Dietary Intake of Breastfeeding Mothers in Developed Countries: A Systematic Review and Results of the MEDIDIET Study

BACKGROUND: Lactation is a demanding period for women, and a good nutrition is crucial for optimal health of mothers and infants. OBJECTIVES: To provide new data and summarize the overall evidence on maternal nutrient intakes during lactation in developed countries, we present a systematic review (SR) of the literature and concurrently original results of the Italian MEDIDIET study. We compared nutrient intakes with dietary reference values (DRVs) proposed by the European Food Safety Authority. METHODS: Studies were identified searching PubMed/Embase databases up to February 2020. Observational studies reporting at least energy and macronutrient intakes of healthy breastfeeding mothers who followed non-restricted and non-specific diets were included. Studies on populations with severe nutritional deficiencies were excluded. The MEDIDIET study enrolled 300 healthy breastfeeding mothers at 6 ± 1 wk postpartum. Usual diet was concomitantly evaluated through a validated and reproducible FFQ. Nutrient intakes were estimated using a food composition database. RESULTS: Twenty-eight articles regarding 32 distinct study populations were included. Maternal nutrient intakes were generally in agreement across studies included in the SR and conforming to DRVs. Within micronutrients, vitamin D intake was below the recommendation. In the MEDIDIET study, mean intakes of energy (1950 ± 445 kcal/d), carbohydrates (270 ± 20.1 g/d), proteins (87.8 ± 20.1 g/d), and fats (65.6 ± 18.9 g/d) were similar to those observed in the SR. Moreover, observed intakes seemed to reflect the typical Mediterranean diet, with low intakes of carbohydrates, SFAs, and PUFAs and high intakes of MUFAs and vitamins. Conversely, protein intake was mainly derived from animal sources. CONCLUSIONS: This SR showed that nutrient intakes of breastfeeding mothers in developed countries are generally in line with DRVs despite different dietary patterns worldwide. Some nutritional deficiencies emerged, highlighting the need for additional nutritional advice. Mothers participating in the MEDIDIET study showed a nutritional profile in agreement with the Mediterranean diet