Hypothyroidism, which is a Deficiency of the Thyroid, is a condition in which the thyroid gland is not able to produce enough thyroid hormone. The thyroid essentially runs the body's metabolism, so an early symptom is an enlarged thyroid (often referred to as inflamed thyroid), which leads people with this condition to have symptoms like a slow metabolism and weight gain.

Over 42% of Americans are deficient in Vitamin D. This one vitamin plays a vital role in the regulation of calcium and maintenance of phosphorus levels in the blood. This helps with the maintenance of strong bones and healthy muscles. Vitamin D is essential to the body and allows the intestines to stimulate and absorb calcium and reclaim calcium that the kidneys would otherwise excrete. 

Weakness and fatigue are symptoms often correlated with a Vitamin B12 Deficiency. This occurs because your body doesn't have enough Vitamin B12 which helps make red blood cells, which will then transport oxygen throughout your body. With a lack of oxygen to your body's cells, your body will begin to feel weak and tired.