Lack of sufficient vitamin D intake is recognized as a global public health problem.1,2 In fact, the 2011-12 National Health Survey revealed that 20% of adults in Australia were vitamin D deficient, with the highest deficiency in adults aged 25-34 years.3 Due to research emphasizing the importance of vitamin D for bone health and other non-skeletal conditions, it is important to maintain sufficient levels, especially during the winter when the risk of deficiency more than doubles.3,4
Sun exposure is the main source of vitamin D; however, geographical differences, seasonal changes in ultraviolet radiation, differences in skin pigmentation, lifestyle habits, and sun protection methods make it difficult to achieve adequate concentrations. Eggs are one of the few food sources that contain vitamin D, with significant amounts of vitamin D3 and the hydroxylated form of vitamin D3.
In a recent article published in the Journal of Nutrition (DOI: https://doi.org/10.1093/jn/nxac044), researchers conducted a 12-week randomized controlled trial to compare the effects of consuming eggs on serum 25(OH)D concentrations during the autumn-winter months.
The 42 participants who completed the study were aged 25-40 years old, recruited from Melbourne and Geelong in Victoria, Australia, and randomly allocated to a group consuming either 2, 7, or 12 commercial eggs per week. The intervention period ran from May to August 2021 in Melbourne, Australia. To participate in the study, individuals needed to not be allergic to eggs, be a non-smoker, spend less than 3 hours per day outdoors between 10am and 2pm, and could not be taking supplements that contain vitamin D or consume over three eggs per week among other criteria. Participants purchased Woolworths Extra-Large Free-Range Eggs and were advised to eat each of them whole, not as part of a shared meal, and not to consume any alternative eggs while maintaining their typical diet.
Study Findings
The major finding of this 12-week study is that consumption of 7 or 12 commercially available eggs per week was equally effective for attenuating the wintertime decrease in serum 25(OH)D concentrations in young Australian adults; however, in the control group which consumed 2 eggs/week, their serum 25(OH)D concentrations decreased by 28.6nmol/L. Additionally, there were no group differences in body weight or any serum lipid measure emphasizing the lack of adverse health effects regardless of consumption. The acceptability profiles of consuming eggs were also positive with no significant differences between groups.
The researchers conclude that “consumption of 7 commercially available eggs per week, which is in line with the current Australian dietary guidelines, was safe, acceptable, and effective for attenuating the wintertime decrease in serum 25(OH)D concentrations in young Australian adults.”
References
1. Hilger J, Friedel A, Herr R, Rausch T, Roos F, Wahl DA, Pierroz DD, Weber P, Hoffmann K. A systematic review of vitamin D status in populations worldwide. British journal of nutrition. 2014 Jan;111(1):23-45.
2. Amrein K, Scherkl M, Hoffmann M, Neuwersch-Sommeregger S, Köstenberger M, Berisha AT, Martucci G, Pilz S, Malle O. Vitamin D deficiency 2.0: an update on the current status worldwide. European journal of clinical nutrition. 2020 Nov;74(11):1498-513.
3. Malacova E, Cheang PR, Dunlop E, Sherriff JL, Lucas RM, Daly RM, Nowson CA, Black LJ. Prevalence and predictors of vitamin D deficiency in a nationally representative sample of adults participating in the 2011–2013 Australian Health Survey. British Journal of Nutrition. 2019 Apr;121(8):894-904.
4. Daly RM, Gagnon C, Lu ZX, Magliano DJ, Dunstan DW, Sikaris KA, Zimmet PZ, Ebeling PR, Shaw JE. Prevalence of vitamin D deficiency and its determinants in Australian adults aged 25 years and older: a national, population‐based study. Clinical endocrinology. 2012 Jul;77(1):26-35.
