by Jack Norris, RD

A new study has examined the effect of eating nori on vitamin B12 status of vegetarians. Below is an excerpt from our larger article, Vitamin B12 in Plant Foods.

Huang et al. (2024, Taiwan) studied the effect of nori on the B12 status of 24 vegetarians and 6 vegans in a 4-week long trial.

The type of nori used was roasted purple laver (Neopyropia sp., formerly Porphyra sp.). The researchers surveyed the vitamin B12 content of the same brand of nori purchased on different dates and found that the B12 content ranged from 23.1 to 52.8 µg/100 g dry weight. This amount of B12 is similar to that found in purple laver in other studies.

Participants were randomized to three groups: control, low-dose nori, and high-dose nori (as described in the table below).

The authors provide a spreadsheet of all the individual participants’ data in their Supplementary Material 3. I sorted the data by treatment group in the Huang 2024 Individuals tab of our spreadsheet, B12 in Plant Foods.

Serum methylmalonic acid (MMA) increases during vitamin B12 deficiency and a change in serum MMA is the most reliable way to determine the B12 activity of a food or supplement. The table below shows that after treatment, serum MMA normalized to ≤ 270 nmol/L in only 4 participants. For such a short trial, reducing MMA to a normal level in most participants might be too much to expect.

Based on a rough correlation between serum MMA levels and clinical symptoms, as discussed in Appendix A. Minimizing Methylmalonic Acid Levels, I did an analysis on Huang et al.’s data using a cutoff for a harmful level of serum MMA of 500 nmol/L. Low-dose nori resulted in 4 of 8 participants reducing their MMA to below 500 nmol/L which seems like an impressive result.

In contrast, high-dose nori resulted in a net increase from 4 to 5 participants with an MMA level >500 nmol/L. There were two participants in the high-dose group whose MMA levels went from healthy to not healthy (306 to 569 and 222 to 819 nmol/L). These participants’ other B12-related parameters didn’t change enough to suggest an obvious decrease in kidney function which is my best guess for what could have caused a substantial increase in MMA levels. The authors didn’t address these two individuals.

There appeared to be no benefit to eating the high-dose amount of nori. This could be due to the saturation of intrinsic factor that occurs with a single dose, although the amount of B12 in the low-dose protocol (1.9 µg) doesn’t seem like enough to saturate intrinsic factor; I would have thought the high-dose protocol would have provided additional benefits.

While I’m surprised at how impressive these results are for many of the participants, there are enough inconsistencies that I can’t yet feel comfortable recommending nori as a reliable source of B12 for vegans. I also would feel more comfortable with a study performed using only strict vegans taking no other sources of B12 for the duration of the study.

In summary, it seems possible that dried, purple laver nori (Neopyropia sp., formerly Porphyra sp.) can significantly contribute to improving B12 status for many vegetarians and vegans, but more research is needed before it can be recommended as a sole, reliable source of B12.

Reference

Huang QN, Watanabe F, Koseki K, He RE, Lee HL, Chiu THT. Effect of roasted purple laver (nori) on vitamin B12 nutritional status of vegetarians: a dose-response trial. Eur J Nutr. 2024 Oct 1.

by Jack Norris, RD

I just updated the Vegan Health article, Hair Loss.

Quick summary:

Occasionally, people who become vegetarian or vegan report experiencing hair loss. If there’s a dietary cause, it’s most likely due to low zinc, iron, or iodine status. Vitamin B2, B5, and biotin have also been implicated in hair loss and might be worth supplementation. See Nutrition Tips for Vegans for how vegans can meet iron, zinc, and iodine needs. Expensive supplements are probably unnecessary unless recommended by a dermatologist. Washing hair less to prevent hair loss doesn’t work and can make the loss appear worse than it actually is.

Full Article

by Jack Norris, RD

I’ve consolidated the essential nutrition information that a vegan needs to know into one article, Nutrition Tips for Vegans.

You might find it to be a handy resource.

by Jack Norris, RD

A June 10, 2024 article published in the Washington Post, When plant foods are ultra-processed, the health benefits disappear, reported on a U.K. study examining diet and cardiovascular disease outcomes (Rauber, 2024).

The study had an observational prospective design that measured the participants’ diets and followed their health outcomes for an average of 9 years. It found that eating a diet higher in plant foods was associated with lower rates of cardiovascular disease unless those plant foods were ultra-processed. This pattern is consistently found in the scientific literature for cardiovascular disease and other poor health outcomes (Lane, 2024).

The Washington Post article emphasized that “meat substitutes, fruit juices, and pastries” are ultra-processed foods.

But do meat substitutes deserve to be called out?

On average, ultra-processed plant foods were 39% of the caloric intake of the study participants. ​​Pastries, buns, and cakes were 6.9% of calories. Soft drinks, fruit drinks, and fruit juices comprised only 2.0% of calories, suggesting that fruit juice wasn’t highly represented.

But meat alternatives comprised only 0.2% of calories! Such a small amount of meat substitutes cannot provide any statistical meaningfulness regarding their impact on health outcomes. Rauber et al. didn’t examine the role of meat substitutes in any finer detail.

Rauber et al. cite a paper from the United States-based Adventist Health Study-2 that examined the role of ultra-processed plant foods (Orlich, 2022). Although the Adventist Health Study-2 includes a population that tends to eat meat substitutes, Orlich et al. didn’t examine meat substitutes in enough detail to shed light on their relationship with health outcomes.

Meat substitutes can be an excellent source of protein for vegans, so I don’t like to see them unjustifiably implicated in causing poor health outcomes.

While vegan meats can be high in sodium, if you limit other high-sodium foods, you can eat them while keeping your sodium intake within a healthy range.

References

Lane MM, Gamage E, Du S, Ashtree DN, McGuinness AJ, Gauci S, Baker P, Lawrence M, Rebholz CM, Srour B, Touvier M, Jacka FN, O’Neil A, Segasby T, Marx W. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 2024 Feb 28;384:e077310.

Orlich MJ, Sabaté J, Mashchak A, Fresán U, Jaceldo-Siegl K, Miles F, Fraser GE. Ultra-processed food intake and animal-based food intake and mortality in the Adventist Health Study-2. Am J Clin Nutr. 2022 Jun 7;115(6):1589-1601.

Rauber F, da Costa Louzada, ML, Chang K, Huybrechts I, Gunter MJ, Monteiro CA, Vamos EP, Levy RB. Implications of food ultra-processing on cardiovascular risk considering plant origin foods: an analysis of the UK Biobank cohort. The Lancet Regional Health – Europe. Published online: June 10, 2024.

by Jack Norris, RD

Discussions about protein needs tend to revolve around nitrogen balance studies and protein quality scores.

One of the earliest ways to assess protein quality was the protein efficiency ratio (PER) which is based on the growth of rats. In 1989, the Food and Agriculture Organization (FAO) recommended the protein digestibility–corrected amino acid score (PDCAAS) which is based on the protein needs of humans. In 2011, the FAO switched to recommending the digestible indispensable amino acid score (DIAAS) which is based on the digestibility of individual amino acids rather than entire proteins.

Because protein quality scoring lacks standardization with many gaps in the information, Vegan Health emphasizes protein balance studies in assessing the protein needs of vegans.

But because protein quality scoring is a significant part of the conversation around protein, I’ve added Appendix A: Protein Quality Scoring to our Protein: Research article to provide an explanation of the PDCAAS and DIAAS scoring systems and a critical analysis with regard to their application to plant-based diets.

If you’re interested in protein quality scoring with respect to plant-based diets, you might find the Appendix interesting.

by Jack Norris, RD, LD

In February of 2021, I published an extensive article on vegan bone health, Bone Fractures among U.K. Vegans: Implications and Recommendations. In that article, I recommend resistance training for optimal bone health in vegans. We now have evidence for that recommendation.

Wakolbinger-Habel et al. (Austria, 2022) performed a cross-sectional study on the bone health of four groups of people aged 30 to 50: 20 vegans (9 F, 11 M) and 25 omnivores (8 F, 17 M) who performed resistance training at least once a week and 23 vegans (13 F, 10 M) and 20 omnivores (15 F, 5 M) who did no resistance training. There was little difference in bone health between vegans who performed resistance training and omnivores. Vegans who didn’t perform resistance training had poorer bone health. The duration of the vegan diet had no influence on bone microarchitecture. Vegans performing exclusively aerobic activities (n = 16) and vegans performing no sports activities at all (n = 6) had similar bone microarchitecture. The differences in bone couldn’t be explained by any obvious differences in nutrition. The researchers concluded that resistance training seems to be particularly important to preserve bone health when adhering to a plant-based diet.

I’ve added two recent studies to our article, Weightlifting for Vegans, that shed light on the protein needs of vegan athletes.

Hevia-Larraín et al. (Brazil, 2021) studied changes in leg muscle strength and size among 19 male vegans and 19 male omnivores. The participants had to have followed their diet for at least one year. Participants’ protein intakes were increased to 1.6 g/kg of body weight per day, through supplemental soy protein for vegans or whey protein for omnivores, and they followed a lower-body resistance training program for 12 weeks. Muscle mass and size increased among both groups with no statistically significant differences. The authors cautioned that meeting 1.6 g/kg of protein per day would be difficult on a whole foods, plant-based diet and noted that the soy protein isolates the study participants were consuming had been stripped of any factors that might block protein absorption from whole plant foods. At the time this study was conducted, no other study had compared the effects of protein source between vegans and omnivores in response to exercise; therefore, this study suggests that 1.6 g/kg of protein is enough for vegans to match omnivores in gains of muscle strength and size but that much protein might not be required. The study by Conrado de Souza et al., described below, suggests that closer to 1.0 g/kg of protein might be enough.

Conrado de Souza et al. (2022, Brazil) compared the squat, handgrip strength, isometric deadlift strength, jumping, and maximum aerobic speed between a group of physically active, 18 to 40 year-old, male and female vegetarians (9 vegans, 23 lacto-ovo-vegetarians) and 26 omnivores. The only differences between the groups were that the vegetarians had higher “relative strength” and jumping scores, possibly as a function of weighing slightly less. This was apparently the first strength study that compared already-physically active vegetarians and omnivores. The vegetarians had a protein intake of 1.0 g/kg of body weight compared to 1.6 g/kg for the omnivores.

The ideal amount of protein for vegan athletes appears to be between 1.0 and 1.6 g/kg of body weight. My general recommendation is for serious strength athletes to err on the side of closer to 1.6 g/kg but monitor gains in relation to protein intake; it could be that 1.6 g/kg isn’t necessary for optimal strength for most vegan athletes.

References

Conrado de Souza A, da Silva Brandão M, Lima Oliveira D, Garcez de Carvalho F, Costa ML, Aragão-Santos JC, Santos do Nascimento MV, Silva-Grigoletto M, Mendes-Netto RS. Active vegetarians show better lower limb strength and power than active omnivores. Int J Sports Med. 2022 Jan 27.

Hevia-Larraín V, Gualano B, Longobardi I, Gil S, Fernandes AL, Costa LAR, Pereira RMR, Artioli GG, Phillips SM, Roschel H. High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports Med. 2021 Jun;51(6):1317-1330.

Wakolbinger-Habel R, Reinweber M, König J, Pokan R, König D, Pietschmann P, Muschitz C. Self-reported Resistance Training Is Associated With Better HR-pQCT-derived Bone Microarchitecture in Vegan People. J Clin Endocrinol Metab. 2022 Sep 28;107(10):2900-2911.

by Jack Norris, RD

I was requested to write a blog post about what supplements I take. Here’s my daily routine:

A daily Deva Vegan Multivitamin & Mineral Supplement provides 6 µg of vitamin B12, 20 µg (800 IU) of vitamin D2, and 75 µg of iodine in the form of potassium iodide which I prefer instead of kelp. It also provides 36 µg of selenium, although vegans in the U.S. don’t need to supplement due to selenium in the soil. Note that the Amazon link does not provide any commission, I include it only to make it easier for people to order the multivitamin if desired.

Although the Deva multivitamin provides 5 mg of zinc, I seem to need more to prevent getting cracks in the skin on the sides of my mouth, and so I also take a 10 mg zinc tablet.

For omega-3s, I eat about 1/8th cup of chopped walnuts.

For calcium, I drink a cup of calcium-fortified orange juice and eat about 2 cups of cooked collard greens on most days. I recently discovered bags of cleaned and cut collards that can be cooked in the microwave in a large pyrex container with about a 1/4″ of water for 5 minutes, making cooking greens a very convenient process. But the most important thing I do for my bone health is weightlifting once a week.

For vitamin A, I eat about 10 baby carrots dipped in hummus which provides fat for absorption.

I eat plenty of high-protein foods, including a serving or two of vegan meats, a high-protein energy bar, and half a scoop of Orgain protein powder in my morning coffee. I find that I feel better when eating more high-protein foods but don’t think all vegans need to add these sources of extra protein.

That’s it!

For more information on the daily nutrient needs of vegans see our article, Daily Needs.

by Jack Norris, RD, LD

We’ve updated our Iodine article with a new study on the iodine content of the breastmilk of vegetarians and vegans.

Pawlak et al. (2022, United States) compared the iodine content of breastmilk of 12 vegans, 6 vegetarians, and 12 omnivores; the median iodine content was 65 lg/L (32– 194 lg/L), 108 lg/L (62–189 lg/L), and 99 lg/L (62–1,719 lg/L) respectively. The difference between diet groups wasn’t statistically significant. Although 75% of the vegans used supplements, the researchers didn’t determine whether they contained iodine.

The researchers estimated a daily iodine intake of each infant, assuming a daily breastmilk intake of 0.78 L per day, and found that 75% of vegans, 67% of vegetarians, and 58% of omnivores wouldn’t meet the DRI; the difference between diet groups wasn’t statistically significant. We don’t know if any of the infants in this study were suffering from iodine deficiency. According to the researchers, the low iodine content of breastmilk could be more of a concern for vegan infants because vegan mothers are more likely to breastfeed and to breastfeed for longer periods than omnivores.

The authors write that “[The American Thyroid Association] and the American Academy of Pediatrics (AAP) recommend using 150 µg/day iodine supplements during lactation. Only ~15% of lactating women in the United States adhere to this recommendation.”

Pawlak R, Juddb N, Donati GL, Perrin MT. Prevalence and Predictors of Low Breast Milk Iodine Concentration in Women Following Vegan, Vegetarian, and Omnivore Diets. Breastfeed Med. 2022 Nov 24.

by Jack Norris, RD, LD

We’ve updated our recommendations for omega-3 fatty acid intakes for pregnancy, nursing, and infants.

December 29, 2022 update: This post has been moved to the Vegetarian Pregnancy, Nursing, and Infants section of our Omega-3: Research article.

by Jack Norris, RD, LD

We’ve added two appendices to our article, Omega-3s Part 2: Research:

• Appendix A: Biomarkers of DHA Status
• Appendix B: Evolutionary Arguments for a Dietary Requirement for DHA

Without DHA supplementation, vegans have lower levels of DHA in their blood than fish eaters. Much of our article, Omega-3s Part 2: Research, is an attempt to assess whether there’s a clinical significance to these lower levels.

In Appendix A, we added a short section evaluating the citations for one paper in particular. The article Biomarkers of DHA status argues that the percentage of fatty acids as DHA in plasma or red blood cells is a generally adequate marker of overall DHA status. We show that the evidence they cite for this claim doesn’t adequately support it.

A number of researchers, and many more nutrition writers with an anti-vegan stance, have used evolutionary arguments to argue that DHA is an essential nutrient for human brain health.

In Appendix B, we address evolutionary arguments made in the published research claiming that DHA is an essential nutrient. We conclude that the evidence cited doesn’t justify the claim.

Appendix B: Evolutionary Arguments for a Dietary Requirement for DHA is too long to reproduce in this blog post, but I hope you’ll click through to read it. I’m interested to know what readers of this newsletter think. You can reply to this email or leave a comment at the bottom of the page.

Thank you!