Vegetarian and Vegan Diet

  • Author:
    Betty Kovacs, MS, RD

    Betty is a Registered Dietitian who earned her B.S. degree in Food and Nutrition from Marymount College of Fordham University and her M.S. degree in Clinical Nutrition from New York University. She is the Co-Director and Director of nutrition for the New York Obesity Research Center Weight Loss Program.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Calcium

The most well-known source of calcium is dairy foods, which are often omitted or greatly limited in vegetarian diets and are completely omitted in vegan diets. Dairy products provide 70% of the dietary calcium of the U.S. population. The nondairy foods that provide calcium are calcium-fortified tofu, some roots and legumes, and fortified soy milk.

Certain factors will impact how much calcium you actually absorb from the food, such as the amount of calcium that is present and the presence of vitamin D. The presence of vitamin D will enhance absorption, while the presence of oxalic acid and phytic acid will interfere with the absorption. Foods rich in oxalic acid are spinach, rhubarb, sweet potatoes, and beans. Foods rich in phytic acid are unleavened bread, nuts, seeds, and raw beans. You will absorb some of the calcium in foods that you consume when oxalic acid and phytic acids are present but not as much as you would when they are not present. For example, calcium absorption from dried beans is about half of that absorbed from milk, and calcium absorption from spinach is about one-tenth of that from milk.

The following are recommendations for consuming an adequate amount of calcium:

  1. Consume two servings of dairy products per day, with 200 mg coming from other food sources.
  2. Vegans should consume calcium-fortified juices or soy milk on a daily basis, calcium-rich foods throughout the day, and consider taking a daily supplement.
  3. Calcium intake needs to be spread throughout the day for optimal absorption. We do not efficiently absorb more than 500 mg at a time, so there is no need to try to consume high amounts all at once.

Vitamin D

Vitamin D deficiency has become a worldwide epidemic. People who exclude fish and dairy from their diet can be even more susceptible to a vitamin D deficiency. There are numerous benefits to vitamin D, including decreased incidence and severity of cardiovascular disease, lowering of blood pressure in hypertension, prevention and treatment of depression, decreased risk of type 2 diabetes, prevention of osteoporosis and osteopenia, decreased inflammation, decreased dental cavities, reduced risk of allergies in children and adolescents, decreased mortality from various forms of cancer, decreased incidence of rickets, possible decrease in erectile dysfunction, and regulation of blood cholesterol.

The only way to know for sure if you are getting enough vitamin D is to have your blood tested. It is a good idea for people following a vegetarian diet to do this, especially children. Exposing your skin to the sun for 10 to 15 minutes, without sunscreen, a couple of times per week is an option for some to meet their vitamin D needs. When this is not an option, research shows that supplementation can be effective in preventing this deficiency.

Medically Reviewed by a Doctor on 4/8/2015
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