onsumed less than the EAR for magnesium. In addition, 25.6% of females reported intakes that provided less than the EAR for iron, although the majority of iron intakes were from heme protein sources (i.e., chicken, hamburger, other beef and pork).

The finding of high sodium, phosphorus and vitamin A intakes in the setting of insufficient intakes of other key micronutrients emphasizes the need for medical students to learn how to optimize the nutrient density of their daily intakes. Certain simple additions or substitutions could be recommended that are likely to yield significant improvements. For example, substituting foods from the legumes group (i.e., dry beans, peas and lentils) as protein sources in main meals and adding various types of nuts and seeds as between-meal snacks would be a relatively easy strategy to better balance dietary intakes and a potential solution to improving the intakes of vitamin E as well as folate, iron, calcium, magnesium, potassium, fiber and protein [45]. Students could also be taught to make intentional choices regarding their staple foods such as selecting calcium-fortified orange juice and cereals that are folate-fortified and high in fiber.

While foods and beverages are the preferred sources of micronutrient intakes because of the variety, synergy and bioavailability of nutrients provided, the present data suggest that inadequate total food intake may be a problem in this population. In light of this concern, multivitamin multimineral (MVM) supplementation may be another strategy to close the gap between intakes and requirements [46]. Consistent with prior literature [47], the present data showed that about half (51%) of students in each cohort reported taking MVM regularly for an average of three years. For supplement users, total folate, vitamin E, vitamin D, calcium, magnesium and iron intakes were significantly greater than non-supplement users (all Ps < 0.001). Thus, supplement use increased total micronutrient intakes to levels that met the respective nutrient reference values, except for vitamin E which remained deficient in 14% - 28% of students in each cohort.

In interpreting these data, some limitations should be noted. The data were not collected from a random sample but rather a convenience sample of medical students.

While it is possible the findings might differ in the group of students who did not respond to the survey, the demographics of the responders are consistent with a recent nationally representative survey [48] and the findings from these students agree with larger and more representative investigation of medical students’ energy and nutrient intakes [21]. Secondly, like most methods of dietary assessment, all of the data are self-reported; it is possible that using a reduced-length FFQ allows underor over-reporting of energy and nutrient intakes by as much as 20% [50]. However, the actual reporting error rate in medical students overall and those sampled herein is unknown. Thus, it would not be possible to reliably correct for potential error rate in the present study [49]. Notably, the Block FFQs are widely used, have been tested in numerous populations, and the data collected are strongly associated with reference measures of intakes

(a)(b)

Table 1. (a) Average micronutrient intakes from reported food and beverage intakes of male second year medical students across six years; (b) Average micronutrient intakes from reported food and beverage intakes of female second year medical students across six years.

[21]. Moreover, using the FFQ allowed investigation of the absolute, unadjusted levels of micronutrient intakes, and thus, how much of each micronutrient subjects consumed (i.e., in millior micrograms). By doing so, comparison to the Dietary Reference Intakes was performed, as opposed to assessing only percentages or percentiles of intakes [50]. The other strengths of this study are the consistency of data collection methodology over several years and the assessment of important dietary factors that have not been previously reported in this population.

4. CONCLUSIONS

This is the first comparison of the specific micronutrient intakes of students enrolled in a US medical school to the Dietary Reference Intake values. The main finding was that dietary intakes were especially low in male and female students for key nutrients related to maintaining health and preventing chronic disease, that is, folate, vitamin D, vitamin E, calcium, magnesium, potassium and iron. Insufficient dietary intakes for these specific nutrients were consistent across all students in all years and lower than demographically-matched population-based data [51,52]. It is notable that only 25% of males and 22% of females reported consuming more than 2 servings of fruits per day. Likewise, only 23% of males and 19% of females reported consuming 3 or more servings of milk and dairy products per day. Even with the increased number of daily vegetable servings observed in female cohorts across the six years, vegetable intakes did not meet most recent guidelines which suggest consuming twice as many vegetable servings as previously recommended to achieve adequate intakes of the variety of vitamins, minerals and other micronutrients necessary for maintaining health [44].

Inadequate or excessive intakes of micronutrients can lead to various disorders. For one example, vitamin D deficiency combined with inadequate calcium intakes predisposes persons to demineralization of the skeleton which leads to osteomalacia, bone loss, osteopenia and/ or osteoporosis [53]. In addition to bone health, vitamin D may also have a role in risk for certain types of cancer and type 2 diabetes. For another example, iron, folate and vitamin B12 cause varying forms of anemia [54]. While the occurrence of macrocytic anemia from folate or vitamin B12 deficiency is rarer than iron deficiency anemia, folate intake is also crucial for prevention of neural tube defects, a serious consideration for women of reproductive age, such as those studied herein. Other functions of suboptimal B vitamin intake, including the role on plasma homocysteine concentration and development of cardiovascular disease continue to be investigated. Moreover, inadequate micronutrient intake (ie, vitamin A, vitamin D, the B vitamins, calcium, iron and zinc) may be associated with increased adiposity, a major public health concern as obesity is epidemic worldwide [55].

The reasons for the micronutrient inadequacies identified herein are likely multi-factorial and may include the significant time constraints inherent in the medical school environment [56], the high level of stress in that environment that has the potential to affect appetite and eating behaviors [57], financial considerations that may influence food purchasing patterns [58], as well as perceptions of body image that may limit the quantity of foods consumed [59]. Clearly, further investigation is warranted to elucidate the determinants of the dietary practices of medical students, as well as other health care professionals.

Nevertheless, the findings from this study may be used to design practical interventions for medical student populations to help them improve their dietary intakes, especially to improve the balance of micronutrients consumed, which may serve to reduce risk for development of chronic disease in these young adults. These data may also be used to enhance the nutrition education content of the medical school curriculum, possibly using publicly available tools such as those produced under the Nutrition Academic Award Program [17]. Ultimately, the goal is to stimulate greater awareness among medical students of their dietary intakes—not only to identify their personal dietary imbalances, and thus, improve their food selection choices to better meet public dietary recommendations, but also to enhance their preparedness as future healthcare providers so they are better able to identify and meet the nutrition needs of their patients.

5. ACKNOWLEDGEMENTS

The authors thank Charles D. Keil and Jessica Landsgesell, RD for assistance with data analysis and manuscript preparation.

REFERENCES

  1. US Department of Health and Human Services. http://health.gov/dietaryguidelines/2010.asp
  2. Frank, E., Galuska, D., Elon, L. and Wright, E. (2004) Personal and clinical exercise-related attitudes and behaviors of freshmen US medical students. Research Quarterly for Exercise & Sport, 75, 112-121.
  3. Frank, E. (2004) Physician health and patient care. The Journal of the American Medical Association, 291, 637. doi:10.1001/jama.291.5.637
  4. Frank, E., Rothenberg, R., Lewis, C. and Belodoff, B.F. (2000) Correlates of physicians’ prevention-related practices Findings from the Women Physicians’ Health Study. Archives of Family Medicine, 9, 359-367. doi:10.1001/archfami.9.4.359
  5. Frank, E., Wright, E.H., Serdula, M.K., Elon, L.K. and Baldwin, G. (2002) US women physicians’ personal and clinical nutrition-related practices. The American Journal of Clinical Nutrition, 75, 326-332.
  6. Spencer, E.H., Frank, E., Elon, L.K., Hertzberg, V.S., Galuska, D. and Serdula, M.K. (2006) Predictors of nutrition counseling behaviors and attitudes among US medical students. The American Journal of Clinical Nutrition, 84, 655-662.
  7. Frank, E., Breyan, J. and Elon, L. (2000) Physician disclosure of healthy personal behaviors improves credibility and ability to motivate. Archives of Family Medicine, 9, 287-290. doi:10.1001/archfami.9.3.287
  8. Podell, R.N., Gary, L.R. and Keller, K. (1975) A profile of clinical nutrition knowledge among physicians and medical students. Journal of Medical Education, 50, 888- 892.
  9. Phillips, M.G. (1971) The nutrition knowledge of medical students. Journal of Medical Education, 46, 86-90.
  10. Mlodinow, S.G. and Barrett-Connor, E. (1989) Physicians’ and medical students’ knowledge of nutrition. Academic Medicine, 64, 105-106. doi:10.1097/00001888-198902000-00017
  11. Davis, C.H. (1994) The report to Congress on the appropriate federal role in assuring access by medical students, residents, and practicing physicians to adequate training in nutrition. Public Health Report, 109, 824-826.
  12. Conroy, M.B., Delichatsios, H.K., Hafler, J.P. and Rigotti, N.A. (2004) Impact of a preventive medicine and nutriation curriculum for medical students. The American Journal of Preventive Medicine, 27, 77-80. doi:10.1016/j.amepre.2004.03.009
  13. Talip, W.A., Steyn, N.P., Visser, M., Charlton, K.E. and Temple, N. (2003) Development and validation of a knowledge test for health professionals regarding lifestyle modification. Nutrition, 19, 760-766. doi:10.1016/S0899-9007(03)00101-1
  14. Frankle, R.T., Williams, E.R. and Christakis, G. (1972) Nutrition education in the medical school: Experience with an elective course for first-year medical students. The American Journal of Clinical Nutrition, 25, 709-719.
  15. Thomson, C.A., Taren, D., Koff, N., Marian, M., Canfield, L., Bassford, T. and Ritenbaugh, C. (2000) An integrated nutrition curriculum in medical education. Journal of Cancer Education, 15, 127-129.
  16. Ammerman, A., McGaghie, W.C., Siscovick, D.S., Maxwell, K., Cogburn, W.E. and Simpson, R.J. Jr. (1989) Medical students’ knowledge, attitudes, and behavior concerning diet and heart disease. The American Journal of Preventive Medicine, 5, 271-278.
  17. Van Horn, L. (2006) The nutrition academic award: Brief history, overview and legacy. The American Journal of Clinical Nutrition, 83, 936S-40S.
  18. Wong, V., Millen, B.E., Geller, A.C., Rogers, A.E., Maury, J.J. and Prout, M.N. (2004) What’s in store for medical students? Awareness and utilization of expert nutrition guidelines among medical school preceptors. Preventive Medicine, 239, 753-759. doi:10.1016/j.ypmed.2004.02.046
  19. Mellen, P.B., Palla, S.L., Goff, D.C. Jr. and Bonds, D.E. (2000) Prevalence of nutrition and exercise counseling for patients with hypertension. United States, 1999 to 2000. Journal of General Internal Medicine, 19, 917-924. doi:10.1111/j.1525-1497.2004.30355.x
  20. Heimburger, D.C., Ullmann, D.O., Ramsey, M.J., Wooldridge, N.H., Epps, L.A., Hardin, J.M. and Hsu, C. (1994) Dietary habits of first-year medical students assessed during clinical nutrition course. Nutrition, 10, 214-220.
  21. Banks, W.L. Jr., Chan, W.M. and Williams, W.L. (1989) Use of food frequency questionnaire results to emphasize nutritional concepts for first year medical students—Medical College of Virginia. Bulletin of the New York Academy of Medicine, 65, 928-934.
  22. Spencer, E.H., Elon, L.K., Hertzberg, V.S., Stein, A.D. and Frank, E. (2005) Validation of a brief diet survey instrument among medical students. Journal of the American Dietetic Association, 105, 802-806. doi:10.1016/j.jada.2005.02.003
  23. US Department of Health and Human Services (2010) Dietary Guidelines for Americans. Office of Disease Prevention and Health Promotion. http://health.gov/dietaryguidelines/2010.asp
  24. Holick, M.F. (2004) Vitamin D: Importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis. The American Journal of Clinical Nutrition, 79, 362-371.
  25. Bakhireva, L.N., Barrett-Connor, E., Kritz-Silverstein, D. and Morton, D.J. (2004) Modifiable predictors of bone loss in older men: A prospective study. The American Journal of Preventive Medicine, 6, 436-442. doi:10.1016/j.amepre.2004.02.013
  26. Centers for Disease Control and Prevention (1991) Use of folic acid for prevention of spina bifida and other neural tube defects: 1983-1991. Morbidity and Mortality Weekly Report, 30, 513-516.
  27. Blot, I., Papiernik, E., Kaltwasser, J.P., Werner, E. and Tchernia, G. (1981) Influence of routine administration of folic acid and iron during pregnancy. Gynecologic and Obstetric Investigation, 6, 294-304. doi:10.1159/000299659
  28. Krishna, G.G. and Kapoor, S.C. (1991) Potassium depletion exacerbates essential hypertension. Annals of Internal Medicine, 115, 77-83.
  29. Coruzzi, P., Brambilla, L., Brambilla, V., et al. (2001) Potassium depletion and salt sensitivity in essential hypertension. The Journal of Clinical Endocrinology & Metabolism, 86, 2857-2562. doi:10.1210/jc.86.6.2857
  30. Sommer, A. and West, K.P. Jr. (1996) Vitamin A deficiency: Health, survival and vision. Oxford University Press, New York.
  31. Dawson, H.D. and Ross, A.C. (1999) Chronic marginal vitamin A status effects the distribution and function of T cells and natural T cells in aging Lewis rats. Journal of Nutrition, 129, 1782-1790.
  32. Stephensen, C.B. (2001) Vitamin A, infection and immune function. The Annual Review of Nutrition, 21, 167-192. doi:10.1146/annurev.nutr.21.1.167
  33. Mocchegiani, E., Giacconi, R., Muzzioli, M. and Cipriano, C. (2000) Zinc, infections and immunosenescence. Mechanisms of Ageing and Development, 121, 21-35. doi:10.1016/S0047-6374(00)00194-9
  34. Wintergerst, E.S., Maggini, S. and Hornig, D.H. (2006) Immune-enhancing role of vitamin C and zinc and effect on clinical condition. Annals of Nutrition and Metabolism, 50, 85-94. doi:10.1159/000090495
  35. Selhub, J., Jacques, P.F., Wilson, P.W., Rush, D. and Rosenberg, I.H. (1993) Vitamin status and intake as primary determinants of homocysteinemia in an elderly population. The Journal of the American Medical Association, 270, 2693-2698. doi:10.1001/jama.1993.03510220049033
  36. Ali, M.M. and Vaidya, R.R. (2007) Vitamin D and cancer. Journal of Cancer Research, 4, 225-230. doi:10.4103/0973-1482.38998
  37. White, E., Shannon, J.S. and Patterson, R.E. (1997) Relationship between vitamin and calcium supplement use and colon cancer. Cancer Epidemiology, Biomarkers & Prevention, 6, 769-774.
  38. Kampman, E., Slattery, M.L., Caan, B. and Potter, J.D. (2000) Calcium, vitamin D, sunshine exposure, dairy products and colon cancer risk (United States). Cancer Causes Control, 11, 459-466. doi:10.1023/A:1008914108739
  39. Block, G., Hartman, A.M. and Naughton, D. (1990) A reduced dietary questionnaire: Development and validation. Epidemiology, 1, 58-64. doi:10.1097/00001648-199001000-00013
  40. United States Department of Agriculture (2000) Agricultural Research Service. Nutrient Data Laboratory. http://www.ars.usda.gov/nutrientdata/
  41. Institute of Medicine (2005) Food and Nutrition Board. The dietary reference intakes for energy, carbohydrates, fiber, fat, protein and amino acids (macronutrients). National Academies Press, Washington DC.
  42. Institute of Medicine (2000) Food and Nutrition Board. Dietary reference intakes: Applications in dietary assessment. National Academies Press, Washington DC.
  43. United States Department of Agriculture. http://www.mypyramid.gov/
  44. Britten, P., Marcoe, K., Yamini, S. and Davis, C. (2006) Development of food intake patterns for the MyPyramid food guidance system, Journal of Nutrition Education and Behavior, 38, S78-S92. doi:10.1016/j.jneb.2006.08.007
  45. Mitchell, D.C., Frank, L.R., Hartman, T.J. and Curran, J.M. (2009) Consumption of dry beans, peas, and lentils could improve diet quality in the US population. Journal of the American Dietetic Association, 109, 909-913. doi:10.1016/j.jada.2009.02.029
  46. American Dietetic Association (2000) Position of the American Dietetic Association: Fortification and nutriational supplements. Journal of the American Dietetic Association, 105, 1300-1311.
  47. Spencer, E.H., Bendich, A. and Frank, E. (2006) Vitamin and mineral supplement use among US medical students: A longitudinal study. Journal of the American Dietetic Association, 106, 1975-1983. doi:10.1016/j.jada.2006.09.003
  48. Frank, E., Carrera, J.S., Elon, L. and Herzberg, V.S. (2006) Basic demographics, health practices, and health status of US medical students. The American Journal of Preventive Medicine, 31, 499-505. doi:10.1016/j.amepre.2006.08.009
  49. Subar, A.F., Kipnis, V., Troiano, R.P., et al. (2003) Using intake biomarkers to evaluate the extent of dietary misreporting in a large sample of adults: The OPEN study. American Journal of Epidemiology, 158, 1-13. doi:10.1093/aje/kwg092
  50. Block, G. (2000) Invited commentary: Another perspective on food frequency questionnaires. American Journal of Epidemiology, 154, 1103-1104. doi:10.1093/aje/154.12.1103
  51. Wakimoto, P. and Block, G. (2001) Dietary intake, dietary patterns, and changes with age: An epidemiological perspective. The Journals of Gerontology: Series A, 56, 65- 80.
  52. US Department of Agriculture and US Department of Health and Human Services (2000) What we eat in America, NHANES 2007-2008.
  53. Chung, M., Balk, E.M., Brendel, M., Ip, S., Lau, J., Lee, J., et al. (2009) Vitamin D and calcium: Systematic review of health outcomes. Agency for Healthcare Research and Quality, Rockville.
  54. Selhub, J. and Paul, L. (2011) Folic acid fortification: Why not vitamin B12 also? Biofactors, 37, 269-271. doi:10.1002/biof.173
  55. Garcia, O.P., Long, K.Z. and Rosado, J.L. (2009) Impact of micronutrient deficiencies on obesity. Nutrition Reviews, 67, 559-572. doi:10.1111/j.1753-4887.2009.00228.x
  56. Mothersbaugh, D.L., Hermann, R.O. and Warland, RH. (1993) Perceived time pressure and recommended dietary practices: The moderating effect of knowledge of nutrition. Journal of Consumer Affairs, 27, 106-126. doi:10.1111/j.1745-6606.1993.tb00740.x
  57. Dyrbye, L.N., Thomas, M.R. and Shanafelt, T.D. (2006) Systematic review of depression, anxiety, and other indicators of psychological distress among US and Canadian medical students. Academic Medicine, 81, 354-373. doi:10.1097/00001888-200604000-00009
  58. Drewnowski, A. and Darmon, N. (2005) Food choices and diet costs: An economic analysis. Journal of Nutrition, 135, 900-904.
  59. Futch, L.S., Wingard, D.L. and Felice, M.E. (1988) Eating pattern disturbances among women medical and graduate students. Journal of Adolescent Health, 9, 378-383. doi:10.1016/0197-0070(88)90032-0

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