A new "junk food disease," a kind of "marginal malnutrition" almost akin to beriberi, is appearing in adolescents, according to a Cleveland Clinic doctor.

Beriberi is a severe thiamin (vitamin B1) deficiency seen in the Orient among people who subsist on polished rice.

Twenty persons, mainly adolescents, studied by Dr. Derrick Lonsdale at the Cleveland medical center turned out to have thiamin deficiencies linked in most cased he believes to diets common among teen-agers.

The diets, he says, consisted almost entirely of high-calorie but often nutritionally deficient sugar-laden drinks, pastries, candy and snack foods such as potato chips and pretzels. They were supplemented, perhaps, by some milk, sandwiches, french fries and hamburgers. The diets included some protein and other nutrients, but not as much as fast-growing bodies required.

Junk food eaters with thiamin deficiency often undergo severe personality changes, generally becoming highly aggressive and irritable, Lonsdale says. Some suffer severe abdominal or chest pains, as well as restlessness, lack of sleep, night terrors and frightening dreams.

Many doctors see such youngsters, Lonsdale believes, but treat their symptoms as behavior or psychiatric problems, or sometimes give them drugs for supposed infections.

Lonsdale and Dr. Raymond Shamberger report the Cleveland study in the American Journal of Clinical Nutrition.

"We studied 20 persons biochemically," Lonsdale said in an interview, "but I've seen many in the past few years. I think there are probably a lot of them around. What these kids were eating was a fairly average American teen-age diet.

"No breakfast. Maybe school lunch, maybe not. But lots of doughnuts, snacks, nibbles, washing it down with various colas and such."

The Lonsdale diagnosis of thiamin deficiency and marginal malnourishment is a new and controversial one. Nutritionists and biochemists disagreed last week on whether it may exist in many adolescents.

Dr. Artemis Simopoulos at the National Institutes of Health said the surveys generally have found only a few common nutritional defects in adolescents. The most common is iron-deficiency anemia in menstruating girls on poor diets.

But some scientists called the Lonsdale suggestion a provocative one that needs more study before being called true or false.

Dr. Carroll Leevy of the New Jersey Medical College -- though disagreeing with much that Lonsdale said -- said in an editorial in the nutrition journal that a 1967 study of 642 New York schoolchildren found low thiamin blamed on diet in 68 percent of black and 52 percent of white pupils.

In another editorial, Dr. Myron Brin of the Roche Research Center in Nutley, N.J., a leading thiamin authority, said "serious public health and medical attention to the adverse health effects of marginal vitamin deficiency is long overdue."

"We need to be very cautious about jumping to any conclusion about a B vitamin deficiency," said Dr. Audrey Cross, Agriculture Department nutrition coordinator.

"But adolescents are really a forgotten group. We do a lot of nutritional studies on the infants and aging. But there's not a lot of work on adolescents, the period of a huge growth spurt."

She said she, too, worries about youngsters who get their main nourishment from snacks or fast-food chains. "They may get animal protein and carbohydrates and fats," she said, but often no fruits or vegetables and, as a milk source, "shakes" without much milk.

As for Lonsdale's patients, most have slowly improved after changing their diets.

The frightening thing, he said, is that: "The symptoms in all . . . were relatively trivial, never life-threatening but nevertheless debilitating and extremely frustrating, since many . . . had already received conventional therapy . . . None of them or their parents had the slightest notion that their symptoms might be related to their diet."