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September 26th, 2021 by Jack Norris RD

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B12 and Lung Cancer

September 5th, 2017 by Jack Norris RD

A recently-released study from the University of Washington found an increase in lung cancer among male smokers with a vitamin B12 intake of 55 µg per day or more (3). There was no increase in lung cancer among women, women smokers, or non-smoking men.

Because this study raises concern about vitamin B12 supplements for smokers, I’ve updated the article, Smokers and Cyanocobalamin. The article is short, so I’ve reproduced it here:

Because smokers receive cyanide from smoking, and vitamin B12 can actually be used to detoxify cyanide due to its strong affinity for the cyanide molecule, there’s a concern that perhaps cyanocobalamin will not be effective for smokers.

For example, hydroxocobalamin injections decreased blood cyanide levels by 59% in smokers (1.5-3 packs/day) and cyanide was eliminated in the urine as cyanocobalamin (1). In another study, smokers were found to excrete 35% more B12 than nonsmokers (2). But in another, serum B12 of smokers didn’t differ from nonsmokers, and the Institute of Medicine concluded that “The effect of smoking on the B12 requirement thus appears to be negligible (2).”

But most smokers have an intake of hydroxocobalamin, and other non-cyanocobalamin forms of B12, through animal foods, while vegan smokers do not have a non-cyanocobalamin source of B12 unless they seek out a supplement. There’s no research on B12 and vegan smokers, but I’m not aware of any who have had trouble warding off B12 deficiency.

Additionally, one prospective study found an increase in lung cancer with B12 supplements among male smokers for the highest intake group of 55–275 µg/day (3). Other research has not found an association with vitamin B12 in cancer, but it hasn’t been studied thoroughly among male smokers. However, an arguably better piece of evidence comes from a randomized, clinical trial that did not find an increase in cancer with increasing serum B12 levels (from 400 µg/day) in a population with a high rate of smoking (4).

At this time, there doesn’t seem to be enough evidence to warrant separate vitamin B12 recommendations for smokers.


1. Forsyth JC, Mueller PD, Becker CE, Osterloh J, Benowitz NL, Rumack BH, Hall AH. Hydroxocobalamin as a cyanide antidote: safety, efficacy and pharmacokinetics in heavily smoking normal volunteers. J Toxicol Clin Toxicol. 1993;31(2):277-94.

2. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press; 2000.

3. Brasky TM, White E, Chen CL. Long-Term, Supplemental, One-Carbon Metabolism-Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort. J Clin Oncol. 2017 Aug 22:JCO2017727735.

4. Ebbing M, Bønaa KH, Nygård O, Arnesen E, Ueland PM, Nordrehaug JE, Rasmussen K, Njølstad I, Refsum H, Nilsen DW, Tverdal A, Meyer K, Vollset SE. Cancer incidence and mortality after treatment with folic acid and vitamin B12. JAMA. 2009 Nov 18;302(19):2119-26.

Nutrient Intakes of Vegans

May 14th, 2017 by Jack Norris RD

In 2016, a paper reporting vegetarian nutrient intakes was released from EPIC-Oxford (1). Nothing earth shattering was reported, but in keeping the Nutrient Intakes of Vegetarians and Vegans article complete, I’ve incorporated this latest analysis.

EPIC-Oxford is a cohort study of “generally health-conscious” British residents, and it follows large numbers of vegetarians. The assessment was conducted in 2010.

I track these nutrient intake reports to get an idea of how vegans, on average, typically eat, and if we’re meeting our nutrient requirements. However, they have some drawbacks:

  • The nutrient intakes are based on food frequency questionnaires (FFQ). FFQ are more useful for judging relative nutrient intakes between groups than for measuring absolute amounts of nutrients for comparison to dietary recommendations.
  • FFQ don’t include all the foods vegans typically eat, and in the case of EPIC-Oxford, it’s likely they don’t accurately reflect typical portion sizes either. This could explain why a much higher percentage of vegans reported calorie intakes that were implausibly low (43% and 33% of vegan men and women, respectively, compared to 33% and 19% of meat-eating men and women).
  • Nutrients amounts are estimated from nutrient database tables rather than directly measuring the nutrient content of the food. Direct measurements are very expensive to perform.
  • Nutrients from fortified foods—such as vitamin B12 fortified foods—are rarely accounted for, nor are supplements.

Given all these potential problems, the studies should mainly be used to spot glaring problems or trends.

The table below notes the most interesting findings from this current report.

I was pleasantly surprised by the calcium intakes for vegans which were significantly higher than the previous EPIC-Oxford report from 2003. I’m wondering how it was so high without fortified foods being represented. [May 22, 2017 update: The researches appeared to assume some calcium fortification of nondairy milks which represented almost one-third of vegans’ calcium intake.]

Vitamin A and zinc intakes are a little low (the DRI for vitamin A is 900 RAE for men and 700 RAE for women while the RDA for zinc is 11 mg for men and 8 mg for women). I also prefer to see vegan protein intakes higher than the .9 g/kg of body weight (for men). But given that the overall food intake reported for vegans was low, intakes of these nutrients were probably a bit higher than reported.

Vitamin A and zinc are nutrients I consider to be important for vegans and if you don’t know much about them, please check out the articles, Vitamin A and Zinc.

The report includes information on supplement intake, indicating that 50% of vegans were supplementing with vitamin B12.

All in all, British vegans seem to be doing well, though let’s hope that much more than 50% are now getting a source of vitamin B12!

The report is available for free here.


1. Sobiecki JG, Appleby PN, Bradbury KE, Key TJ. High compliance with dietary recommendations in a cohort of meat eaters, fish eaters, vegetarians, and vegans: results from the European Prospective Investigation into Cancer and Nutrition-Oxford study. Nutr Res. 2016 May;36(5):464-77. • link

New Position Paper on Vegetarian Diets

November 27th, 2016 by Jack Norris RD

Position of the Academy of Nutrition and Dietetics: Vegetarian Diets has been released!

It states:

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage.

The paper contains a review of all the nutrients of concern for vegetarians and a summary of the research on the health and environmental benefits.

As of this writing, a free PDF was downloadable at the links to the paper above and below.

If you like my posts, please like or share them! Thank you!


1. Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016 Dec;116(12):1970-1980. • link

Petition: Vegan Cheese Pizza at California Pizza Kitchen

November 17th, 2016 by Jack Norris RD

One of the most common reasons people give for not being vegan is a lack of vegan options at restaurants. Vegan Outreach has launched a campaigns program to increase the number of vegan entrees in national and regional restaurant chains.

Our first campaign is to get a vegan cheese on the menu at California Pizza Kitchen.

Please help us out by signing the petition.

And please share it:

Thank you!

Vegan Diet Improves Type 2 Diabetes in Koreans

July 30th, 2016 by Jack Norris RD

A clinical trial from Korea compared the effect of a vegan diet to a conventional diabetic diet, as prescribed by the Korean Diabetes Association (KDA), on glycemic control among Koreans (1).

The trial lasted three months. The vegan diet group had 46 people while the KDA diet group had 47. After three months, there was a statistically significant, greater reduction in HbA1c in the vegan group compared to the KDA group (0.5% vs. 0.2%, p = 0.017). When including only participants with high diet compliance, the vegan diet fared even better (0.9% vs. 0.3%, p = .01).

The vegan group ate less calories and saturated fat than the KDA group. Fiber intake for the vegan group and KDA group was 33.7 g and 24.9 g.

The vegan group lost weight while the KDA group didn’t. However, neither group’s blood pressure or LDL-cholesterol went down. The vegan group’s triglycerides went up while the KDA group’s went down; this might indicate the vegan group was eating more simple sugars.

I have posted these results in the article Type 2 Diabetes and the Vegan Diet.


1. Lee YM, Kim SA, Lee IK, Kim JG, Park KG, Jeong JY, Jeon JH, Shin JY, Lee DH. Effect of a Brown Rice Based Vegan Diet and Conventional Diabetic Diet on Glycemic Control of Patients with Type 2 Diabetes: A 12-Week Randomized Clinical Trial. PLoS One. 2016 Jun 2;11(6):e0155918. | link

Story from a Once-Failing, Now-Thriving Vegan

March 21st, 2016 by Jack Norris RD

From an anonymous, female animal advocate:

I went vegan in 1992 at age 15. At that time, most of us in the vegan community believed and promoted that eating only plants was the most natural and complete diet for humans. We pointed to our flat molars and long intestines as proof that humans are natural herbivores. We rejected supplements because we thought our diet was naturally perfect. We thought we’d get our B12 from mushrooms, sea vegetables, or microscopic bits of soil clinging to our farmer’s market produce. We thought we’d get enough vitamin D naturally from the sun. We had never heard of DHA and EPA.

After seven years of being an unsupplemented vegan, I had a health crisis when I was 22 and in graduate school. I wasn’t a junk food vegan–I cooked my own meals and ate my share of fresh produce. I’d always been an ace student, but I was finding it harder and harder to read my textbooks. I couldn’t concentrate. My short-term memory was shot. I felt tired and weak all the time and I was diagnosed with depression. I learned that these are all symptoms of B12 deficiency and I started to take vegan supplements: B12 and a multi-vitamin for extra insurance.

I have now proudly celebrated my 25th year as a vegan, and I take supplements regularly. In addition to the B12 and multi-vitamin, I now take vegan vitamin D3 supplements (I was diagnosed as vitamin D deficient a couple of years ago), algae-based DHA/EPA, and the occasional calcium pill.

I am healthier than any of my family members who are all omnivores. They suffer from a variety of illnesses (including diabetes and heart disease). In contrast, I can walk into a doctor’s office at 40 years old and check exactly zero disease boxes. I’m an active rock climber and hiker and still weigh what I did in high school, which is uncommon in my genetic family.

One other very powerful experience I had with my diet was using a nutrition-tracking food diary website for about a year. I logged every single food I ate, including home-cooked recipes, and the website broke down my daily, weekly, and monthly nutrition stats. It taught me a few important things:

  • I am not going to eat enough variety of food every single day to get all the nutrients I need, so a multi-vitamin really is a good idea for me.
  • I feel better when I eat a balance of good fats, protein, and healthy carbs at every meal.
  • I need a significant amount of vegan protein to feel my best.

I think many of us vegans get so fed up with being questioned about, “Where do you get your protein?” and we spend so much time debunking the protein combining myth, that we overcorrected in the other direction and began to believe that we’ll get enough protein no matter what plants we eat. It just isn’t true for me, at least based on how I feel after eating a low-protein meal. This is one of the reasons why I love and embrace the vegan meats (seitan, veggie burgers, veggie dogs and sausages, Field Roast, Beyond Beef, etc.) and soy products (tofu, tempeh, soyrizo). They may not be “natural”, but they help keep me healthy and feeling good as an active vegan, and that’s my most important dietary value.

Thank you for sharing your story!

Dr. Greger Strikes Again!

March 21st, 2016 by Jack Norris RD

Dr. Michael Greger of has another DVD out, Latest in Clinical Nutrition: Volume 29. It covers Splenda, lupus, CoQ10, and reversing diabetes. As always, it’s packed with interesting and often surprising info!

All proceeds are donated to charity.

Breast Cancer in Vegetarians & Vegans

March 21st, 2016 by Jack Norris RD

There’s a new report from Adventist Health Study-2 (AHS-2) comparing breast cancer incidence in vegetarians and vegans to non-vegetarians (1).

The study included 24,211 non-vegetarians, 3,748 vegans, 14,336 lacto-ovo vegetarians, 5,179 pesco-vegetarians, and 2,930 semi-vegetarians. Meat intake among non-vegetarians was quite low at less than a serving per day (54 g/day). Participants were followed for an average of 7.8 years (which isn’t very long for a cancer study).

All vegetarians combined had similar rates of breast cancer to non-vegetarians (0.97, 0.84-1.11), while vegans had a 22% lower risk that didn’t reach statistical significance (0.78, 0.58-1.05). After adjusting for body mass index, the reduced risk was 15% for vegans (0·86, 0·62-1·21), indicating that lower body weight could explain some of the lower risk for vegans.

The authors write, “In conclusion, participants in this cohort who follow a vegetarian dietary pattern overall did not experience a lower risk of [breast cancer] as compared with non-vegetarians. However, those adhering to a vegan dietary pattern showed consistently lower point estimates in various subgroups but these were not statistically significant. Numbers of cancers in vegans were relatively small, and these analyses should be repeated in the AHS-2 cohort after a longer follow-up to determine whether the same trends continue when power is greater.”

I have posted these results in the article Cancer, Vegetarianism, and Diet.


1. Penniecook-Sawyers JA, Jaceldo-Siegl K, Fan J, Beeson L, Knutsen S, Herring P, Fraser GE. Vegetarian dietary patterns and the risk of breast cancer in a low-risk population. Br J Nutr. 2016 Mar 18:1-8. • link

Ginny Messina on Irritable Bowel Syndrome

March 21st, 2016 by Jack Norris RD

Never afraid of providing too much information, Ginny Messina has done a great service by putting together an informative post on Vegan Diets and Irritable Bowel Syndrome.

If you suffer from IBS, I highly recommend checking it out!