Best Study on Vegan Protein Intakes to Date

January 31st, 2016 by Jack Norris RD

I just updated the Protein page at with a new section, Intakes and Plasma Amino Acid Levels in Vegans, based on a recent study from EPIC-Oxford.

The new research cannot substitute for a nitrogen balance or protein synthesis study on vegans, which I have been hoping to see, but for now it’s what we have.

The takeaway message is that vegans, and particularly vegan women, should continue to make sure they eat plenty of lysine-rich foods, and that if you do, you should be covering all your protein needs.

I have reproduced the new section below.

Intakes and Plasma Amino Acid Levels in Vegans

A 2015 report from EPIC-Oxford analyzed the dietary intakes and blood levels of amino acids in various diet groups in adult men (15). The study included 98 men for each diet group (vegan, lacto-ovo, pesco, and meat-eater). The authors say, “[T]his is the largest study to date of amino acids in the circulation or in the diet by habitual diet group, and on average participants had followed their diet for several years.”


The study didn’t compare the intakes of the various diet groups to the US RDA for amino acids, but I have done so in Table 4 below.


Vegan men met the RDA for all essential amino acids.

This study bolstered the idea that lysine is the limiting amino acid in vegan diets, with vegan men surpassing the RDA by the lowest amount–9%. Methionine, the amino acid of second most concern, surpassed the RDA at the next lowest level of 33%.

The 95% confidence interval for lysine was 2.69-2.95 g/day; with the lower margin coming in at 104% of the RDA. The people on the lower end might have been the people who weighed less (and thus had a lower RDA than the average vegan).

The RDA for protein and amino acids is the same for women as it is for men (based on a percentage of their body weight). Male vegans in EPIC-Oxford were found to eat 10.7% more protein than female vegans (62 vs. 56 g per day; link). If you assume female vegans eat the same percentage of high-lysine foods as men, their average lysine intakes would be only 98.7% of the RDA.

Given that women have a lower percentage of lean body mass on average, it might seem curious that they have the same RDA for protein (and amino acids). In determining the RDAs, the Institute of Medicine says (Ref 2, p. 644):

Although the data indicate that women have a lower nitrogen requirement than men per kilogram of body weight, this was only statistically significant when all studies were included, but not when the analysis was restricted to the primary data sets. This difference may be due to differences in body composition between men and women, with women and men having on average 28 and 15 percent fat mass, respectively. When controlled for lean body mass, no gender differences in the protein requirements were found. However, in view of the uncertain significance of the difference between the genders, the same protein EAR [i.e., Estimated Average Requirement, a foundation for the RDA] on a body weight basis for both men and women is chosen.

Another consideration is that the vegans in the UK may eat lower amounts of protein than those in the U.S. Adventist Health Study-2 found an average protein intake of 71 g/day for men and women combined, considerably more than in EPIC-OXford (link). It seems safe to assume that Seventh Day Adventist woman are likely getting plenty of lysine and other amino acids.

Finally, according to the authors, “[T]he validation of the [food frequency questionnaire] showed that protein intake was particularly difficult to estimate.”

Blood Levels

In comparing blood levels of amino acids between diet groups, vegans had lower levels of lysine, methionine, tryptophan, and tyrosine, and higher levels of alanine and glycine.

Interestingly, arginine, a dietary concern for vegans with herpes virus, was actually lower in the blood of vegans, but not significantly. It was also lower in the diet (3.92 g/day for vegans vs. 4.13 g/day for meat-eaters; lacto-ovo vegetarians had the lowest intake at 3.36 g/day).

The authors didn’t seem alarmed by any of the differences found between diet groups. I decided to take things a bit further and compare the plasma levels found in this study to the reference ranges given by the U.S. National Library of Medicine in Table 5 below.


In comparing the vegan’s blood levels to the reference range:

  • Alanine, glutamate, glycine, leucine, ornithine (a non-protein amino acid), phenylalanine, and serine are higher.
  • Aspartate is also higher, but the reference range is curiously low.
  • There is no reference range for tryptophan, with no explanation as to why.
  • There is a reference range for cystine (which is two cysteine molecules combined), but EPIC-Oxford didn’t list plasma levels for cystine or cysteine.

It is not clear what any of this means and the U.S. Library of Science notes that these numbers are dependent on the specific laboratory methods used.


The above research is not a great substitute for a nitrogen or protein synthesis study on vegans, but for now it’s what we have. The takeaway message is that vegans, and particularly vegan women, should continue to make sure they eat plenty of lysine-rich foods. There is no reason to think that the vegans in this study were aware of lysine or trying to increase their lysine intakes, so any vegan who does so should be well covered.


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Pangea – The Vegan Store
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Thank you!


2. Dietary Reference Intakes: Macronutrients. National Academy of Sciences. Institute of Medicine. Food and Nutrition Board. DRI table for carbohydrate, fiber, fat, fatty acids and protein. | PDF

15. Schmidt JA, Rinaldi S, Scalbert A, Ferrari P, Achaintre D, Gunter MJ, Appleby PN, Key TJ, Travis RC. Plasma concentrations and intakes of amino acids in male meat-eaters, fish-eaters, vegetarians and vegans: a cross-sectional analysis in the EPIC-Oxford cohort. Eur J Clin Nutr. 2015 Sep 23. | link

16. Plasma amino acids. Medline Plus. U.S. National Library of Medicine. Accessed January 30, 2016. | link

Mortality Rates of Vegetarians and Vegans

January 10th, 2016 by Jack Norris RD

A paper came out in December reporting mortality rates of different diet groups from the large EPIC-Oxford study containing 60,310 people from the UK  (1).

The mortality rate before age 90 was no different between vegetarians (including vegans) and regular meat-eaters (1.02, 0.94-1.10). Vegetarians had lower rates of mortality from pancreatic cancer (0.48, 0.28-0.82) and lymphatic cancer (0.50, 0.32-0.79). Semi-vegetarians had lower rates of death from pancreatic cancer (0.55, 0.36-.86). Pesco-vegetarians had lower death rates from all cancers (0.82, 0.70-0.97) but higher rates of cardiovascular disease (1.22, 1.02-1.46).

In the main analysis (in the paragraph above), some participants were recategorized based on a change in their diet over the course of the study which included over one million person-years of follow-up. The researchers did a second analysis in which participants who changed their diets were removed, and found an 8% reduced risk of early death in vegetarians that was just statistically significant (0.92, 0.84-0.99). Limiting the results further, to deaths before age 75, strengthened the finding (0.86, 0.77-0.97).

When vegans were separated from other vegetarians, there were no statistically significant differences in mortality rates for the six main categories of death. Eliminating participants who had changed diet categories didn’t significantly change the results for vegans. There were only 166 vegan deaths as distinct from 1,929 deaths in the entire cohort; meaning that reaching statistical significance was going to be unlikely.

Results above were not adjusted for differences in body mass index (BMI); such adjustments were performed but they didn’t change the results substantially.

The fact that vegetarians didn’t have lower rates of death from heart disease in this study is surprising given that a 2013 report from EPIC-Oxford showed a highly statistically significant, 31% reduction in heart disease incidence among vegetarians (0.69, 0.58-0.82). This discrepancy as well as the lower death rates for vegetarians before age 75, but not before age 90, might be explained by cases of nonfatal heart disease leading to effective treatment.

See the link in the reference for a free copy of the paper. For results of other similar studies, please see Disease Rates of Vegetarians and Vegans.


1. Appleby PN, Crowe FL, Bradbury KE, Travis RC, Key TJ. Mortality in vegetarians and comparable nonvegetarians in the United Kingdom. Am J Clin Nutr. 2016 Jan;103(1):218-30. | link

Ginny on Fire

January 10th, 2016 by Jack Norris RD

In the last month, Ginny Messina, MPH, RD has put out a number of great articles for vegans to check out:

Vegan Diets and Orthorexia: How Should Activists Respond?

Lettuce and Bacon and the Environment: Some Thoughts for Vegan Activists

Will a Vegetarian Diet Make You Depressed?

Your Vegan New Year’s Diet: Don’t Forget the Protein

Dr. Greger on Vitamin C and Cancer Treatment

January 10th, 2016 by Jack Norris RD

Dr. Michael Greger has some very interesting videos on the history of using vitamin C for cancer treatment:

Intravenous Vitamin C for Terminal Cancer Patients

Vitamin C Supplements for Terminal Cancer Patients

He also recently ran two very interesting videos discussing the role of fiber in weight loss:

Are There Foods With Negative Calories?

Eating More to Weigh Less

Increase the Number of Vegans…By Two!

November 29th, 2015 by Jack Norris RD

Some of my readers might not be aware that my day job is Executive Director of Vegan Outreach.

Vegan Outreach persuades people to go vegan by visiting college campuses throughout the USA, Canada, Mexico, Australia and New Zealand, giving our hard-hitting booklets about modern animal farming to students, persuading many of them to leave animals off their plates.

We also have a large Vegan Mentor Program and a Vegan Living & Advocacy Blog to help aspiring, new, or veteran vegans. In fact, now is a great time to sign up for our blog as we’re about to start doing vegan product giveaways!2015-08-01 Norris Jack ARNC

Right now, your donation to Vegan Outreach will be doubled–meaning you will persuade twice as many people to go vegan by donating now!

Click here to donate.

Thank you!

– Jack Norris, RD

Dr. Greger: Latest in Clinical Nutrition – Volume 28

November 29th, 2015 by Jack Norris RD

Dr. Michael Greger has released his Latest in Clinical Nutrition – Volume 28. It can be ordered as a digital download or a DVD.

In discussing Volume 28, Dr. Greger says, “Alternative medicine practitioners continue to treat thousands of cancer patients with vitamin C, but why isn’t it the standard of care in mainstream medicine? Has it been successfully debunked or is it a Big Pharma conspiracy to suppress the truth?”

Find out in Volume 28!

Lower Risk of Prostate Cancer among Vegans

November 29th, 2015 by Jack Norris RD

The Adventist Health Study-2 has published results of their study on prostate cancer risk among various diet groups after 7.8 years of follow-up.

Vegans were shown to have a 34% lower risk of being diagnosed with prostate cancer than regular meat-eaters. The other diet groups were not found to be statistically different than regular meat-eaters. Here are the confidence intervals:

  • Non-Veg: 1.00
  • Semi-Veg: 1.18 (.91, 1.54)
  • Pesco: 1.07 (.88, 1.31)
  • Lacto-Ovo: .96 (.83, 1.12)
  • Vegan: .66 (.50, .87)

The results were adjusted for age, race, family history, education, screening, caloric intake, and body mass index. There were 2,140 vegans in the study.

A similar trend was found when looking only at African American participants, but the results didn’t reach statistical significance.

Among those diagnosed with advanced prostate cancer (as distinct from all types of prostate cancer) vegans had a 30% reduced risk, but it wasn’t statistically significant.

The authors speculated on a number of mechanisms that could be responsible for the lower rates among vegans:

  • Lower levels of insulin-like growth factor 1
  • Lower insulin resistance
  • Lower calcium intakes increasing the need for the conversion of vitamin D into its active form which might reduce prostate cancer
  • Reduced inflammation due to higher antioxidant intakes
  • Increased soy consumption which has been linked to lower prostate cancer risk (with a large number of possible mechanisms)

I have updated the prostate cancer section of the article, Cancer, Vegetarianism, and Diet.


If you like my posts, please like my posts! Or share them!

I am very grateful for donations of any amount (click here).

Purchase anything through these links and gets a percentage:

Pangea – The Vegan Store
Vegan for Life by Jack Norris & Ginny Messina

Thank you!

Methylcobalamin & Adenosylcobalamin: Consolidated

November 11th, 2015 by Jack Norris RD

It’s raining B12!

I have consolidated all the information from my blog and regarding the benefits and drawbacks of supplementing with the co-enzyme forms, methylcobalamin and adenosylcobalamin, over cyanocobalamin.

Click here: Methylcobalamin & Adenosylcobalamin


If you like my posts, please like my posts! Or share them!

I am very grateful for donations of any amount (click here).

Purchase anything through these links and JackNorrisRD gets a percentage:

Pangea – The Vegan Store
Vegan for Life by Jack Norris & Ginny Messina

Thank you!

Two B12 Deficiency Cases

November 11th, 2015 by Jack Norris RD

I have updated the page, Individual Cases of Deficiency, with two recent cases below. In the past, readers have asked me to post these when they come out, so I will continue to do so.

Biyani S, Jha SK, Pandey S, Shukla R. Acute bilateral useless hand syndrome: a rare presenting manifestation of vitamin B12 deficiency. BMJ Case Rep. 2015 Oct 16;2015. | link

A 38-year-old man, “strict vegetarian,” developed “useless hand syndrome.” Laboratory tests showed vitamin B12 deficiency. He was given B12 injection and after 8 weeks was free of symptoms.

Førland ES, Lindberg MJ. [Severe macrocytic anaemia and secondary hyperparathyroidism in a vegan]. Ugeskr Laeger. 2015 Aug 10;177(33). | link

“In this case report we present a 39-year-old male vegan with severe macrocytic anaemia due to vitamin B12 deficiency as well as secondary hyperparathyroidism due to severe vitamin D deficiency.”

Vegan Health & Fitness Magazine: Vegans Need B12

November 8th, 2015 by Jack Norris RD

Over the past couple of years a number of readers and colleagues have contacted me about the apparent stance of Vegan Health & Fitness Magazine (VHFM) that vegans do not need to supplement with vitamin B12. People have contacted the magazine about this issue but they have not modified their position.

Currently, VHFM has an article, The Science is in: B12, by Brian Acree, which has been available for some time (no publication date is listed).

Despite the name of the article, Acree suggests that the science is actually not in. He argues that we have no definitive answers, but that if vegans eat a variety of plant foods, including foods like seaweed, we’ll be fine.

Acree bases his argument mostly on research from the Watanabe group, research that I detail in B12 in Plant Foods.

Acree says, “Of particular interest is the fact that Watanabe cited two studies that showed that vegans who consumed nori and/or chlorella (the green substance in all green vegetables) had serum vitamin B-12 concentrations ‘twice as high as those not consuming these algae.'”

Acree appears to be mistaking the algae, chlorella, for the molecule chlorophyll and, because of this mistake, seems to be suggesting that all green vegetables contain B12. But in reality, chlorophyll has nothing to do with vitamin B12.

Readers of this blog probably remember that just a couple weeks ago, and after this article by Acree was published, the first study came out indicating that chlorella has B12 activity (see Chlorella Shown to Have B12 Activity in Humans—Caution Warranted).

As for nori, in the one study looking at nori’s B12 activity in humans, it didn’t have any (more info).

In 2014, VHFM ran an article by Deobrah Nasmyth that pointed out that the editor of VHFM, Brenda Carey, doesn’t take B12 supplements or eat fortified foods and hasn’t developed B12 deficiency. Acree also uses his own personal lack of B12 deficiency symptoms as evidence that vegans don’t need to supplement with B12.

The problem with this reasoning is that unless you’re getting your methylmalonic acid and homocysteine levels checked, there’s no way for someone to know they don’t have B12 deficiency.

The study on chlorella mentioned above shows that many vegans come down with vitamin B12 deficiency due to a lack of vitamin B12 in the diet. Long periods of mild B12 deficiency are linked with dementia, and poor bone health in vegans.

And even if some vegans don’t develop vitamin B12 deficiency or obvious symptoms, too many vegans do develop them and sometimes with horrible consequences (see the Background section of Vitamin B12: Are You Getting It).

It’s not worth risking people’s health in order to make a philosophical statement and I hope to see Vegan Health & Fitness take a more responsible position regarding vitamin B12.