Four Weeks Vegan: What Happened to B12 in 53 Healthy Adults
Fifty three healthy meat eaters were randomly split. Half went vegan with no supplements for four weeks; half ate a meat rich diet. In 25 of the 26 people who went vegan, holotranscobalamin, the blood marker for active B12, went down, on average from 67.3 to 43.6 pmol/L.
Four weeks is fast. It is also not the same thing as deficiency, and the authors are careful to say so. Both halves of that matter.
THE STUDY
- Title: Vitamin B12 Status Upon Short-Term Intervention with a Vegan Diet: A Randomized Controlled Trial in Healthy Participants
- Journal: Nutrients, 2019, volume 11, issue 11, article 2815
- Authors: Lederer AK, Hannibal L, Hettich M, Behringer S, Spiekerkoetter U, Steinborn C, Gründemann C, Zimmermann-Klemd AM, Müller A, Simmet T, Schmiech M, Maul-Pavicic A, Samstag Y, Huber R, led from the Medical Center, University of Freiburg, Germany
- Design: Single center, randomized, controlled, explorative trial with parallel groups, run between April and June 2017 and registered with the German Clinical Trial Register (DRKS00011963)
- Read it: PubMed 31752105
WHO WAS IN IT
53 healthy adults who normally ate meat, randomized to a vegan diet (26 people) or a meat rich diet (27 people). To be eligible, people had to be healthy, between 18 and 60 years of age, with a BMI between 21 and 30, and not already vegan or vegetarian. Long term medication, pregnancy and eating disorders were among the exclusions.
They were young: mean age 33.2 ± 11.2 years in the vegan group and 29.9 ± 9.5 in the meat rich group. Women made up 69% of the vegan group and 56% of the meat rich group.
WHAT THEY TOOK
Nothing, and that is the point. This trial did not test a B12 supplement. The vegan group ate a controlled unsupplemented vegan diet for four weeks, so the experiment measures what happens to B12 markers when intake drops, not what happens when you add it back.
The authors say this plainly in their limitations: "Our study did not include a supplementation phase."
WHAT THEY FOUND
- Active B12 fell in the vegan group: holotranscobalamin went from 67.3 ± 23.5 to 43.6 ± 20.0 pmol/L (p < 0.001). Twenty five out of 26 vegans showed a decrease
- It dipped a little in the meat eaters too: from 69.7 ± 29.7 to 64.4 ± 28.7 pmol/L (p = 0.041), with 17 of 27 showing a decrease. The drop on the vegan diet was far larger
- Total serum B12 fell in the vegan group, from 362.9 ± 110.9 to 296.1 ± 94.1 (p < 0.001), and stayed stable in the meat rich group (p = 0.919). See the note on units below
- The cellular markers did not move. Methylmalonic acid and total homocysteine, which rise when cells are actually short of B12, were unaffected by four weeks on either diet
- Low readings were not significantly more common on the vegan diet. Holotranscobalamin ended below the normal range in 7 vegans and 3 meat eaters (p = 0.185); serum B12 ended below normal in 4 and 2 (p = 0.426)
- The authors' own reading: holotranscobalamin "may be a fast-responding biomarker" of B12 supply in people eating plant based
WHAT IT DOES NOT SHOW
- It does not show deficiency. The authors draw this line themselves: a lower holotranscobalamin from lower intake "does not equate to cellular vitamin B 12 deficiency," which also requires the cellular markers to rise. In this trial, they did not
- Four weeks only. The authors write that their observations "may not be valid to describe vitamin B 12 status in long-term vegetarians and vegans," and that longer follow up is needed to see whether the marker keeps falling or levels off
- No supplement was tested. Nothing here tells you what a B12 supplement does, at any dose or in any form
- Small and unblinded. 53 people, planned as a pilot. "Blinding was not possible due to the nature of the intervention", since you know whether you are eating meat. The authors report that results were analyzed blinded
- A units inconsistency in the paper. The results text reports the serum B12 values in ng/mL; the figure legend gives the same values in ng/L and prints the vegan baseline as 362.8 rather than 362.9. We have left the unit off that line rather than pick one
- Diet records were imperfect. Nine of the 53 were excluded from the food intake analysis, six of them for reporting an implausibly low calorie intake, though all 53 stayed in the blood analysis
- Young, healthy, German adults, recruited through a newspaper. Nobody over 60 was eligible, so the results do not reach older adults
- Funding and conflicts: an investigator initiated trial. The state Ministry of Science, Research and Arts of Baden-Württemberg funded one author's position, and the study was otherwise financed by institutional resources. The authors declare no conflict of interest
WHY IT IS ON THIS SHELF
Because it puts a clock on something people usually hear about in years. Last week this shelf posted sixty six adult vegans, where nearly a third of the women were still below the B12 intake target even with supplements counted. This trial is the other end of that timeline: healthy people, randomly assigned, and an active B12 marker that moved within a month of cutting animal foods. Neither study shows deficiency. Together they show why B12 is the nutrient plant based eaters get told to watch.
Each four gummy serving of Vybrance Labs creatine gummies carries 120mcg of vitamin B12 as methylcobalamin, alongside 5g of creatine monohydrate and 500mg of taurine. This trial did not test a supplement of any kind, so it is not evidence that ours, or anyone's, changes these markers. How much of an oral dose is actually absorbed is a separate question, and an earlier entry on this shelf is a reminder that intake and absorption are not the same thing.
The Lab covers the practical side in vegan or vegetarian? you may be running low on creatine and B12.
see you in the wild!
-Lawrence
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Nothing on this page is medical advice. Reference: PMID 31752105, DOI 10.3390/nu11112815.
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