Q. I recently read a short newspaper item that said a soft-drink manufacturer is planning to add B vitamins and Vitamin C to artificially sweetened beverages. What is your opinion of this?

A. We are less than enthusiastic. Fortifying carbonated beverages, whether they are sweetened with sugar or artificial sweeteners, may sell soda. But from a nutritional standpoint, we find little reason to support the idea of adding an arbitrary selection of vitamins to such drinks. People who eat varied and well-balanced diets get enough of these nutrients anyway.

Surpluses of the vitamins you listed would simply be excreted in the urine. Conversely, for those whose diets do not meet nutritional standards, choosing soft drinks fortified with vitamins that may or may not be the nutrients in short supply in their diets is likely to be of scant benefit to their well-being.

Q. In answering a reader's question, you mentioned that many crackers contain a lot of fat. Could you provide me with more definite information about the differences in fat content among various types of crackers?

A. Your query prompted a trip to the cracker section of the supermarket. We were pleased to find that there has been progress, however slow and fragmented, among one of the major holdouts in adopting nutrition labeling. In our informal survey, complete nutrition information, including sodium content, was provided by Borden, which makes Old London melba toast and toast products. Pepperidge Farm, which is owned by Campbell Soup Co., also had complete nutrition information on all but a small number of its packages.

Many smaller producers of specialty crackers supplied all the information, including sodium content. Others put complete information on some of their products, only sodium content on some and none on others. The optimistic view is that some of this inconsistency can be attributed to using up old packages.

Even with nutrition-labeling information, it is hard to compare the fat content of various crackers. The size of the crackers varies, as does the portion size specified by the manufacturer (although most commonly it is half an ounce). Using both nutrition-labeling information where it is available and food tables where it is not, we found that a half-ounce portion of crackers contained anywhere from no fat to more than four grams, equal to almost a teaspoon of fat. That is a fair amount, if you consider that a half-ounce might include just four small crackers, and that an individual might eat at least twice the portion size specified. Moreover, with few exceptions, the type of fat used in crackers is saturated.

For the consumer trying to control fat intake, the easiest approach is to use nutrition labeling wherever available. Alternatively, you can write to the manufacturer and ask to be provided with the information you need to make a decision. Perhaps enough of these requests would motivate all manufacturers to put complete nutrition-labeling information on all products.

Q. Is milk intolerance the same thing as lactose intolerance?

A. Not exactly. Lactose intolerance is a more specific term. It is usually reserved for symptoms that appear following a so-called lactose tolerance test, where a large dose of lactose (usually the amount in a quart of milk) is consumed at one time. Milk intolerance, by contrast, is a more general term. It is sometimes used to describe symptoms related to lactose intolerance that occur after taking much smaller amounts of milk, usually a cup or two. But it may also be used to describe the hypersensitivity associated with milk proteins.

It is now believed that sometime after weaning, usually before the age of 6, lactase activity (the availability of the sugar-splitting enzyme in the intestine) is reduced to between 5 to 10 percent of preweaning levels for much of the world's population. Current evidence suggests that this loss of enzyme activity is genetically programmed and is not influenced by lactose consumption. Fortunately, the majority of individuals with loss of lactase activity can tolerate some milk without discomfort. 1986, Washington Post Writers Group