Succinate is a naturally occurring molecule produced inside mitochondria, the powerhouses of our cells, as part of a fundamental energy-generating pathway. While its primary function relates to cellular metabolism, emerging research has uncovered other roles for succinate. Its presence and concentration can influence how cells communicate and respond to their environment, and subtle shifts in this molecule can have widespread effects on health.
Role in Cellular Energy Production
Succinate is a participant in the citric acid cycle, a process that occurs within the mitochondria of every cell. This cycle is the primary way that cells convert energy from food into adenosine triphosphate (ATP), the main energy currency used to power cellular activities. The process can be visualized as a multi-step assembly line where molecules are systematically transformed to release energy.
In this metabolic pathway, succinate is formed from succinyl-CoA and serves as fuel for the enzyme succinate dehydrogenase (SDH). This enzyme catalyzes the conversion of succinate into the next molecule, fumarate. The SDH enzyme has a dual function, participating in the citric acid cycle and acting as a direct component of the electron transport chain.
The reaction facilitated by SDH involves the transfer of high-energy electrons from succinate to a carrier molecule, which then delivers them to the electron transport chain. This process uses the electrons to generate a large amount of ATP. Through its interaction with SDH, succinate directly links the citric acid cycle with the final stages of cellular energy production, ensuring an efficient conversion of nutrients.
Function as a Signaling Molecule
Beyond its well-established role inside mitochondria, succinate also functions as a signaling molecule that communicates between cells. When produced in large amounts, it can be transported out of the cell and into the bloodstream. From there, it can travel to other tissues and act like a hormone, carrying messages that influence cellular behavior.
This signaling function is mediated by a specific receptor on the surface of various cells, known as succinate receptor 1 (SUCNR1). When succinate binds to this receptor, it triggers a cascade of events inside the target cell, changing its activity. This mechanism allows succinate to act as a sensor for metabolic stress; high levels of extracellular succinate can signal that an area is experiencing a disruption in its energy balance, such as during periods of low oxygen (hypoxia).
The SUCNR1 receptor is found in a variety of tissues, including the kidneys, liver, fat tissue, and certain immune cells. For example, succinate signaling can influence blood pressure by acting on cells in the kidney. It can also play a role in activating immune cells, drawing them to sites of injury or inflammation. This extracellular signaling role is distinct from its intracellular function in energy metabolism.
The Link Between Succinate and Disease
The signaling functions of succinate, while important for normal physiology, can contribute to disease when they become dysregulated. Abnormally high levels of succinate accumulating outside of cells are now recognized as a pro-inflammatory signal that can drive chronic health conditions. This accumulation can occur under various pathological states, including metabolic stress, low-oxygen conditions (hypoxia), or genetic mutations affecting the enzyme succinate dehydrogenase (SDH).
Elevated extracellular succinate is increasingly implicated in a range of inflammatory diseases. By activating its receptor, SUCNR1, on immune cells, succinate can amplify inflammatory responses. This mechanism has been linked to conditions such as rheumatoid arthritis and inflammatory bowel disease. In the context of metabolic syndrome and obesity, high succinate levels are associated with inflammation in fat tissue and have been connected to insulin resistance.
The succinate signal has been tied to the progression of certain cancers. In some tumors, mutations in the SDH enzyme cause a massive buildup of succinate. This excess succinate can leak into the tumor microenvironment, where it can promote the growth of blood vessels that feed the tumor and alter the function of immune cells to help the cancer evade detection. Research shows a connection between high succinate levels and conditions like coronary artery disease, where it exacerbates inflammation in blood vessels.
Succinate in Foods and Supplements
The chemical form of succinate, known as succinic acid, is naturally present in some foods and is also used as a food additive. It can be found in fermented products like beer and wine, as well as in some aged cheeses. As a food additive, succinic acid is used to regulate acidity and enhance flavor, contributing a slightly sour and salty taste.
Succinate is also available in dietary supplements, most commonly bound to minerals. Products like magnesium succinate or potassium succinate are sold as mineral sources. In these formulations, the primary purpose of the succinate component is often to increase the bioavailability and absorption of the mineral it is paired with. The body can absorb these organic mineral salts more easily than some inorganic forms.
While succinate itself is a key part of the body’s energy production, taking succinate supplements is not a recognized method for directly boosting cellular energy levels. The amount of succinate obtained from these supplements is generally small in the context of the body’s total metabolic needs. The safety of taking large amounts of succinate for medicinal purposes has not been well-established through scientific research.