One of the most popular beliefs is that chocolate is an aphrodisiac, sweetening the act of making love, but there's little scientific evidence to back the claim. (CBC)

The myths surrounding the power of chocolate have been around since the ancient people of America brewed their first cocoa-bean confections.

Aztecs and Mayans believed chocolate passed on knowledge and power to those who consumed it. Don't laugh. The truth about chocolate isn't any less of a mystery today. Scientists seem to know as much about how chocolate affects the body as they know about why people fall in love.

One of the most popular beliefs is that chocolate is an aphrodisiac, sweetening the act of making love, though there's little scientific evidence to back this up.

Chocolate is made up of about 300 chemicals, many of which are thought to have mood-altering effects — chemicals such as caffeine, theobromine and phenyethylamine. Caffeine brings along its usual energy-boosting properties. Theobromine stimulates the heart and the nervous system.

Phenyethylamine, an amphetamine-like substance, is said to stimulate the same reaction in the body as the feeling of falling in love.

However, the reality is that none of these chemicals exists in chocolate in any substantial amount. In the case of caffeine, you'd have to eat more than a dozen chocolate bars to get the same amount that is in a single cup of coffee.

Some scientists also say chocolate contains substances that have the same effect on the brain as marijuana. A University of Michigan study says chocolate causes the brain to release b-endorphin, a naturally occurring chemical similar to opium. The opiates dull pain and increase a feeling of well-being.

Again, you'd have to eat about 25 pounds of chocolate to get "high." There's no proof that it's addictive, either.

The fact is many people regularly eat chocolate and don't become addicted. A University of Pennsylvania study that tested so-called chocoholics found that the cravings might not lie in chemistry at all but the melt-in-your-mouth texture of chocolate. The study found that addicts preferred chocolate bars, even white chocolate bars, which don't contain any chocolate, over capsules of cocoa powder full of chocolate's active ingredients.

Tell this to the people who attend Chocolate Anonymous Association meetings in the U.S. There's also nothing to back up the claim that chocolate makes people feel better, although it's hard to ignore people who say they become more pleasant or feel less tense after eating it. Scientists say the effect of chocolate on mood is likely psychological. Chocolate tastes good, so we feel good when eating it.

Chocolate saves lives, some say

Then there are those who say chocolate cures fevers and can be used as a remedy for other health problems. This seems a little more plausible. After all, chocolate contains a wide-range of vitamins and minerals that the body needs, including potassium, sodium, iron, fluorine and vitamins A, B1, C, D, and E. In fact, researchers at Harvard University go as far as to say chocolate might help people live longer.

The study, which tracked about 8,000 men with an average age of 65, found those who ate chocolate and candy lived almost a year longer than those who didn't.

Although the researchers don't know why chocolate seems to extend life, they think it has something to do with the fact that chocolate contains antioxidants. Antioxidants are believed to prevent the oxidation of cholesterol that causes clogged arteries and leads to heart disease. However, health experts say the benefits of chocolate should be taken with a grain of salt.

A recent review of chocolate studies in 88 publications by Canadian researchers failed to "draw conclusions" about its ability to lower the risk of stroke. Only two of three studies deemed "relevant" by the researchers found an association with eating chocolate and lowering the risk of stroke.

One study, published in 2007 in the American Journal of Clinical Nutrition, looked at more than 34,000 post-menopausal women who were part of the Iowa Women's Health Study and found that those who ate one serving of chocolate per week were 22 per cent less likely to have a stroke than people who ate no chocolate.

Another study published last year in the Journal of Internal Medicine involved more than 1,100 people in Sweden and found that those who ate 50 grams of chocolate once a week were 46 per cent less likely to die following a stroke than people who did not eat chocolate.

But researchers caution that the findings are associations rather than cause and effect. As well, subjects did not identify what kind of chocolate they had eaten (dark chocolate is highest in flavonoids — compounds known for their antioxidant properties).

"More research is needed to determine whether chocolate truly lowers stroke risk or whether healthier people are simply more likely to eat chocolate than others," said study author Sarah Sahib of McMaster University in Hamilton.

In March 2010, German researchers who followed almost 20,000 people over eight years said they found people who had an average of six grams of chocolate per day — or about one square of a chocolate bar — had a 39 per cent lower risk of either a heart attack or stroke.

Eating that small amount of chocolate could lead to 85 fewer heart attacks and strokes per 10,000 people over a period of 10 years, the researchers said.

Nutritionists noted that it was difficult to link the reduction in heart disease and stroke risk to the chocolate alone, since there may have been other differences between participants. And chocolate was also not given directly to test its effects.

Some researchers allege studies that say chocolate prevents health problems such as cardiac arrest are funded in part by chocolate manufacturers that want to sweeten chocolate's soured image. These researchers believe the saturated fat found in chocolate can actually increase bad cholesterol.

Chocolate may or may not be good for humans, but one thing is for sure: it's definitely not good for animals. About two ounces of milk chocolate can be poisonous to a 10-pound dog and more than that can be lethal. The stimulation of the cardiac and nervous systems caused by chocolate is too much for dogs to handle. The same goes for cats and other pets.