What are keto aminos?
Keto aminos, or ketogenic amino acids, are a specific category of amino acids that can be broken down to produce ketone bodies rather than glucose. In contrast, glucogenic amino acids are converted into glucose via gluconeogenesis, and some are both glucogenic and ketogenic. The body relies on these ketogenic aminos as a supplementary energy source during a ketogenic diet, fasting, or other states of low glucose availability. This metabolic flexibility is a core tenet of the ketogenic diet, where the body primarily burns fat for fuel.
The two exclusively ketogenic amino acids
There are 21 standard amino acids, and each has a different metabolic fate. Of these, only two are considered exclusively ketogenic in humans:
- Leucine: This is a branched-chain amino acid (BCAA) that is critical for stimulating muscle protein synthesis and energy production. Its catabolism yields acetyl-CoA and acetoacetate, both precursors for ketone body synthesis.
- Lysine: This is an essential amino acid that is also purely ketogenic. It is involved in metabolizing fatty acids into energy.
Both ketogenic and glucogenic amino acids
Several other amino acids have dual metabolic pathways, meaning they can be converted into both ketone bodies and glucose precursors. These include:
- Tryptophan
- Isoleucine
- Threonine
- Phenylalanine
- Tyrosine
How keto aminos work on a ketogenic diet
During ketosis, the body's glucose supply is limited due to reduced carbohydrate intake. This triggers the liver to break down fatty acids into ketone bodies through a process called ketogenesis. Keto aminos, particularly leucine and lysine, contribute to this process by being degraded into acetyl-CoA and acetoacetate, which are then used to create ketone bodies. These ketone bodies, like beta-hydroxybutyrate (βHB), circulate in the bloodstream and can be used as fuel by the brain, muscles, and other organs.
This is a critical function for those on a ketogenic diet, as it helps maintain energy levels and preserves lean muscle mass. Without sufficient protein and ketogenic amino acids, the body might start to break down muscle tissue to convert glucogenic amino acids into glucose, a process that can interfere with staying in ketosis.
Key metabolic functions
- Energy Production: Provides a source of fuel when glucose is unavailable, supporting energy for both brain and muscle function.
- Muscle Preservation: Helps increase protein synthesis and prevents muscle breakdown, which is especially important during caloric restriction.
- Improved Recovery: Assists in repairing muscles after intense exercise, contributing to faster recovery.
Keto aminos vs. BCAAs
There is often confusion between keto aminos and BCAAs (Branched-Chain Amino Acids), but it is important to note the key differences. All BCAAs (leucine, isoleucine, and valine) are part of the essential amino acids (EAAs), but not all EAAs are ketogenic.
| Feature | Keto Aminos | Branched-Chain Amino Acids (BCAAs) |
|---|---|---|
| Composition | Include the exclusively ketogenic (leucine, lysine) and conditionally ketogenic aminos (tryptophan, etc.). | Include leucine, isoleucine, and valine. |
| Metabolism | Primarily used to produce ketone bodies and support fat burning, which can spare muscle. | Primarily involved in stimulating muscle protein synthesis, with varying metabolic fates. Leucine is ketogenic, isoleucine is both, and valine is glucogenic. |
| Ketosis Impact | Supports ketosis by providing precursors for ketone bodies. | Generally considered keto-friendly, but valine could potentially be converted to glucose, though typically not enough to disrupt ketosis at moderate doses. |
| Target Audience | Those on a strict ketogenic diet looking for fuel and muscle support. | Athletes focused on muscle recovery, growth, and endurance. |
Benefits of supplementing with keto aminos
While a well-formulated ketogenic diet rich in whole food proteins can provide sufficient amino acids, supplements offer targeted benefits, particularly for athletes or those with chronic conditions. Some potential advantages of supplementing include:
- Enhanced performance: Exogenous ketone supplements, which may be paired with keto aminos in some formulas, can improve endurance and cognitive function during exercise by providing an additional energy source.
- Muscle sparing: Ensures the body has an readily available source of aminos for muscle repair and protein synthesis without needing to break down existing muscle tissue.
- Reduced fatigue: Can help prevent the drop in performance that can occur during intense exercise on a low-carb diet.
- Nutritional support: Provides essential amino acids that might be lacking, especially if a ketogenic diet is not optimally planned.
Considerations and potential side effects
For those on a standard ketogenic diet, sufficient amino acids should come from whole-food protein sources such as meat, fish, eggs, and dairy. However, individuals with certain conditions, such as chronic kidney disease (CKD), may be prescribed ketoanalogue supplements under medical supervision.
Potential side effects of amino acid supplements are generally rare when taken at recommended doses, but can include gastrointestinal issues like nausea or diarrhea. High doses can potentially lead to electrolyte imbalances. Always consult a healthcare professional before starting a new supplement regimen, especially if you have pre-existing health conditions.
Conclusion
Keto aminos represent a unique class of amino acids that play a vital role in supporting metabolism and providing energy within a ketogenic framework. By being converted into ketone bodies instead of glucose, these aminos help sustain energy levels, particularly for the brain and muscles, during periods of carbohydrate restriction. While a balanced diet rich in protein is the primary source, supplements can offer targeted benefits for athletes or those needing additional support for muscle preservation and performance. Understanding the distinct roles of ketogenic versus glucogenic amino acids is key to optimizing a ketogenic diet for your health and fitness goals. For a comprehensive overview of how these amino acids are metabolized, it is helpful to consult resources like the biochemical pathways available on science-focused educational sites like ScienceDirect.
