Vegetarian Diet, Glutathione and Oxidative Stress
A reader sent me a link to the following article, Back-Loading Interview w Kiefer, Part III. Upon doing some checking, it turns out that “Kiefer” is the mastermind behind a weight-loss and bodybuilding program he calls Carb Backloading. For $57 you can download his PDF on carb backloading and learn all about it (something I have not done). What I’ve gleaned about the program is that Kiefer says that the body’s circadium rhythms are such that if you eat carbohydrates in the early part of the day, they will be stored as fat. But if you do a hard workout and then eat carbohydrates later in the day, they will be stored as glycogen to prime you for your next workout.
I don’t know if there is any truth to this – it’s certainly not something the American College of Sports Medicine has endorsed at this time and I, for one, eat carbohydrates (and fat and protein) in the mornings and have been fairly successful at keeping off the body fat.
But this isn’t why I’m writing this post.
The reader who sent me the link was mostly concerned about what Kiefer had to say about the antioxidant potential of a vegetarian diet. From his interview with Sean Hyson:
Sean: Here’s something else I was blown away by when I read it, the idea that whey protein might be a better antioxidant than fruits and vegetables. You say that it works “by increasing levels of an amino acid called glutathione, which fuels the main antioxidant machinery of the cells in the body. Eating fruits and vegetables pales in comparison to the glutathione mechanism. Glutathione also helps recycle other antioxidants like Vitamin C and Vitamin E, decreasing the need to use vitamins. …”
Kiefer: …When you look at the research, some of the most compelling research was done with vegetarians….vegetarians literally have 10,000 times the concentration of antioxidants in their systems, but they have the same rate of all cancers….So for all that extra antioxidant machinery that vegetarians supposedly have, it offers no extra protection.
Oh, no you didn’t, Mr. Kiefer!
When I read the study from my last post, Near Vegan Diet Improves Type 2 Diabetes (1), I couldn’t help but notice that the researchers measured the glutathione levels in the subjects and found that the vegetarian diet actually increased reduced glutathione (as distinct from oxidized glutathione) during both the non-exercise and exercise phases, while the reduced glutathione levels in the control group went down in both phases of the study.
My understanding is that you want higher levels of reduced glutathione as that is the version that can do it’s free radical scavenging.
Three enzymes also were measured in the study: glutathione reductase, glutathione peroxidase, and glutathione transferase. My sense is that you want these enzymes to be low as they indicate oxidative activity, but this is not clear to me – if you are living a lifestyle with a lot of oxidative stress, then these enzymes being high would indicate that glutathione is doing its job.
The enzyme levels changed between the diet groups, but there was no clear direction (they were all over the map for both diet groups during both phases). See the postscript for the changes in these enzymes.
Based on this study, it would seem that a vegetarian diet does have ample glutathione potential. But it’s just one study, so I looked further and came across another one I will post about tomorrow. And there might be more after that. Stay tuned.
1. Kahleova H, Matoulek M, Malinska H, Oliyarnik O, Kazdova L, Neskudla T, Skoch A, Hajek M, Hill M, Kahle M, Pelikanova T. Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes. Diabet Med. 2011 May;28(5):549-59. | Link
Below are the enzymes followed by the diet group and the changes in the enzymes during the non-exercise and exercise phases of the study:
vegetarian – decreased, decreased
control – decreased, increased
vegetarian – increased, stabilized
control – decreased, increased much higher than vegetarian
vegetarian – increased, stabilized
control – increased, stabilized