Red Bull - energy drinks

In recent years, the market for so-called energy drinks has grown rapidly. These beverages are often advertised as nutritious, with some containing vitamins or herbal extracts. But their main ingredients are sugar and caffeine - and lots of both.

Nutritionist Dee Rollins with Baylor University in Texas says she's aware of more than 200 energy drinks that are on the market. She says the amount of caffeine contained in these energy drinks can be amazingly high.

Some of these energy drinks run a couple of hundred milligrams of caffeine per one drink. But according to Rollins, many of the drinks don't advertise the amount of caffeine they contain. So people drinking them could easily be taking in too much of this powerful stimulant.

Caffeine is a central nervous system stimulant. A small amount increases our awareness, decreases our fatigue, makes us feel a little bit better. Generally, 250 mg per day would be what would, in America, be recognized as safe to take. A (level of) 300 mg is often considered excessive.

Rollins says some energy drinks contain over 200 milligrams of caffeine in one bottle. She says when people buy these products, they don't realize that they've consumed close to the daily limit of caffeine in their drink. Then, just a single cup of coffee - containing between 80 to 120 milligrams of caffeine -can quickly put them over the recommended limit. Rollins says researchers have found that topping 250 milligrams of caffeine in a day can lead to health problems.

A maximum amount of caffeine a day would lead to symptoms such as nervousness, or headaches, or increased heart rate, higher blood pressure. The more we take, the more symptoms we might have, depending on the genetics of the person. We might have G.I. (gastro-intestinal) irritation -- that would be the gut, the stomach, the intestines -- we might
have diarrhea. If we take too much we might actually move into depression, insomnia is not uncommon, poor concentration.

Too much caffeine can also contribute to changes in heart rhythms. And Rollins says psychiatrists have found that people with mental health problems may find their symptoms exacerbated by caffeine. These include depression, bipolar disorder, anxiety and sleep problems.

Rollins says the way to avoid taking in too much caffeine is to know how much caffeine is in an energy drink, and to drink them in moderation. 

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