Power of Garlic is well known for its ability to lower blood pressure (19) as well as reduce the oxidative stress inherent in those with hypertension. However, this tasty little herb contains hundreds of phytochemicals, flavonoids, and various sulphur-related compounds that offer the health-conscious individual a host of diverse benefits.
One of its flavonoids, diallyldisulfide, has been demonstrated to cause an increase in luteinizing hormone(LH) (1). LH is released from the anterior pituitary gland where it travels to the testis to initiate the process of testosterone production. A recent study connecting garlic with LH levels utilized rats placed on a high-protein diet with either .8 grams of garlic per 100 gram of protein or a high-protein diet only. Researchers discovered an enhanced excretion of 17-ketosteroids in the garlic group. This is indicative of enhanced metabolic clearance – and thus presence – of testosterone. In addition, corticosterone levels (think cortisol) were greatly reduced. Implications for the natural bodybuilder are obvious. 6-oxo, avena sativa, 1,4-androstadiene – 3,6,17-dione are common legal means utilized to increase T production. Now we have a much cheaper and tastier option to add to the list.
The reduction or glucocorticoids would benefit those prone to visceral or central obesity and the other ramifications of metabolic syndrome, of which excessive cortisol production is a primary contributor (12). Cortisol also has a proteolytic capacity in skeletal muscle tissue, so the actives in garlic might play a role in preventing muscle loss and/or maintaining gains during the post-cycle period, when cortisol levels can be out of balance with testosterone.
Through the 5-alpha reductase enzyme, testosterone is converted to dihydrotestosterone (DHT). In the prostate gland, elevated DHT can be problematic as it increases susceptibility to prostate hypertrophy, decreased urine volume, and possibly, cancer (15). The good news is that while garlic can increase T levels, the diallydisulfide it contains induces apotosis in prostate cancer cell lines (2) and acts as a chemoprotective agent in the prostate (13).
Apparently, diallydisulfide slows the cancer cell line proliferation, or the increase in the number of cancer cells, by apoptosis, or programmed cell death (2,6,14)
Supplementation with stimulants such as ephedrine or clenbuterol are effective in enhancing lipolysis in fat cells via the stimulation of the G-protein receptor. A hormonal cascade ensues resulting in the eventual breakdown of trigylercides to fatty acids, which can then be oxidized. While generally safe when used as directed, uncomfortably high blood pressure and heart rate elevations can occur (18)
Garlic, while not nearly as potent as these sympathomimetic agents, provides a modest fat burning effect mainly through enhancing uncoupling protein activity, while actually lowering systolic blood pressure (19). Uncoupling Protein-1(UCP-1) is expressed in mitochondria of brown adipose tissue (BAT). It functions to uncouple the process of oxidative phosphorylation away from useful energy production in favor of the dissipation of heat. The mitochondria, in turn, speeds up the degradation of foodstuffs in an attempt to match the need for ATP synthesis for said energy production. In essence, the catabolism of foods – and thus calories – is accelerated when UCP-1 is activated. Garlic consumption can lead to an elevated expression of UCP-1 in mitochondria of BAT and potentiate thermogenic processes (5).
Its potential for reducing bodyfat is further supported in that garlic can decrease fatty acid synthase (FAS) expression. FAS is involved in several facets of triglyceride physiology including the conversion of acetyl-CoA to malonyl-CoA, which happens to be the first committed step in lipid synthesis. Upon exposure of rat liver cells to several cysteine compounds contained in garlic, expression of FAS was reduced by nearly one-third relative to placebo (7). Lipolytic activity, in general, is positively affected by garlic intake, which seems to parallel its ability to lower both cholesterol and low-density lipoproteins levels (8,9).
A common drawback of oral androgen use is the excessive strain it places upon the liver. Abnormally long cycles can elevate liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin (17). The use of methylated or 17-alpha-alkalated androgens is a means to enhance the oral bioavailability of the steroid, which otherwise is not particularly potent upon ingestion, metabolism, and eventual degradation to inactive derivatives by the liver. Their use, unfortunately, creates a somewhat toxic environment for the liver, as it attempts to efficiently metabolize these foreign substances. S.-allylmercaptocysteine, another sulphur-containing compound found in garlic, aids in preventing liver enzyme elevation even upon exposure to potentially hazardous drugs such as acetominophen (3) and ethanol (10). More specifically, garlic can prevent altered levels of ALT, AST, and bilirubin, the very same enzymes affected during steroid use (4).
The usefulness of garlic during an oral androgen cycle certainly seems warranted for these hepatoprotective properties as well as its aforementioned LDL-lowering abilities, as LDL levels have been shown to reach above-normal values during steroid use (11).
In terms of garlic intake, the simplest method is to use it in cooking. If you have a taste for it, garlic can really spice up a meat-based meal or it can be added to salads or mixed vegetables. It should be noted that garlic does not lose any of its potency upon cooking (15). In fact it appears that cooking garlic activates many of its cysteine and flavonoid compounds. A Milliard reaction occurs during interaction between sugar and amino acids contained in various foods, including garlic. Through this reaction, the herb becomes “turned on” in a sense, producing several of its beneficial components (18). If you do not enjoy the pungency, garlic tablets that have been de-odorized are readily available and cost-efficient.
Hopefully, you have a greater appreciation for garlic beyond its well-supported anti-coagulant, blood-pressure lowering, and cholesterol reducing capabilities. This little herb can be a big asset in your bodybuilding and fitness endeavors.
Tom Rayhawk is available for online personal training and nutritional counseling at www.fitnessgenerator.com/trayhawk
1. Yuriko Oi1, Mika Imafuku, Chiaki Shishido, Yutaka Kominato*, Syoji Nishimura* and Kazuo Iwai. Garlic Supplementation Increases Testicular Testosterone and Decreases Plasma Corticosterone in Rats Fed a High Protein Diet. Molecular Cell Biochemistry 2005 Jul;275(1-2):85-94.
2. Gunadharini DN, Arunkumar A, Krishnamoorthy G, Muthuvel R, Vijayababu MR, Kanagaraj P, Srinivasan N, Aruldhas MM, Arunakaran J. Antiproliferative effect of diallyl disulfide (DADS) on prostate cancer cell line LNCaP. Cell Biochem Functi. 2005 Sep 2; [Epub ahead of print] 3. Sumioka I, Matsura T, Yamada K. Therapeutic effect of S-allylmercaptocysteine on acetaminophen-induced liver injury in mice. Eur J Pharmacol. 2001 Dec 21;433(2-3):177-85.
4. Sener G, Sehirli O, Ipci Y, Ercan F, Sirvanci S, Gedik N, Yegen BC. Aqueous garlic extract alleviates ischaemia-reperfusion-induced oxidative hepatic injury in rats. J Pharm Pharmacol. 2005 Jan;57(1):145-50.
5. Oi Y, Kawada T, Shishido C , Wada K, Kominato Y, Nishimura S, Ariga T, Iwai K. Allyl-containing sulfides in garlic increase uncoupling protein content in brown adipose tissue, and noradrenaline and adrenaline secretion in rats. J Nutri. 1999 Feb;129(2):336-42.
6. Arunkumar A, Vijayababu MR, Venkataraman P, Senthilkumar K, Arunakaran J. Chemoprevention of rat prostate carcinogenesis by diallyl disulfide, an organosulfur compound of garlic. Biol Pharm Bull. 2006 Feb;29(2):375-9
7. Liu L, Yeh YY. Water-soluble organosulfur compounds of garlic inhibit fatty acid and triglyceride syntheses in cultured rat hepatocytes. Lipids 2001 Apr;36(4):395-400
8. Sheela CG, Augusti KT. Effects of S-allyl cysteine sulfoxide isolated from Allium sativum Linn and gugulipid on some enzymes and fecal excretions of bile acids and sterols in cholesterol fed rats. Indian J Exp Biol. 1995 Oct;33(10):749-51
9. Johnson C, Banerji A, Oommen OV. A comparative study of allitin and garlic on lipid turnover in a teleost, Anabas testudineus (Bloch). Indian J Exp Biol. 2003 Mar;41(3):242-7.
10. Kishimoto R, Ueda M, Yoshinaga H, Goda K, Park SS. Combined effects of ethanol and garlic on hepatic ethanol metabolism in mice. J Nutr Sci Vitaminol (Tokyo) 1999 Jun;45(3):275-86.
11. Webb OL, Laskarzewski PM, Glueck CJ. Severe depression of high-density lipoprotein cholesterol levels in weight lifters and body builders by self-administered exogenous testosterone and anabolic-androgenic steroids. Metabolism 1984 Nov;33(11):971-5
12. Putignano P, Pecori Giraldi F, Cavagnini F. Tissue-specific dysregulation of 11beta-hydroxysteroid dehydrogenase type 1 and pathogenesis of the metabolic syndrome. J Endocrinol Invest. 2004 Nov;27(10):969-74.
13. Tarter TH, Vaughan ED Jr. Inhibitors of 5alpha-reductase in the treatment of benign prostatic hyperplasia. Curr Pharm Des. 2006;12(7):775-83.
14. Arunkumar A, Vijayababu MR, Kanagaraj P, Balasubramanian K, Aruldhas MM, Arunakaran J. Growth suppressing effect of garlic compound diallyl disulfide on prostate cancer cell line (PC-3) in vitro. Biol Pharm Bull. 2005 Apr;28(4):740-3.
15. Lanzotti V. The analysis of onion and garlic. J Chromatogr A. 2005 Dec 30; [Epub ahead of print] 16. Ide N, Lau BH, Ryu K, Matsuura H, Itakura Y. Antioxidant effects of fructosyl arginine, a Maillard reaction product in aged garlic extract. J Nutr Biochem. 1999 Jun;10(6):372-6.
17. Urhausen A, Torsten A, Wilfried K. Reversibility of the effects on blood cells, lipids, liver function and hormones in former anabolic-androgenic steroid abusers. J Steroid Biochem Mol Biol. 2003 Feb;84(2-3):369-75.
18. Haller CA, Jacob P, Benowitz NL. Short-term metabolic and hemodynamic effects of ephedra and guarana combinations. Clin Pharmacol Ther. 2005 Jun;77(6):560-71.
19. Al-Qattan KK, Thomson M, Al-Mutawa’a S, Al-Hajeri D, Drobiova H, Ali M. Nitric oxide mediates the blood-pressure lowering effect of garlic in the rat two-kidney, one-clip model of hypertension. J Nutri. 2006 Mar;136(3 Suppl):774S-776S.