The Journal of nutrition
-
The Journal of nutrition · Feb 1998
Review Comparative StudyToxicity considerations when revising the Nordic nutrition recommendations.
The Nordic countries have issued common nutrition recommendations since 1980. In connection with the 3rd revision, a joint working group of nutritionists and toxicologists assessed the toxicology of selected trace elements. ⋯ The safety factors between the lowest intakes at which adverse effects had been reported and the suggested upper limits of intake were small. In the toxicological evaluation of upper safe intake levels of essential trace elements, interactions between trace elements as well as long-term exposure to moderately elevated trace element intakes have to be considered.
-
The Journal of nutrition · Feb 1998
ReviewEffects of maternal caloric restriction and exercise during lactation.
In affluent populations, breast-feeding women often wish to return to their prepregnancy weight as soon as possible postpartum and may restrict energy intake or increase exercise to achieve this goal. Gradual weight loss (< or = 2 kg/mo) seems to have no adverse effect on milk volume or composition, provided that the mother is not undernourished and is breast-feeding her infant on demand. Aerobic exercise improves cardiovascular fitness and does not affect milk energy transfer to the infant, but exercise alone is not likely to increase the rate of weight loss unless dietary intake is controlled. ⋯ Exercise enhances maintenance of lean body mass and is therefore a recommended component of any weight loss program. Maternal plasma prolactin concentration generally increases under conditions of negative energy balance, which may serve to protect lactation. Further research is required on the longer-term effect of energy restriction and on the effects of energy balance in lactating women with low fat reserves.