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.

Reference

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

Postscript

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:

Glutathione reductase:
vegetarian – decreased, decreased
control – decreased, increased

Glutathione peroxidase:
vegetarian – increased, stabilized
control – decreased, increased much higher than vegetarian

Glutathione transferase:
vegetarian – increased, stabilized
control – increased, stabilized

This study is from 2011 from the Czech Republic. I mentioned it in my post on the type 2 diabetes treatment meta-analysis that I made last week, Type 2 Diabetes Meta-Analysis: What Happened to the Vegan Diet?

I’ve also had it in my nutrition queue to read for some time. In fact, anyone who’s read this blog for awhile might be wondering how many studies might actually be lurking in my nutrition queue! Well, I’m happy to report that I had over 200 emails (many with studies attached) to go through last Friday at noon and it’s now down to 81. So, I’m catching up!

The reason this study got buried is because the abstract calls the diet “vegetarian,” rather than “vegan.” But once you read the study, you see that the “vegetarian” diet contained no animal products except for a maximum of one serving of low-fat yogurt per day – that’s as vegan as the diet used in Dean Ornish’s heart disease reversal study.

In fact, it makes me rethink that type 2 diabetes meta-analysis – they said they only included diets that had been studied at least twice, saying that only one study looked at a vegan diet and one looked at a “vegetarian” diet when in reality, the diets were virtually both vegan given that people in these studies tend to cheat a little bit anyway. Oh, well.

One difference is that the diet in the PCRM study was about 21% fat, whereas the diet in the Czech Republic study was…drum roll please…38% fat!

The rest of this post is copied from the blurb I just added to Type 2 Diabetes and the Vegan Diet at VeganHealth.org:

In 2011, researchers from the Czech Republic studied a vegetarian (near-vegan) diet compared to a conventional (control) diet for type 2 diabetes (1). The study tested only diet for 12 weeks and then combined diet and exercise for another 12 weeks. Animal products were limited to maximum of one portion of low-fat yogurt a day. The calories in both diets were limited (as distinct from the PCRM studies in which the vegan diet was unlimited in calories). The vegetarian diet was about 38% fat.

The vegetarian diet group had a greater reduction in diabetes medication (43% vs. 5%), HbA1c, waist circumference, and body fat. LDL cholesterol went down 8% in the vegetarian group only, but HDL cholesterol went up in the control group. Exercise caused the positive differences for the vegetarian diet to be even greater and also raised the HDL in the vegetarian group.

The authors stated:

Several possible mechanisms may explain the beneficial effects of a vegetarian diet: higher intake of fibre, lower intake of saturated fat [and a higher polyunsaturated and saturated fatty acid (P⁄S) ratio], higher intake of non-heme iron and reduction in iron stores, higher intake of vegetable protein in place of animal protein, higher intake of antioxidants and plant sterols. A vegetarian diet was reported to reduce intramyocellular lipid concentrations and this, together with the effect on visceral fat which we observed, might be responsible for a substantial portion of the effect of a vegetarian diet on insulin sensitivity and enzymatic oxidative stress markers.

And, oddly enough:

Especially during exercise, it became evident in our trial that it was easier for subjects to follow a vegetarian diet than a conventional diabetic diet.

And I’m happy to report that VeganHealth.org’s Type 2 Diabetes and the Vegan Diet section is now up to date. I am considering paring down a lot of the details on that page – if anyone has read it and has an opinion on if you prefer the details or would like to see them pared down quite a bit, please let me know in the comments here. Thank you!

Reference

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

On January 4th, I posted Part 1 of my interview with Erin O’Sullivan of Animal Voices podcast:

Everything You Ever Wanted to Know About Vegan Nutrition But Were Afraid to Ask, Part 1

Part 2 is now available:

Everything You Ever Wanted to Know About Vegan Nutrition But Were Afraid to Ask, Part 2

Of the interviews I’ve done, these are my two favorite because we covered so many things other than the 10 nutrients vegans need to be aware of and vegetarian disease rate statistics. Erin’s questions were great! I look forward to her coming up with another batch some time.

Dr. Greger has been posting videos at NutritonFacts.org from Volume 12 of his Latest in Clinical Nutrition series. But if your workplace does not allow plant-based-nutrition-porn to be played on your computer at work, you might want to get the DVD (click here).

Volume 12 covers fibromyalgia, coconut oil, gargling to prevent colds, and tons on flaxseeds and their ability to prevent prostate cancer, breast cancer, and type 2 diabetes. Dr. Greger does not back off his pro-antioxidant stance. He also has a section on dried fruit suggesting that raisins are just as effective as sports gels for energy while working out.

Harish has an interesting post at Counting Animals showing the amount of foodborne illness and deaths attributable to various food categories:

Do pathogens in animal products cause deadlier illnesses?

On the same day that the study showing vegetarians to have a 30% reduced risk of heart disease was released on PubMed, a meta-analysis of diets used to treat type-2 diabetes was also released (1).

The abstract mentions vegan diets:

“We included randomized controlled trials (RCTs) with interventions that lasted ≥ 6 mo that compared low-carbohydrate, vegetarian, vegan, low-glycemic index (GI), high-fiber, Mediterranean, and high-protein diets with control diets including low-fat, high-GI, American Diabetes Association, European Association for the Study of Diabetes, and low-protein diets.”

And their conclusion is:

“Low-carbohydrate, low-GI, Mediterranean, and high-protein diets are effective in improving various markers of cardiovascular risk in people with diabetes and should be considered in the overall strategy of diabetes management.”

Knowing that PCRM had conducted a clinical trial using a whole-foods vegan diet to treat type-2 diabetes with some decent success (more info), I was surprised that the vegan diet didn’t get mentioned in the conclusion. It turns out that they weeded out any diets that were not tested in at least two different trials. They did have some good things to say about the vegan diet in the paper and suggested more studies were needed. Ditto for the one trial using a vegetarian diet (2).

In terms of the other diets, they found that low-carbohydrate, low-GI, Mediterranean, and high-protein diets all reduced Hb A1c (a marker of blood sugar levels; lower is better), and all but the high-protein diets also improved lipid profiles.

What is the difference between a low-carbohydrate diet and a high-protein diet? A “low-carbohydrate diet” is defined as limiting carbohydrate to 20 to 60 g/day, which is very low. A “high-protein” diet is more than 20% of daily calories as protein, and generally has a higher amount of carbohydrate than the low-carbohydrate diets.

They defined a Mediterranean Diet as, ” rich in olive oil, legumes, unrefined cereals, fruit, and vegetables, low in meat and meat products, and with moderate contents of dairy products (mostly cheese and yogurt), fish, and wine.” They attributed the benefits of a Mediterranean diet to the higher monounsaturated fat (MUFA) content which has been shown “to have an impact on the lipid profile, insulin sensitivity, and postprandial glucose concentrations [blood sugar after a meal].”

I can’t vouch for the analytical methods used in this meta-analysis – there were an enormous amount of details comparing all sorts of different metrics – but the above are the author’s main points. They stated that no funding was received for the study.

Reference

1. Ajala O, English P, Pinkney J. Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes. Am J Clin Nutr. 2013 Jan 30. [Epub ahead of print] | link

2. 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. (Abstract only) | link

I’ve looked for solid information on microwave cooking a few times and found very little. I recently learned of an interesting article by Ryan Andrews, RD at Precision Nutrition which he posted last March and thought I’d pass it on:

All About Microwave Cooking

Not being completely clear on his conclusion, I wrote Ryan and he confirmed that the take-home message is that it’s safe to microwave your food as far as the food goes, but you should stand a few feet away from the microwave oven when it is on to prevent any accumulation of radiation entering your body.

As promised last week, here is a write-up of the 2009 studies associating poor bone health with low B12 status in vegetarians. This is an important reason for lacto-ovo vegetarians, as well as vegans, to make sure they are getting a reliable source of vitamin B12.

VeganHealth.org’s Bones, Vitamin D, and Calcium updated:

“A 2009 cross-sectional study from Slovakia compared lacto-ovo vegetarian women to omnivores. They found that the vegetarians’ higher homocysteine (16.5 vs. 12.5 µmol/l; 78% vs. 45% were elevated) and lower vitamin B12 levels (246 vs. 302 pmol/l; 47% vs. 28% were deficient) were associated with significantly lower bone mineral density in the femur (1). Participants were not allowed to have been taking vitamin or mineral supplements. The researchers did not measure calcium intake or vitamin D status.

“Another 2009 cross-sectional study of German omnivores, lacto-ovo vegetarians, and omnivores, and Indian lacto-ovo vegetarians and omnivores found higher markers of bone turnover associated with low vitamin B12 status (2). The findings were no worse for the lacto-ovo vegetarians than the vegans, indicating that poor bone health can start with just moderate B12 deficiency. None of the participants were taking B12, calcium, or vitamin D supplements.”

References

1. Krivosikova Z, Krajcovicova-Kudlackova M, Spustova V, Stefikova K, Valachovicova M, Blazicek P, Nemcova T. The association between high plasma homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet. Eur J Nutr. 2009 Oct 7. | link

2. Herrmann W, Obeid R, Schorr H, Hübner U, Geisel J, Sand-Hill M, Ali N, Herrmann M. Enhanced bone metabolism in vegetarians–the role of vitamin B12 deficiency. Clin Chem Lab Med. 2009;47(11):1381-7. | link

Released last week:

Heart disease rates of all vegetarians compared to all non-vegetarians were calculated for EPIC-Oxford from 1993 until 2009 (1). These participants were all thought to be free of heart disease at the beginning of the study. The results showed that vegetarians had a statistically significant, ~30% reduced risk of heart disease (.68, .58-.81). That is a fairly impressive finding for a nutrition study.

All results were adjusted for age, smoking, alcohol, physical activity, education, socioeconomic status, oral contraceptives, and hormone replacement therapy. The findings held after adjusting for body mass index (BMI) and removing the first two years of follow-up. (See the table in EPIC-Oxford: Heart Disease (2013) of VeganHealth.org for the relative risks.)

The researchers believed the difference in heart disease rates to be due mainly to the lower non-HDL cholesterol and systolic blood pressure of the vegetarians. The non-vegetarians had an average total cholesterol level of 222 mg/dl vs. 203 mg/dl for the vegetarians, while HDL was 52 vs. 50 mg/dl respectively. Systolic blood pressure was 134 for non-vegetarians and 131 mm Hg for vegetarians.

Given that vegetarians had cholesterol levels an average of 203 mg/dl – a full 33% higher than the 150 mg/dl, upper-end-of-healthy that many of the very low-fat doctors recommend – it might come as a surprise to learn that, in the authors’ words, “On the basis of the absolute rates of hospitalization or death from IHD [ischemic heart disease], the cumulative probability of IHD between ages 50 and 70 y was 6.8% for nonvegetarians compared with 4.6% for vegetarians.”

In other words, with cholesterol levels that high in both groups, you might think they would have a very high rate of heart disease, but, from what I can tell (see reference #2), their rates are relatively comparable to the general population of the United States (2).

*** Don’t forget to share this post! ***

Reference

1. Crowe FL, Appleby PN, Travis RC, Key TJ. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study. Am J Clin Nutr. 2013 Jan 30. [Epub ahead of print] | link

2. Prevalence of Coronary Heart Disease — United States, 2006–2010
Morbidity and Mortality Weekly Report (MMWR) for October 14, 2011. Accessed February 3, 2013. | link (PDF)

[Breaking news: A paper was released today showing vegetarians to have a lower risk of heart disease – I will write about that next week. Update: Click here.]

It’s raining B12 this week!

Yet another paper was released on vegetarians and vitamin B12, this time reviewing all the studies that have measured B12 status using methylmalonic acid (MMA) or holo-transcobalamin II levels (1).

Holo-transcobalamin II is thought to be a better predictor of vitamin B12 deficiency than blood B12 levels because it is the last refuge of B12 being transported to cells, while MMA levels are the best way to know that the cells are not getting enough vitamin B12 to function normally.

The review included 18 studies, eight of which were done on German vegetarians. The authors did not combine results from the studies, but rather provided a handy chart to see what each study found.

They concluded that all vegetarians – not just vegans – are at a significant risk of B12 deficiency and recommend a B12 supplement of 250 µg per day.

This is higher than what I recommend on a daily basis, which is 25 to 100 µg. I do not think this review provides enough evidence to change my recommendations, but I would not discourage anyone from taking 250 µg per day.

The authors state:

“Supplements, when taken in an adequate dose, are very effective in both the prevention and treatment of B12 deficiency and are very cost effective. However, many vegetarians, for different reasons, refuse to take B12 supplements. This is largely due to various misconceptions, including the belief that it takes many years for B12 deficiency to develop.”

The authors also noted a connection between low vitamin B12 status in vegetarians and low bone mineral density, citing a paper from 2009. Upon reading this, I thought “Ha, I remember that paper,” only to find out that the study I had written about in Bones, Vitamin D, and Calcium, was a different one from 2009! (2) The paper they cited (3) had flown under my radar, but never fear, I intend to review it for an upcoming post.

References

1. Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B(12) deficiency among vegetarians? Nutr Rev. 2013 Feb;71(2):110-7. Epub 2013 Jan 2. | link

2. Krivosikova Z, Krajcovicova-Kudlackova M, Spustova V, Stefikova K, Valachovicova M, Blazicek P, Nemcova T. The association between high plasma homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet. Eur J Nutr. 2009 Oct 7. | link

3. Herrmann W, Obeid R, Schorr H, Hübner U, Geisel J, Sand-Hill M, Ali N, Herrmann M. Enhanced bone metabolism in vegetarians–the role of vitamin B12 deficiency. Clin Chem Lab Med. 2009;47(11):1381-7 (Abstract only) | link