Grape Seed oil is a good oil which may increase good cholesterol levels and reduce bad cholesterol levels, and pure Grape Seed Extract contains beneficial substances (OPCs or Oligomeric ProanthoCyanidins) which slow or stop colon cancer.
Unfortunately the quite unrelated commercial product Grapefruit Seed Extract, purportedly from grapefruit as opposed to grapes, is often adulterated or even almost entirely made up from poisonous chemicals, since pure GSE has little or no antibacterial properties. Chief among the impurities is benzalkonium chloride. In a 2008 study synthetic disinfectants such as benzethonium or benzalkonium chloride were identified in most of the commercial GSE products:
Shokuhin Eiseigaku Zasshi. 2008 Feb;49(1):56-62.
[Survey of synthetic disinfectants in grapefruit seed extract and its compounded products].
[Article in Japanese] Sugimoto N, Tada A, Kuroyanagi M, Yoneda Y, Yun YS, Kunugi A, Sato K, Yamazaki T, Tanamoto K.
National Institute of Health Sciences, Tokyo, Japan.
Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.
PMID: 18344660 [PubMed – indexed for MEDLINE] Free full text