roasted seaweed

Americans are accustomed to being told to just eat a well-balanced diet. The implication is clear that if they did so, they wouldn’t need to take any dietary supplements. But “a well-balanced diet’ is hardly ever defined by the experts making such recommendations. Some people, including those who choose to avoid all foods of animal origin, may become low in certain nutrients. One reader would like to know if eating seaweed can make up for not getting vitamin B12 from animal foods.

Is Seaweed a Source of Vitamin B12?

Q. I live on a vegan diet. I take Vitamin B12 pills but would rather get this vitamin from my plant-based foods.

According to what I’ve heard, seaweed has natural vitamin B12, so I eat 0.6 oz of organic roasted seaweed daily. It’s tasty, but I was hoping that this would cover my vitamin B12 requirement. Is there enough vitamin B12 in seaweed to do this?

A. Tieraona Low Dog, MD, is author of Fortify Your Life: Your Guide to Vitamins, Minerals, and More. She notes, “No matter what you might read, you cannot get vitamin B12 by eating non-fortified grains, nutritional yeast, algae, or seaweed.”

Where Can You Get Vitamin B12?

Since you are a vegan, avoiding all animal products, you need a synthetic vitamin B supplement. The best form for most of us is methylcobalamin. Some individuals may have genetic tweaks (called single nucleotide polymorphisms, or SNPs) that make another form of vitamin B12 more bioavailable (Paul & Brady, Integrative Medicine, Feb. 2017). Unfortunately, testing for such SNPs is not widely available, so patients need to use a trial-and-error approach to find the best form for them.

What Happens If You Don’t Take Vitamin B12?

If you don’t get enough vitamin B12, you could suffer nerve damage, heart palpitations, fatigue, dizziness, weakness, tingling in the hands and feet and sore tongue. In the event of prolonged lack of vitamin B12, people may develop cognitive difficulties, megaloblastic anemia and an impaired ability to walk (Almoallim et al, Case Reports in Neurological Medicine, online Dec. 13, 2016).

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  1. Vivian
    Rocky Mount

    Does Vitamin B 12 affect your urinary tract? I have to get up 4 or 5 times at night to use the bathroom since I started taking this—25 MCGSUB.

  2. Carey

    Please describe what you mean by sore tongue. I have had a sore tongue lately. I was tested for B12 a year or so ago, but I know what the test shows and what your body needs don’t always match up. Thank you.

  3. mary

    When my doctor first told me that I had no vitamin B12 in my blood, I was shocked how come? I started on vitamin B 12 shots once a month to build up a healthy supply in my body. Now I take two vitamin B 12 pills under my tongue daily. My blood work always shows that I now have enough supply. Eating red meat supplies us with vitamin B12 but not all of us are able to absorb it. Such is life.

  4. Nellymae

    How much b-12 daily does a vegan need?

  5. CP
    Springfield, MO

    After taking 600mg of Alpha lipoic acid and 1,000 mcg (1 mg) of methylcobalamin for 8 weeks, I was able to cut my Gabapentin in half, as per Dr. David Perlmutter, Neurologist suggested.

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