There are some days where no amount of coffee can perk you up. When those days become all too frequent, it's time to look beyond your caffeine intake and sleep habits to determine what's causing low energy levels. Certain vitamin and mineral deficiencies manifest as excessive fatigue, so talk to your doctor about modifying your diet or adding supplements to boost your energy.
Boost With B-12
Anywhere from 15 percent to 40 percent of Americans are lacking enough vitamin B-12 for optimal health, according to registered dietitian Kate Geagan. This vitamin -- one of eight in the B complex -- helps make healthy blood cells, form DNA for new cells and convert food into energy. When you consistently don't get the 2.4 micrograms you need per day, you'll experience fatigue, as well as symptoms such as irritability and memory problems. Prevent low levels of B-12 by adding more of it to your diet through animal products such as poultry, beef and seafood, fortified cereals, or fortified soy or almond milk. You can also take a daily supplement, particularly if you're a vegetarian or vegan.
More than a billion people worldwide are deficient in vitamin D, according to a study published in the "International Journal of Health Sciences" in 2010. This deficiency can show up, along with other symptoms, as chronic fatigue. Anywhere between 50 and 90 percent of vitamin D is produced by exposing your skin to sunlight, while the remainder comes from dietary sources such as egg yolks, fatty fish and fortified dairy products. If you're low on D, increase your energy by ensuring you get 600 international units a day, unless you're over age 71, in which case you need 800 IUs daily.
It's not just vitamins that can make or break your energy supply -- minerals play a role, too. For example, magnesium is required for more than 300 biochemical reactions, which includes converting glucose into energy. Get too little, and you might feel like you're dragging. Consume 300 milligrams a day if you're a woman or 350 milligrams a day if you're a man from sources such as almonds, whole grains or fish such as halibut.
Low iron levels are also a likely culprit, given that it's the No. 1 nutritional deficiency in the world. Without enough iron, your body has to work extra-hard to produce hemoglobin, the part of red blood cells that transport oxygen, which leaves you feeling lethargic. Women need 18 milligrams of iron a day until age 50, when the requirement drops to 8 milligrams. When pregnant, that need jumps to 27 milligrams a day. Men need 8 milligrams a day as well. While you can take a supplement, you can also get iron from ground beef, oysters and clams, as well as plant-based foods such as beans, spinach and broccoli.
Additional Energy-Boosting Strategies
If you're eating a well-balanced diet and have ruled out vitamin and mineral deficiencies as the cause of your low energy levels, talk to your doctor to rule out underlying medical conditions. Other easy fixes include boosting the amount of exercise you get, as physical activity can increase energy. Additionally, dehydration can make you feel fatigued, so drink plenty of water every day.