The culprit behind feeling tired can be as innocent as poor sleep habits to something much more serious, such as nutritional deficiencies. When no cup of coffee will get you feeling perky, talk to your doctor about potential causes. By doing blood work, he might discover that you're deficient in one or more vitamins, which can leave you feeling lethargic.
Identify the Deficiency
Before you start popping vitamins with the assumption that they can boost your energy, make an appointment with your doctor. While increasing consumption of certain vitamins and minerals can boost energy if you're deficient, it won't do much if you're not. The laboratory tests that a health care provider can do when you come in complaining of chronic fatigue will rule out other illnesses or confirm a deficiency. When discussing potential blood tests, ask your doctor what he plans to order from the lab -- nutritional deficiency tests are not part of a complete blood count test.
Boost Your B-12
Anywhere between 15 percent and 40 percent of Americans are deficient in vitamin B-12, which helps your body make DNA for new cells, create red blood cells and turn food into energy. Without enough B-12, you might lack energy, as well as have difficulty remembering things, feel tingling or numbness in the hands or feet and have mood swings or irritability. Vegans are particularly prone to a deficiency, as B-12 is found naturally in animal products, as are those over age 50 because their ability to absorb the vitamin diminishes. Aim to get 2.4 micrograms of B-12 a day to prevent a deficiency and the fatigue that can come along with it. The vitamin occurs naturally in animal products, as well as fortified foods; get your fix from clams, beef liver, eggs, dairy products and fortified breakfast cereals or nutritional yeasts.
Increase Vitamin D
Low vitamin D levels -- those that are less than the normal of level 30 nanograms per milliliter -- can result in chronic fatigue syndrome. While vitamin D can be found in fatty fish, egg yolks and fortified dairy products, 50 percent to 90 percent of the vitamin D in your body comes from exposing your skin to sunlight. If you work indoors, regularly use sunblock or are dark-skinned, you might experience tiredness as a symptom of a deficiency. Prevent this by spending 15 to 20 minutes in the sun daily with at least 40 percent of your skin exposed. You can also take a vitamin D supplement to reach the recommended level of 600 international units per day for adults.
Consider a Mineral Deficiency
It's not just a vitamin deficiency that can cause fatigue. You might want to boost your consumption of iron, a mineral, particularly if you're a woman with a heavy menstrual period or pregnant, or if you avoid meat as part of your diet. Talk to your doctor about taking an iron supplement to meet your daily recommendation of 8 milligrams for a male and 18 milligrams for a female. If you're pregnant, you need even more -- 27 milligrams a day. Good food sources of iron include fortified breakfast cereals, oysters, white beans, lentils and spinach. Additionally, a magnesium deficiency can cause fatigue, according to the University of Maryland Medical Center, but it needs more scientific examination. Green leafy vegetables, almonds, cashews and soy milk are all good sources of the mineral.
Food Vs. Supplement
Generally, a well-balanced diet full of produce, whole grains, lean protein and low-fat dairy gives you all the vitamins and minerals you need per day. Taking too many vitamins and minerals in supplement form increases the risk of toxicity. But talk to your doctor about the best way to correct a deficiency; in some cases -- such as if you suffer from pernicious anemia as a cause of a B-12 deficiency -- changing your diet won't fix the problem.