1. Clin Chem Lab Med. 2009;47(2):120-7. Related Articles, Links
Vitamin D: current status and perspectives
Cavalier E, Delanaye P, Chapelle JP, Souberbielle JC
Department of Clinical Chemistry, University Hospital of Liege, University of Liege, Belgium. Etienne.firstname.lastname@example.org
The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25-OH vitamin D into its most active metabolite, 1,25-(OH)(2) vitamin D, has led to a very promising future for this "old" molecule. Indeed, observational studies, and more and more interventional studies, are raising the importance of a significant vitamin D supplementation for not-only skeletal benefits. Among them, 25-OH vitamin D has been found to play an important role in prevention of cancers, auto-immune diseases, cardiovascular diseases, diabetes, and infections. Vitamin D deficiency, defined as serum 25-OH vitamin D levels <30 ng/mL, is very common in our population. The cost/benefit ratio and some recently published studies are clearly now in favor of a controlled and efficient vitamin D supplementation in these patients presenting a 25-OH vitamin D level <30 ng/mL. More attention should also be focused on pregnant and lactating women, as well as children and adolescents.
2. Int J Circumpolar Health. 2008 Sep;67(4):349-62. Related Articles, Links
Dietary assessment of Indigenous Canadian Arctic women with a focus on pregnancy and lactation
Berti PR, Soueida R, Kuhnlein HV
HealthBridge, Ottawa, Ontario, Canada. email@example.com
OBJECTIVES: To assess the diet of Indigenous women, including pregnant and lactating women, in the Canadian Arctic in terms of dietary adequacy, and to assess the contribution of traditional food to the diet. STUDY DESIGN: Population-based cross-sectional design, using 24-hour dietary recalls. METHODS; Twenty-four hour quantitative dietary recalls were collected in 47 communities in 5 surveys between 1987 and 1999, including non-pregnant and non-lactating women (n = 1300), pregnant women (n = 74) and lactating women (n = 117). Unique methods of assessment were undertaken using Software for Intake Distribution Assessment (SIDE) partitioned intra- and interindividual variance that allowed the estimation of the distribution of usual daily nutrient intakes for comparison to North American dietary reference intakes. RESULTS: Contributions of traditional Arctic food to energy intakes varied and the prevalence of inadequacies were generally high for magnesium, vitamin A, folate, vitamin C and vitamin E. Supplement use was infrequent. Many women met their needs for iron, and some exceeded the recommended upper limit for iron with food alone. Average intakes of manganese and vitamin D met recommended levels, but calcium did not. CONCLUSIONS: These results are the only data to date reporting an assessment of the dietary intakes of pregnant and lactating Canadian Arctic Indigenous women. Special attention is required for inadequacies of magnesium, zinc, calcium, folate, and vitamins E, A and C; and for use of supplements during pregnancy. Most pregnant and lactating women met iron needs without supplements.
3. Eur J Clin Nutr. 2006 Oct;60(10):1214-21. Epub 2006 May 24. Related Articles, Links
Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women
Møller UK, Ramlau-Hansen CH, Rejnmark L, Heickendorff L, Henriksen TB, Mosekilde L
Department of Endocrinology and Metabolism C, Aarhus University Hospital, Aarhus, Denmark. Kristine.firstname.lastname@example.org
OBJECTIVE: To examine vitamin D status and parathyroid function in normal Danish women postpartum. DESIGN: Three cross-sectional measures during follow-up of 89 women postpartum. SUBJECTS AND INTERVENTION: We assessed vitamin D status by measuring plasma 25-hydroxyvitamin D (P-25OHD) and the degree of secondary hyperparathyroidism by measuring plasma parathyroid hormone (P-PTH) in 89 Caucasian women at three consecutive visits: (mean (range)) 23 (10-37) days (spring), 117 (95-140) days (late summer) and 274 (254-323) days (winter) postpartum. RESULTS: P-25OHD showed seasonal variations with higher values in late summer than in the other periods (P < 0.001). At the first visit, 65% received vitamin D supplements. At the following visits, almost 50% were supplemented. Vitamin D insufficiency (P-25OHD < 50 nmol/l) occurred more often during winter (28%) than in spring (14%) (Fisher's exact test, P = 0.02) or late summer (7%) (P = 0.0001). Irrespective of season, vitamin D insufficiency occurred most frequent in women who did not take vitamin D supplements (Fisher's exact test, P < 0.02). Frank vitamin D deficiency (P-25OHD < 25 nmol/l) was observed during winter in 6%. At all three periods, P-25OHD correlated inversely with P-PTH indicating secondary hyperparathyroidism at deficient vitamin D status. During spring, late summer and winter three, one and four females, respectively, had elevated plasma PTH. CONCLUSION: Vitamin D insufficiency with secondary hyperparathyroidism is a frequent finding in healthy Danish women postpartum and especially during winter. Vitamin D supplements reduced the risk of vitamin D insufficiency, especially during winter. Our results support the importance of increased alertness regarding information of pregnant and lactating women about vitamin D supplements. Furthermore, it has to be studied whether the present recommendations of an intake of 5-10 microg vitamin D/day are sufficient, especially during winter months.
4. Am J Clin Nutr. 2004 May;79(5):717-26. Related Articles, Links
Assessment of dietary vitamin D requirements during pregnancy and lactation
Hollis BW, Wagner CL
Division of Neonatology, Department of Pediatrics, Medical University of South Carolina, 114 Doughty Street, PO Box 205770, Charleston, SC 29403, USA. email@example.com
Concerns about vitamin D have resurfaced in medical and scientific literature because the prevalence of vitamin D deficiency in the United States, particularly among darkly pigmented persons, has increased. The primary goals of this review were to discuss past and current literature and to reassess the dietary reference intake for vitamin D in adults, with particular focus on women during pregnancy and lactation. The appropriate dose of vitamin D during pregnancy and lactation is unknown, although it appears to be greater than the current dietary reference intake of 200-400 IU/d (5-10 microg/d). Doses of < or =10 000 IU vitamin D/d (250 microg/d) for up to 5 mo do not elevate circulating 25-hydroxyvitamin D to concentrations > 90 ng/mL, whereas doses < 1000 IU/d appear, in many cases, to be inadequate for maintaining normal circulating 25-hydroxyvitamin D concentrations of between 15 and 80 ng/mL. Vitamin D plays no etiologic role in cardiac valvular disease, such as that observed in Williams syndrome, and, as such, animal models involving vitamin D intoxication that show an effect on cardiac disease are flawed and offer no insight into normal human physiology. Higher doses of vitamin D are necessary for a large segment of Americans to achieve concentrations equivalent to those in persons who live and work in sun-rich environments. Further studies are necessary to determine optimal vitamin D intakes for pregnant and lactating women as a function of latitude and race.
5. J Nutr. 2003 May;133(5 Suppl 2):1693S-1699S. Related Articles, Links
Micronutrients and the bone mineral content of the mother, fetus and newborn
MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, UK, CB1 9NL. firstname.lastname@example.org
The fluxes of the primary bone-forming minerals, calcium, phosphorus, magnesium and zinc, across the placenta and through breast milk place considerable demands on maternal mineral economy. Increases in food consumption, elevated gastrointestinal absorption, decreased mineral excretion and mobilization of tissue stores are several possible biological strategies for meeting these extra mineral requirements. This paper presents a review of the evidence on the extent to which these strategies apply in the human situation, the mechanisms by which they occur, the limitations imposed by maternal diet and vitamin D status and the possible consequences for the growth of the infant and bone health of the mother. On the strength of current evidence it appears that pregnancy and lactation are associated with physiological adaptive changes in mineral metabolism that are independent of maternal mineral supply within the range of normal dietary intakes. These processes provide the minerals necessary for fetal growth and breast milk production without requiring an increase in maternal dietary intake or compromising maternal bone health in the long term. This may not apply to pregnant women whose mineral intakes or sunlight exposure are marginal. As a vehicle for promoting optimal growth and bone mineral content of infants, supplementation of lactating women with minerals or vitamin D is unlikely to prove effective. The situation in pregnancy is less certain. Until more studies have been conducted, a precautionary case can be made for targeted supplementation of pregnant women who have very low intakes of calcium or who are at risk of vitamin D deficiency.
6. Nutrition. 1995 Sep-Oct;11(5):409-17. Related Articles, Links
Optimal calcium intake. Sponsored by National Institutes of Health Continuing Medical Education
[No authors listed]
The National Institutes of Health Consensus Development Conference on Optimal Calcium Intake brought together experts from many different fields including osteoporosis and bone and dental health, nursing, dietetics, epidemiology, endocrinology, gastroenterology, nephrology, rheumatology, oncology, hypertension, nutrition and public education, and biostatistics, as well as the public, to address the following questions: 1) What is the optimal amount of calcium intake? 2) What are the important cofactors for achieving optimal calcium intake? 3) What are the risks associated with increased levels of calcium intake? 4) What are the best ways to attain optimal calcium intake? 5) What public health strategies are available and needed to implement optimal calcium intake recommendations? and 6) What are the recommendations for future research on calcium intake? The consensus panel concluded that: A large percentage of Americans fail to meet currently recommended guidelines for optimal calcium intake. On the basis of the most current information available, optimal calcium intake is estimated to be 400 mg/day (birth-6 months) to 600 mg/day (6-12 months) in infants; 800 mg/day in young children (1-5 years) and 800-1,200 mg/day for older children (6-10 years); 1,200-1,500 mg/day for adolescents and young adults (11-24 years); 1,000 mg/day for women between 25 and 50 years; 1,200-1,500 mg/day for pregnant or lactating women; and 1,000 mg/day for postmenopausal women on estrogen replacement therapy and 1,500 mg/day for postmenopausal women not on estrogen therapy. Recommended daily intake for men is 1,000 mg/day (25-65 years). For all women and men over 65, daily intake is recommended to be 1,500 mg/day, although further research is needed for this age group. These guidelines are based on calcium from the diet plus any calcium taken in supplemental form. Adequate vitamin D is essential for optimal calcium absorption. Dietary constituents, hormones, drugs, age, and genetic factors influence the amount of calcium required for optimal skeletal health. Calcium intake, up to a total intake of 2,000 mg/day, appears to be safe in most individuals. The preferred source of calcium is through calcium-rich foods such as dairy products. Calcium-fortified foods and calcium supplements are other means by which optimal calcium intake can be reached in those who cannot meet this need by ingesting conventional foods. A unified public health strategy is needed to ensure optimal calcium intake in the American population.
7. Am J Clin Nutr. 1994 Feb;59(2 Suppl):484S-490S; discussion 490S-491S. Related Articles, Links
Do North American women need supplemental vitamin D during pregnancy or lactation?
Department of Pediatrics, University of Cincinnati Medical Center, OH 45267-0541.
Studies in European and other countries have shown that vitamin D deficiency during pregnancy may adversely affect fetal growth, bone ossification, tooth enamel formation, and neonatal calcium homeostasis. Whether effects of vitamin D deficiency on pregnant or lactating mothers differ from effects observed in nonpregnant or nonlactating women is not clear. Poor maternal vitamin D status during lactation results in low breast-milk vitamin D. However, human milk usually contains small vitamin D amounts and, under normal circumstances, the sunshine exposure of human-milk--fed infants is the major factor affecting their vitamin D status. Mothers at risk of vitamin D deficiency are those who avoid dairy products, which are routinely vitamin D fortified, and live in more northern latitudes. Dark-skinned women also are theoretically at risk of vitamin D deficiency. Sunshine exposure is a major vitamin D source, and given adequate exposure, supplemental vitamin D is not necessary. However, defining adequate sunshine exposure is difficult.
8. Postgrad Med. 1987 Jan;81(1):301-5, 308. Related Articles, Links
Key issues in nutrition. From conception through infancy
Fahey PJ, Boltri JM, Monk JS
Pregnant and lactating women and infants are at nutritional risk because of their special needs; both require adequate dietary nutrition and, often, dietary supplementation. For example, the mother's increased requirements for iron, calcium, folic acid, and vitamin D usually must be met with increased milk intake and multivitamin-with-mineral supplements. Since the pregnant and the lactating woman can pass both nutrients and nonnutrients to the child, she should be advised on a well-balanced, high-quality diet that is free of drugs or other additives that may be harmful. Although either breastfeeding or the use of formula may fulfill energy and protein needs, the infant may require supplemental vitamins K and C, fluoride, and iron.
9. Br J Nutr. 1986 Jul;56(1):59-72. Related Articles, Links
The nutrient intakes of pregnant and lactating mothers of good socio-economic status in Cambridge, UK: some implications for recommended daily allowances of minor nutrients
Black AE, Wiles SJ, Paul AA
MRC Dunn Nutrition Unit, Cambridge.
1. Forty-two mothers from social classes I, II and III non-manual and twenty-one from social classes III manual M), IV and V were studied longitudinally. The mean daily nutrient intakes in months 4-9 of pregnancy, months 2-4 of lactation and 3 and 6 months post-lactation are presented and are compared with the UK and the US recommended daily allowances (RDA). 2. The quality of the diets (nutrients per 4184 kJ (1000 kcal] was found to be better than that of other adult female populations studied in the UK, except for a group of dietitians. 3. The mean daily intakes of nutrients for which there are UK RDA were almost all greater than 100% of the RDA. The exceptions were iron, which in the manual group (social classes IIIM, IV and V) was 85% of the RDA in pregnancy and 75% post-lactation, and vitamin D. 4. Among the nutrients for which there are US, but not UK RDA, only phosphorus and vitamin B12 intakes were greater than 100% of the RDA in both groups at all stages of the study. Intakes of other nutrients were below the RDA: pantothenate 70-91, vitamin B6, zinc, vitamin E and copper 40-72, folate 21-44, and biotin less than 20% of the RDA. 5. The bases of the RDA for adult women were examined; for most nutrients the information is limited. It was concluded that the RDA for magnesium, vitamin E and pantothenate are probably higher than necessary and that deficiency is unlikely; that zinc, copper, vitamin B6 and folate are probably 'marginal' nutrients for 'at risk' groups; and that information on biotin is insufficient even roughly to assess the dietary requirement.
10. Am J Physiol. 1985 Feb;248(2 Pt 1):E182-7. Related Articles, Links
Regulation of bone mineral loss during lactation
Brommage R, DeLuca HF
The effects of varying dietary calcium and phosphorus content, vitamin D deficiency, oophorectomy, adrenalectomy, and simultaneous pregnancy on bone mineral loss during lactation were examined in rats. Unless otherwise stated, the diet contained 0.47% calcium and 0.3% phosphorus and the rats were given 26 nmol of vitamin D3. Femur ash weights were determined after 21 days of lactation and on age-matched nonlactating rats. Decreasing dietary calcium to 0.02% caused an increased loss of bone mineral, whereas increasing dietary calcium to 1.4% increased plasma calcium levels to 12 mg/100 ml but did not diminish the bone mineral loss observed during lactation. Varying dietary phosphorus did not have a major effect on bone mineral loss during lactation. In vitamin D-deficient rats, bone mineral loss during lactation was independent of dietary calcium levels and slightly greater than the loss observed in vitamin D-replete rats fed the normal calcium diet. Oophorectomy and adrenalectomy did not produce changes in femur ash weights of nonlactating rats or reduce bone mineral loss during lactation. Rats mated during their postpartum estrus and thus simultaneously pregnant and lactating, lost the same amount of bone mineral as caused by lactation alone.
11. Br J Obstet Gynaecol. 1983 Oct;90(10):971-6. Related Articles, Links
Vitamin D metabolism in normal and hypoparathyroid pregnancy and lactation. Case report
Markestad T, Ulstein M, Bassoe HH, Aksnes L, Aarskog D
Plasma concentrations of vitamin D metabolites in 17 non-pregnant women, 22 pregnant women at delivery, and in eight lactating women 3 and 16 days after delivery, were compared with those in a postpartum hypoparathyroid patient treated with 1 alpha-hydroxyvitamin D (1 alpha-OHD). The mean concentration of 1,25-dihydroxyvitamin D [1,25-(OH)2 D] was 203 (SD 61) pmol/l in the pregnant, and 86 (SD 27) pmol/l in the non-pregnant women (P less than 0.0005). The levels 3 and 16 days after delivery were similar [57 (11) compared with 62 (19) pmol/l], and lower than the non-pregnant value (P less than 0.01). The 25-hydroxyvitamin D (25-OHD) concentration remained unchanged between the 3rd and 16th days after delivery, whereas the 24,25-dihydroxyvitamin D [24,25-(OH)2D] level increased from 2.7 (SD 1.8) to 3.7 (SD 2.3) nmol/l (P less than 0.025). The patient temporarily required an increased supplement of l alpha-OHD during pregnancy, but a dose which was appropriate before pregnancy resulted in marked hypercalcaemia and a rise of 1,25-(OH)2D concentration within 16 days of delivery despite lactation. The results suggest that the metabolic need for the active vitamin D metabolite 1,25-(OH)2D is increased during pregnancy and rapidly reduced during early lactation in healthy and hypoparathyroid women.
12. J Steroid Biochem. 1983 Jul;19(1B):505-10. Related Articles, Links
Circulating levels and function of 1,25-(OH)2D3 in lactation
Toverud SU, Boass A, Haussler MR, Pike JW
During lactation in the rat, vitamin D is required for maintenance of a normal serum calcium level and maximal enhancement of active calcium transport in the duodenum. Vitamin D does not appear to be required for part of the adaptive increase in intestinal calcium transport or for calcium transport into the milk. The functions of vitamin D appear to be mediated by 1,25-(OH)2D3, the circulating level of which increases during lactation. Two days after sudden weaning, the serum level of 1,25-(OH)2D3 falls to levels below the pre-pregnant control level in parallel with a sharp increase in serum calcium; normal levels of calcium and 1,25-(OH)2D3 are observed one week after weaning. The initial stimulus for the increase in circulating 1,25-(OH)2D3 during lactation appears to be a small decrease in serum calcium which stimulates parathyroid hormone secretion, which in turn enhances synthesis of 1,25-(OH)2D3. Vitamin D is also required by the lactating rat to insure normal development of the suckling pup, since vitamin D deprivation during pregnancy and lactation causes significant decreases in body weight gain, in serum levels of 25-OHD3, calcium and phosphorus, in bone ash content and clear evidence of histological rickets by 20 days of age.
（摘自Vitamin D Today）