Helping Breastfeeding Mothers Find the Facts
Cynthia Good Mojab, MS, IBCLC, RLC
Hillsboro OR USA
From: LEAVEN, Vol. 39 No. 4, August-September 2003, pp. 75-79.
The American Academy of Pediatrics (AAP) recently released a clinical report recommending vitamin D supplementation for all breastfed infants in the United States.1 In a variety of countries, media reports of the AAP’s recommendation have questioned the adequacy of human milk. La Leche League International’s April 17, 2003 media release provides a brief overview of the issue and corrects some of the misinformation commonly disseminated in the popular media.2 Other resources are also available that provide the more detailed information that mothers need for informed decision making.
Sunlight deficiency is not a new issue. Inadequate exposure to sunlight may occur whenever ultraviolet B (UVB) radiation is not readily available from sunlight and/or among populations whose beliefs and behaviors limit the exposure of their skin to the sun. No matter where they live, La Leche League Leaders may be called on to help breastfeeding mothers sort myth from fact in the complex and controversial issue of sunlight deficiency and breastfeeding.
Myth 1: "Vitamin D" Is a Vitamin
Fact: "Vitamin D" was misclassified as a vitamin in 1922 during the era of discovery of trace nutrients.3 It is actually a steroid hormone produced in the body after direct exposure of the skin to UVB radiation in sunlight. The direct, casual exposure of skin to sunlight is the most common and the biologically normal way that human beings attain sufficient levels of this hormone. Since only a few foods naturally contain significant levels of vitamin D (e.g., oils and livers of some fish), it is unusual for people to obtain adequate vitamin D from their diet alone without supplementation or the fortification of foods.4 When there are no underlying organic causes, such as prematurity (birth before completion of 37 weeks of gestation) or liver or kidney disease, vitamin D deficiency is actually sunlight deficiency.
Author’s note: The focus of this article is vitamin D deficiency caused by inadequate exposure to sunlight among otherwise healthy nurslings born full term. While vitamin D deficiency due to underlying organic causes is not addressed here, Leaders should be aware that sunlight deficiency is not the only cause of vitamin D deficiency and rickets. A referral to a physician is appropriate any time a mother, infant, or child is suspected to be vitamin D deficient or at risk for vitamin D deficiency.
The hormone "vitamin D" plays many roles in human health. It acts as a chemical messenger in a wide variety of biological responses.5 It is perhaps most widely known for its role in maintaining proper blood calcium and phosphorous concentrations and facilitating bone mineralization by stimulating the absorption of calcium and phosphorous in the small intestine. In infants and children, vitamin D deficiency can lead to rickets, a bone disease. Symptoms of rickets include bone fractures and deformities, muscle weakness, developmental delays, failure-to-thrive, short stature, respiratory distress, tetany (repeated prolonged contraction of muscles caused by low blood calcium), and, rarely, heart failure.6 Studies have also shown that lower vitamin D levels and living in higher latitudes are related to type 1 diabetes, several cancers, as well as other diseases.4, 7, 8
Myth 2: Human Milk Is Deficient in Vitamin D
Fact: Human milk contains less than the 200 to 400 International Units (IU) per day commonly recommended for infants under one year of age.4 Depending on the measuring method and on maternal vitamin D status during lactation, the range of vitamin D in human milk has been found to be from five to 136 IU per liter.9, 10, 11 However, the natural sources of vitamin D for nurslings are primarily the stores they developed before birth (for newborns) and the vitamin D they produce when their skin is exposed to sunlight; human milk contributes an additional smaller amount of vitamin D.12, 13 Since the biologically normal means of obtaining sufficient vitamin D in humans of all ages is through sunlight exposure, not diet, human milk should not be considered "deficient" in vitamin D.4, 12, 13 Artificial substitutes for human milk (infant formulas) would not contain adequate levels of vitamin D to prevent vitamin D deficiency and rickets if they were not fortified with vitamin D.
Myth 3: All Exclusively Breastfed Infants are at Risk of Vitamin D Deficiency
Fact: Vitamin D deficiency occurs because of too little sunlight exposure, not because of a deficiency in human milk. Healthy full-term infants who are exclusively breastfed from birth to six months and who have adequate exposure to sunlight are not at risk for developing vitamin D deficiency or rickets. In addition, unless their mothers were vitamin D deficient during pregnancy, healthy, full-term infants are born with a supply of vitamin D that will last for two months in the absence of sun exposure.13 In the presence of adequate sun exposure, fetal stores will last longer and can be augmented. Vitamin D produced via sun exposure, but not immediately needed, can be stored for later use.14
Risk factors for vitamin D deficiency and rickets include:
- maternal vitamin D deficiency during pregnancy 15, 16, 17
- indoor confinement during daylight hours (e.g., due to cultural custom, unsafe neighborhoods, exclusively indoor day care)18
- living at higher latitudes (e.g., virtually no vitamin D is produced with sun exposure from November to February in Boston, USA [42° N] and from mid-October to mid-April in Edmonton, Canada [52º N])19, 20
- darker skin pigmentation21, 22, 23, 24
- living in urban areas with buildings and/or pollution that block sunlight19, 22, 23
- use of sunscreen4, 25, 26
- seasonal variations resulting in less UVB radiation (e.g., early spring and late winter in the northern hemisphere)19, 20
- covering most or all of the body when outside (e.g., due to cold climate, cultural custom, concern about skin cancer)21, 22, 23, 24
- higher birth order (e.g., a mother’s sixth child is at greater risk of vitamin D deficiency than is her first child)24, 27
- the replacement of human milk with foods that reduce the absorption of calcium (e.g., grains and some green leaves containing phylates, oxalates, tannates, and phosphates; cereals grown in soil high in strontium)17, 28, 29
- the replacement of human milk with foods that are low in calcium17, 22, 23, 27, 30
- exposure to lead (because lead inhibits vitamin D synthesis)31, 32
At the beginning of the 20th century, rickets occurred at epidemic levels in the industrialized cities of northern Europe and North America. With the use of vitamin D supplements and the fortification of cow’s milk, rickets was nearly eliminated in most developed nations by the 1960s. However, since the 1970s, rickets has been documented in breastfed infants among at-risk populations in northern Europe, North America, and former Soviet countries.6 The national prevalence of rickets in the US has not been tracked, so no one currently knows what proportion of US infants develops rickets.33 However, case reports and descriptive studies clearly indicate that rickets does still occur in the US. Rickets remains a major health problem in some developing countries today.17, 29, 34, 35 Overt rickets occurs more frequently in children six to 36 months of age than in infants less than six months of age.6, 22, 23, 24 In full-term or premature newborns, the development of bone deformities suggestive of rickets is very rare.6 Many children affected by rickets in early childhood experience poor socioeconomic conditions and sometimes show signs of general malnutrition.3
Myth 4: Experts around the World Agree that Vitamin D Supplementation is the Best Way to Prevent Vitamin D Deficiency in Exclusively Breastfed Infants.
Fact: Vitamin D supplementation for breastfed infants is a complex, controversial, and global issue. Recommendations for the prevention of vitamin D deficiency vary from country to country due to different incidences of vitamin D deficiency, risk factors, cultural practices, and financial resources.36 There is no global consensus on how to prevent vitamin D deficiency or on how to screen for its presence among nurslings or their mothers.36, 37 In some countries, health agencies recommend supplementing all breastfed infants (universal supplementation), such as the AAP in the United States (19–71° N), the Ministry of Social Welfare (Socialstyrelsen-SOS) in Sweden (55–69° N), and the Canadian Paediatric Society in Canada (42–83° N).1, 38, 39 In other countries, health agencies recommend supplementing at-risk infants only (conditional supplementation), such as the Department of Health in the United Kingdom (50–61° N) and the National Health and Medical Research Council (NHMRC) in Australia (11–44° S).40, 41 The Ministry of Health in New Zealand (33–53° S) recommends supplements only in the case of a proven vitamin D deficiency.42 The NHMRC in Australia, the Ministry of Health in New Zealand, the World Health Organization (for infants older than 12 months, children, and adults), and the United Nations Children’s Fund all recommend small doses of regular sun exposure for the prevention of vitamin D deficiency and rickets.41, 42, 43, 44
Vitamin D supplementation has been shown to be useful in infants at risk of vitamin D deficiency and has been used to prevent rickets for decades in many countries. No known risks exist with 200 to 400 IU per day of oral vitamin D supplementation.36 However, many questions have not yet been researched.36 For example, no one knows whether vitamin D supplementation has any harmful physiologic effects on otherwise exclusively breastfed infants (e.g., harmful alterations of the infant gut; increased rates of allergy or infection; vomiting and aspiration when the supplement is not tolerated) or whether a universal recommendation of vitamin D supplementation adversely affects breastfeeding beliefs and behavior (e.g., increasing the use of other supplements, premature introduction of other foods, weaning). Given the well-documented importance of exclusive breastfeeding in the first six months, research on potential harmful physiologic and behavioral effects of vitamin D supplementation is warranted. Another question not adequately researched is: What means of preventing maternal vitamin D deficiency would be most effective in reducing the risk of early vitamin D deficiency in infants? For example, what levels of maternal vitamin D supplementation or sunlight exposure might be required during pregnancy for infants to be born with optimal fetal stores of vitamin D? Informed decision-making requires that mothers know that such questions remain unanswered.37
Single-vitamin supplements of vitamin D may or may not be available where the mother lives. In the US, for example, nonprescription vitamin drops containing vitamin D also contain other vitamins unnecessary for breastfed infants (e.g., vitamins A, C, and E). However, single-vitamin supplements of vitamin D are available in Canada. Supplements may also contain glycerin, propylene glycol (a petroleum derivative), preservatives, sweeteners, and natural or artificial flavors. The sources of ingredients in the supplement may or may not be labeled, which may be of concern to people preferring to consume foods and food products that are not derived from animals or that are prepared in accordance with Jewish or Islamic religious beliefs. Manufacturers may provide information on supplement ingredients upon request. Mothers can consult their health care providers regarding the type(s) of supplements available in their area.
Myth 5: It Takes a Great Deal of Sun Exposure to Avoid Vitamin D Deficiency
Fact: The AAP recommends no direct sun exposure for infants under six months of age, as does the World Health Organization for infants under 12 months of age.44, 45 Chronic, excessive sun exposure has been shown to be strongly associated with a marked increase in the incidence of skin cancer in fair-skinned populations around the world, as well as with the development of cataracts regardless of skin pigmentation.46 However, the skin has a tremendous capacity to produce vitamin D. Exposure of the entire adult body to the smallest amount of UVB radiation that produces transient, just detectable skin reddening is similar to taking 10,000 to 25,000 IU of vitamin D orally.19, 47 Therefore, sufficient levels of vitamin D can be developed from partial exposure of the body to small amounts of sunlight well before sunburn occurs.37 As of this writing, no research has examined the relationship between the risk of skin cancer and a lifetime of minimal levels of sun exposure just sufficient for producing adequate levels of vitamin D. So, there is currently no evidence that these minimal levels of sun exposure increase the lifetime risk of skin cancer.37
Research has demonstrated that children are able to store several months worth of vitamin D when they are exposed to only a few hours of summer sunlight.8, 18, 48 Research has also shown that exclusively breastfed Caucasian infants under six months of age (39° N; Cincinnati, Ohio, US) maintain adequate vitamin D status when exposed to sunlight for 30 minutes per week (wearing a diaper only) or two hours per week (fully clothed without a hat).18 The sunlight exposure needed by darkly pigmented infants has not been adequately researched.18 In adults, studies of the influence of skin pigmentation on the body’s ability to produce vitamin D have shown conflicting results.49, 50 But, when episodes of UVB exposure occurred periodically over time (i.e., biweekly for six weeks), darkly and lightly pigmented adults were shown to be equally capable of producing vitamin D.47
Many international agencies recommend small amounts of UVB radiation as beneficial for the prevention of vitamin D deficiency, including the United Nations Children’s Fund (UNICEF), World Health Organization (WHO), World Meteorological Association, United Nations Environment Programme, and International Commission on Non-Ionizing Radiation Protection.46 UNICEF states that cases of vitamin D deficiency that occur outside of temperate regions with weak sunlight are the result of overprotection from the sun and that, "The best prevention is to change these habits, and health professionals must insist on the need to be in sunlight."43 According to the World Health Organization:
Some UV radiation is essential to the body as it stimulates the production of vitamin D. There is no doubt that a little sunlight is good for you! But 5 to 15 minutes of casual sun exposure of hands, face, and arms two to three times a week during the summer months is sufficient to keep your vitamin D levels high. Closer to the equator, where UV levels are higher, even shorter periods of exposure suffice.44
The amount of UVB radiation available in sunlight varies with many factors, such as latitude, altitude, season, weather, time of day, air pollution, reflectivity of ground surfaces, and degree of shade. More UVB radiation is available closer to the equator (lower latitude), at higher altitudes, in summer, from clearer skies, in the late morning and early afternoon, in less polluted areas, from more reflective ground surfaces (e.g., snow, sand), and in open areas; less UVB is available farther from the equator (higher latitude), at lower altitudes, in winter, from heavily clouded skies, in the early morning, late afternoon, and early evening, in more polluted areas, from less reflective ground surfaces (e.g., grass, soil), and in shaded areas. According to the World Health Organization:
- over 90 percent UV may penetrate clouds
- the sun’s UV rays are strongest between 10 am and 4 pm (up to 50 percent daily UV is emitted between 11 am and 2 pm)
- UV increases with increasing altitude (four percent at ascending intervals of 300 meters)
- grass, soil, and water reflect less than 10 percent of UV radiation
- fresh snow reflects up to 80 percent sunburning UV
- shade provides up to 50 percent ambient UV
- sand reflects up to 25 percent UV
- sea foam reflects about 25 percent of UV radiation
- 95 percent UV penetrates water and 40 percent UV penetrates water down to 50 cm.44, 51, 52
Windowpane glass, Plexiglas (Dupont Chemical Company, Memphis, Tennessee, USA), and most other plastics efficiently absorb UVB radiation, preventing the body from producing vitamin D from sunlight that has passed through these materials.53
Environmental variations in the availability of UVB radiation, variations in skin cancer risk based on skin pigmentation (i.e., the risk of skin cancer decreases with increasing skin pigmentation51), as well as beliefs and behaviors related to sun exposure, influence vitamin D supplementation and sunlight exposure recommendations made by health agencies around the world. They also influence mothers’ decisions on whether to rely on small amounts of sun exposure for their exclusively breastfed infant’s vitamin D needs or to give them oral vitamin D supplements.
Helping Mothers Make Informed Decisions
Mothers and their health care providers may contact Leaders with other questions and misconceptions about sunlight deficiency, vitamin D, and breastfeeding. More information can be found in a variety of resources—in print and via the Internet (see Resource box). Leaders without access to the Internet may be able to obtain the information they need from the reference librarian at their local library and/or from their Area Professional Liaison Leader. As with all other breastfeeding issues, La Leche League Leaders cannot make recommendations on what mothers should do. However, they can:
- explain that oral supplementation with the hormone "vitamin D" has been shown to be useful for those infants at risk of vitamin D deficiency
- provide information about risk factors for developing vitamin D deficiency
- inform mothers about the available research and clarify that some questions have not yet been investigated
- share local and global recommendations related to vitamin D supplementation and sunlight exposure, and
- encourage mothers to consult with their health care providers.
Each mother must weigh for her particular child the balance of several risks: the risk of vitamin D deficiency, the risk of skin cancer, and the unknown but potential risk of adverse health consequences from vitamin D supplementation. Some mothers will choose to give vitamin D supplements to their children. Others will choose to rely on regular, small amounts of sunlight exposure. Still others will prefer to engage in medical evaluations (e.g., measuring vitamin D levels in their infant’s blood) before making a decision. What meets the needs of one nursling may not meet the needs of another. Leaders can play an important role in helping mothers find the information they need to make informed decisions that take into account their nursling’s individual circumstances.
1. American Academy of Pediatrics. Prevention of rickets and vitamin D deficiency: New guidelines for vitamin D intake. Pediatrics 2003; 111(4):908-10.
2. La Leche League International. Sunlight Deficiency, "Vitamin D," and Breastfeeding. April 17, 2003 Media Release.
3. Fraser, D. The physiological economy of vitamin D. Lancet 1983; 1:969-72.
4. Holick, M. "Evolution, Biological Functions, and Recommended Dietary Allowance for Vitamin D." Vitamin D: Physiology, Molecular Biology, and Clinical Applications. Totawa, NJ: Humana Press, 1999; 1-16.
5. Holick, M. Noncalcemic actions of 1,25-dihydroxyvitamin D3 and clinical applications. Bone (Suppl.) 1995; 17(2): 107S-11S.
6. Garabédian, M. and Ben-Mekhbi, H. "Rickets and Vitamin D Deficiency." In Physiology, Molecular Biology, and Clinical Applications. Totawa, NJ: Humana Press, 1999; 273-86.
7. Hyppönen, E. et al. Intake of vitamin D and risk of type 1 diabetes: A birth-cohort study. Lancet 2001; 358(9292): 1500-03.
8. Holick, M. Sunlight 'D'ilemma: Risk of skin cancer or bone disease and muscle weakness. Lancet 2001; 357: 4-6.
9. Specker, B. et al. Effect of race and normal maternal diet on breast milk vitamin D concentrations. Pediatr Res 1984; 18:213A.
10. Hollis, B. et al. Vitamin D and its metabolites in human and bovine milk. J Nutr 1981; 111(7): 1240-1248.
11. Butte, N. et al. Nutrient Adequacy of Exclusive Breastfeeding for the Term Infant during the First Six Months of Life. Geneva: World Health Organization, 2002; 27.
12. Makin, H. et al. Vitamin D and its metabolites in human breast milk. Arch Dis Child 1983; 58: 750-53.
13. Ala-Houhala, M. 25-Hydroxyvitain D levels during breast-feeding with or without maternal or infantile supplementation of vitamin D. J Pediatr Gastroent Nutr 1985; 4(2): 220-26.
14. Holick, M. Vitamin D and bone health. J Nutr 1996; 126: 1159S-64S.
15. Pal, B. and Shaw, N. Rickets resurgence in the United Kingdom: Improving antenatal management in Asians. J Pediatr 2001; 139(2):337-38.
16. Daaboul, J. et al. Vitamin D deficiency in pregnant and breast-feeding women and their infants. J Perinatol 1997; 17:10-14.
17. Thacher, T. et al. A comparison of calcium, vitamin D, or both for nutritional rickets in Nigerian children. New Engl J Med 1999; 341(8):563-68.
18. Specker, B. et al. Sunshine exposure and serum 25-hydroxyvitamin D concentrations in exclusively breastfed infants. J Pediatr 1985; 107:372-76.
19. Holick, M. Environmental factors that influence the cutaneous production of vitamin D. Am J Clin Nutr (Suppl.) 1995 ; 61:638S-45S.
20. Webb, A. 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 1988; 67:373-78.
21. Grover, S. and Morley, R. Vitamin D deficiency in veiled or dark-skinned pregnant women. MJA 2001; 175:251-52.
22. Feldman, K. et al. Nutritional rickets. Am Fam Physician 1990; 42: 1311-18.
23. Sills, I. et al. Vitamin D deficiency rickets: Reports of its demise are exaggerated. Clin Pediatr 1994; 33:491-93.
24. Pugliese, M. et al. Nutritional rickets in suburbia. J Amer College Nutr 1998; 17(6):637-41.
25. Matsuoka, L. et al. Sunscreens suppress cutaneous vitamin D3 synthesis. J Clin Endocrinol Metab 1987; 64(6):1165-68.
26. Matsuoka, L. et al. Chronic sunscreen use decreases circulating concentrations of 25-hydroxyvitamin D. Arch Dermatol 1988; 124(12):1802-04.
27. Muhe, L. et al. Case-control study of the role of nutritional rickets in the risk of developing pneumonia in Ethiopian children. Lancet 1997; 349:1801-04.
28. Robertson, I. 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 1981; 48:17-22.
29. Özgür, S. et al. Rickets and soil strontium. Arch Dis Child 1996; 75:524-26.
30. Carvalho, N. et al. Severe nutritional deficiencies in toddlers resulting from health food milk alternatives. Pediatrics 2001; 107(4):E46.
31. Metropolitan Toronto Teach Health Units and the South Riverdale Community Health Center. 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.
32. Berglund, M. et al. Metal-bone interactions. Toxicol Lett 2000; 112-113:219-25.
33. Scanlon, K. Ed. Final Report, Vitamin D Expert Panel Meeting. Atlanta, GA, Oct. 11-12, 2001; Online: www.cdc.gov/nccdphp/dnpa/nutrition/pdf/Vitamin_D_Expert_Panel_Meeting.pdf
34. Ma, X. Epidemiology of rickets in China. J Pract Pediatr 1986; 1:323.
35. Rafii, M. Rickets in breast-fed infants below six months of age without vitamin D supplementation. Arch Irn Med 2001; 4(2):93-95.
36. Good Mojab, C. Sunlight deficiency and breastfeeding. BREASTFEEDING ABSTRACTS 2002; 22(1):3-4.
37. Good Mojab, C. Sunlight deficiency: A review of the literature. Mothering 2003 Mar-Apr; 117:52-55:57-63.
38. Greiner, Ted. Personal communication, 5 November, 2002.
39. Canadian Paediatric Society et al. Nutrition for Healthy Infants. Ottawa: Minister of Public Works and Government Services, 1998.
40. Committee on Medical Aspects of Food and Nutrition Policy. Nutrition and Bone Health with Particular Reference to Calcium and Vitamin D, Department of Health Report 49. London: The Stationery Office, 1998.
41. National Health and Medical Research Council. Recommended Dietary Intakes for Use in Australia. Commonwealth of Australia, 1991.
42. Ministry of Health. Food and Nutrition Guidelines for Healthy Infants and Toddlers (Aged 0-2 Years): A Background Paper. Wellington, New Zealand: Public Health Commission, 2000.
43. UNICEF. Vitamin D: Rickets in children and osteomalacia in pregnant women. The Prescriber: Guidelines on the Rational Use of Drugs in Basic Health Services Dec 1993; 8:11.
44. World Health Organization. Intersun: The Global UV Project. Online: www.who.int/peh-uv/FAQ/faq3.htm.
45. American Academy of Pediatrics. Ultraviolet light: A hazard to children. Pediatrics 1999; 104(2):328-33.
46. World Health Organization. Global Solar UV Index: A Practical Guide. Geneva, Switzerland: World Health Organization, 2002.
47. Brazerol, W. 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 1988; 7(2):111-18.
48. Poskitt, E. et al. Diet, sunlight, and 25-hydroxyvitamin D in healthy children and adults. Br Med J 1979; 1:221-23.
49. Lo, C. 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 1986; 44:683-85.
50. Clemens, T. et al. Increased skin pigment reduces the capacity of the skin to synthesize vitamin D. Lancet 1982; 1:74-76.
51. World Health Organization and United Nations Environment Programme. Health and Environmental Effects of Ultraviolet Radiation. A Scientific Summary of Environmental Health Criteria 160 Ultraviolet Radiation. Geneva: WHO and UNEP, 1995.
52. World Health Organization. Ultraviolet Radiation as a Hazard in the Workplace. Online: www.who.int/peh-uv/Info_sheet/UV_Occupational_Risk.pdf
53. Holick, M. F. McCollum award lecture: Vitamin D: New horizons for the 21st century. Am J Clin Nutr 1994; 60: 619-30.
- Good Mojab, C. Sunlight deficiency and breastfeeding. BREASTFEEDING ABSTRACTS 2002; 22(1):3-4.
- Good Mojab, C. Sunlight deficiency: A review of the literature. Mothering 2003 Mar-Apr; 117:52-63.
- La Leche League International. Sunlight Deficiency, "Vitamin D," and Breastfeeding. April 17, 2003 Media Release.
- Mohrbacher, N., Stock, J. THE BREASTFEEDING ANSWER BOOK. Schaumburg, IL: LLLI 2003; 605-607.
The myths and facts of this article were adapted with permission from "Sunlight Deficiency: A Review of the Literature," by Cynthia Good Mojab, orignally printed in the March-April 2003 issue of Mothering. That article can be found online at: www.mothering.com/12-0-0/html/12-1-0/sunlight-deficiency.shtml
Cynthia Good Mojab, MS clinical psychology is an International Board Certified Lactation Consultant, has been an LLL Leader for over five years, and works as Research Associate in the Publications Department of La Leche League International. She is a member of the Ask the Experts panel on Mothering magazine’s Web site, answering questions about breastfeeding. She is also an independent researcher, author, and educator in the areas of psychology, culture, and family, particularly in relation to breastfeeding. Many of her publications can be accessed from her Web site (http://home.comcast.net/~ammawell), which provides breastfeeding and parenting information—including still more resources on vitamin D. She lives in Oregon, USA with her husband and their six-year-old daughter.