In terms of health, a vegetarian diet can be one of the most healthy options. A new study even suggests a vegan diet could actually be the best when it comes to lowering heart disease and blood pressure.  It begs the question, is there any downside? The key with a vegan diet, as with any, is that a variety of foods is necessary in order to get the wide variety of nutrients your body needs. Apples, for example, are a great snack, but you can't survive on apples alone. Let's take a look at nutrients it's easy to miss out on if you're just beginning.
Vegan Diet Dangers
The dangers of the vegan diet are few and far between and are greatly outweighed by the widely-acknowledged benefits. Let’s go over 5 common nutritional concerns you could face from a vegan diet.
1. Vitamin A Deficiency
While you’ll only find pre-formed vitamin A in animal products, there are certain compounds — you’ve likely already heard of one, beta-carotene — the body can convert into the vitamin. Because of its role in good vision (night blindness is one of the first signs of a deficiency), immune system health, and cell growth, making sure you get enough is key.   For vegans, there are quite a few vegetable options for getting the A you need, but keep in mind, a poorly balanced vegan diet could lead to not getting enough of the vitamin.
2. Lack of B12
If you’re not getting enough B12, you could develop anemia or damage to your nervous system. For vegans, getting enough becomes a little tricky since their only reliable sources are fortified foods and supplements. But even with just enough to prevent the major issues mentioned above, studies suggest too little could also lead to pregnancy complications.  
3. Low Calcium Intake
Many vegans typically only get about 400-600 mg of calcium each day compared to the U.S. recommendations of 1,000 mg each day. While recommendations to increase your milk consumption for your calcium is very outdated, you still need to incorporate as many foods as you can to get enough calcium. If you’re eating plenty of green leafy vegetables, like kale, spinach, and mustard greens, you’ll be getting enough calcium. Supplementing with calcium can be helpful, but watch out – you want to go for a highly-absorbable option, like calcium orotate, instead of using calcium carbonate or citrate.
4. Vitamin D Insufficiency
And research suggests Vitamin D — necessary for calcium absorption — is also just as important in preventing osteoporosis.  Most vegans won’t get any of the vitamin from food sources, so supplementing with vitamin D3 – make sure it’s vitamin D3 and not vitamin D2 – could be crucial for bone health.
5. Iodine Depletion
Iodine is needed for a healthy thyroid, and getting too little can cause concerns with the body’s metabolic functions. Because your body can’t produce iodine, getting trace amounts in food and supplements are your only options. Keep in mind that one study suggests vegans could have iodine deficiencies due to lower iodine levels in plants. 
The Take Home
True, vegans could be some of the healthiest folks out there, but that’s only with the right vitamins and minerals. Supplementation with specific nutrients, like vitamin D3 and iodine, can only improve the quality of your diet, no matter which dietary philosophy you follow.
- Craig, W. J. Health effects of vegan diets. The American Journal of Clinical Nutrition. 89 (5).
- Dowling, J. E. & Wald, G. Vitamin A Deficiency and Night Blindness. Proceedings of the National Academy of Sciences of the United States of America. 44 (7).
- Clifford, L. J. Reversible night blindness – A reminder of the increasing importance of vitamin A deficiency in the developed world. Journal of Optometry. 6 (3).
- Molloy, A. M. et al. Effects of folate and vitamin B12 deficiencies during pregnancy on fetal, infant, and child development. Food and Nutrition Bulletin. 29 (2 Supplement).
- VanderJagt, D. J. et al. Assessment of the Vitamin B12 Status of Pregnant Women in Nigeria Using Plasma Holotranscobalamin. ISRN Obstetrics and Gynecology.
- Barr, S. I et al. Spinal bone mineral density in premenopausal vegetarian and nonvegetarian women: cross-sectional and prospective comparisons. Journal of the American Dietetic Association. 98 (7).
- Krajcovicová-Kudlácková M et al. Iodine deficiency in vegetarians and vegans. Annals of Nutrition & Metabolism. 47 (5).
†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.