Effects of egg consumption on vitamin D status of adults

Despite Australia’s reputation as a sunburnt country, the vitamin D deficiency rate in Australians is among the highest in the world during the winter months. Data shows that 36% of Australian adults will experience a wintertime drop in their vitamin D levels this year, making them more prone to flus and respiratory infections through the peak of the season.

This new peer-reviewed research from Melbourne’s Deakin University has shown that consuming at least seven eggs a week or one egg per day can help maintain the body’s levels of vitamin D throughout winter.

Aim of the Research

The primary aim of this 12-week randomised controlled trial was to compare the effects of consuming 2, 7 and 12 commercially available eggs/week on serum 25(OH)D concentrations during the autumn-winter months in Australian adults.

Secondary aims were to investigate the effects of the intervention on blood lipids as there has been some concerns that eggs might increase the risk of cardiovascular disease, and the feasibility (adherence) and acceptability to consuming the different doses of eggs.

The current Australian Dietary Guidelines don’t have a limit for how many eggs can be consumed per week as part of a healthy, balanced diet. This study is the first to investigate if there is a dose-response relationship between commercially available Australian eggs and blood vitamin D levels

Method

The research used randomised controlled trials whereby 51 adults aged 25-40 years residing in Melbourne and Geelong, Australia, were randomly allocated (like the flip of a coin) to consume either 2 eggs/week (n=17), 7 eggs/week (n=17) or 12 eggs/week (n=17) for 12 weeks.

Key Findings

• Vitamin D deficiency is a common problem in Australia, with 20% of Australian adults (~3.3 million people) aged 25 years and over reported to be deficient and a further 43% classified as having insufficient circulating vitamin D concentrations. Young adults aged 25-34 years are at the greatest risk of being deficient, particularly at higher latitudes and during the winter months when circulating vitamin D levels decrease by 25-30%.
• Consumption of 7 commercially available eggs per week for 12 weeks, which is in line with the current Australian dietary guidelines which recommends up to 7 eggs per week, was safe, acceptable, and effective for attenuating the wintertime decrease in blood vitamin D concentrations in young Australian adults. Consuming either 7 or 12 eggs per week did not adversely influence body weight or blood lipid concentrations in the young adults completing the study.
• Participant acceptability profiles to eating the eggs were positive and similar for young adults consuming 7 or 12 eggs per week over the 12-week study period.
• Although not related to the objectives of the study, consumption of 12 eggs per week was effective for increasing dietary protein intake.
• This study indicates that weekly consumption of at least 7 commercially available eggs should be considered as an important dietary approach to help to optimise vitamin D status during the winter months in Australia.

The study has also been published in The Journal Of Nutrition.