The Role of Essential Amino Acid Lysine in Health and Disease

Lysine is an essential amino acid, meaning that it must be consumed by dietary means and cannot be manufactured within the body. It occurs in protein-containing foods, such as eggs, meat, and dairy products, and is abundant in beans and legumes. While most people in developed nations consume an adequate amount of lysine, some may be deficient depending on their diet, among other factors.

Lysine can exist in a “D or L” form (which refers to the chirality of the molecule). However, the L form of lysine is the essential component of the diet and is the form available in dietary supplements.

Lysine for Protection Against Glycation

While lysine’s most important role is in protein synthesis, a critical action for the amino acid is in the prevention of glycation: the nonenzymatic bonding of a sugar molecule to a protein or fat that results in the formation of advanced glycation end products (AGEs) which damage tissues, including the lining of the arteries. A similar phenomenon, known as glycosylation, refers to enzymatic bonding of carbohydrates to proteins or fats. Diabetics, who have elevated blood glucose levels, experience an increase in glycation-related damage.

Glucose in the body bonds to proteins that contain lysine. According to the authors of a study that found an 86% reduction in the glycation of collagen in the kidneys of rats that received L-lysine prior to the induction of elevated blood glucose, “The rationale is that the administered lysine would combine with the circulating glucose and make it unavailable to react with epsilon-amino groups of lysine of various proteins in these diabetic rats.”1

Lysine and Cataracts

In cataract formation, which involves glycation of the crystalline lens, a drug that contains L-lysine inhibited the early stages of protein glycation and the formation of advanced glycation end products.2 L-lysine has also been demonstrated to inhibit the glycation of fibrinogen (involved in blood clotting) in the plasma of type 2 diabetics.3

Lysine and Diabetics

In patients being treated for type 2 diabetes, 3 grams of L-lysine per day reduced advanced glycation end products in serum and reversed lysozyme glycation, thereby increasing its activity.4 (Lysozyme is an antimicrobial enzyme that forms a part of the innate immune system.) “Structure and function of glycated lysozyme are significantly improved by L-lysine; therefore it can be considered an effective therapeutic supplementation in type 2 diabetes mellitus, decreasing the risk of infection in these patients,” authors H. Mirmiranpour and colleagues conclude.

Interestingly, lysine ingested with glucose resulted in a 44% decrease in the 2.5-hour serum glucose response without a change in insulin response in comparison with the serum response to glucose alone in a study that involved healthy participants.5

Lysine and Herpes Simplex Virus

One of lysine’s best-known uses is as an aid to suppress herpes simplex virus 1 (HSV1) or HSV2. The virus is the cause of “cold sores” or “fever blisters” that appear on the lips, mouth, or genitals. While there are several prescription drugs that can treat HSV, L-lysine is used by some individuals to help maintain results during periods in which drugs are not being used to treat active lesions.

The rationale for using L-lysine against HSV is based on the fact that L-lysine has a competitive relationship with another amino acid, L-arginine, which is needed for HSV to replicate. In research conducted in tissue cultures, lysine antagonized the ability of L-arginine to promote viral growth, thereby suppressing HSV replication.6

Although plenty of anecdotal evidence exists in favor of the use of L-lysine against herpes, clinical data is limited. An early double-blind multicenter trial in which men and women with recurrent herpes simplex infection received 1 gram L-lysine from L-lysine monohydrochloride or a placebo three times daily for six months resulted in an average of 2.4 fewer HSV infections, decreased severity of symptoms and reduced healing time among those who received the amino acid.7 In a double-blind crossover study involving subjects with frequently recurring herpetic lesions, one gram L-lysine daily was associated with fewer lesions in comparison with the control group.8 Researchers D. J. Thein and W. C. Hurt found that when serum lysine levels exceeded 165 nanomoles per milliliter, herpes lesion recurrence decreased significantly. “These results suggest that prophylactic lysine may be useful in managing selected cases of recurrent herpes simplex labialis if serum lysine levels can be maintained at adequate concentrations,” they conclude.

Another, crossover study, found positive effects for 1,248 milligrams (mg) L-lysine monohydrochloride daily in the prevention of HSV lesions, but no benefit for 624 mg per day in comparison with a placebo.9 In a survey of 1,543 subjects with HSV, 84% reported that supplementation with L-lysine prevented recurrence or decreased the frequency of lesions, while decreasing symptom severity and healing time. Eighty-eight percent considered supplemental L-lysine effective.10

Cold sores, while generally considered an annoyance, could have more serious implications. Herpes simplex type 1 has been found in the cerebrums of the majority of older adults, in many areas affected by Alzheimer’s disease. Herpes encephalitis, a condition in which HSV causes severe brain infection, has been known to result in memory loss. It has been hypothesized that L-lysine supplementation could help protect against the development of Alzheimer’s.11

Lysine and Heart Disease

Another use for lysine is in the prevention of atherosclerosis. According to Nobel Prize-winning scientist Linus Pauling, "Knowing that lysyl residues are what causes lipoprotein(a) to stick to the wall of the artery and form atherosclerotic plaques, any physical chemist would say at once that to prevent that put the amino acid lysine in the blood to a greater extent than it is normally. You need lysine, it is essential, you have to get about one gram a day to keep protein in balance, but we can take lysine, pure lysine, a perfectly nontoxic substance as supplements, which puts extra lysine molecules in the blood. They enter into competition with the lysyl residues on the wall of arteries and accordingly count to prevent lipoprotein(a) from being deposited, or even will work to pull it loose and destroy atherosclerotic plaques."12

The Impact of Lysine

Due to its presence in protein sources, it’s no surprise that a high lysine diet also benefits muscle. A study in young men who consumed 80 mg lysine per kilogram body weight resulted in improved muscle strength after eight weeks.13 The finding is of relevance to the residents of developing countries whose populations are at risk of lysine deficiency. In Ghana, a randomized trial of L-lysine supplementation that included men, women, and children resulted in decreased diarrheal episodes and number of days ill among the children and fewer colds and number of days ill among the men.14 The authors note that lysine impacts diarrhea as well as anxiety by its effects on serotonin receptors, intestinal repair, and opioid peptide transport.

“Lysine could be viewed as the ‘forgotten’ amino acid in human nutrition,” writes D. H. Baker in the Journal of Nutrition.15 “This amino acid is rich in the food supply of developed countries. However, in poor countries where cereals dominate the food supply, lysine is the most limiting amino acid in the food supply.”

“Lysine has probably been studied more in animal nutrition than any other amino acid, but it has not received the same degree of emphasis in human nutrition. This is perhaps because few pharmacologic uses for lysine in the clinical setting have been advanced.” It is to be hoped that this “forgotten” amino acid will be remembered in future research and that additional uses in human health are uncovered.

References

  1. Jyothirmayi GN. Nephron. 2001 Feb;87(2):148-54.
  2. Marques C et al. Doc Ophthalmol. 1995;90(4):395-404.
  3. Mirmiranpour H et al. Thromb Res. 2012 Sep;130(3):e13-9.
  4. Mirmiranpour H et al. Acta Med Iran. 2016 Jan;54(1):24-31.
  5. Kalogeropoulou D et al. Am J Clin Nutr. 2009 Aug;90(2):314-20.
  6. Griffith RS et al. Chemotherapy. 1981;27(3):209-13.
  7. Griffith RS et al. Dermatologica. 1987;175(4):183-90.
  8. Thein DJ et al. Oral Surg Oral Med Oral Pathol. 1984 Dec;58(6):659-66.
  9. McCune MA et al. Cutis. 1984 Oct;34(4):366-73.
  10. Walsh DE et al. J Antimicrob Chemother. 1983 Nov;12(5):489-96.
  11. Rubey RN. Neuropsychiatr Dis Treat. 2010 Oct 27;6:707-10.
  12. Fonorow O. “No Prescription Required.” Linus Pauling’s Therapy® www.paulingtherapy.com 1996. Accessed 2017 July 19.
  13. Unni US et al. Clin Nutr. 2012 Dec;31(6):903-10.
  14. Ghosh S et al. Am J Clin Nutr. 2010 Oct;92(4):928-39.
  15. Baker DH. J Nutr. 2007 Jun;137(6 Suppl 2):1599S-1601S.

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