Lactate: It's Not What You Think
Lactate has long been misunderstood as a waste product—a byproduct of exertion and nothing more. However, modern research has shattered this misconception, revealing lactate’s critical roles in energy production, inflammation regulation, and even brain health. For those managing ME/CFS, fibromyalgia, or post-viral fatigue, understanding lactate's function is crucial for improving symptoms and tailoring treatment strategies.
What is Lactate, and Where Does It Come From?
Lactate accumulates in the body through two primary pathways:
Glycolysis (Breakdown of Glucose): Lactate is produced when glucose is metabolized to generate energy.
Hypoxia (Low Oxygen Levels): When oxygen is scarce, lactate is produced as an energy alternative.
Lactate is not just a metabolic byproduct—it’s a valuable energy source. Specialized lactate shuttles transport lactate to tissues where it is needed, including the brain, heart, and skeletal muscles. Once there, lactate can be:
Converted back into glucose.
Oxidized into pyruvate, which fuels ATP production
The Many Roles of Lactate
Contrary to its outdated reputation, lactate has a variety of beneficial functions:
Energy Source:
During exercise, lactate helps maintain acid-base balance in muscles.
It serves as an emergency energy reserve for the brain, heart, and other organs.
Immune Cell Support:
Immune cells have specialized receptors for lactate, which is shuttled into T cells to support their function.
However, in conditions like rheumatoid arthritis, lactate accumulation can trap immune cells in inflamed areas, worsening local inflammation.
Brain Function:
Lactate produced in the body can cross the blood-brain barrier to fuel neurons.
It supports memory formation and neuroplasticity through its transfer from astrocytes (brain support cells) to neurons.
Lactate and Chronic Illness
Lactate in Fibromyalgia
Studies have found elevated lactate levels in the brains and tissues of fibromyalgia patients. Notably, a clinical trial demonstrated that the drug milnacipran reduced brain lactate levels in fibromyalgia patients, correlating with reduced pain.
Lactate in ME/CFS
Lactate has been a recurring focus in ME/CFS research, particularly in exercise studies. Elevated lactate levels have been observed in:
Brain Ventricles: Studies from 2012 and 2017 detected abnormal lactate levels in the brains of ME/CFS patients.
Exercise Testing: During a 2-day bike test, ME/CFS patients exhibited early spikes in lactate and worsened performance on the second day, compared to healthy controls. This suggests impaired lactate clearance and heightened exertional stress.
Does Lactate Cause Post-Exertional Malaise (PEM)?
While elevated lactate correlates with post-exertional malaise (PEM), it is not likely the direct cause. Instead, lactate may serve as a defense mechanism to counteract inflammation. Its anti-inflammatory properties may represent the body's attempt to mitigate excessive immune responses triggered by exertion.
“Lactate concentrations were 2.8x higher in multiple sclerosis patients than healthy controls...” Does high lactate cause post-exertional malaise? Probably not.”
Could Gut Bacteria Be a Source of Lactate?
The gut microbiome plays a surprising role in lactate dynamics. Certain bacteria, like Streptococcus and Enterococcus, produce D-lactate, a form of lactate distinct from the L-lactate generated by cellular metabolism. Elevated levels of these bacteria have been found in the stool samples of ME/CFS patients.
What is D-Lactate?
D-lactate can also result from abnormal glucose metabolism. High-carbohydrate diets can push glucose through a pathway that produces methylglyoxal, a toxic molecule converted into D-lactate. Methylglyoxal and advanced glycation end-products (AGEs) contribute to oxidative stress and inflammation.
Strategies to Reduce Lactate and Improve Symptoms
Reducing lactate may help alleviate exercise intolerance and PEM. Here are some potential approaches:
1. Supplements
Magnesium: Known to reduce lactate production after exercise.
Citrulline Malate: Commonly used by athletes to lower lactate levels and enhance recovery.
2. Pharmacological Options
Milnacipran: An FDA-approved drug for fibromyalgia that has been shown to lower brain lactate levels and reduce pain.
3. Gut Microbiome Modulation
Reduce lactate-producing bacteria through:
Antibiotics or natural antimicrobials.
Prebiotics and probiotics.
A low-carbohydrate or ketogenic diet.
4. Ketogenic Diet or Exogenous Ketones
The ketone β-hydroxybutyrate can help clear lactate by converting it into energy, potentially reducing its buildup.
Key Takeaways
Lactate is more than just a byproduct of exertion—it’s a versatile molecule with critical roles in energy production, brain function, and inflammation regulation. For those with ME/CFS, fibromyalgia, or similar conditions:
Lactate is not a waste product.
Lactate is not inherently inflammatory or pain-producing.
Elevated lactate is a sign of the body attempting to regulate inflammation.
Future research may uncover more targeted ways to manage lactate levels and harness its benefits, providing new hope for reducing fatigue, pain, and other debilitating symptoms. For now, understanding lactate’s dual role as both a helper and a signal of underlying issues can guide smarter treatment strategies.
References
van Hall G, et al. (2009) Blood lactate is an important energy source for the human brain. J Cereb Blood Flow Metab. 29(6):1121-9.
Pucino, V., Bombardieri, M., Pitzalis, C., & Mauro, C. (2016). Lactate at the crossroads of metabolism, inflammation, and autoimmunity. European Journal of Immunology, 47(1), 14–21.
Ratter JM et al (2018) In vitro and in vivo Effects of Lactate on Metabolism and Cytokine Production of Human Primary PBMCs and Monocytes. Front. Immunol.,9: 2564.
Magistretti PJ, Allaman I. (2018) Lactate in the brain: from metabolic end-product to signalling molecule. Nat Rev Neurosci. 19(4):235-249.
Lien K, et al. (2019) Abnormal blood lactate accumulation during repeated exercise testing in myalgic encephalomyelitis/chronic fatigue syndrome. Physiol Rep. 7(11): e14138.
Cinar V, Nizamlioğlu M, Moğulkoc R. (2006) The effect of magnesium supplementation on lactate levels of sportsmen and sedanter. Acta Physiol Hung. 93(2-3):137-44.
Kiyici F, Eroğlu H, Kishali NF, Burmaoglu G. (2016) The Effect of Citrulline/Malate on Blood Lactate Levels in Intensive Exercise. Biochem Genet. 55(5-6):387-394.
Natelson, BH et al. (2015) Effect of Milnacipran Treatment on Ventricular Lactate in Fibromyalgia: A Randomized, Double-blind, Placebo-controlled Trial. J Pain. 16(11): 1211–1219.
