Author Archive

Vitamin K2: Part One

Thursday, January 16th, 2014

In the past year and a half, vitamin K2 has been the second most common topic, after oxalate, that I’ve received questions about.

Vitamin K2 is relevant to vegan diets because the only plant food that has an appreciable amount is natto, a fermented soy product that most of us don’t eat and which has a taste many people don’t care for.

Until recently, mainstream science has considered K2 to be unnecessary both because people can get the same benefits from K1 (which is found in leafy greens) and because K2 is made by common intestinal bacteria. But then research came out at the end of the 00’s suggesting that K2 might have benefits.

K2 is now being used to promote eating animal products such as in the article Vitamin K2: A Little Known Nutrient Can Make a Big Difference in Heart and Bone Health, by Aglaée Jacob, MS, RD, CDE in Today’s Dietitian (June 2013). Jacob promotes animal products to prevent heart disease because of the vitamin K2.

As an aside, I’m not sure if this is Today’s Dietitian’s position on saturated fat and animal products, but it’s not the only article they have run in which Jacob jettisons the idea that saturated fat causes heart disease (see also Coconut Oil – Learn More About This Superfood That Contains Healthful Saturated Fats).

My plan is to review the studies on K2 more closely to try to figure out to what extent, if any, vegans are setting themselves up for heart disease, osteoporosis, or other diseases by not having an intake of vitamin K2.

A quick refresher on the forms of vitamin K:

– Phylloquinone is vitamin K1 and found primarily in plant foods, especially leafy greens.

– Menaquinone (forms MK4 through MK10) is vitamin K2. It is found in animal tissues and made by bacteria.

More background info can be found in the article vitamin K at VeganHealth.org.

The first study I’ll review is from one of the two Dutch cohorts of the European Prospective Investigation Into Cancer (EPIC). It was published in 2009 (1). They followed over 16,000 women for an average of 8 years.

The researchers did a fairly rigorous job in measuring vitamin K intake which ranged from 1 – 128 µg, with an average of 29 µg.

They found that every 10 µg increase in vitamin K2 intake was associated with an decreased risk of heart disease but the finding was of only borderline statistical significance (.92, .85 – 1.00). Interestingly, even though they divided the group into quartiles of vitamin K2 intake, they did not report on the relative risk between the different quartiles.

In contrast, intake of vitamin K1 was not associated with risk of heart disease.

Unlike Aglaée Jacob, the authors caution against getting vitamin K2 through typical animal foods:

“Thus, although our findings may have important practical implications on [cardiovascular disease] prevention, it is important to mention that in order to increase the intake of vitamin K2, increasing the portion vitamin K2 rich foods in daily life might not be a good idea. Vitamin K2 might be, for instance more relevant in the form of a supplement or in low-fat dairy. More research into this is necessary.”

I’m skeptical that their findings have important practical implications for cardiovascular disease prevention, but I’ll be reviewing other papers in the days ahead to find out more.

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References

1. Gast GC, de Roos NM, Sluijs I, Bots ML, Beulens JW, Geleijnse JM, Witteman JC, Grobbee DE, Peeters PH, van der Schouw YT. A high menaquinone intake reduces the incidence of coronary heart disease. Nutr Metab Cardiovasc Dis. 2009 Sep;19(7):504-10. | link

Ginny’s Book for People Over 50 and Post on which Diet is Best

Monday, January 13th, 2014

Ginny Messina, MPH, RD has a new book out, Never Too Late to Go Vegan, for people 50 years and older. She writes about it here:

Never Too Late to Go Vegan: The Book!

And she had an interesting post last week, Vegan, DASH, Mediterranean—Which Diet is Best?

Paleo Dieters Eat Crickets, Jack Eats Crow

Wednesday, January 8th, 2014

I’ve criticized paleo eaters in the past for not taking their diet seriously and eating bugs (see my article Can a Natural Diet Require Supplements?).

But on Monday, the NY Times ran an article about a paleo dieter who started an energy bar company that uses crickets as the protein source (Energy Bars That Put a Chirp in Your Step).

Excerpt:

“According to the two men’s research, the insects are 69 percent protein by dry weight as compared with 31 percent for chicken breast and 29 percent for sirloin steak; they provide more iron than beef does and nearly as much calcium as milk. They produce one-eightieth the amount of methane that cattle do, and need one-twelfth their feed, based on 100-gram portions of each. And they can reproduce quickly and don’t require acres of grassland to graze.”

A move from people eating mammals and birds to crickets is something I can get behind.

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Amy’s Gluten-Free Vegan Burritos and other Odds and Ends

Tuesday, January 7th, 2014

Gluten-Free Vegan Burrito

Amy’s has a gluten-free, vegan burrito. More info.

Vitamin D & Bone Pain: A Study of One

I received a nice note from a reader:

“You may want to know that after reading your book and watching your presentation at the Vegetarian Society of Hawaii, I started taking Vitamin D in winter and autumn, which “cured” my muscular pain. Also, your recommendations helped my mother fix her high homocysteine level. Since she is vegetarian and not vegan, I thought she needed just a little B12 (wrong!).”

Food for Thought: Adopting an animal-friendly menu policy

If you are involved with an animal shelter that doesn’t serve vegan food at their functions, check out Animal Place’s Food for Thought campaign which strives to make shelter events friendly to all animals. More info.

Eyes

Dr. Greger just finished releasing a 4-part video series on nutrition and eyesight that I found very informative. Link.

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PeaCounter Database Updated

Saturday, January 4th, 2014

I have updated the PeaCounter.com database to the latest USDA Nutrient Database Release 26.

If you don’t know about Pea Counter, it’s a site where you can record the foods you eat, see what nutrients they provide, and compare to your recommended requirements.

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Austrian Vegetarians: Good News?

Friday, January 3rd, 2014

A study was released a couple weeks ago from Austria – a cross-sectional survey of eating habits and various health outcomes. But it has so many issues that I don’t think it’s worth commenting on except in the interest of being thorough in documenting the research on vegetarians.

Trying to infer dietary effects on health by using cross-sectional studies is always fraught with problems, but this study had even more than usual.

The diet categories included vegan, lacto-ovo-vegetarian, and pesco-vegetarian which was fine; in the final analysis all of these were grouped as “vegetarians.” The remaining diet groups were:

– carnivorous diet rich in fruits and vegetables
– carnivorous diet less rich in meat
– carnivorous diet rich in meat

This is unusual, and they didn’t define them even for the participants when they were asking them which category they belonged to.

For the health outcomes, instead of a list of diseases and incidence rates, they created a number of indicators that I would not have much confidence in. Finally, their p-values made little sense to me.

To sum up their findings, they say, “Both a vegetarian diet and a carnivorous diet rich in fruits and vegetables were related to the best self-rated health and the lowest incidence of chronic conditions. However, the quality of life was better in subjects who consume a carnivorous diet rich in meat. Nevertheless, as diets rich in fruits and vegetables were associated with better health as well as better health-related behavior, these diets should be recommended, and public health programs will be needed to reduce the health risk due to nutritional factors.”

So for what it’s worth, I suppose this is good news.

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References

1. Burkert NT, Freidl W, Großschädel F, Muckenhuber J, Stronegger WJ, Rásky E. Nutrition and health: different forms of diet and their relationship with various health parameters among Austrian adults. Wien Klin Wochenschr. 2013 Dec 17. [Epub ahead of print] | link

Soy Protein, Weightlifting, and Testosterone

Monday, December 30th, 2013

A reader asked me to comment on a study comparing soy protein, whey protein, and a carbohydrate placebo and their effects on hormones (1).

The study was mainly conducted to see if soy increased estrogen levels. Unsurprisingly, it did not.

On all 3 supplements, testosterone levels went up during the workout. But compared to both whey and carbohydrate placebo, testosterone levels were not sustained as high post-workout. And cortisol, which can break down muscle tissue for energy, was higher on the soy and carbohydrate regimens than on whey.

The study was done on 10 young men who took each supplement for 2 weeks, with washout periods between regimens. The supplements were taken 30 minutes before a bout of exercise: 6 sets of squats, 10 repetitions each, 2 minutes rest between sets, weight was 80% of their maximum. The hormones were measured before, during, and at a number of times after the exercise up to one hour.

All 3 supplements were 80 calories worth of energy.

It’s possible that the lower testosterone levels are a result of either the much lower amounts of leucine in soy versus whey protein (about 39% lower) or due to the isoflavones. The authors of the study say, “The majority of evidence from previous research on isoflavones alone has shown no effect on testosterone,” making me think it’s the lower leucine leading to lower testosterone.

As for the cortisol, that soy didn’t perform as well as carbohydrate is odd and might be due to the fairly intense workout, soy and carbohydrate caused higher cortisol levels. When I lift weights, I try not to push my muscles to the point where I’m breaking down muscle for a significant portion of energy, and six intense sets of squats to 10 reps seems like a lot. The carbohydrate, or the extra leucine in the whey (which muscles can use for energy), could have been enough to prevent muscle from being degraded for energy.

It was not clear from the write-up whether the participants were blinded to which regimen they were on, though I assume they were. If not, that could have played a role.

More research is needed – we don’t even know if this would result in a noticeable difference in strength gains, particularly on a different weight-lifting program that isn’t quite so focused on so many reps for the same muscle groups.

But if you are a serious weightlifter and this worries you, adding some leucine to your soy protein powder, or a non-soy protein powder, might be the way to go. Or perhaps just carbohydrate instead, to prevent the cortisol response.

The Vegetarian Resource Group has information on where leucine is sourced in their 2011 article, Leucine, Isoleucine, and Valine May Be Derived from Duck Feathers or Human Hair.

Addendum 12-31-2013:

For testosterone, whey and carbohydrate achieved similar results. Soy was not as high from 5 to 30 minutes post exercise, but was about the same at 60 minutes. Although the differences were statistically significant, they were not all that great – the biggest difference was about 30% between soy and whey.

For cortisol, I had said that soy didn’t perform as well as carbohydrate, but the differences were so small that I shouldn’t have said this. Soy and carbohydrate resulted in statistically significant, higher levels than whey at 5, 15, and 30 minutes post exercise. The biggest difference between soy and whey was about 45%.

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References

1. Kraemer WJ, Solomon-Hill G, Volk BM, Kupchak BR, Looney DP, Dunn-Lewis C, Comstock BA, Szivak TK, Hooper DR, Flanagan SD, Maresh CM, Volek JS. The effects of soy and whey protein supplementation on acute hormonal reponses to resistance exercise in men. J Am Coll Nutr. 2013;32(1):66-74. | link

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Monday, December 23rd, 2013

Due to my oxalate research hiatus, it’s been awhile since I’ve made a post dedicated to asking for support.

As many of you know, I am the co-founder of Vegan Outreach. Vegan Outreach focuses on reaching students at colleges across the country with our booklets promoting compassionate eating. This past Fall was another record-breaking semester in which our leafleters personally handed booklets to 987,551 students at 884 schools.

This level of person-to-person outreach was so mind-blowing that Dan Murphy from Drover’s Cattle Network has claimed that we must be lying about our numbers (see Lies, damn lies, and vegan statistics).

Vegan Outreach is currently in the midst of our year-end donation drive and, in addition to annoying Dan Murphy, anything you give to Vegan Outreach will be doubled! Donations to Vegan Outreach are tax-deductible. Click here.

Or, you can also support this blog directly by donating to me via PayPal. You do not need a PayPal account. Click here.

Below are other ways to support JackNorrisRD.com

Thank you so much for supporting my project of getting vegans the most scientifically accurate nutrition information possible!

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Cholesterol Levels in Vegans: EPIC-Oxford Study

Sunday, December 22nd, 2013

I have updated the blood lipids section of the VeganHealth.org article, Disease Markers of Vegetarians, with a new report from EPIC-Oxford measuring the cholesterol levels of 422 vegans living in the UK (1).

Vegan men had an average total cholesterol level of 170 mg/dl compared to 204 mg/dl for non-vegetarians. Vegan women had an average cholesterol level of 172 mg/dl compared to 195 mg/dl for non-vegetarians. More results, including those for lacto-ovo and pesco-vegetarians, can be seen in Table 1 (link).

Vegans also had a significantly lower amount of apolipoprotein B which is thought to promote fat deposits in the arteries.

The authors of the study suggest that vegans have lower cholesterol levels due to a lower body mass index, replacement of saturated fats with polyunsaturated fats, and higher fiber intakes.

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References

1. Bradbury KE, Crowe FL, Appleby PN, Schmidt JA, Travis RC, Key TJ. Serum concentrations of cholesterol, apolipoprotein A-I and apolipoprotein B in a total of 1694 meat-eaters, fish-eaters, vegetarians and vegans. Eur J Clin Nutr. 2013 Dec 18. [Epub ahead of print] | link

Brain Creatine Content in Vegetarians vs. Omnivores

Friday, December 20th, 2013

Good news on the creatine front!

In October of 2010, I reported a study which found that creatine supplementation improved cognition in vegetarians and vegans (Creatine Improves Cognition in Vegetarians). A few months later, in December of 2010, I reported a study that found creatine supplementation in vegetarian and vegan women boosted their cognition to beyond that of omnivores who also supplemented (Creatine Improves Cognition to Beyond that of Omnivores).

Today I’m reporting on a 2013 study from Brazil that measured the brain creatine content of vegetarians and found it to be the same as for omnivores (1).

They compared the creatine content of the posterior cingulate cortex between vegetarians (6 women and 8 men) and omnivores. The posterior cingulate cortex was chosen because it is related to emotion formation and cognitive function (processing, learning and memory).

Although the vegetarians ate much less creatine than the omnivores (.03 vs. 1.34 g, respectively), they had similar brain creatine levels (6.0 vs. 5.9 IU, respectively). The authors say:

“It has been shown previously that oral [creatine] intake can have beneficial effects on cognitive function in vegetarians rather than in omnivorous individuals, suggesting that the former may show some deficit in brain [creatine] content. However, the present study refutes this hypothesis, reinforcing previous experimental data suggesting that brain [creatine] content relies primarily on local endogenous synthesis rather than on [creatine] dietary intake.”

I have updated the VeganHealth.org article Creatine.

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References

1. Yazigi Solis MY, de Salles Painelli V, Artioli GG, Roschel H, Otaduy MC, Gualano B. Brain creatine depletion in vegetarians? A cross-sectional 1H-magnetic resonance spectroscopy (1H-MRS) study. Br J Nutr. 2013 Nov 29:1-3. | link