Ginkgo

Plant Part Used

Leaf

Introduction

Ginkgo is among the oldest living plant species on earth and has been used extensively as a medicinal agent worldwide for centuries. Today, it is the most frequently prescribed medicinal herb in Europe. Ginkgo has been the subject of hundreds of scientific studies that have reported positive effects in a wide range of health areas. The remedy has been popularized for its use in the support of mental function. There are many other, less publicized, applications. The leaf of the ginkgo tree is used to derive a standardized extract.

Interactions and Depletions

Interactions

Dosage Info

Dosage Range

40-80mg (standardized extract), 3 times a day.

Most Common Dosage

40mg (standardized extract), 3 times a day.

Standardization

Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.

The most current available medical and scientific literature indicates that this dietary supplement should be standardized to 24% ginkgo flavoglycosides and 6% triterpenes per dose; also standardized to 27% flavoglycosides 7% triterpenes per dose.

Reported Uses

Ginkgo has been extensively researched for its possible benefits to the elderly. Studies indicate ginkgo has the ability to increase circulation which can lead to enhanced memory. (1) , (2) This effect can in turn delay the onset of Alzheimers and reduce the effects of senile dementia, tinnitus, and vertigo. (3) , (4) , (5) , (6) Studies indicate that ginkgo’s support of healthy brain function is related to its ability to increase blood flow to the brain, thus improving delivery of nutrients and disposal of waste products. (7)

The effectiveness of ginkgo in treating dementia is debated. Numerous studies have been completed evaluating numerous patients with various types of demetia, including Alzheimer's disease. These studies have had very differing results. In a study involving over 200 patients, a standardized ginkgo preparation (40mg three times a day) was compared to placebo. The ginkgo was reported safe and capable of stabilizing and improving mental and social functioning for up to a year. (8) Another trial involving over 200 patients, compared the same ginkgo preparation with placebo and reported no advantage with the gingko when used for 24 weeks. (9) A third trial compared 115 people over 60 years old using ginkgo to 115 people over 60 years old using placebo. The study evaluated these participants using 15 different tests for memory and learning. The results of this study showed no improvement in the tests for both the ginkgo and the placebo group. (10)

Four commonly used medications for dementia (tacrine, donepezil, rivastigmine, and metrifonate) were compared to a standardized ginkgo extract and a placebo for their use in Alzheimer's disease. The authors concluded that second-generation cholinesterase inhibitors (donepezil, rivastigmine, and metrifonate) and the standardized ginkgo extract should be considered equally effective in the treatment of mild to moderate Alzheimer's disease. (11)

Because of its effects on the circulatory system, ginkgo may also ease the leg pain that arises from intermittent claudication and similar disorders. (12) , (13) One study even found that ginkgo performed as well as a leading prescription medication for treating intermittent claudication.

Ginkgo’s ability to support healthy circulation and brain function has applications in younger populations as well. Disorders it may improve include diabetes and various circulatory conditions including cyanosis and Raynaud’s Syndrome. (14)

Ginkgo has also been used to treat impotence, especially when associated with antidepressant therapy. (15) , (16) Ginkgo may also be involved in a chemical process that reduces the potential for clot formation in the blood by inhibiting platelet activating factor (PAF). (17) Scientists think this function, along with a potential ability to dilate blood vessels, accounts for its record of use in treating asthma in China for thousands of years.

Finally, ginkgo is an antioxidant, giving it the ability to help rid the body of free radicals and thus lessen the risk of chronic degenerative diseases. (18) Also due to the antioxidant activity of ginkgo, it may help treat macular degeneration (19) and decrease the damaging effects of radiation, chemotherapy, (20) and certain medications. (21)

Toxicities & Precautions

Introduction

Be sure to tell your pharmacist, doctor, or other health care providers about any dietary supplements you are taking. There may be a potential for interactions or side effects.

General

This dietary supplement is considered safe when used in accordance with proper dosing guidelines.

Fresh seeds of the ginkgo tree should not be eaten because they may be toxic.

If you are planning to have any type of surgery or dental work, stop using this dietary supplement for at least 14 days prior to the procedure. (22)

Allergy

Some individuals experience an allergic skin reaction when taking this dietary supplement. Although extremely rare, call your doctor or seek medical attention if you have fast or irregular breathing, skin rash, hives or itching. (23)

Health Conditions

If you have a bleeding disorder, talk to your doctor before taking this dietary supplement. (24)

Side Effects

Side effects are possible with any dietary supplement. Although extremely rare, this dietary supplement may cause gastrointestinal distress or headache. (25) Tell your doctor if these side effects become severe or do not go away.

Pregnancy/ Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Yet limited information exists regarding the use of this dietary supplement while pregnant or breast-feeding. Therefore, it is recommended that you inform your healthcare practitioner of any dietary supplements you are using while pregnant or breast-feeding. (26)

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Since young children may have undiagnosed allergies or medical conditions, this dietary supplement should not be used in children under 10 years of age unless recommended by a physician.

References

  1. View Abstract: Kleijnen J, et al. Ginkgo biloba for Cerebral Insufficiency. Br J Clin Pharm. 1992;34:352-58.
  2. Kleijnen J, et al. Ginkgo biloba. Lancet. 1992;340(8828):1136-39.
  3. View Abstract: Maurer K, et al. Clinical Efficacy of Ginkgo biloba Special Extract EGb 761 in Dementia of the Alzheimer Type. J Psychiatr Res. 1997;31(6):645-55.
  4. View Abstract: Kanowski S, et al. Proof of Efficacy of the Ginkgo biloba Special Extract EGb 761 in Outpatients Suffering from Mild to Moderate Primary Degenerative Dementia of the Alzheimer Type or Multi-infarct Dementia. Pharmacopsychiatry. 1996;29:47-56.
  5. View Abstract: Meyer B. Multicenter Randomized Double-blind Drug versus Placebo Study of Ginkgo biloba Extract in the Treatment of Tinnitus. Presse Med. 1986;15:1562-64.
  6. Odawara M, et al. Ginkgo biloba. Neurology. 1997;48(3):789-90.
  7. View Abstract: Ernst E. Ginkgo biloba in the Treatment of Intermittent Claudication. A Critical Review. Fortschritte der Medizin. 1996;114(8):85-87.
  8. View Abstract: Le Bars PL, Katz MM, Berman N, et al. A Placebo-controlled, Double-blind, Randomized Trial of an Extract of Ginkgo biloba for Dementia. North American EGb Study Group. JAMA. Oct1997;278(16):1327-32.
  9. View Abstract: Van Dongen MC, van Rossum E, Kessels AG, et al. The Efficacy of Ginkgo for Elderly People with Dementia and Age-associated Memory Impairment: New Results of a Randomized Clinical Trial. J Am Geriatr Soc. Oct2000;48(10):1183-94.
  10. View Abstract: Solomon PR, Adams F, Silver A, Zimmer J, DeVeaux R. Ginkgo for memory enhancement: a randomized controlled trial. JAMA. Aug2002;288(7):835-40.
  11. View Abstract: Wettstein A. Cholinesterase Inhibitors and Gingko Extracts--Are They Comparable in the Treatment of Dementia? Comparison of Published Placebo-controlled Efficacy Studies of at Least Six Months' Duration. Phytomedicine. Jan2000;6(6):393-401.
  12. Kleijnen J, et al. Ginkgo biloba. Lancet. 1992;340(8828):1136-39.
  13. View Abstract: De Felice M, Gallo P, Masotti G. Current Therapy of Peripheral Obstructive Arterial Disease. The Non-surgical Approach. Angiology. 1990;41:1-11.
  14. View Abstract: Muir AH, Robb R, McLaren M, Daly F, Belch JJ. The use of Ginkgo biloba in Raynaud's disease: a double-blind placebo-controlled trial. Vasc Med. 2002;7(4):265-7.
  15. View Abstract: Cohen AJ, et al. Ginkgo biloba for Antidepressant-induced Sexual Dysfunction. J Sex Marital Ther. 1998;24(2):139-43.
  16. Sikora R, et al. Ginkgo biloba Extract in the Therapy of Erectile Dysfunction. J Urol. 1989;141:188A.
  17. Braquet P. Anti-anaphylactic Properties of BN 52021: A Potent Platelet Activating Factor Antagonist. Advances in Experimental Medicine and Biology. 1987;215:215-33.
  18. View Abstract: Hu B, Sun S, Mei G, Chen L, Tong E. Protective effects of Ginkgo biloba extract on rats during cerebral ischemia/reperfusion. Chin Med J (Engl). Sep2002;115(9):1316-20.
  19. View Abstract: Lebuisson DA, et al. Treatment of Senile Macular Degeneration with Ginkgo biloba Extract. A Preliminary Double-blind Drug vs. Placebo Study. Presse Med. Sep1986;15(31):1556-58.
  20. View Abstract: Inselmann G, Blohmer A, Kottny W, et al. Modification of Cisplatin-induced Renal P-aminohippurate Uptake Alteration and Lipid Peroxidation by Thiols, Ginkgo biloba Extract, Deferoxamine and Torbafylline. Nephron. 1995;70(4):425-9.
  21. View Abstract: Barth SA, Inselmann G, Engemann R, et al. Influences of Ginkgo biloba on Cyclosporin A Induced Lipid Peroxidation in Human Liver Microsomes in Comparison to Vitamin E, Glutathione and N-acetylcysteine. Biochem Pharmacol. May1991;41(10):1521-6.
  22. Pribitkin ED. Herbal therapy: what every facial plastic surgeon must know. Arch Facial Plast Surg. Apr2001;3(2):127-32.
  23. PDR for Herbal Medicines, 2nd ed. Montvale, NJ: Medical Economics Company; 2000:344.
  24. Behrman: Nelson Textbook of Pediatrics, 16th ed. W B Saunders Company; 2000:2304.
  25. Odawara M, et al. Ginkgo biloba. Neurology. 1997;48(3):789-90.
  26. View Abstract: Ondrizek RR, Chan PJ, Patton WC, King A. An alternative medicine study of herbal effects on the penetration of zona-free hamster oocytes and the integrity of sperm deoxyribonucleic acid. Fertil Steril. Mar1999;71(3):517-22.