RESUMO
BACKGROUND: Maternal supplementation with vitamin A is one of the strategies for controlling its deficiency in the mother-child dyad, although studies with animals showed that supplementation with high doses of vitamin A reduces the levels of α-tocopherol (vitamin E) in the mother's serum and milk. The objective of the present study was to assess the influence of maternal supplementation with vitamin A on the concentration of retinol and α-tocopherol in human milk. METHODS: Healthy puerperal women were randomly distributed into a control group (n = 44) and a supplemented group (n = 44). Blood and colostrum samples were collected after delivery, and mature milk samples were collected 30 days later. The supplemented group received 200 000 IU of retinyl palmitate after the first colostrum collection. The retinol and α-tocopherol levels in the samples were determined by high-performance liquid chromatography. RESULTS: The mean (SD) retinol and α-tocopherol levels in the maternal serum were considered adequate at 46.4 (15.9) and 1023.6 (380.4) µg dL(-1) , respectively. The colostrum retinol levels of the supplemented group increased significantly 24 h after the intervention (P < 0.001). However, the retinol levels in the mature milk of both groups did not differ (P > 0.05). Moreover, after maternal supplementation with vitamin A, the colostrum α-tocopherol level decreased by 16.4%, which is a significant reduction (P < 0.05). However, vitamin A supplementation did not affect the α-tocopherol level of mature milk (P > 0.05). CONCLUSIONS: Maternal supplementation with high doses of vitamin A increased the colostrum level of this nutrient but reduced the bioavailability of α-tocopherol, which may harm the newborn's health because newborns have limited vitamin E reserves.
Assuntos
Colostro/metabolismo , Suplementos Nutricionais/efeitos adversos , Lactação/metabolismo , Fenômenos Fisiológicos da Nutrição Materna , Estado Nutricional , Vitamina A/análogos & derivados , alfa-Tocoferol/antagonistas & inibidores , Brasil/epidemiologia , Países em Desenvolvimento , Diterpenos , Feminino , Maternidades , Humanos , Recém-Nascido , Lactação/sangue , Perda de Seguimento , Masculino , Leite Humano/metabolismo , Período Pós-Parto , Ésteres de Retinil , Risco , Vitamina A/administração & dosagem , Vitamina A/efeitos adversos , Vitamina A/sangue , Vitamina A/metabolismo , Vitamina A/toxicidade , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/epidemiologia , Deficiência de Vitamina A/metabolismo , Deficiência de Vitamina A/prevenção & controle , Deficiência de Vitamina E/sangue , Deficiência de Vitamina E/epidemiologia , Deficiência de Vitamina E/etiologia , Deficiência de Vitamina E/metabolismo , alfa-Tocoferol/sangue , alfa-Tocoferol/metabolismoRESUMO
In Portugal, commercial milk is obtained almost entirely from cows of the Holstein breed. However, other breeds may also show dairy aptitude, and produce milk of good quality. The aim of this study was to investigate the effect of the breed factor in the vitamin contents of milks from Holstein and the autochthonous Portuguese breed Minhota, as well as possible variations due to season. Milk samples were collected from 15 cows of each breed. Milk from Minhota cows showed higher contents of retinol, retinyl palmitate, α-tocopherol, and ß-carotene. No differences were verified between breeds regarding vitamin D(3) content, but Holstein cows presented higher amounts of provitamin D(3). Seasonal variations were not observed for milk samples from Holsteins, and only a very small variation was observed for milk samples from Minhota cows, mainly in retinol, α-tocopherol, and provitamin D(3) levels. This study revealed that breed has a pronounced effect on milk fat-soluble vitamins, which is an important observation regarding future genetic selection plans. Also, the increased vitamin amounts found in milk from Minhota cows can be regarded as an important nutritional parameter that can potentiate the economical value of this breed.
Assuntos
Leite/química , Vitamina A/análise , Vitamina D/análise , Vitamina E/análise , beta Caroteno/análise , Animais , Cruzamento , Bovinos , Cromatografia Líquida de Alta Pressão/veterinária , Diterpenos , Feminino , Portugal , Ésteres de Retinil , Estações do Ano , Especificidade da Espécie , Vitamina A/análogos & derivados , alfa-Tocoferol/análiseRESUMO
1. The purpose of this study was to assess the incorporation of retinol into quail egg yolk and cholesterol concentration in response to supplementation with different quantities of retinyl palmitate (600, 1200, 2400 and 4800 microg). 2. Supplementations were performed weekly for 4 weeks and the yolk retinol was measured using high performance liquid chromatography. 3. The results showed a progressive increase in the incorporation of retinol into the egg yolk in response to supplementation, reaching values 384% higher than control values. 4. At the end of supplementation we observed a significant decrease in egg yolk retinol concentrations with supplementations of 2400 and 4800 microg, the most enduring showing high retinol contents even after 3 weeks. 5. Supplementation increased egg weight but neither egg production nor cholesterol levels were significantly altered.