January 2, 1985

IF a group of physicians who call themselves clinical ecologists are right - there are those in the medical profession who do not believe that they are - thousands, perhaps millions, of Americans are ''allergic'' to the world they live in: to common foods such as wheat, milk, corn and eggs; to food additives and pesticides; to chemical pollutants in the air and water. The symptoms of their sensitivities are said to include such behavioral and emotional problems as depression, fatigue, irritability and even schizophrenia, as well as such physical ones as headaches, stuffy sinuses, nausea and diarrhea. Some of these people have put in weeks in isolation in hospitals and spent thousands of dollars on diagnostic tests only to be told that they are reacting adversely to myriad substances encountered in the course of daily living. Many others have returned dozens of times to the doctor's office for costly, time-consuming treatment to curb their presumed food and chemical sensitivities. Some live on highly restrictive diets in hopes of avoiding the foods thought to trigger their symptoms. Others have paid large sums to ''detoxify'' their homes by replacing all gas cooking and heating units with electric ones, buying hypoallergenic carpets and bedding, and banishing all sprays and scents. Not a few have abandoned ''contaminated'' urban and suburban dwellings and moved to a relatively unpolluted mountaintop or seashore.

Jan. 1, 1985, was Peter Powers's first day back on the track, Simone Garvey's first day without coffee and Juliana Harkavay's first day. It was gray and overcast, and as a gentle mist whispered through the city, Mr. Powers was in Central Park running, Miss Garvey was at a diner drinking orange juice, and Miss Harkavay was squinting at the light that filtered through the window at St. Luke's Hospital, where she was the hospital's first baby delivered in 1985. Yesterday was a day tinged with firsts, when anyone could find something to begin anew - a diet neglected during holiday parties, an exercise program abandoned when the summer sun set, a book that seemed too long, a friendship that was somehow forgotten. For Berta Carela-Harkavay and Michael Harkavay, the new year began with a burst of crying at 1:27 A.M., when an 8-pound, 2-ounce little person with a shock of black hair entered their world.

''CUCINA GENUINA'' is not a new phrase in Italy, but it has been gaining fresh currency lately. Cucina genuina means cooking that is genuine, in the sense of authentic, unadulterated and natural. It also means cooking that is closely tied to the traditions of a particular region. In Italy that meaning is as manifold as the 19 separate regions into which the country is divided. Many dishes in the regional Italian cook's repertory now appear nationwide, whether on restaurant menus or in home kitchens, from Turin to Palermo - dishes like spaghetti bolognese or pasta alla carbonara. But Italians are the first to point out there is really no such thing as Italian cooking. When Italians talk about food - which they do constantly, unabashedly and with gusto - they talk about regional food, the cooking of Piemonte in the northwest or of the Abruzzi hill country east of Rome, or the rich, Arab-influenced cuisine of the south. Even within regions such as Tuscany, there are discernible and cherished differences among the cooking styles of Florence, Siena, Lucca and Arezzo. After a brief fling with nouvelle cuisine, which often seemed a press agent's airy fantasy rather than a response to actual needs,

WEDNESDAY, JANUARY 2, 1985 International China's new ''open door'' policy to the West is the only way to overcome the legacy of ''poverty, backwardness and ignorance'' the country brought on itself by hundreds of years of isolation, according to Deng Xiaoping. China's pre-eminent leader made the statement to his fellow Communist Party leaders in a speech made public in Peking. (Page A1, Column 4.) The new arms control talks scheduled next week in Geneva have raised hopes among many Russians for improved relations with the United States. However, Soviet officials seem to be approaching the ministerial talks cautiously. (A10:1-4.)

Two years ago, a group of Boy Scouts walking along the beach in the State of Washington spotted a red-and- white sphere bobbing in the water. On its sides, written in Russian and English, was the phrase ''USSR Academy of Sciences,'' suggesting that it was an innocuous research buoy. But when military investigators examined the sphere's innards, they concluded that it had a more sinister purpose. It was actually a military sonobuoy that had been dropped offshore, the investigators say, to eavesdrop on Trident missile submarines based in nearby Bremerton. Moreover, the acoustic buoy appeared to have been copied from American designs and electronic components. It even contained an extraneous screw, threaded the wrong way, that served no purpose whatever but was identical to the extraneous screws an American designer had used as a ''signature.''