By Abram KatzRegister Science Editor
Chocolate is great stuff.
Aside from its captivating flavor, it seems to increase blood flow to the heart and brain, protects the body against damaging metabolic products and helps protect pregnant women against a potentially lethal condition called pre-eclamsia.
But before you stock up on chocolate bars, chocolate chip cookies, chocolate cake, chocolate ice cream, chocolate-covered strawberries, chocolate-encased cherries, Kisses and M&Ms, keep one important fact in mind.
What we call chocolate is only palatable because it contains a hefty percentage of sugar and cocoa fat.
Unadorned chocolate looks innocent, but is fantastically bitter.
So, you can eat all of the unsweetened chocolate you want, you just can’t eat the sweet variety unless you’re under doctor’s orders to gain weight and boost triglycerides and cholesterol.
Pity.
It’s not clear which of the 600 or so chemicals in chocolate are responsible for the unappetizing flavor. What interests scientists are the compounds they’re finding in the fruit of the cacao tree, Theobromacacao.
The list includes stimulants, marijuanalike chemicals, antioxidants, and apparent antidepressants.
The most familiar of the chemicals are caffeine and theobromine. Theobromine is almost chemically identical to caffeine, but is a much more modest stimulant.
In addition to giving chocolate-eaters a lift, theobromine also seems to protect pregnant women against pre-eclampsia, according to investigations by research scientist Elizabeth Triche, associate director of the Center for Perinatal, Pediatric, and Environmental Epidemiology at Yale University.
Pre-eclampsia affects about 5 percent to 8 percent of pregnancies and is characterized by high blood pressure and protein in the urine. Women may also experience swelling, sudden weight gain, headaches and vision problems.
The Preeclampsia Foundation estimates the syndrome kills about 76,000 women annually worldwide.
Triche and colleagues screened more than 10,000 women to find 1,681 who reported consuming more than five servings of chocolate a week.
Of this group, umbilical cord data was available for 1,346. Triche found that those women with higher levels of theobromine in their cord blood had a significantly lower risk of developing pre- eclampsia.
“It appears that chocolate may protect against pre-eclampsia,” Triche said.
“We’re not sure why. Chocolate does affect the cardiovascular pathway,” she said.
Triche said theobromine appears to be the protective factor, but chocolate contains about 600 plant compounds, including flavonoids, which seem to help defend the body against heart disease and cancer. Moreover, determining how much chocolate a person has consumed is difficult, she said. Products containing cocoa powder are ubiquitous, so researchers decided to use theobromine levels as a proxy measure.
Research is further complicated by the mysterious nature of pre- eclampsia and related hypertensive disorders, she said.
“No one knows what causes it,” Triche said. Inadequate blood circulation in the placenta is one theory. This adds plausibility to the chocolate effect, because chocolate is known to dilate, or widen, blood vessels.
Flavonols, a subset of flavonoids, are also believed to relax blood vessels and reduce oxidative stress.
Oxidative stress is a constant problem because highly reactive oxygen molecules are produced as a byproduct or metabolism.
These “free radicals” cause damage to DNA, mitochondria and cell walls unless they are neutralized. The body has several mechanism to dowse free radicals. Vitamins C and E also help.
A little chocolate can’t hurt.
There is evidence that chocolate is good for men, too. Preliminary studies suggest compounds in chocolate may reduce blood pressure in men, and increase sensitivity to insulin, which would help offset the effects of type II diabetes.
Of course, chocolate is not the only source of flavonoids. They are present in green tea, red wine, red beans, blueberries, cranberries, avocados, whole wheat bread, and many other fruits and vegetables. Ounce for ounce, chocolate is near the top.
Chocolate is suspected of having many other wonderful properties, based mostly on insubstantial studies or projects paid for by Mars and other chocolate companies:
A–Chocolate may contain a natural antidepressant. Not only does it contain tryptophan, the precursor for the neurotransmitter serotonin, it also bears a compound called anandamide, a cannabinoid- like substance naturally made in the brain. These chemicals, N- oleothanolamine and N-linoleoylethanolamine, also appear to inhibit the breakdown of anandamide. Critics point out that to have any effect, a person would have to eat a large amount of chocolate.
A–Chocolate seems to carry a group of chemicals called tetrahydro-beta-carbolines, also apparently present in wine, beer and liquor. This may contribute to the chocolate euphoria that overcomes some “chocoholics.”
A–Beyond all of that, chocolate is thought to release endorphins, the brain’s own pain-killing self-medication. It even seems to keep platelets from sticking together, thus, supposedly, reducing the risk of heart attack and stroke.
In fact, chocolate has been getting such good press that some people, generally at the behest of chocolate manufacturers, are making fabulous claims, such as chocolate increases longevity, does not add weight and is good for all.
Triche said that the darker the chocolate, the higher the level of apparently beneficial compounds, and the less sugar, cocoa butter and milk - the fattening stuff.
So, how much chocolate should we be eating? (Everyone in Switzerland eats about 21 pounds of it a year).
“We don’t know how much chocolate one must eat” to benefit from its seemingly beneficial compounds, Triche said.
An epidemiologist at Harvard University suggests four to five servings of raw cocoa a day, not something many people would tolerate.
Abram Katz can be reached at akatz@nhregister.com.
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