Q: What is the nutritional value of tomato paste?

A: Tomato paste contains a high concentration of tomato solids and theoretically impressive amounts of several nutrients. However, the amount of tomato paste used in recipes is generally small, and thus its nutritional contribution is likely to be limited.

Two tablespoons contain about 30 calories, about 5 percent of the day's iron for an adult woman, some vitamin A, and small amounts of several B vitamins. It also provides considerable amounts of ascorbic acid, but when used in recipes that require prolonged cooking, much of it may be destroyed before it is consumed.

Tomato paste is available both with and without salt. Two tablespoons of the salt-free variety contain just 20 mg. of sodium, while the same variety prepared with salt contains nearly 260 mg.

Q: I know heavy drinking during pregnancy is associated with serious problems in infants. But has there been any research showing that smaller amounts of alcohol can be damaging?

A: One problem in quantifying the risks associated with alcohol is that drinking is often linked with other behavior like smoking that also raises risk. Recently, however, a group of researchers reported the results of a study that investigated the effects of drinking early in pregnancy on the infant. Study participants were a select group of women who formed part of a larger study conducted at the University College Obstetrics Hospital in London.

The women were all considered "low risk" as measured by a variety of socio-demographic characteristics. All were between 8 and 16 weeks pregnant at the time of their first prenatal visit, nonsmoking, nonalcoholic and in general good health. Each woman was interviewed about her alcohol consumption for the week before she recognized she was pregnant, and in the week before her first visit for care.

Three categories of drinking habits were established. Regular drinking was defined as 15 grams of pure alcohol a day, the equivalent of about 1 1/2 ounces of 80 proof liquor, 1 1/3 glasses of 12 percent wine, or a bottle of 6 percent beer. Occasional drinking was defined as 7.5 grams but less than 15 grams per day. Infrequent drinking was set at less than 7.5 grams per day. As expected, the number of women classified as regular drinkers for the week prior to their first prenatal visit dropped sharply from the earlier interview period before pregnancy was known. By the first prenatal visit, few women fell into this category.

Results showed that a daily average intake of 10 grams of pure alcohol (about one drink) prior to the recognition of pregnancy was associated with a drop in average birth weight of nearly half a pound. Drinking at this level in the week before the first prenatal visit was associated with a comparable drop in birth weight in male but not female children. However, the number of male infants born to women classified as regular drinkers in the week before their first prenatal visit was small, and the reason for the observed difference between the sexes remains unexplained. This question will be studied further. Moreover, the study examined only the influences of alcohol early in pregnancy, and did not collect information about continued drinking throughout pregnancy.

Nevertheless, it does appear that drinking in the early stages of pregnancy affects birth weight negatively. These data support the idea that women who suspect they might be pregnant or who are trying to become pregnant should avoid alcohol.