Advertisement
Annals
Established in 1927 by the American College of Physicians
:
Advanced search
 

box Article
 arrow  Table of Contents                
space
 arrow  Related articles in Annals
space
 arrow  Articles citing this article
space
box Services
 arrow  Send comment/rapid response letter
space
 arrow  Notify a friend about this article
space
 arrow  Alert me when this article is cited
space
 arrow  Add to Personal Archive
space
 arrow  Download to Citation Manager
space
 arrow  ACP Search                        
space
 arrow  Get Permissions
space
box PubMed
Articles in PubMed by Author:
  arrow  Marriott, B. M.
space
 arrow  Related Articles in PubMed
space
 arrow  PubMed Citation
space
 arrow  PubMed
space

EDITORIAL

Vitamin D Supplementation: A Word of Caution

right arrow Bernadette M. Marriott, PhD

1 August 1997 | Volume 127 Issue 3 | Pages 231-233


Osteoporosis and metabolic bone disease are estimated to affect more than 25 million persons in the United States [1]. Advances in scientific understanding of the development of osteoporosis and its medical treatment and prevention have been dramatic over the past 10 years [2, 3]. It is now clear that what we ingest and probably our exercise patterns throughout life can substantially affect the incidence, severity, and progression of osteoporosis. A critical component of this picture is the role of nutrition [4].

Intake of calcium and its regulator, vitamin D, are important in the development and progression of osteoporosis. Vitamin D is involved in mineral homeostasis through a large group of metabolites, among which is 1{alpha},25-dihydroxyvitamin D3 [5]. This metabolite is considered to be a steroid hormone because it acts as a chemical messenger not only in mineral metabolism but in a wide array of biological responses. This hormone initiates biological responses through the regulation of gene transcription and a signal transduction pathway; this regulation includes rapid stimulation of intestinal calcium absorption and mobilization of calcium and phosphorus stores from bone [1, 5]. Vitamin D3 is synthesized in the body through exposure to sunlight [6]. In older adults, vitamin D deficiency has been documented among homebound older persons [7, 8]; however, studies have indicated that serum concentration of 25-dihydroxyvitamin D3 levels are lower in older adults overall than in young and middle-aged persons, regardless of exposure to sunlight [9]. These results have led to recommendations for vitamin D supplementation in older adults [10, 11].

Recent research has indicated that the requirement for vitamin D probably increases with chronological age [12]. Older persons have less exposure to sunlight because they spend less time engaged in outdoor activities, and their use of protective sun-blocks further reduces exposure. In addition, evidence indicates that 1) the skin of older persons cannot synthesize vitamin D as well as that of younger persons when both are exposed to ultraviolet light [13] and 2) the vitamin D that is produced in older persons is less readily absorbed in the intestine [14]. Recommended intake of vitamin D for persons older than 51 years of age ranges from 200 to 800 IU. Dairy products are the main source of vitamin D in the U.S. diet. Current surveys indicate that most older persons consume less than the recommended level of vitamin D through their diet. Recommendations for vitamin D supplementation thus seem to be reasonable for persons at risk for osteoporosis and metabolic bone disease. Before such recommendations are made, however, the current diet and dietary supplement use of the individual patient should be considered.

Supplemental vitamin D is commonly found in multivitamin and single-nutrient preparations. Evidence for vitamin A and D toxicity as a result of dietary supplementation was more commonly seen in clinical practices in the earlier part of this century. More recently, vitamin D toxicity has been documented in several accidental situations that have usually involved food fortification errors, but it is rarely seen [5]. In this issue, Adams and Lee [15] report several cases of vitamin D toxicity in older adults who reported consumption of vitamin D supplements. The sources and doses of the supplements differed, but all patients regularly consumed (in addition to their diets) single-nutrient sources of vitamin D, other supplements that contained vitamin D, and multivitamin supplements. The patients were not aware that they were consuming more than 1200 IU of vitamin D each day.

There is currently no recommended safe upper limit for vitamin D intake [16]. The intakes reported by Adams and Lee are greater than earlier estimates of safe recommended ranges [16, 17]. Adams and Lee show that discontinuation of use of supplemental vitamin D led to the return of serum 25-hydroxyvitamin D levels to within the normal range and to a rebound increase in bone mineral density. Their study is particularly valuable because their 3-year follow-up phase showed that the increase in bone mineral density persisted after initial recovery.

The data from this study will undoubtedly be of interest to the Food and Nutrition Board, National Academy of Sciences panel, which is developing the new Recommended Dietary Allowances (RDAs) (to be called the Dietary Reference Intakes [DRIs]). The DRIs will include at least three reference values for each age and sex grouping for each nutrient or food component: the Estimated Average Requirement, the traditional RDA, and a Tolerable Upper Intake Level. The new DRIs will incorporate the concept of reduction in risk for chronic disease across the lifespan, values that can be used by health care practitioners when counseling individual persons, and reference levels for older adults [18]. The values for calcium and related nutrients are expected to be released late in 1997.

In their discussion, Adams and Lee [15] express concern about the potential for more widespread occult hypercalciuria and vitamin D toxicity given the high level of dietary supplement use in the United States today. They recommend that physicians test economically advantaged osteopenic patients for hypercalciuria and high 25-hydroxyvitamin D levels. Although such testing is unlikely to be cost-effective, the simple addition of routine screening for dietary supplement use to practice routines may reduce the risk for toxicity and adverse drug and nutrient interactions. Specifically, questions about dietary supplement use should be added to standard medical history forms. Four aspects of dietary supplement use information are important to obtain: the specific supplements used (with brand name information, if possible), the frequency of use, the concentration, and the dose. Information on the usage patterns of nutrient, botanical (herbal), and other supplements-including less readily classified types, such as shark cartilage and melatonin-must be recorded.

Health care practitioners can no longer assume that dietary intake consists primarily of food. Estimates indicate that more than one third of the U.S. population regularly use dietary supplements and that the number and diversity of supplements used by a person change frequently. It would thus be beneficial if information on dietary supplement use was updated with each health care visit, or at least annually. In addition to the possibility of hypervitaminosis, presented by Adams and Lee, it is well known that supplements in high doses can interfere with the diagnosis and treatment of certain diseases [19]. Large daily intakes of one supplemental nutrient may also affect the absorption and metabolism of other nutrients [20]. Data on nutrient-drug and nutrient-nutrient interactions are known to be slim [16]. Even less is known about the interactions of the wide array of botanical supplements with nutrients, pharmaceutical agents, and each other. It would therefore benefit overall health care if practitioners routinely asked patients about dietary practices and supplement use before prescribing medication.

The growth in scientific understanding of the role of diet, overall nutrition, exercise, disease prevention, and health promotion is reflected in the current public awareness of and attention to these factors in personal health. For health care professionals, the possible interactions of these factors in diagnosis and treatment require similar attention. Fall-related injuries, such as hip fracture, increase with age because of numerous factors, including osteoporosis. In one study, fall-related traumas accounted for 5.3% of all hospitalizations for older adults in Washington State [21]. Yet hospitalization for falls accounted for only a small portion of the total cost of such trauma to the person and society. Heaney [11] commented that a 20% reduction in hip fractures alone in the United States would lead to an estimated annual savings of $1.5 billion to $2.0 billion. Heaney also recommended use of supplemental calcium and vitamin D.

The study by Adams and Lee [15] suggests that vitamin D supplementation, although important to overall bone health, particularly in older adults, must be recommended with care. The supplements consumed by the older adults in this study were not individually outside of the range normally indicated for persons at risk for osteoporosis, but the combination and number of daily supplements used led to toxicity. Many authors have cited the increased tendency of older adults to self-medicate and the potential complications of this practice [22]. Thus, health care practitioners may also be taking a prudent step toward reducing health care costs due to unintentional toxicity by recording, reviewing, and discussing supplement use with their clients. The assistance of appropriately trained consultants, professionally trained nutritionists, and registered dietitians can also play an important role. Health care practitioners tend to think of toxicity in terms of the use and abuse of prescription drugs or over-the-counter medications, but this report brings to the forefront the need to carefully consider everything that persons consume, no matter what their age, in an overall approach to improving the prevention, diagnosis, and treatment of disease.


Author and Article Information
space
up arrowTop
dotAuthor & Article Info
down arrowReferences

National Institutes of Health; Bethesda, MD 20892
Requests for Reprints: Bernadette M. Marriott, PhD, Office of Dietary Supplements, Office of Disease Prevention, Office of the Director, National Institutes of Health, 7550 Wisconsin Avenue, Suite 610, Bethesda, MD 20892.


References
space
up arrowTop
up arrowAuthor & Article Info
dotReferences

1. Optimal Calcium Intake. NIH Consensus Statement. 1994; 12:1-31.

2. DeLuca H. The vitamin D story: a collaborative effort of basic science and clinical medicine. FASEB J. 1988; 1; 2(3):224-36.

3. Sowe MF. Nutrition advances in osteoporosis and osteomalacia. In: Ziegler EE, Filer LJ Jr, eds. Present Knowledge in Nutrition. 7th ed. Washington, DC: ILSI Pr; 1996:456-63.

4. Heaney RP. Nutritional factors in osteoporosis. Annu Rev Nutr. 1993; 13:287-316.

5. Norman AW. Vitamin D. In: Ziegler EE, Filer LJ Jr, eds. Present Knowledge in Nutrition. 7th ed. Washington, DC: ILSI Pr; 1996:120-9.

6. Webb AR, DeCosta BR, Holick MF. Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation. J Clin Endocrinol Metab. 1989; 68:882-7.

7. Webb AR, Pilbeam C, Hanafin N, Holick MF. An evaluation of the relative contributions of exposure to sunlight and of diet to the circulating concentrations of 25-hydroxyvitamin D in an elderly nursing home population in Boston. Am J Clin Nutr. 1990; 51:1075-81.

8. Gloth FM 3d, Gundberg CM, Hollis BW, Haddad JG Jr, Tobin JD. Vitamin D deficiency in homebound elderly persons. JAMA. 1995; 274:1683-6.[Abstract]

9. Aksnes L, Rodland O, Odegaard OR, Bakke KJ, Aarskog D. Serum levels of vitamin D metabolites in the elderly. Acta Endocrinol (Copenh). 1989; 121:27-33.

10. Holick MF. Environmental factors that influence the cutaneous production of vitamin D. Am J Clin Nutr. 1995; 61:638S-45S.

11. Heaney RP. Thinking straight about calcium [Editorial]. N Engl J Med. 1993; 328:503-5.

12. Russell RM. Vitamin requirements in old age. Age and Nutrition. 1992; 3:20-3.

13. MacLaughlin J, Holick MF. Aging decreases the capacity of human skin to produce vitamin D3. J Clin Invest. 1985; 76:1536-8.

14. Ebeling PR, Sandgren ME, DiMagno EP, Lane AW, DeLuca HF, Riggs BL. Evidence of an age-related decrease in intestinal responsiveness to vitamin D: relationship between serum 1,25-dihydroxyvitamin D3 and intestinal vitamin D receptor concentrations in normal women. J Clin Endocrinol Metab. 1992; 75:176-82.

15. Adams JS, Lee G. Gains in bone mineral density with resolution of vitamin D intoxication. Ann Intern Med. 1997; 127:203-6.

16. National Research Council. Recommended Dietary Allowances. 10th ed. Washington, DC: National Academy Pr; 1989:96-97.

17. Hathcock JN. Quantitative evaluation of vitamin safety. Journal of Practical Nursing. 1986; 36:20-7.

18. Food and Nutrition Board. How Should the Recommended Dietary Allowances Be Revised? Washington, DC: National Academy Pr; 1994:1-36.

19. Dreyfus PM. Diet and nutrition in neurological disorders. In: Shils ME, Young VE, eds. Modern Nutrition in Health and Disease. Philadelphia: Lea & Febiger; 1988:1458-70.

20. National Research Council. Diet and Health: Implications for Reducing Chronic Disease Risk. Washington, DC: National Academy Pr; 1989:517.

21. Alexander BH, Rivara FP, Wolf ME. The cost and frequency of hospitalization for fall-related injuries in older adults. Am J Public Health. 1992; 82:1020-3.

22. Roe DA. Geriatric Nutrition. 3d ed. Englewood Cliffs, NJ: Prentice-Hall; 1992:196-204.

Related articles in Annals:

Brief Communications
Gains in Bone Mineral Density with Resolution of Vitamin D Intoxication
John S. Adams and Gene Lee
Annals 1997 127: 203-206. (in ) [Abstract] [Full Text]  



This article has been cited by other articles:


Home page
Am. J. Clin. Nutr.Home page
R. P Heaney, K M. Davies, T. C Chen, M. F Holick, and M J. Barger-Lux
Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol
Am. J. Clinical Nutrition, January 1, 2003; 77(1): 204 - 210.
[Abstract] [Full Text] [PDF]


Home page
NEJMHome page
P. Koutkia, T. C. Chen, and M. F. Holick
Vitamin D Intoxication Associated with an Over-the-Counter Supplement
N. Engl. J. Med., July 5, 2001; 345(1): 66 - 67.
[Full Text] [PDF]


Home page
Am. J. Clin. Nutr.Home page
R. Vieth, P.-C. R Chan, and G. D MacFarlane
Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level
Am. J. Clinical Nutrition, February 1, 2001; 73(2): 288 - 294.
[Abstract] [Full Text] [PDF]


Home page
GutHome page
E M Scott, I Gaywood, and B B Scott
Guidelines for osteoporosis in coeliac disease and inflammatory bowel disease
Gut, January 1, 2000; 46(90001): I1 - 8.
[Full Text] [PDF]


Home page
Am. J. Clin. Nutr.Home page
R. Vieth
Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety
Am. J. Clinical Nutrition, May 1, 1999; 69(5): 842 - 856.
[Abstract] [Full Text] [PDF]


box Article
 arrow  Table of Contents                
space
 arrow  Related articles in Annals
space
 arrow  Articles citing this article
space
box Services
 arrow  Send comment/rapid response letter
space
 arrow  Notify a friend about this article
space
 arrow  Alert me when this article is cited
space
 arrow  Add to Personal Archive
space
 arrow  Download to Citation Manager
space
 arrow  ACP Search                        
space
 arrow  Get Permissions
space
box PubMed
Articles in PubMed by Author:
  arrow  Marriott, B. M.
space
 arrow  Related Articles in PubMed
space
 arrow  PubMed Citation
space
 arrow  PubMed
space


 Home | Current Issue | In the Clinic | Past Issues | Search | Collections | CME | PDA Services | Subscribe | Contact Us | Help | ACP Online