Yes, the best way to get all the nutrients your body needs is through whole foods. That should be easy right? Our culture of fast and convenient foods means that we are eating a lot of processed foods that don't contain enough of the nutrients we need. As a result, nutritional supplements are big business because we know we aren't eating right. Even in developed countries like the United States it is still possible to become deficient in important nutrients. Illness, poor diet and environment can all create deficiencies. Here are the signs and symptoms associated with a deficiency in specific vitamins:

A - A lack of this can create problems with vision, particularly night-time sight. It can also cause the conjunctivitis of the eye to thicken or form milky white spots. If you take a nutritional supplement for A, be aware that it is fat soluble which means it stays in the body longer making it easier to take too much.

Thiamine (B1) - This is an example of how poor diet and illness can create deficiencies. Alcoholics commonly lack enough thiamine. Beriberi is the disease that results and it attacks the nervous and cardiovascular systems of the body. Memory acuity and muscle control are greatly compromised. Edema and congestive heart failure are also a risk. B vitamins are water-soluble so they pass through the body faster than fat-soluble ones. It also means that you don't have to take these nutritional supplements with food. However, you may have to take more of it throughout the day as opposed to one dose with a meal.

D- Sunlight helps the body produce its own D, but dangers of skin cancer have more and more people covering up. Luckily, most dairy foods have D added to it. But, if there is a deficiency, osteoporosis is an increased risk. Vitamin D facilitates the absorption of the calcium in the body and without it; bones lose out on the calcium they need. There is also a correlation to depression and fatigue. Research has shown that a D nutritional supplement works to alleviate the symptoms of seasonal affective disorder or SAD. Vitamin D is fat-soluble so, again, it stays in the body longer making it more possible to take too much.

C- Not enough C affects collagen production in the body. Collagen is a major building block for bones and tissue to it is essential. Because it facilitates the absorption of iron, a lack of C may cause you to become iron deficient anemic. C is water-soluble, so like the B vitamins, it passes through the body rather quickly and may require you to stagger your nutritional supplement dosing throughout the day to maintain good levels.

B12- B12 is essential to red blood cell production and proper functioning of the nervous system. It is found in the liver. Vegetarians and people with autoimmune diseases are at risk of a deficiency. Anemia is the result when the body is low on red blood cells. Fatigue, weakness, numbness and reduced mental acuity are all symptoms of a deficiency. Because it is water-soluble, regular dosing may be necessary to maintain proper levels, particularly if you fall into the at-risk categories above.

Before taking any nutritional supplements, it is a good idea to talk with your doctor. If you are concerned about deficiencies, he can test you and then prescribe a proper dosing schedule. It is possible to take much of a good thing, so read the dosing instructions on the bottle and follow your doctor's recommendations.