Health-food and vitamin companies are touting more "energy-boosting" supplements and exotic-sounding brews to help you leap tall buildings in a single bound -- or so it may seem.
But do these supplements work? Can they be harmful? Samantha Heller, a nutritionist at NYU Medical Center and a contributor to Health magazine, says there is no magic energy supplement bullet. But, she says, there are important vitamins and minerals in food that many people may be lacking that could help boost energy.
Heller gave "Good Morning America" the lowdown on some popular supplements on the market today, and where to find natural energy boosters in the foods you eat.
Co Enzyme Q10 Gel Caps
One of the most popular supplements, co enzyme Q10 is an enzyme found in every cell in the body (and in many foods) to help produce energy; it's also an antioxidant.
Bottom line: Although claims are made it will help you leap tall buildings in a single bound (even help cure cancer and HIV), it only has limited energy-boosting effectiveness after it is taken for several weeks. However, it is safe -- and expensive.
The Noni plant has been used for centuries in traditional Polynesian medicine for a variety of ailments -- including cancer, hypertension and diabetes; however, scientific evidence to support these claims is limited at best.
Bottom line: It will give you a short burst of energy, but only because of its high natural sugar content. Because it's from a plant, it also contains some vitamins and minerals like potassium, which your body needs.
Warnings: Diabetes and kidney patients should avoid it.
Yerba Mate is now being marketed in this country as an energy-boosting diet tea. It contains various minerals, including phosphorous, iron, calcium, and vitamins C, B1 and B2.
But it also contains caffeine (and, in limited amounts, theophylline and theobromine), which are all stimulants. Some manufacturers of Yerba Mate say their brands contain a caffeinelike substance that doesn't make you jittery called "mateine." Heller says chemically, it's identical to caffeine.
Bottom line: It will give you a hit of energy, but it's due to the caffeine.
Warning: Research has found chronic consumption of this tea over years may increase the risk of head and neck cancers.
Guarana is usually combined with green tea in a beverage and also sold in capsules. As with Yerba Mate, it's being marketed as an energy-boosting diet herb.
Bottom line: As with Yerba Mate, it will give you a jolt of energy -- but only because of the large amounts of caffeine and smaller amounts of theophylline and theobromine.
Warning: The Journal of Alternative and Complementary Therapies reports that, due to the high caffeine content, Guarana should be avoided by those with high blood pressure. Other adverse effects have been reported, including heart palpitations, anxiety, and other serious central nervous system disorders -- all classic symptoms of stimulant overdose.
So you're feeling fatigued and you walk into a health-food store to try and get a boost. Where should you go?
"Not to the supplement section, but to the fresh produce -- whole grains, nuts, and so on are a better choice than these temporary fixes based on sugar and caffeine," Heller said. "It's food that gives you energy and gives you the vitamins and minerals and chemicals that work together to give you the energy you need."
She adds that if you're chronically fatigued, you should visit your doctor. But studies find that many Americans are lacking iron and magnesium, two minerals found in food.
The recommended daily allowance of iron for men and women over 50 years old is 8 milligrams a day, while women from 19 to 50 should get 18 milligrams a day. Symptoms of iron deficiency include fatigue, paleness, and being frequently cold.
Iron (ferrous sulfate) food sources:
Whole wheat spaghetti
Heller says that magnesium is a powerhouse mineral used in more than 300 biochemical reactions in the body, including proper muscle, nerve and heart function, protein synthesis and energy metabolism, and again, many Americans are deficient. The recommended daily allowance is 300 milligrams to 400 milligrams a day.
"There is no doubt that you need to boost your intake of high magnesium foods to get your engine running at its peak," Heller said.
Magnesium food sources: