Measuring Oxidative Stress
Integrative Medicine ● Vol. 8, No. 3 ● Jun/Jul 2009
Joseph Pizzorno, ND
● Oxidative stress plays a key role in virtually all chronic diseases.
● Goal is to find a simple, widely available and inexpensive assessment of oxidative stress. One test that may meet these demands is gamma glutamyltransferase (GGT)
● GGT is found on the membranes of all cells and at particularly high concentrations in the liver, bile ducts, and kidneys. Primary role of GGT is to metabolize and transport extracellular reduced glutathione (GSH), allowing for precursor amino acids to be assimilated and reutilized for intracellular GSH synthesis.
● As the need for glutathione production increases, for example as a protective response to oxidative stress or heavy metal exposure, so does the production of GGT to facilitate GSH production.
● GGT levels at the higher end of the “normal” range are known to be risk indicators for diabetes and cardiovascular disease.
● GGT helps to transport vitamin C into the cell.
● GGT levels >35 U/L confer a 3 times greater risk of having a cardiovascular event.
Ways to Decrease Serum GGT Levels
(1) Milk thistle (Silybum marianum)
(2) Fenugreek (Trigonella foenum-graecum)
(3) N-Acetylcysteine (NAC) – 600 mg daily for 4 weeks reduced GGT from 62.7 to 46.3 U/L in patients with non-alcoholic steatohepatitis – most likely as result of increased GSH production
(4) Vitamin E – 400 mg/day of alpha tocopherol acetate reduced GGT from 64.0 to 28.50 U/L in just 7 days
(5) Vitamin C – protects the liver from many oxidative toxins and lowers GGT
(6) Probiotics – 5 days of Bifidobacterium bifidum and Lactobacillus plantarum 8PA3 resulted in 14% drop in serum GGT
(7) Homeopathy – Arsenicum album 30x once daily caused GGT reduction from 40 to 10 U/L in men and 30 to 6 U/L in two months
● Recommended optimal ranges for GGT
– Males: 11-20 U/L
– Females: 7-20 U/L
GGT is a value that I run on all new patients in my office as part of our Restore Profile. This test, combined with an in-office urinary assessment of oxidative stress, provides a glimpse into the oxidation (think rust) that is occurring inside your body. I’ve always kind of thought about free radicals that produce oxidative damage as the little bombs that Mario would carry around in Super Mario 2. You have to forgive the reminiscing of my younger days. Super Mario would grab a bomb, the fuse would light, rapid flashing would warn you to get out of the way, and then *BOOM* whatever was nearby was damaged. Unfortunately, sometimes that even meant me losing a Mario life. Think of GGT as the rapid flashing, warning you that something is going on. The functional ranges that Dr. Pizzorno presents in his article are good guidelines. I have seen some published studies showing even lower ranges and that GGT levels above 10 may be problematic. The moral of the story is this…have your GGT levels checked as part of a complete blood assessment looking at functional ranges.