WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
Strictly speaking, a vegetarian is a person who doesn’t eat meat — red, white, fish or fowl. Vegetarian Nation1 helps further define the types of diets from which to choose if you are seeking a mostly plant-based diet. Some eat a highly restricted number of foods, while others have a more flexible outlook on their meal plan.
The most restricted eating plan is practiced by vegans who don’t eat any animal products or by-products. This includes all meat, all dairy products and honey, beeswax, insects, gelatin or other products derived from those sources, such as leather, silk or wool. Those following a less restricted meatless plan are lacto-, ovo- or lacto-ovo vegetarians.
Lacto-vegetarians allow dairy products, but not eggs; ovo-vegetarians eat eggs but not dairy products. Lacto-ovo vegetarians don’t eat meat but will eat dairy products and eggs. The remaining three levels of vegetarians are not strictly vegetarians, but practice eating a limited number or types of meats.
These levels fall under the umbrella term of flexitarian, or those who are flexible in the type or amount of meat they allow into the diet. A pescatarian restricts the type of meat to fish or seafood, while a pollotarian restricts meat eating to poultry and other fowl. A true flexitarian eats a mostly plant-based diet with a limited amount of meat of any type.
Are You Planning Veganuary?
Moving into the New Year, many resolve to make changes affecting their physical, mental and emotional health. The numbers who chose to move into a vegan or vegetarian lifestyle are so great in January, some experts have dubbed the month “Veganuary.”
A professor emeritus at Oregon State University2 was curious about why people consider the switch away from meat and launched a two-year survey across 14 states to find out. For answers, he and a co-investigator sought out people at animal rights conferences, vegan body-building lectures and vegetarian food festivals.
In general, those who completed the survey were women who had little experience around small farms, 4-H or other arenas where they might have encountered livestock. There was no single reason that stood out from the results, and many cited multiple motivations for the decision, including animal welfare, chemical/hormonal additives and health.
Vegetarians Face Real Risk of Vitamin B12 Deficiency
Tim Key, a longtime practicing vegan from the Cancer Epidemiology Unit at Oxford University, expressed concern to BBC News3 that there is a real risk of vitamin B12 deficiency when people restrict their diet without researching the nutrients they may need to supplement.
While those who practice vegetarianism commonly consume more plant-based foods high in fiber and phytonutrients, they may also fall into the trap of eating more processed foods high in chemicals, toxins and carbohydrates. The added health risks of processed foods aside, neither plant-based nor processed foods deliver enough bioavailable vitamin B12 to prevent a deficiency.
The vitamin, also known as cobalamin, is one of a complex of B vitamins that helps the body convert food into fuel.4 All of the B complex vitamins are water soluble, but the liver will store some vitamin B12.5 Vitamin B12 is especially important to the nervous system, which explains many of the symptoms of deficiency.
Over a period of two months, one 62-year-old man developed symptoms leading to severe joint pain, jaundice and shortness of breath.6 Symptoms of deficiency are varied and sometimes confused with other health conditions. They may appear suddenly or come on gradually. But in any case, the various claims on the internet related to the notion that vegans do not need supplemental B12 are not based on scientific evidence.7
If the deficiency is left untreated it may be fatal8 or cause severe and permanent neurological disease. If you are a strict vegetarian or have any other of the conditions listed below that increases your risk of a vitamin B12 deficiency, it is important to talk with your physician about getting your B12 levels checked. Symptoms may include:9
Anemia |
Mood swings |
Headache |
Swollen or inflamed tongue |
Weakness or fatigue |
Lack of motivation and apathy |
Balance problems (loss of proprioception) |
Mental fogginess and difficulty with memory |
Numbness or tingling in the hands, feet or legs |
After a deep dive into the research, experts found that those who eat a primarily plant-based diet do not live longer due to this single factor.10 When the endpoint of data is death from all causes, both meat eaters and vegetarians live approximately the same number of years.
Some studies have found a lower risk of all-cause mortality in vegetarian groups but also find vegetarians have a healthier lifestyle overall. One 17-year study11 compared vegetarians to omnivores who shopped at health food stores in the U.K. The data showed no difference in death rates between the two, but both lived longer than the general population.
Why You Can’t Get B12 From Plants
There are a few plant sources of B12, but these also have B12 analogues, or a substance blocking the uptake of true vitamin B12. In fact, this means as you eat more of the plant foods with the analogue, your need for B12 increases.12
True vitamin B12 is found almost exclusively in animal tissue, including foods like beef and beef liver, lamb, venison, poultry and eggs. Therefore, those who practice strict vegetarianism are often deficient and may be unaware of a problem until it's too late.
Some of the plant foods containing vitamin B12 are sea vegetables, algae like spirulina and fermented foods. However, along with active vitamin B12, they also contain the analogue that may ultimately make your levels worse.
Another argument for not using B12 supplements is that your body produces active vitamin B12 from bacteria living in the large intestines. However, since it's produced in an area of the intestines lower than where the vitamin may be readily absorbed, it is not bioavailable.
What Else Increases Your Risk of Deficiency?
B12 deficiency is not uncommon in the elderly, as they often have less stomach acid needed to absorb the vitamin. Other conditions or choices placing an individual at increased risk include:
Diabetes |
HIV |
Weight loss surgery |
Long-term antacid use13 |
Conditions reducing nutrient absorption such as Crohn’s disease, pancreatic disease or H. pylori infections |
Some medications, such as metformin and proton pump inhibitors14 |
Eating disorders |
Regularly drinking more than four cups of coffee daily15 |
Regular alcohol consumption as B12 is stored in the liver16 |
Exposure to nitrous oxide (laughing gas)17 |
In a review of the literature,18 researchers reviewed studies of those following different types of vegetarian diets for the prevalence of vitamin B12 deficiency. They found deficiency in infants could reach up to 45%, while in children and adolescents it could reach 33.3%.
While the exact prevalence of deficiency in the general population is difficult to estimate, adults and the elderly in this study had a greater range of deficiency, from 0 to 86.5% of those tested. However, with few exceptions the data revealed the highest prevalence was in practicing vegans. They also found other types of vegetarians also had a higher prevalence than the general public.
Your Heart and Nervous System Depend on Vitamin B12
Another effect of vitamin B12 deficiency is myeloneuropathy, a unique class of peripheral neuropathies.19 In one presentation of two case studies,20 doctors described how patients who suffered from cognitive impairment and some psychotic symptoms showed improvement after receiving vitamin B12 supplementation.
In a review21 of 51 patients with a confirmed diagnosis of Alzheimer's disease, researchers found low levels of vitamin B12 and recommended assessments of cognitively impaired patients for deficiency of this important vitamin.
In another study22 researchers evaluated the risks associated with vitamin B12 deficiency. They found that “vascular studies have demonstrated impaired arterial endothelial function” in people living in communities with poor access to B12-rich meats, dairy and eggs — but not in lactovegetarians.
Vitamin B12 supplements had a positive impact on patients, leading researchers to recommend regular monitoring for early detection and treatment of deficiency to prevent atherosclerosis related diseases. Unfortunately, even animal foods are a questionable source of B12 due to conventional farming practices. The recommended dietary allowance for vitamin B12 is:23
- 0.4 to 1.8 micrograms (mcg) for newborns and children up to 13, depending on their exact age
- 2.4 mcg for people age 14 and older
- 2.6 mcg for pregnant women
- 2.8 mcg for breastfeeding women
It is difficult to overdose on the vitamin, since it’s water soluble and your body flushes out the excess. Check the label for the form of B12 in the supplement. The best and most bioavailable to support your nervous system is methylcobalamin, which is the naturally occurring form in food.
Considering the many health risks associated with B12 deficiency, and the fact CAFO animal products — which are what most people eat — tend to be low in B12, it may be wise for most people to take a high-quality methylcobalamin supplement.