Grey Duck Garlic
By Susan Fluegel PHD
One of my hobbies is reading really long scientific research papers and condensing them. Edna, Jane and I have a lot of discussions about this material in the garlic field. I'll be putting my shortened version of new garlic and health research on this page. For those of you who like to read the long orginal version I provide references to the papers.
WSU researchers recently reported that diallyl sulfide, a compound found in garlic, is 100 times more effective than the antibiotics erythromycin and ciprofloxacin in killing the toxic bacteria Campylobacter jejuni (Lu et al. 2012). Campylobacter jejuni is the most common cause of food poisoning in the United States. Food poisoning strikes over 2.4 million Americans each year and symptoms include stomach pains, cramping, diarrhea and fever.
Campylobacter jejuni is hard to kill because it produces a slimy protective biofilm that helps it repels antibiotics and stick to surfaces. The garlic compound diallyl sulfide dissolves the biofilm and kills the cowering bacteria underneath. Diallyl sulfide combines with a sulfur containing enzyme in the bacteria. This changes the enzyme’s function and shuts down cell metabolism; killing bacteria better and faster than antibiotics!
Previous work by Lu and WSU researchers reported that diallyl sulfide and other organosulfur compounds can kill other food-borne pathogens, such as Listeria monocytogenes and Escherichia coli O157:H7 (Lu et al. 2011). Organosulfur compounds combine with sulfur containing proteins and enzymes to kill pathogens. Lu et al. 2011 also demonstrated that organosulfur compounds, not garlic phenol compounds, were responsible for most of the antimicrobial activity of garlic.
Garlic has been shown to protect against other types of food pathogens. Irkin and Korukluoglu (2007) demonstrated that an extract of garlic protects food against Aspergillus niger, a toxic fungus. Garlic inhibited growth of Aspergillus niger in foods. The Aspergillus fungus family produces dangerous mycotoxins, including aflatoxin B1. Fungal toxins are detoxified by the liver. Unfortunately mycotoxin exposure can harm DNA replication increasing the risk of cancer. This is a particular danger to people with hepatitis B. Hepatitis B and mycotoxins are both liver carcinogens. They have an additive effect on liver damage which increases the risk of liver cancer.
Take home message: These studies were done in a laboratory not in a kitchen. However, all the current evidence indicates that adding fresh raw garlic to food will have some anti-bacterial and anti-fungal effects. Interestingly, garlic has been used to help preserve and protect food for centuries.
Side Note: Dr. Barbara Rasco, co-author of the Lu et al. studies, was my professor for the food science class in which I wrote my Grey Duck Garlic business plan. She is a very intelligent and fun woman with a passion for food science and food law.
- Irkin R and Korukluoglu M. Control of Aspergillus niger with garlic, onion and leek extracts. African Journal of Biotechnology, 2007; 6 (4): 384-387.
- Lu X, Samuelson DR, Rasco BA, Konkel ME. Antimicrobial effect of diallyl sulphide on Campylobacter jejuni biofilms. J. Antimicrob. Chemother. May 1, 2012.
Lu X, Rasco BA, Jabal JMF, Aston DE, Lin M, Konkel ME. Investigating Antibacterial Effects of Garlic (Allium sativum) Concentrate and Garlic-Derived Organosulfur Compounds on Campylobacter jejuni by Using Fourier Transform Infrared Spectroscopy, Raman Spectroscopy, and Electron Microscopy. Applied and Environmental Microbiology, 2011; 77 (15): 5257.
- Lu X, Rasco BA, Kang DH, Jabal JM, Aston DE, Konkel ME. Infrared and Raman spectroscopic studies of the antimicrobial effects of garlic concentrates and diallyl constituents on foodborne pathogens. Anal Chem. 2011; 83(11):4137-46.
Eating raw garlic lowers fasting blood sugar, LDL cholesterol and triglycerides in hyperglycemic and/or hyperlipidemic people
Mahmoodi et al. (2011) looked at the effect of eating raw garlic on three groups of people. Volunteers ate 10 grams of garlic daily (one small/medium clove) for 42 days.
- Group 1: People who had high fasting blood sugar (over 126 mg/dl)
- Group 2: People who had high blood cholesterol (over 245 ml/dl)
- Group 3: People who had high blood cholesterol (over 245 ml/dl)and high fasting blood glucose levels (over 126 mg/dl)
Eating garlic had no effect on group 1; however, it had a significant effect on groups 2 and 3.
Group 2: had significant decreases in fasting blood sugar, triglycerides and total cholesterol. At the same time good HDL cholesterol increased.
Group 3: had significant decreases in fasting blood sugar, glycated hemoglobin and total cholesterol. Again good HDL cholesterol increased.
Other studies support these findings. Kannar et al. (2001) reported that people using a garlic supplement for 12 weeks decreased total cholesterol by 4.2% and and LDL-C by 6.6%.
Take home message: If you have elevated cholesterol, high trigylcerides or diabetes eating a clove of garlic everyday may help.
- Mahmoodi, M., Zijoud, S., Hassanshahi, G., Toghroli, M., Khaksari, M., Hajizadeh, M. and Mirzajani, E. (2011) The effects of consumption of raw garlic on serum lipid level, blood sugar and a number of effective hormones on lipid and sugar metabolism in hyperglycemic and/or hyperlipidemic individuals ——Benefit of raw garlic consumption. Advances in Biological Chemistry, 1, 29-33.
- Kannar, D., Wattanapenpaiboon, N., Savige, G.S. and Wahlqvist, M.L. (2001) Hypocholesterolemic effect of an enteric-coated garlic supplement. Journal of the American College of Nutrition, 20, 225-231.