Name three deficiency diseases associated with diet and state their causes

Iron deficiency, hypoglycemia, and scurvy.

Step-by-step explanation:

Iron deficiency is the lack of iron in the blood, usually caused by blood loss. Because the body doesn't produce iron, people need to consume items with iron to rise up the amount of iron.

Hypoglycemia is the lack of blood sugar (known as glucose), people who are diabetic or drink excessive alcohol can have hypoglycemia.  People would have to consume more glucose or take insulin shots to get the amount back to normal.

Scurvy is caused by the lack of Vitamin C (found in fruits and vegetables) , usually within 3 months.