Interview with Brenda Davis, RD: Vitamin B12 Foods, B12 Deficiency Symptoms

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Part 2 - B12 Deficiency Symptoms And Myths About Vitamin B12 Foods

If you are over 50 year old, vegan or not, or you are a parent of a vegan baby, this information about Vitamin B12 foods is a MUST READ.
The second part of interview with Brenda Davis, RD addresses this and many other hot topics related to Vitamin B12. Is it true that only meat is a reliable source of Vitamin B12? Do you or your children have signs of B12 deficiency? Read the first part dedicated to the Calcium Rich Foods here. Brenda is a leader in her field, so please take a note as she shares the most up-to-date scientific knowledge and guidelines on Vitamin B12.

Brenda Davis

What are the best Vitamin B12 rich foods in the plant kingdom?

  • A lot of people say that they rely on seaweed for B12. Seaweed, actually does contain B12. However, most seaweed contains what we call "inactive B12 analogs." They look like B12, they attach to B12 receptor sites, but they do not do the job of a B12, and they can actually contribute to a functional B12 deficiency because they take the spots B12 needs to do its job. Serum B12 tests do not distinguish between true B12 and these inactive analogs, so if you eat a lot of seaweed, your B12 levels could look OK, but you could actually be deficient. Be careful about that. And another thing about seaweed is when you dry it, some of the real B12 can be converted into B12 analogs. You can’t really rely on seaweeds as primary source of B12

    There are two types of seaweed that look more promising as B12 sources – chlorella and a blue-green algae called AFA. Studies are being done in the UK and Italy right now looking at those sources.

  • Even though a lot people say that fermented foods provide B12, they are not reliable sources. We used to ferment foods in big wooden barrels that were contaminated with B12 producing bacteria. We use clean stainless steel now, thus there is far less B12.

  • Organic vegetables, when you grow them in night soil (human manure), might contain some B12, but you might get some pathogenic bacteria along with that B12, so it’s best to wash our vegetables.

The bottom line is that plant foods are not generally reliable B12 sources. Some people think that this proves that people need to eat meat. This is not the case.

So you don't think that the lack of B12 in plants proves that people need to eat meat?

The reality is vitamin B12 is produced by bacteria, not by plants or animals. Animals, including humans, have B12 in our body because bacteria produce it in our intestines.

Vitamin B12 is found in anything contaminated with B12-producing bacteria – dirty plants, unclean water, foods or fermented in bacteria-ridden containers. It is also present in animal products because B12-producing bacteria reside in their intestinal tracts and is absorbed into the bloodstream.

Before we eat plants, we wash them in an effort to rid them of the pathogenic bacteria that might be on them (this bacteria usually comes from irrigation water that has been contaminated by nearby factory farms). Of course, we get rid of most of the B12-producing bacteria in the process. 

Some people claim that we produce enough B12 in our stomachs and our intestines, and we don’t really need to get any B12 from foods. But the truth is that the production of B12 happens in the large intestine, and you absorb B12 in your small intestine… things don’t usually go backwards. We can produce some B12 in our mouths; the only problem is you have to have an extremely poor oral hygiene to produce enough. The bacteria reside with the plaque in your mouth, so the more plaque, the more B12. This is not a reliable source, but even if it were, poor oral hygiene can cut years from your life.

How long can we live without Vitamin B12 before we become deficient?

Generally, humans are very efficient at recycling B12. Some people can manage on B12 stores for two or three years without taking in any in their diet. However, I’ve seen people who have become deficient within 6 months. 

Newborn babies have minimal B12 stores, and a lack of dietary B12 can result in serious health consequences in short order. Within 9 – 12 months, they can have irreversible brain damage. If you are breastfeeding, be sure you have a reliable B12 source. 

Unfortunately, some cases of B12 deficiency in vegan infants have ended up in the courts and parents have lost custody of their children (if the children survived). When this happens it sends a very clear message to the world – people need to eat meat. If we want to convince the mainstream that vegan diets are safe and adequate for everyone, we need to be sure that this never happens.

Vegetarians do a little better than vegans where B12 is concerned, but their status is still below that of general population. Vegans are significantly below that of general population, unless they use B12-fortified foods or supplements - and that’s what you need to do.

What is the recommended daily amount, and what are the signs of B12 deficiency?

On average, people that don’t eat fortified foods and supplements have B12 level of approximately 120 – 160 pg/ml We need at least 300 pg/ml (some experts say 400 pg/ml) to keep our homocysteine levels down. High homocysteine levels may increase risk of heart disease, premature death and birth defects in infants. B12 deficiency can cause anemia, nerve damage and gastro-intestinal disturbances.

The first sign of B12 deficiency that many people notice is numbness and tingling in the extremities (fingers and toes). At more advanced stages people have difficulty with balance and walking, memory loss, confusion and eventually, psychosis.

What are the good sources of Vitamin B12 and how can we make sure we get enough B12?

Include B12-fortified foods and/or supplements that are reliable sources of B12, suitable for vegans or lacto-ovo vegetarians. You can eat fortified foods; and if you’re under 50 and you are a lacto-ovo vegetarian, you can rely on dairy products and eggs.

If you’re over 50, based on NIH nutrition recommendations, do not rely on animal products for B12. B12 is bound to protein in animal products. And a lot of people over 50 cannot cleave the B12 off of the protein it is bound to. It is recommended that everyone over 50 get B12 from the same places that vegans get it fortified foods or supplements.

We need is at least 4 mcg a day in two or more meals from fortified foods. Nutritional yeast (with added B12 such as Red Star Vegetarian Support Formula) contains a reliable form of B12, so it is an excellent addition (it also contains many other B-vitamins).

If you prefer to avoid fortified foods, you can take a supplement of 25 mcg a day or or 1000 mcg twice a week. That’s a huge amount of B12 but you only absorb about 0.5-1% of it.

Vegans are on trial in the eyes of the world. Until there are lifelong vegans succeed brilliantly from birth to death at an advanced age, people are going to be skeptical about vegan diets.

Just remember, you are often the only vegan that friends, neighbors and colleagues have ever met. They judge all vegans based on you, and if you are a poor example of health, you will be exhibit number one for why they are justified in eating meat.

The practical advice here… "DO NOT MESS WITH VITAMIN B12". Just take care of it.


Brenda Davis, RD, is a leader in her field and an internationally acclaimed speaker. She is co-author of seven books: Becoming Raw, Becoming Vegan, Becoming Vegetarian, The New Becoming Vegetarian, The Raw Food Revolution Diet, Defeating Diabetes and Dairy-free and Delicious. Brenda is the lead dietitian in a diabetes intervention project in Majuro, Marshall Islands. She is a past chair of the Vegetarian Nutrition Dietetic Practice Group of the American Dietetic Association. Brenda is currently working on an updated and expanded Becoming Vegan. She is married to Paul Davis, has two adult children, Leena and Cory, and lives in Kelowna, British Columbia.

Visit Brenda's website, for in-depth unbiased information about vegan and vegetarian nutrition.


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