Frequently Asked Questions About
Vitamin D, Sunlight, and Breastfeeding 

by Cynthia Good Mojab, MS, IBCLC, RLC

© Cynthia Good Mojab 2003. All rights reserved. This article may be printed once for personal use. Any other form of transmission, duplication, or translation is prohibited without permission from the author.
 

1. Is human milk "deficient" in vitamin D?

No. This point of view is a cultural artifact. Just the phrase "vitamin D deficiency" illustrates how much we have missed the point, as "vitamin D" was misclassified as a vitamin and subsequently found to be a hormone produced via exposure of the skin to sunlight and not contained in most foods. What we are really talking about is sunlight deficiency.

"Vitamin D is actually not a vitamin at all, but a steroid hormone produced in the body after direct exposure of the skin to ultraviolet B (UVB) radiation in sunlight." (Good Mojab 2003)

"The direct, casual exposure of skin to sunlight is the most common and the biologically normal way that human beings attain sufficient levels of vitamin D. ... Because only a few foods naturally contain significant levels of vitamin D (e.g., the oils and livers of some fatty fish), it would be unusual for people to obtain adequate vitamin D from their diet alone without supplementation or enrichment.⁷" (Good Mojab 2003)

"The natural sources of vitamin D for nurslings are primarily the stores they developed prenatally (for newborns) and the vitamin D they produce with exposure of their skin to sunlight; a smaller additional contribution is from human milk.^{15, 16} The concentration of fat-soluble vitamin D in human milk varies from 5 to 136 IU/L, depending on how its activity is measured and on maternal vitamin D status during lactation.^17-19This concentration provides less than the 200 to 400 IU/day commonly recommended for infants under one year of age.²⁰ However, human milk should not be considered "deficient" in vitamin D, because the biologically normal means of obtaining sufficient vitamin D in humans is via sunlight exposure, not diet.^21-23" (Good Mojab 2003)

2. Are the statements "Exclusively breastfed infants are at increased risk of vitamin D deficiency and rickets. This is because human milk contains only small amounts of vitamin D, insufficient to prevent rickets."* accurate?

*Statements contained in: AAP Report: Infants Need Vitamin D Supplementation, the AAP's April 7, 2003 news release on its clinical report: American Academy of Pediatrics. Prevention of Rickets and Vitamin D Deficiency: New Guidelines for Vitamin D Intake. Pediatrics  2003; 111(4): 908-910.
 

No. They are as inaccurate as saying something like: "breathing increases the risk of lung cancer." While statistically true (people who don't breathe are not going to die of lung cancer), it fails to acknowledge that certain things are happening while breathing that increase the incidence of lung cancer: the inhalation of cigarette smoke to be specific. Breathing is biologically normal. Intentionally and repeatedly breathing cigarette smoke is not. Breastfeeding is biologically normal. Inadequate sun exposure is not. Exclusively breastfed infants who are inadequately exposed to sunlight are at increased risk of vitamin D deficiency and rickets. Exclusively breastfed infants who are adequately exposed to sunlight are not at increased risk of vitamin D deficiency and rickets. Sunlight deficiency, a biologically abnormal situation, is the problem.

"Anyone with inadequate exposure to UVB radiation in sunlight is at risk for vitamin D deficiency. Risk factors for nurslings and their mothers overlap and interact, and include indoor confinement during the day (e.g., due to exclusively indoor daycare, unsafe neighborhoods, custom),³⁹ living at higher latitudes (e.g., essentially no vitamin D is produced with sun exposure from November to February in Boston [42° N] and from mid-October to mid-April in Edmonton, Canada [52º N]),^{40, 41} darker skin pigmentation,^42-45 living in urban areas with pollution and/or buildings that block sunlight,^46-48 sunscreen use,^49-51 seasonal variations resulting in less ultraviolet radiation (e.g., late winter and early spring in the northern hemisphere),^{52, 53} covering much or all of the body when outside (e.g., due to custom, fear of skin cancer, cold climate),^54-57 increased birth order (e.g., a mother's sixth child has a higher risk of vitamin D deficiency than does her first child),^{58, 59} the replacement of human milk with foods low in calcium,^60-64 the replacement of human milk with foods that reduce calcium absorption (e.g., grains and some green leaves containing phylates, oxalates, tannates, and phosphates; cereals grown in soil high in strontium),^65-67 and exposure to lead (due to lead's inhibition of vitamin D synthesis).^{68, 69}" (Good Mojab 2003)

"...sunlight exposure for many people around the world has been reduced by industrialization, urbanization, migration, concern about skin cancer, and social inequities." (Good Mojab 2003)
 

3. How much sunlight exposure is needed to prevent vitamin D deficiency in breastfed infants?

The amount of sunlight exposure needed to prevent vitamin D deficiency depends on such factors as skin pigmentation, latitude, degree of skin exposure, season, time of day, amount of pollution, degree of use of sunscreen, altitude, weather, the vitamin D status of the lactating mother, and the current status of vitamin D stores in the infant's body. Recommendations do and should, therefore, vary around the world, taking into account local conditions and practices.

"The skin has a large capacity to produce vitamin D. Exposure of the entire adult body to the smallest amount of UVB radiation that produces transient, just perceptible skin reddening is comparable to taking an oral dose of 10,000 to 25,000 IU of vitamin D.^{8, 9} Therefore, sufficient levels of vitamin D can be developed from partial exposure of the body to sunlight well before sunburn occurs." (Good Mojab 2003)

"Exclusively breastfed Caucasian infants under six months of age (39° N; Cincinnati, Ohio, US) are expected to achieve adequate vitamin D status when exposed to sunlight for 30 minutes per week (diaper only) or two hours per week (fully clothed without a hat).³⁴ The sunlight exposure needed by darkly pigmented infants is poorly understood.³⁵ Studies of the influence of skin pigmentation on the cutaneous production of vitamin D in adults have shown conflicting results.^{36, 37} However, a study by Brazerol and colleagues showed that darkly and lightly pigmented adults were equally capable of producing vitamin D when episodes of UVB exposure occurred periodically over time (i.e., biweekly for six weeks in their study).³⁸" (Good Mojab 2003)

"There is no global consensus on whether or how to screen infants, children, or pregnant women for vitamin D deficiency or on how to best prevent vitamin D deficiency in breastfed infants and children. Recommendations for preventing vitamin D deficiency in breastfed infants include universal supplementation, supplementation of at-risk breastfed infants, and habitual small doses of sunshine; some regions with plentiful sunshine have not yet developed recommendations.^{28, 29, 30, 31,32} ... The determination of the exact amount of regular, brief, and nonerythemal sunlight exposure needed just to produce sufficient vitamin D in specific infants and children depends on many factors." (Good Mojab 2002)
 

4. What is the prevalence of rickets among breastfed infants?

"There are currently no national data on the prevalence of rickets in the US,⁷⁷ though case reports and descriptive studies clearly indicate that rickets is not a disease of the past. ... Rickets in breastfed infants has been documented among at-risk populations in northern Europe, North America, and former Soviet countries since the 1970s.⁷⁸ In some developing countries it remains a serious health problem.^79-82 Overt rickets is more common in children 6 to 36 months of age than in infants under 6 months of age.^83-86 Findings of bone deformities suggestive of rickets are very rare in full-term or premature neonates.⁸⁷" (Good Mojab 2003)

5. Does the water soluble form of vitamin D prevent rickets? 

No, the water soluble form of vitamin D has not been shown to have antirachitic activity. It certainly has some other biochemical role, but it does not prevent vitamin D deficiency or rickets.
 

6. How long do a newborn's prenatal stores of vitamin D last without exposure to sunlight?

"The neonate's stores of vitamin D depend on maternal vitamin D status during pregnancy.^{24, 25} A study of exclusively breastfed infants in Tampere, Finland (61° N) in winter showed that, without UVB exposure or vitamin D supplementation, vitamin D stores of fetal origin were depleted by eight weeks of age.²⁶ Although these vitamin D-depleted infants had serum levels of vitamin D at which rickets can occur, none had active or biochemical rickets." (Good Mojab 2003)

Adequate exposure to sunlight after birth, however, prevents depletion of vitamin D stores of fetal origin, making them available for use past eight weeks of age. Depending on the degree of sunlight exposure, an infant's stores of vitamin D can also be increased, making them available for use during periods of inadequate sunlight exposure.
 

7. Can vitamin D be made with exposure of the skin to sunlight from a window?

The answer is that it depends on whether the glass of the window is open or closed. Exposure of the skin to sunlight that has passed through plexiglas (Dupont Chemical Company, Memphis, TN, USA), most other plastics, or window pane glass (e.g., in buildings, motorized vehicles, covered strollers or prams, etc.) does not allow the endogenous production of vitamin D because these materials efficiently absorb ultraviolet B radiation (Holick 1994). Without UVB radiation, the skin cannot initiate the body's process of making vitamin D.

Holick, M. F. McCollum Award Lecture: Vitamin D: New horizons for the 21st century. Am J Clin Nutr 60: 619-30, 1994.
 

8. Are there any risks of vitamin D supplementation?

Let me be clear that 1) prophylactic vitamin D supplementation is demonstrably useful for infants who are at risk of vitamin D deficiency and 2) no known risks of supplementation exist with 200 to 400 IU per day. Still, I believe that there is a great potential for harm from a recommendation that all US breastfed infants be supplemented with vitamin D when only some are at risk, not the least of which is via the marketing of vitamin supplements produced by formula companies who violate the WHO/UNICEF International Code of Marketing of Breast-milk Substitutes. In addition…

"Many potential risks of vitamin D supplementation, however, have not been investigated. No one knows whether vitamin D supplementation has any deleterious physiological effects on the infant, such as aspiration when supplementation is not tolerated, harmful alterations of the infant gut, or increased rates of infection.⁹⁹ ... In addition, the effects of universal recommendation of vitamin D supplementation on breastfeeding beliefs and behaviors (e.g., use of other supplements, premature introduction of other foods, weaning) have not been studied. ... If mothers--or other caregivers--see no difference between vitamin drops and other supplementation or believe that human milk is inadequate because supplements are recommended for all breastfed infants, then recommendations of universal vitamin D supplementation could indirectly serve to increase the risk of illness and disease for many infants, including those not at risk for vitamin D deficiency." (Good Mojab 2003)

"When rickets occurs in breastfed infants, it indicates that something is very wrong with the context in which breastfeeding is happening, not with breastfeeding itself. Social and environmental problems in that context warrant assessment, further research, and amelioration. Breastfeeding is the foundation of normal health and development, the original paradigm for nourishing and nurturing young human beings. Health policies and healthcare systems must first and foremost protect breastfeeding. Otherwise, they will ultimately serve to undermine the health they seek to enhance." (Good Mojab 2003)
 

References

Good Mojab, C. Sunlight deficiency and breastfeeding. Breastfeeding Abstracts. 2002; 22(1):3-4. url: http://www.lalecheleague.org/ba/Nov02.html

References cited in the excepts above that come from this reference:

28. American Academy of Pediatrics Committee on Nutrition. Pediatric Nutrition Handbook. 4th ed. Elk Grove Village, IL: American Academy of Pediatrics, 1998, 275-76.
29. American Academy of Pediatrics. Breastfeeding and the use of human milk. Pediatrics 1997; 100(6):1035-39.
30. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride. Washington, DC: National academy Press, 1997, 264-66.
31. Vitamin D Expert Panel Meeting. October 11-12, 2001. Atlanta, Georgia. Final Report. url: http://www.cdc.gov/nccdphp/dnpa/nutrition/pdf/Vitamin_D_Expert_Panel_Meeting.pdf
32. UNICEF. Vitamin D: Rickets in children and osteomalacia in pregnant women. The Prescriber: Guidelines on the Rational Use of Drugs in Basic Health Services. December 1993; 8:11.
 

Good Mojab, C. Sunlight deficiency: A review of the literature. Mothering. March-April 2003; 117:52-55; 57-63. url: http://www.mothering.com/articles/new_baby/breastfeeding/sunlight-deficiency.html

Notes cited in the excerpts above that come from this reference:

7. M. Holick, “Evolution, Biological Functions, and Recommended Dietary Allowance for Vitamin D,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 1–16.
8. M. Holick, “Environmental Factors that Influence the Cutaneous Production of Vitamin D,” Am J Clin Nutr 61 (suppl.) (1995): 638S–645S.
9. W. Brazerol et al., "Serial Ultraviolet B Exposure and Serum 25 Hydroxyvitamin D Response in Young Adult American Blacks and Whites: No Racial Difference," J Am Coll Nutr 7, no. 2 (1988): 111–118.
15. H. Makin et al., “Vitamin D and Its Metabolites in Human Breast Milk,” Arch Dis Child 58 (1983): 750–753.
16. M. Ala-Houhala, “25-Hydroxyvitain D Levels during Breast-Feeding with or without Maternal or Infantile Supplementation of Vitamin D,” J Pediatr Gastroent Nutr 4, no. 2 (1985): 220–226.
17. B. Specker et al., “Effect of Race and Normal Maternal Diet on Breast Milk Vitamin D Concentrations,” Pediatr Res 18 (1984): 213A.
18. B. Hollis et al., “Vitamin D and Its Metabolites in Human and Bovine Milk,” J Nutr 111, no. 7 (1981): 1240–1248.
19. N. Butte et al., Nutrient Adequacy of Exclusive Breastfeeding for the Term Infant during the First Six Months of Life (Geneva: World Health Organization, 2002), 27.
20. M. Holick, “Evolution, Biological Functions, and Recommended Dietary Allowance for Vitamin D,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 1–16.
21. M. Holick, “Evolution, Biological Functions, and Recommended Dietary Allowance for Vitamin D,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 1–16.
22. H. Makin et al., “Vitamin D and Its Metabolites in Human Breast Milk,” Arch Dis Child 58 (1983): 750–753.
23. M. Ala-Houhala, “25-Hydroxyvitain D Levels during Breast-Feeding with or without Maternal or Infantile Supplementation of Vitamin D,” J Pediatr Gastroent Nutr 4, no. 2 (1985): 220–226.
24. B. Pal and N. Shaw, “Rickets Resurgence in the United Kingdom: Improving Antenatal Management in Asians,” J Pediatr 139, no. 2 (2001): 337–338.
25. J. Daaboul et al., “Vitamin D Deficiency in Pregnant and Breast-Feeding Women and Their Infants,” J Perinatol 1997; 17: 10–14.
26. M. Ala-Houhala, “25-Hydroxyvitain D Levels during Breast-Feeding with or without Maternal or Infantile Supplementation of Vitamin D,” J Pediatr Gastroent Nutr 4, no. 2 (1985): 220–226.
33. B. Specker et al., “Sunshine Exposure and Serum 25-Hydroxyvitamin D Concentrations in Exclusively Breastfed Infants,” J Pediatr 107 (1985): 372–376.
34. B. Specker et al., “Sunshine Exposure and Serum 25-Hydroxyvitamin D Concentrations in Exclusively Breastfed Infants,” J Pediatr 107 (1985): 372–376.
35. B. Specker et al., “Sunshine Exposure and Serum 25-Hydroxyvitamin D Concentrations in Exclusively Breastfed Infants,” J Pediatr 107 (1985): 372–376.
36. C. Lo et al., "Indian and Pakistani Immigrants Have the Same Capacity as Caucasians to Produce Vitamin D in Response to Ultraviolet Radiation," Am J Clin Nutr 44 (1986): 683–685.
37. T. Clemens et al., "Increased Skin Pigment Reduces the Capacity of the Skin to Synthesize Vitamin D," Lancet 1 (1982): 74–76.
38. W. Brazerol et al., "Serial Ultraviolet B Exposure and Serum 25 Hydroxyvitamin D Response in Young Adult American Blacks and Whites: No Racial Difference," J Am Coll Nutr 7, no. 2 (1988): 111–118.
39. B. Specker et al., “Sunshine Exposure and Serum 25-Hydroxyvitamin D Concentrations in Exclusively Breastfed Infants,” J Pediatr 107 (1985): 372–376.
40. M. Holick, “Environmental Factors that Influence the Cutaneous Production of Vitamin D,” Am J Clin Nutr 61 (suppl.) (1995): 638S–645S.
41. A. Webb et al., “Influence of Season and Latitude on the Cutaneous Synthesis of Vitamin D3: Exposure to Winter Sunlight in Boston and Edmonton Will Not Promote Vitamin D3 Synthesis in Human Skin,” J. Clin Endocrinol Metab 67 (1988): 373-–378.
42. S. Grover and R. Morley, “Vitamin D Deficiency in Veiled or Dark-Skinned Pregnant Women,” MJA 175 (2001): 251–252.
43. K. Feldman et al., “Nutritional Rickets,” Am Fam Physician 42 (1990): 1311–1318.
44. I. Sills et al., “Vitamin D Deficiency Rickets: Reports of Its Demise Are Exaggerated,” Clin Pediatr 33 (1994): 491–493.
45. M. Pugliese et al., “Nutritional Rickets in Suburbia,” J Amer College Nutr 17, no. 6 (1998): 637–641.
46. 8. M. Holick, “Environmental Factors that Influence the Cutaneous Production of Vitamin D,” Am J Clin Nutr 61 (suppl.) (1995): 638S–645S.
47. K. Feldman et al., “Nutritional Rickets,” Am Fam Physician 42 (1990): 1311–1318.
48. I. Sills et al., “Vitamin D Deficiency Rickets: Reports of Its Demise Are Exaggerated,” Clin Pediatr 33 (1994): 491–493.
49. M. Holick, “Evolution, Biological Functions, and Recommended Dietary Allowance for Vitamin D,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 1–16.
50. L. Matsuoka et al., “Sunscreens Suppress Cutaneous Vitamin D3 Synthesis,” J Clin Endocrinol Metab 64, no. 6 (1987): 1165–1168.
51. L. Matsuoka et al., “Chronic Sunscreen Use Decreases Circulating Concentrations of 25-Hydroxyvitamin D,” Arch Dermatol 124, no. 12 (1988): 1802–1804.
52. B. Hollis et al., “The Effects of Oral Vitamin D Supplementation and Ultraviolet Phototherapy on the Antirachitic Sterol Content of Human Milk,” Calcif Tissue Int 34 (suppl.) (1982): 582.
53. A. Webb et al., “Influence of Season and Latitude on the Cutaneous Synthesis of Vitamin D3: Exposure to Winter Sunlight in Boston and Edmonton Will Not Promote Vitamin D3 Synthesis in Human Skin,” J. Clin Endocrinol Metab 67 (1988): 373-–378.
54. Grover and R. Morley, “Vitamin D Deficiency in Veiled or Dark-Skinned Pregnant Women,” MJA 175 (2001): 251–252.
55. K. Feldman et al., “Nutritional Rickets,” Am Fam Physician 42 (1990): 1311–1318.
56. I. Sills et al., “Vitamin D Deficiency Rickets: Reports of Its Demise Are Exaggerated,” Clin Pediatr 33 (1994): 491–493.
57. M. Pugliese et al., “Nutritional Rickets in Suburbia,” J Amer College Nutr 17, no. 6 (1998): 637–641.
58. M. Pugliese et al., “Nutritional Rickets in Suburbia,” J Amer College Nutr 17, no. 6 (1998): 637–641.
59. L. Muhe et al., “Case-Control Study of the Role of Nutritional Rickets in the Risk of Developing Pneumonia in Ethiopian Children,” Lancet 349 (1997): 1801–1804.
60. K. Feldman et al., “Nutritional Rickets,” Am Fam Physician 42 (1990): 1311–1318.
61. I. Sills et al., “Vitamin D Deficiency Rickets: Reports of Its Demise Are Exaggerated,” Clin Pediatr 33 (1994): 491–493.
62. L. Muhe et al., “Case-Control Study of the Role of Nutritional Rickets in the Risk of Developing Pneumonia in Ethiopian Children,” Lancet 349 (1997): 1801–1804.
63. T. Thacher et al., “A Comparison of Calcium, Vitamin D, or Both for Nutritional Rickets in Nigerian Children,” New Engl J Med 341, no. 8 (1999): 563–568.
64. N. Carvalho et al., “Severe Nutritional Deficiencies in Toddlers Resulting from Health Food Milk Alternatives,” Pediatrics 107, no. 4 (2001): E46.
65. T. Thacher et al., “A Comparison of Calcium, Vitamin D, or Both for Nutritional Rickets in Nigerian Children,” New Engl J Med 341, no. 8 (1999): 563–568.
66. I. Robertson et al., “The Role of Cereals in the Etiology of Nutritional Rickets: The Lesson of the Irish National Nutrition Survey 1943–8,” Br J Nutr 48 (1981): 17–22.
67. S. Özgür et al., “Rickets and Soil Strontium,” Arch Dis Child 75 (1996): 524–526.
68. Why Barns Are Red: Health Risks from Lead and Their Prevention (Toronto, Ontario: Metropolitan Toronto Teach Health Units and the South Riverdale Community Health Center, 1995).
69. M. Berglund et al., “Metal-Bone Interactions,” Toxicol Lett 112–113 (2000): 219–225.
77. K. Scanlon, ed., Final Report, Vitamin D Expert Panel Meeting, Atlanta, GA, Oct. 11–12, 2001; see www.cdc.gov/nccdphp/dnpa/nutrition/pdf/Vitamin_D_Expert_Panel_Meeting.pdf 
78. M. Garabédian and H. Ben-Mekhbi, “Rickets and Vitamin D Deficiency,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 273–286.
79. T. Thacher et al., “A Comparison of Calcium, Vitamin D, or Both for Nutritional Rickets in Nigerian Children,” New Engl J Med 341, no. 8 (1999): 563–568.
80. S. Özgür et al., “Rickets and Soil Strontium,” Arch Dis Child 75 (1996): 524–526.
81. X. Ma, “Epidemiology of Rickets in China,” J Pract Pediatr 1 (1986): 323.
82. M. Rafii, “Rickets in Breast-Fed Infants below Six Months of Age without Vitamin D Supplementation,” Arch Irn Med 4, no. 2 (2001): 93–95.
83. M. Garabédian and H. Ben-Mekhbi, “Rickets and Vitamin D Deficiency,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 273–286.
84. K. Feldman et al., “Nutritional Rickets,” Am Fam Physician 42 (1990): 1311–1318.
85. I. Sills et al., “Vitamin D Deficiency Rickets: Reports of Its Demise Are Exaggerated,” Clin Pediatr 33 (1994): 491–493.
86. M. Pugliese et al., “Nutritional Rickets in Suburbia,” J Amer College Nutr 17, no. 6 (1998): 637–641.
87. M. Garabédian and H. Ben-Mekhbi, “Rickets and Vitamin D Deficiency,” in Vitamin D: Physiology, Molecular Biology, and Clinical Applications, M. Holick, ed. (Totawa, NJ: Humana Press, 1999), 273–286.
99. K. Scanlon, ed., Final Report, Vitamin D Expert Panel Meeting, Atlanta, GA, Oct. 11–12, 2001; see www.cdc.gov/nccdphp/dnpa/nutrition/pdf/Vitamin_D_Expert_Panel_Meeting.pdf 

Cynthia Good Mojab, MS (clinical psychology), IBCLC, RLC, is Research Associate in the Publications Department of La Leche League International and Senior Editor at Platypus Media. She is the coauthor of Breastfeeding at a Glance: Facts, Figures, and Trivia About Lactation (Platypus Media 2001). Her publications can be accessed from her website, Ammawell (http://home.comcast.net/~ammawell), which provides breastfeeding and parenting information.
 

Citation: Good Mojab, C. Frequently Asked Questions About Vitamin D, Sunlight, and Breastfeeding. Ammawell website 2003.

July 22, 2003. Subject to revision.