U.S. dark chocolate sales are anything but bittersweet, as its much-touted health benefits and mass marketing introduced by companies such as Hershey Co. and Lindt & Sprungli Co. Plc. turn the product into a popular, guilt-free indulgence.

Dark chocolate sales increased 49 percent to $1.88 billion between 2003 and 2006, according to one study.

"It tastes good and at the same time people have the perception that it has added health benefits," said Marcia Mogelonsky, a senior analyst with research firm Mintel International, who authored the March 2007 study.

Analysts expect to see more competition in this segment, as more companies begin marketing dark chocolate through grocery stores and other mass outlets -- called the "mass" or "entry-level" premium chocolate category. Some companies are even beginning to market chocolate as a "health" food.

"Mass has been under-penetrated as far as dark and premium chocolate goes," said Mitchell Corwin, an analyst who follows the confectionery industry for Morningstar Inc.

"You're seeing more premium brands hit the mass retailers because that's where consumers are going in greater numbers and they are demanding higher quality products."

DARK IS EVERYWHERE

The dark chocolate trend began about five years ago and is peaking now, Mogelonsky said.

"Companies have been working hard to introduce people to different ranges of dark chocolate, from 45 percent to 75 percent cacao," she said.

Last year, Mars Nutrition for Health & Well-Being, a division of Mars Inc., launched CocoaVia, a line of dark and premium chocolates and chocolate products sold purely on a heart-healthy platform.

Lindt and Ghirardelli, which are perceived as premium brands, have also expanded their distribution in mass channels through products such as Lindt's 72 percent Cocoa Bar and Ghirardelli's Intense Dark range.

Hershey's Extra Dark and Cacao Reserve premium dark chocolate lines drove sales growth in the most recent quarter, the company said recently.

Hershey has acquired niche dark and organic chocolate brands such as Dagoba and is also investing in research and marketing to drive category growth.

"Continued growth in both our Special Dark and Extra Dark enabled us to maintain our leadership share within a segment that is experiencing explosive growth," Chief Executive Richard Lenny recently told investors in a conference call.

CHOCOLATE AS HEALTH FOOD

But some analysts and nutritionists have warned against overselling chocolate as a health food.

"If you consume about an ounce of dark chocolate a day, you will see some cardiovascular benefits," said Jeffrey Blumberg, a professor of nutrition science and policy at Tufts University.

Speaking at a symposium on chocolate trends organized by the Chocolate Manufacturers Association, an industry body, on Friday, Blumberg said there is strong scientific evidence of dark chocolate's antioxidant benefits, "but it is high in fat and calories."

Consumers also do not want to buy chocolate as a "healthy food," said Douglas Healy, the project director of HealthFocus International, a health and wellness consulting firm, at the panel.

"Consumers will react against it" if companies stop selling dark chocolate as an indulgence, albeit one with benefits, he added.