DNC News

Why we don't sell grapefruit seed extract.

July 21, 2005

Subject: Grapefruit seed extract may owe its antimicrobial action to toxic chemical additives.

The widespread promotion and usage of grapefruit seed extract (GSE) within the health food industry and its promotion by practitioners of alternative medicine is a matter of concern to me.  We stopped selling it a number of years ago.  I want to explain why.

The problem is that it works, just like the company's promotional literature says it does, but for all the wrong reasons.  The germ killing properties of commercial GSE do not come from any chemical within grapefruit seeds but to chemical additives that are slipped in during manufacture.

I have reports going back over ten years in which chemical analysis of GSE  found methyl-p-hydroxybenzoate and triclosan. in the products  These two chemicals are preservatives.  Other studies which have analyzed GSE have found benzethonium chloride and methyl parabene. None of these chemicals occur naturally in grapefruit seeds.  It wasn't a surprise then when these reports were confirmed by published research.

In 1999 German scientists evaluated six commercial preparations of grapefruit seed extract and tested their antimicrobial properties.  Five of the six extracts showed a strong inhibitory effect.  In all five of the extracts which 'worked' they found the bensethonium chloride, a preservative.  Three of the extracts contained triclosan and methyl parabene.  The one extract with no antimicrobial activity had no preservative agents added. A 'homemade' extract which the researchers prepared had no antimicrobial activity.  The researchers concluded that the potent and nearly universal antimicrobial activity attributed to grapefruit seed extract is due to synthetic preservatives added and not due to the actual extract.

What is a surprise is that this information hasn't slowed sales of these products or that the health food industry feels no need to dump these products off their collective shelves for fraud and misrepresentation.

Benzethonium chloride is a disinfectant commonly used in cosmetics and is categorized as a class 2 poison because of its teratogenicity and caustic effects.  Upwards of 8% has been found in GSE products, far more than ever used in cosmetics.  The Environmental Defense Fund describes this chemical as a "suspected endocrine toxicant." According to the National Institute for Occupational Health and Safety, taking benzethonium chloride internally could cause, " diarrhea, nausea, vomiting, collapse, convulsions (and) coma."  This chemical and by extension, grapefruit seed extract is a potentially harmful compound and is not approved for internal use.

Triclosan isn't much better.  The EPA lists it as a pesticide and although widely used in cosmetics is not approved for internal use.
Of late I have received a great many communications from the health food industry and from 'public advocates' decrying attempts by the FDA and other regulatory bodies to oversee the sale of supplements and other natural products.  It is hard to hear the merit of these arguments when we see such egregious conduct as the continuing promotion and sale of products like Grapefruit Seed Extract.   

Pharmazie. 1999 Jun;54(6):452-6.
Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained.

von Woedtke T, Schluter B, Pflegel P, Lindequist U, Julich WD.

Institute of Pharmacy, Ernst Moritz Arndt University, Greifswald, Germany.

The antimicrobial efficacy as well as the content of preservative agents of six commercially available grapefruit seed extracts were examined. Five of the six extracts showed a high growth inhibiting activity against the test germs Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16, Staphylococcus aureus SBUG 11, Serratia marcescens SBUG 9, Escherichia coli SBUG 17, Proteus mirabilis SBUG 47, and Candida maltosa SBUG 700. In all of the antimicrobial active grapefruit seed extracts, the preservative benzethonium chloride was detected by thin layer chromatography. Additionally, three extracts contained the preserving substances triclosan and methyl parabene. In only one of the grapefruit seed extracts tested no preservative agent was found. However, with this extract as well as with several self-made extracts from seed and juiceless pulp of grapefruits (Citrus paradisi) no antimicrobial activity could be detected (standard serial broth dilution assay, agar diffusion test). T
 hus, it
is concluded that the potent as well as nearly universal antimicrobial activity being attributed to grapefruit seed extract is merely due to the synthetic preservative agents contained within. Natural products with antimicrobial activity do not appear to be present.

PMID: 10399191

We hope you find the information in these newsletters useful, informative and hopefully entertaining. If you want your name removed simply leave a message at the office (303-337-4884) or go to the website: denvernaturopathic.com and unsubscribe, or reply with the message "REMOVE" in the subject line.  If on the other hand you want to be added to the mailing list follow the prior instructions but subscribe. 
We are posting most of these newsletters in our 'NEWS' section of the website.  The website versions contain more complete references and often abstracts of the references quoted and links to the full text of many of the journal articles mentioned. You don't have to be a patient to sign up and we encourage you to get your friends on our mailing list so you don't have to keep forwarding the newsletters that you find interesting.

Ask the Doctor:
What's the difference between naturopathy and homeopathy?

[click here for the answer]

Submit your question here.

Enter your email to recieve the latest Health and Wellness newsletters from the clinic.