The pretzel may seem to be a humble snack food -- lagging in sales behind the more popular potato chip and hanging around in beer parlors and ball parks -- but its origins are anything but ordinary.

It all started with a seventh century monk who twisted some leftover bread dough into the shape of crossed praying arms to be given to children as a reward for saying their prayers. The word pretzel comes from the Latin word pretiola -- meaning a little award.

Whether pretzels can replace potato chips as one of America's favorite snack foods remains to be seen, but the signs are encouraging. Pretzel sales have jumped from $470 million in 1988 to $558 million in 1989, an 18.6 percent increase, according to the Alexandria-based Snack Food Association, a trade group.

The increase is attributed to more health-conscious consumers seeking tasty, low-calorie snacks. Pretzels are among the few salted snack foods that are low in fat, according to Pat Harper, a registered dietitian and nutrition consultant in Pittsburgh. "They are a complex carbohydrate, which we are encouraging people to increase in their diet."

A 1 ounce serving -- about six pretzels -- has 110 calories, 1 gram of fat and no cholesterol. They come in a variety of shapes and sizes, and manufacturers are experimenting with ways to make them more nutritious.

Mixing oat bran with wheat flour, yeast, malt and water to form pretzel dough is one way to boost the snack's fiber content. Key Stone Pretzel Bakery in Lititz, Pa., considers its oat bran pretzel a popular item, selling 200,000 pounds of the product each month.

Pretzels are also a good value. Depending on the brand, a family can purchase two 16-ounce bags for under $2. "When compared with potato chips or cookies, pretzels represent the best value," said E. Terry Groff, president of the Reading Pretzel Machinery Corp. in Robesonia, Pa.

The problem with pretzels, according to nutritionists, is the sodium content. The amount of salt can range from 250 milligrams per serving up to 800, said Charlene Rainey, a nutrition consultant for the Snack Food Association. The Food and Drug Administration recommends that people consume no more than 2,400 mg of sodium per day.

"Manufacturers can reduce the sodium level considerably and still have a good product," said Harper.

As a crunchy, dry, plump snack sprinkled with flakes of rock salt, a pretzel almost crys out for something cold, wet and fizzy to wash it down. Many consider pretzels a perfect snack to munch on with beer during a football game.

"We are trying to get away from the idea that pretzels should be consumed with beer," said Jeff Kring, Key Stone Bakery's operations manager. "They are terrific with cheese and apples and can be an accent to any lunch or sandwich."

Nutritionists agree. Said Harper: "If people would include more vegetable platters at parties along with pretzels and popcorn, they would be offering a variety of snacks that do not contribute to weight or cholesterol problems."