Did you know that the human body is composed of seven main essential ingredients:
Water
Proteins
Fats
Carbohydrates
Nucleic acids
Vitamins
Minerals
(for future reference we will refer to these substances as nutrients).

Some nutrients the body can make internally. These are considered non-essential. Other nutrients the body cannot make and therefore they have to be acquired through the diet. These are referred to as essential. Most vitamins and minerals are essential nutrients. Water, certain fats and amino acids are also essential nutrients. The body cannot function properly when a deficiency of an essential nutrient is present, and when any one these nutrients are deficient long enough, the body will respond with symptoms and/or disease.

Imagine the following analogy:
You are having a house built so you hire a contractor to do the work. His crew begins building your new home. They have all the tools and supplies (nutrients) they need except for nails and screws. They still build your home, but use glue and other bonding agents to put the internal framework together. Now imagine that the house is your body and a strong storm is approaching. Because the proper tools(nutrients) were not present, the house will not last as long as it could have.

It is important to realize that nutrient deficiencies can manifest as generalized symptoms for many years before a disease actually develops. For example, magnesium deficiency may contribute to hypoglycemia for years before adult onset diabetes actually develops. Magnesium deficiency can be the culprit of fatigue for many years before depression is diagnosed. Magnesium deficiency can result in high cholesterol long before atherosclerosis (a form of cardiovascular disease) is identified. That is not to say that a magnesium deficiency is solely responsible for the above conditions, but that a deficiency can be a risk factor or predispose an individual to them. Many nutrient inadequacies or deficiencies are directly and indirectly related to different symptoms and disease states.

View the chart below:

Nutrient Deficiency

Associated Diseases or Symptoms

Calcium

High blood pressure, depression, osteoporosis

Vitamin E

Anemia, heart disease, dementia

Zinc

Diabetes, arthritis, decreased immunity, fatigue

Vitamin A

Acne, fatigue, poor immune function

Selenium

Heart disease, cancer, muscle pain

Vitamin D

Muscle pain and weakness, depression, cancer

Folic Acid

Neural tube defects, heart disease, cancer

Vitamin B12

Depression, fatigue, anemia, nerve damage

Vitamin B6

Depression, fatigue, anemia, heart disease

Pantothenate

High cholesterol, fatigue, nerve damage

Vitamin B2

Chapped lips, dry eyes, fatigue

Vitamin B1

Congestive heart failure, fatigue, depression

Vitamin C

Cancer, heart disease, stroke, muscle pain

Potassium

Muscle cramps, heart disease

Chromium

Hypoglycemia, diabetes, fatigue

Coenzyme Q10

Muscle pain, fatigue, congestive heart failure

L-Carnitine

Heart Disease, obesity, fatigue

Niacin

Dermatitis, dementia, fatigue

Iron

Anemia, increased risk of infection

Biotin

Dry skin, skin rashes, heart disease, nerve damage

http://www.essential-nutrients.net/ Peter Osborne, D.C., D.A.C.B.N Dr. Osborne has practiced integrative nutrition and chiropractic medicine for the past 6 years. He is a native Texan and received his doctorate from Texas Chiropractic College after which he went on to pursue an advanced accreditation in nutrition through the American Clinical Board of Nutrition. He has been on faculty at Texas Women