

The vast majority of ubiquinone is produced endogenously, meaning it is synthesized within the body’s cells. This complex biochemical pathway requires several other nutrients, including B vitamins and vitamin C, to function correctly. Because the body can produce its own supply, ubiquinone is not considered an essential nutrient for most healthy individuals.

Conditions and Medications Affecting Ubiquinone

The body’s ubiquinone levels can decline over time, which may impact cellular function. The natural aging process is associated with a decrease in endogenous ubiquinone production. After about age 20, the body’s ability to synthesize CoQ10 begins to diminish, affecting the energy output and antioxidant capacity of cells.

Certain medications are known to interfere with ubiquinone synthesis. The most widely recognized are statins, which are prescribed to lower cholesterol. Statins work by inhibiting an enzyme called HMG-CoA reductase, a component in the pathway that produces cholesterol. This same pathway is also responsible for producing ubiquinone, so blocking the enzyme inadvertently lowers the body’s production of CoQ10.

Lower levels of ubiquinone have also been observed in individuals with some chronic health conditions. Studies have noted an association between reduced CoQ10 levels and cardiovascular diseases, neurodegenerative disorders like Parkinson’s disease, and diabetes. The connection is an area of ongoing research.

Understanding Ubiquinone Supplements

Ubiquinone is available over-the-counter in two primary forms: ubiquinone and ubiquinol. Ubiquinone is the oxidized form, while ubiquinol is the reduced form. The body can convert ubiquinone into ubiquinol, and both forms are absorbed, though they differ in their bioavailability.

Ubiquinol is considered to have higher bioavailability, meaning it may be more readily absorbed and utilized by the body. This can be beneficial for older individuals or those with certain health conditions, as the body’s ability to convert ubiquinone to ubiquinol may be less efficient with age. As CoQ10 is fat-soluble, its absorption is enhanced when taken with a meal containing fats or oils.

Research comparing the two forms has yielded mixed results, with some studies showing no significant difference in bioavailability, especially since the body constantly converts between them. Individuals should consult a healthcare professional before beginning any supplement regimen to discuss appropriate use and potential interactions with existing medications or health conditions.