- Healthy Eating Slideshow: Fat-Fighting Foods
- Food Frauds Slideshow Pictures
- Take the Diet & Nutrition Quiz
- Introduction to vegetarian and vegan diets
- What types of vegetarian diets are there?
- What are the potential dangers from consuming the various kinds of vegetarian and vegan diets?
- Omega-3 fatty acids
- Vitamin B12
- Vitamin D
- What are the benefits of the various kinds of vegetarian and vegan diets?
- How do I develop a vegetarian or vegan diet plan for myself?
- What are sources for vegetarian and vegan recipes?
- What is included in the vegetarian food pyramid?
- What is included in the vegan food pyramid?
- Where can I get more information on vegetarian and vegan diets during pregnancy?
- Where can I get more information on vegetarian and vegan diets?
Quick GuideVegetarian Diet: Becoming a Vegetarian
Vitamin B12 is attached to the protein in animal foods. There has been considerable research to determine if it is also found in some plant foods. Unfortunately, the B12 that has been found in plant foods can't be used by humans. Supplements that have been made with the plant sources have been shown to contain B12 analogues, compounds that are structurally similar to B12 but do not serve the same function. Research has shown that using supplements with these analogues can actually compete with vitamin B12, inhibit its metabolism, and increase the risk of B12 deficiency.
Vitamin B12 deficiency causes a number of symptoms and problems, including weakness, tiredness, constipation, loss of appetite, weight loss, poor memory, dementia, depression, problems with balance, and megaloblastic anemia. You may also experience nerve problems, such as numbness and tingling in the hands and feet. Vitamin B12 deficiency can damage the nervous system even in people who don't have anemia, so it is important to treat a deficiency as soon as possible.
Vitamin B12 is found in seafood, dairy, eggs, and meat. Vegan diets have the highest risk of deficiency. There are many foods that are fortified with vitamin B12, so it is possible for vegan diets to contain adequate amounts of this nutrient with or without a supplement. The recommendations for reaching your vitamin B12 needs are to
- consume food fortified with vitamin B12 two to three times a day,
- take a B12 supplement if you are unable to consume an adequate amount in your diet or if you have an increased need for it (the elderly and pregnant and lactating women),
- do not take excessive amounts of folate supplements, as this can mask a B12 deficiency,
- have your B12 level checked by your physician.