Common Nutrient Deficiencies for Adult Men

3. Vitamin B12

Lack of vitamin B12 can lead to pernicious anemia. Vitamin B12 is needed for healthy functioning of red blood cells, nerves, and DNA. A deficiency can occur both if too little B12 is consumed or if something is preventing the B12 from being absorbed by the body.

Vegetarian diets tend to be low in B12 because meat is the most abundant source. Conditions such as Celiac or Crohn's disease interfere with B12 absorption, and some heartburn medications also prevent absorption. Symptoms of B12 deficiency include numbness, pins and needles feeling in the hands and feet, shortness of breath, and joint pain. Severe cases may lead to memory loss or dementia symptoms.