Whether you are a vegetarian or know someone who is (or maybe you are considering becoming one), you have probably heard various views on supplements. Some people maintain that you can't be healthy on a vegetarian diet without supplements; others say the vegetarian diet is perfectly adequate, and supplements aren't necessary. It's impossible to give this question a simple “yes or no” answer, but it is possible to explore the issue and discuss what supplements may or may not be necessary.
Follow a Healthy Diet
First, as with omnivores, what a vegetarian eats or doesn't eat is what determines his or her need for supplements. A vegetarian who is living on crackers and lettuce probably isn't getting adequate nutrients, but neither is an omnivore who is subsisting on bologna and bacon. So anyone, regardless of whether or not you are a vegetarian, will likely experience nutrient deficiencies if a poor diet is followed.
Supplements to Consider
Assuming you're eating a balanced, varied, whole-food vegetarian diet, then you may not need supplements. Here are some you might want to consider anyway.
1. Vitamin B12 is lacking in some vegetarian diets, particularly in vegan diets where no meat, dairy, or eggs are consumed. Vitamin B12 is found only in animal flesh, dairy products, and eggs, so a supplement may be necessary on a vegetarian diet. You can eat fortified foods such as store-bought bread instead of taking a supplement if you prefer. Brewer's yeast (not baking yeast) is also a natural source of vitamin B12.
2. Iron is sometimes cited as a nutrient lacking in vegetarian diets, since most people get their iron from meat. But you probably don't need an iron supplement if your vegetarian diet includes lots of whole grains and leafy greens. And you will probably get enough iron if you eat eggs and dairy products in your vegetarian diet. Brewer's yeast also has iron.
3. Vitamin D may be necessary if your location and/or lifestyle involves little exposure to the sun, and if you do not eat Vitamin D-rich dairy products and eggs.
4. Essential fatty acids found in fish, Omega-3s, may need to be taken in supplement form if your vegetarian diet does not include fish. However, Omega-3s are also found in some nuts, seeds, and oils, so as long as nuts and seeds and healthy oils are a regular part of your diet, you may not need a supplement.
5. Calcium supplements will probably not be necessary. It has been shown that leafy green vegetables, sesame seeds, tofu, and other plant sources not only contain adequate calcium, but the body may actually absorb calcium better from these plant sources than from dairy products. Fish-eating vegetarians can get calcium from sardines, bone-in canned salmon, and other fish.