Scientific Update

Mother's Vitamin B12 Status is Key Determinant of Infant's Vitamin B12 Status

VRG has long stressed the importance of adequate vitamin B12 intake during pregnancy. A recent study from Norway provides strong support for this position. According to a study of 186 non-vegetarian women and their infants at four days after birth and six weeks later, 8% of infants and 15% of mothers had abnormally low cobalamin (vitamin B12) levels. There was a strong association between the level of vitamin B12 in the mother's blood and her infant's blood-vitamin B12 level. In other words, if the mother had low blood-vitamin B12 levels, the infant was likely to also have low blood-vitamin B12 levels. Infants who had low vitamin B12 levels at four days after birth also were likely to have low levels six weeks later.

Since vitamin B12 is important for development of the brain and other parts of the nervous system, it is important for all infants to have good vitamin B12 levels. This is not likely to happen unless the mother has adequate dietary vitamin B12 throughout pregnancy.

Monsen A-L B, Ueland PM, Vollset E, et al. 2001. Determinants of cobalamin status in newborns. Pediatrics 108:624-630.

Plant-Based Diet Reduces Risk of Heart Disease in Women

Traditionally, studies of diet and disease have looked at single foods or nutrients and asked questions such as, "Will eating more red meat cause heart disease?" or, "Can a diet high in vitamin A reduce the risk of lung cancer?" Perhaps it is more realistic to look at the total diet, since it may be the interaction of foods consumed together that is important in reducing risk of chronic disease. A recent study examined more than 69,000 women's diets and their incidences of heart disease. Two major dietary patterns were identified. One: the prudent pattern featured higher intakes of fruits, vegetables, legumes, whole grains, and fish and poultry. The other pattern, the so-called "Western" pattern, was high in red and processed meat, sweets, desserts, fried foods, and refined grains. The women were studied for 12 years. Women whose diets were high in fruits, vegetables, legumes, whole grains, fish, and poultry were much less likely to develop heart disease than the women who ate a "Western" diet. The authors state, "This study indicates that a diet high in fruits, vegetables, legumes, whole grains, poultry, and fish, and low in red and processed meats and refined grain products may lower risk of coronary heart disease in women." Of course, vegetarians will ask whether a diet high in fruits, vegetables, whole grains, and legumes without meat, fish, or poultry might be more beneficial. Although this study did not examine that question, it did point out a benefit of a diet containing many plant foods.

Fung TT, Willett WC, Stampfer MJ, et al. 2001. Dietary patterns and the risk of coronary heart disease in women. Arch Intern Med 161:1857-2011.

Is There a "Best" Time of Day to Take Calcium Supplements?

Is it better to take a calcium supplement in the morning or the evening? In one large dose or several smaller doses? Researchers from Finland set out to answer these questions. They found that it does not matter whether you take a calcium supplement in the morning or in the evening. A smaller percentage of calcium was absorbed when a large dose was given, compared to when a smaller dose was given several times a day. However, a large dose of calcium decreased blood levels of parathyroid hormone, a hormone that stimulates calcium loss from bone. A decreased level of this hormone could decrease bone breakdown, but could also limit calcium absorption. So, we're still left with the question, is taking one large dose of calcium better or worse than taking several smaller doses of calcium throughout the day?

Karkkainen MUM, Lamberg-Allardt CJE, Ahonen S, et al. 2001. Does it make a difference how and when you take your calcium? The acute effects of calcium on calcium and bone metabolism. Am J Clin Nutr 74:335-342.

No Long-term Effects of Soy Infant Formula Seen

Concerns have been raised about the effects of exposure to soy in infancy and young childhood since soy products contain naturally-occurring estrogens (isoflavones). A recent study examined adults who were fed soy formula as infants; the results may help provide some insights into the safety of soy products for young children. Nearly 250 adults (ages 20-34) who had received soy formula as infants were compared to more than 500 adults who had received formula based on cow's milk. Study subjects were questioned about their heights, weights, ages at puberty, menstrual histories, difficulties with conception, birth defects in their own infants, and hormonal disorders. There was little difference among the groups in most areas. Use of soy formula appeared to have no effect on fertility, miscarriage rate, birth defects in offspring, and maturation. Subjects were estimated to have an average intake of soy isoflavones of 4.2 to 9.4 milligrams per kilogram of body weight daily as infants. (This would be the equivalent of about 1.5 servings of soy for the average two-year-old or four servings of soy for the average four-year-old.) Certainly, there may be differences in the way that infants absorb and metabolize soy isoflavones, as compared to older children and adults. However, the results of this study do suggest that moderate intakes of soy are safe for infants and young children.

Strom BL, Schinnar R, Ziegler EE, et al. 2001. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA 286:807-814.

Kids Eat More When They Eat Out

Americans are eating more meals outside the home than ever before. In 1977-78 we ate about one meal out of six away from home. In 1995, it was more than one meal out of four. Does this have an impact on our nutritional status? You bet! A study of about 800 children and teens found that when meals were eaten at restaurants, children and teens consumed markedly more fat and saturated fat. The caloric content of restaurant meals was 55% higher than that of meals eaten at home. Hmmm . . . we're eating out more and obesity is becoming more and more of a problem. Could there be a connection?

Zoumas-Morse C, Rock CL, Sobo EJ, et al. 2001. Children's patterns of macronutrient intake and associations with restaurant and home eating. J Am Diet Assoc 101:923-925.