Iron is necessary for energy, formation of hemoglobin, which carries oxygen from lungs to the rest of the body, resistance to diseases and stress reduction. Too much iron can lead to the production of harmful free radicals and is linked to heart disease in men. Fatigue is the most noticeable symptom of a deficiency and a simple blood test can be the proof. Zinc deficiency lowers the ability of the immune system to fight off diseases - zinc lozenges are very popular as a natural cure for sore throats. This is a controversial nutrient, since the body needs only a very small amount, but that small amount is essential for cell growth and healthy nervous system functioning.
New vegans can generally use what is already stored in their bodies for up to three years.
Too little calcium, iron, or vitamins E and B-6 can also lead to deficiencies. There are so many vegetarian sources, especially orange and red vegetables, green vegetables, garlic, alfalfa and spirulina, that adequate intake should not be a problem. Beta-Carotene needs a little fat to enable it to be absorbed optimally. Vitamin A absorption can be inhibited by antibiotics, laxatives, and some cholesterol-lowering drugs. Be careful with taking vitamin A supplements, to many can be harmful.