Do vegans need l-carnitine?

In this brief guide, we will answer the query, “Do vegans need l-carnitine?” and will discuss why l-carnitine is essential for the body?

Do vegans need L-carnitine?

Yes, vegans need l-carnitine. The amount of L-carnitine in your system is determined by what you consume and how much your body makes. Vegetarians and vegans limit or avoid animal products, hence their L-carnitine levels tend to be lower. L-carnitine supplementation may be an option for vegetarians and vegans.

The main sources of dietary carnitine are animal products including red meat, chicken, fish, and dairy products (1).

Carnitine deficiency is associated with impaired fatty acid and glucose utilization and insulin sensitivity. In humans, 75% of carnitine is obtained from the diets of animal origin; thus the vegetarians obtain only negligible amounts. The lost or insufficient carnitine is replenished by dietary carnitine (exogenous) and by endogenous synthesis. Studies indicated that endogenous synthesis provides 90% of total body carnitine in strict vegetarians and approximately 25% in omnivores (5).

What is L-carnitine?

Carnitine is a hydrophilic quaternary amine that plays a number of essential roles in metabolism with the main function being the transport of long-chain fatty acids from the cytosol to the mitochondrial matrix for β-oxidation. Carnitine can be endogenously synthesized. However, only a small fraction of carnitine is obtained endogenously while the majority is obtained from diet,mainly animal products (1).

Carnitine is a fat-burning and cellular toxin-removing substance your body produces on its own. Carnitine levels in your body are kept relatively stable by a balance between production in the liver and kidneys and excretion and reuptake in the kidneys (1).

The endogenous carnitine biosynthesis is estimated to be 1.2 μmol/kg/day, whereas a regular diet provides 2–12 μmol/kg/day carnitine. Therefore, in individuals consuming a regular diet about 75% of carnitine (~300 μmol daily) comes from diet and only 25% of it (~100 μmol daily) comes from endogenous synthesis. Since carnitine is present primarily in animal products, strict vegetarians (vegans) and lacto-ovo-vegetarians obtain very little carnitine from their diet (<0.1 μmol/kg/day). Therefore, vegetarians obtain more than 90% of their carnitine through biosynthesis (1).

For the most part, L-carnitine serves to support mitochondrial activity and energy generation in your body. It aids in the transport of fatty acids into the mitochondria, where they may be burnt for energy in the cell. 

The vast majority of your body’s L-carnitine reserves are found in your muscles, with smaller quantities found in your liver and blood. Studies have shown that L-carnitine may assist improve mitochondrial activity, which is important for health and aging as well.

Carnitine is not required by healthy vegans

Animal goods, such as meat and dairy, are the finest sources of carnitine, yet vegans who completely eschew these items seldom suffer from carnitine insufficiency. To create carnitine, your liver and kidneys need two amino acids that you get from protein intake: lysine and methionine. According to Oregon State University, additional nutrients are necessary, such as iron and vitamins C, B-3, and B-6. Carnitine shortage is unlikely if your liver and kidneys are healthy and your diet is well-balanced. However, certain conditions like pregnancy may result in increased excretion of L-carnitine, potentially increasing the risk for deficiency (2).

Vegans with kidney problems

According to the Office of Dietary Supplementation, vegans with chronic kidney disease, particularly those who are in the last stages of the illness and are on hemodialysis, may need carnitine supplements. In those with renal disease, less carnitine is made and more is eliminated, increasing the risk of a carnitine shortage.

That is because the special contribution of the kidney to the carnitine systemic balance is more evident when we observe subjects on a vegetarian diet characterized by very low carnitine content. It is evident that the exclusion of the kidney makes the liver the main source of endogenous carnitine and increases the risk of deficiency (4).

Vegans should be especially concerned about this since a vegan diet contains very little carnitine. Avocado, asparagus, and whole wheat bread all contain small levels of carnitine, but not nearly as much as in animal sources.

Carnitine deficit can be correlated with severe nutritional inadequacies: vegetables are lacking in carnitine, as are cereal grains, and also may be relatively deficient in lysine and methionine, its amino acid precursors. For this reason, a rigidly vegetarian diet can be the cause of deficit conditions that will appear of greater gravity if quantitatively poor in some protein components (ie, legumes) (4).

Carnitine deficiency may be caused by a variety of factors.

Vitamin C insufficiency may impede carnitine synthesis in the body, which can lead to a shortage among vegans. According to researchers at Oregon State University, tiredness is associated with carnitine deficit and might be an early indicator of vitamin C deficiency. According to a review paper published in the December 2010 edition of “Nutrition in Clinical Practice,” iron insufficiency is a frequent nutritional problem among vegans (3). 

Carnitine production may be hampered by an iron deficit, increasing the demand for dietary sources of carnitine. According to the National Institutes of Health’s research, vegans may receive enough iron from dried fruits like prunes, apricots, and raisins, as well as legumes, whole grains, and iron-fortified foods like spinach, broccoli, and asparagus. Adding vitamin C-rich foods like strawberries and oranges to your meal will help your body better absorb iron from plants. Inhibitors of iron absorption include phytates, calcium, and the polyphenolics in tea, coffee, herb teas, and cocoa. Vitamin C and other organic acids found in fruits and vegetables substantially enhance nonheme iron absorption and reduce the inhibitory effects of phytate. Soaking and sprouting beans and grains as well as leavening of bread can diminish phytate levels and enhance iron absorption (3).

Conquering Carnitine’s Deficit

Carnitine deficiency leads to muscle weakness. Lipid metabolism is severely affected, resulting in storage of fat in muscle and functional abnormalities of cardiac and skeletal muscle. Systemic deficiency is a potentially lethal, autosomal recessive disorder characterized by cardiomyopathy, myopathy, recurrent episodes of hypoketotic hypoglycemia, hyperammonemia, and failure to thrive. It is manifested by low concentrations of carnitine in plasma, muscle, and liver. Symptoms are variable, but include muscle weakness, cardiomyopathy, abnormal hepatic function, impaired ketogenesis, and hypoglycemia during fasting (4).

Carnitine supplements are available for vegans who are low in amino acids. A supplement called acetyl-L-carnitine is also known as L-carnitine in the United States. According to the Office of Dietary Supplements, acetyl-L-carnitine is more readily absorbed and may pass the blood-brain barrier. The more expensive L-carnitine is, the better value it is (2).

The recommended daily dosage for these supplements is between one and three grams. Toxic side effects such as diarrhea may occur at doses of more than 5 g. Before beginning a carnitine supplement, talk to your doctor (2).

Efficacy and Risks

Most individuals may safely use 2 grams or less of caffeine per day without experiencing any negative side effects. There were no side effects reported in research in which participants took 3 grams of the supplement daily for 21 days.

The exact dose of carnitine supplementation should be adjusted accordingly based on the individual’s plasma carnitine level. While carnitine supplementation has relatively few side effects, high doses may result in increased gastrointestinal motility, diarrhea and intestinal discomfort (1).

L-carnitine levels of around 2 grams per day were found to be safe in an assessment of the supplement’s long-term safety. Despite this, moderate adverse effects such as nausea and stomach pain were experienced by individuals. Recently, carnitine supplementation has been approved by the United States Food and Drug Administration not only for treatment, but also for the prevention of carnitine depletion in dialysis patients (4). 

L-carnitine supplementation, on the other hand, has the potential to enhance your blood levels of the neurotransmitter trimethylamine-N-oxide (TMAO). TMAO levels are associated with an increased risk of atherosclerosis, a condition in which the arteries become blocked.

More research is required to determine if L-carnitine supplements are safe to use.

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Conclusion

In this brief guide, we answered the query, “Do vegans need l-carnitine?” and discussed why l-carnitine is essential for the body?

References

1. El-Hattab, Ayman W., and Fernando Scaglia. Disorders of carnitine biosynthesis and transport. Mol gen metab, 2015, 116, 107-112.  
2. Higdon, J. L-Carnitine. 2002. Micronutrient Information Center. Oregon State University.
3. Craig, Winston John. Nutrition concerns and health effects of vegetarian diets. Nutr Clin Pract, 2010, 25, 613-620.
4. Matera, Mario, et al. History of L-carnitine: implications for renal disease. J Renal Nutr, 2003, 13, 2-14.
5. Lin, Tsung-Jen, et al. A comparison of L-carnitine and several cardiovascular-related biomarkers between healthy vegetarians and omnivores. Nutr, 2019, 66, 29-37.