As much as I think plant-based diets promote health, a hidden danger lurks in vegetarian, vegan, and even flexitarian (eats meat and dairy a few times a week) diets.

Our bodies cannot make Vitamin B12, and it is not found in fruits and vegetables. The only source, besides nutritional yeast fortified with B12, is in meat, fish, eggs and dairy.

Sufficient Vitamin B12 intake is vital to your health. Non-omnivores, and people who eat meat, fish, eggs and dairy only occasionally in the week, must take B12 supplements. Not enough of this vitamin results in this horrifying list of symptoms.


pale or yellow skin,




mood disorders,

gastrointestinal problems,

difficulty concentrating,

glossitis (red/painful tongue).

Sensation of pins and needles in hand and feet. (This Neuropathy is common with diabetes, and in fact, diabetes interferes with B12 absorption.)

Muscle cramps and weakness

Impaired co-ordination (ataxia)

Erectile dysfunction

Vision disturbances, possibly because of optic nerve damage.

Diagnosis and Treatment

Because the symptoms cover so many body systems, B12 deficiency often goes undiagnosed or misdiagnosed. Where would a doctor start? A blood test will show the deficiency, but occasionally, even that result is a false normal level.

If I had these symptoms, even if my doc tested for other conditions, I would try supplementing on my own and see what happens. Dr. Greger, in his video, talks about a woman who was psychotic for five years. Finally sufficient B12 brought her out of that psychotic haze that had stolen her life.


Those symptoms would be enough to tempt me to cure my deficiency by eating meat every night! Or instead, I can  take a Vitamin B12 supplement daily, or a large dose weekly. For someone over 65 at least about 1,000 micrograms (mcg) a day should be sufficient. A younger person may be fine with less.

This is a wake-up call for folks who prefer a plant-based, whole foods diet. B12 deficiency is a serious condition. Who knows? While you thought all those fruits and veggies were promoting brain health, your difficulty concentrating could be not enough B12 in your diet!