Requirements: 1. Maintain the original format and structure. 2. The translation should be accurate, fluent, and natural. 3. Maintain professionalism and consistency. 4. Only return the translation result; do not add any explanations. Original Text: On the path to pursuing health and vitality, we often come across various nutrients that sound very “high-tech.” α-Ketoglutarate (AKG), a somewhat difficult-to-pronounce substance, has gained significant attention in recent years in the fields of sports nutrition, anti-aging, and healthy animal husbandry. It is hailed as a “metabolic hub” and is closely related to our energy production and protein synthesis. However, some question whether AKG can be effectively absorbed and utilized by the human body. Can the AKG we supplement through supplements or feed (referred to as “exogenous AKG”) actually be absorbed and used by the body, or does it simply pass through the digestive system without providing any real benefit? Today, we will use a scientific perspective to uncover the “magical journey” of AKG within the body. First Stop: The Gastrointestinal Tract – An Efficient “Customs Station” Imagine AKG as a small boat loaded with important supplies, entering the body through the mouth and beginning its journey. Scientific research has provided a clear answer: This boat not only manages to reach its destination successfully but also does so with high efficiency! Experimental models in pigs and rats have shown that orally administered AKG is primarily absorbed in the upper part of the small intestine, especially the duodenum. It doesn’t wander aimlessly through the digestive system; instead, it is recognized as an important substance by the body and quickly passes through the intestinal barrier, moving on to the next stage. In simple terms, the AKG you consume is not rejected by the digestive system as a foreign substance; most of it is absorbed. Second Stop: The Blood Circulation – A “Hotly Desired” Substance Once AKG enters the bloodstream, it’s like goods being loaded onto a high-speed train, ready to be transported throughout the body. Interestingly, scientists have found that blood levels of AKG do not increase significantly for long. Why is that? Not because less of it is absorbed, but because it is so in demand! Various tissues and organs in the body, especially those that require a lot of energy (such as the liver, kidneys, and muscles), quickly and almost “frantically” take up AKG from the blood. Studies have shown that AKG is widely distributed throughout the body, and even the brain and bones can detect its presence. This process is known as “rapid plasma clearance,” which proves that AKG is not a useless passerby but a much-needed substance. Third Stop: Tissues Throughout the Body – A Versatile “Multi-Tasker” After being absorbed by the tissues and organs, where does AKG go? This is where its true value is realized. It doesn’t just remain unchanged; it actively participates in various bodily functions: - **Amino Acid Synthesis:** AKG is a direct precursor to the amino acids glutamine and glutamate, which are essential for maintaining intestinal health, boosting immunity, and supporting muscle growth. This is particularly significant for athletes and the elderly who want to slow down muscle loss. - **Energy Production:** AKG is a key component of the tricarboxylic acid cycle, the body’s “energy factory.” It is directly involved in this process and is converted into energy (ATP) to power various bodily activities. - **Gene Regulation:** Recent research has found that AKG can also act as a signaling molecule, affecting a range of cellular functions, including potential anti-aging pathways. - **Waste Reduction:** Almost no unmetabolized AKG is detected in urine and feces, indicating that, as long as the dosage is reasonable, the body uses it efficiently with little waste. Based on multiple animal studies, we can conclude with certainty that exogenous AKG is efficiently absorbed by the gastrointestinal tract and quickly transported to various tissues and organs through the bloodstream. It is effectively utilized for amino acid synthesis, energy production, and the regulation of physiological functions, rather than being excreted without any benefit. AKG acts like a precise logistical force that is quickly directed to where it is most needed to support the body’s functions. Therefore, whether as a potential health supplement for humans or to improve the health and feed utilization of livestock, the “bioavailability” of AKG has withstood scientific scrutiny. Next time you hear about AKG, you can be confident that it is not just a passing visitor but a capable and valuable substance. References: [1] FILIP R, PIERZYNOWSKI S G. The absorption, tissue distribution, and excretion of enterally administered α-ketoglutarate in rats. J Anim Physiol Anim Nutr (Berl), 2008, 92(2): 182–189. [2] DABEK M, KRUSZEWSKA D, FILIP R, et al. α-Ketoglutarate (AKG) absorption from pig intestine and plasma pharmacokinetics. J Anim Physiol Anim Nutr (Berl), 2005, 89(11-12): 419–426. [3] KRISTENSEN N B, JUNGVID H, FERNÁNDEZ J A, et al. Absorption and metabolism of α-ketoglutarate in growing pigs. J Anim Physiol Anim Nutr (Berl), 2002, 86(7-8): 239–245. [4] Randal K. Buddingtona, Ana Pajorb, Karyl K. Buddingtona, Stefan Pierzynowski. Absorption of α-ketoglutarate by the gastrointestinal tract of pigs. Comparative Biochemistry and Physiology, Part A 138 (2004): 215–220.