Australians’ usual egg consumption is a document prepared by researchers at the CSIRO. The CSIRO is the premier Australian government-funded research organisation.
The conclusion of this document states:
This document is a marketing document. It needs a lot of imagination to make such a conclusion from the CSIRO’s published research papers. This conclusion also contradicts a number of other studies that show consuming eggs is detrimental.
I sent an email on 28th October 2017 to the lead author of this document, Dr Gilly Hendrie. Hendrie is also the lead author of a number of journal articles relating to the Healthy Diet Index. A copy of this email can be found at CSIRO Healthy Diet Score and Egg Consumption in Australia
The response will be published when it is received.
The survey is based on 38 questions designed to determine how well self-reported dietary intakes reflect compliance to Australian Dietary Guidelines.
First major issue is that self-reported dietary intakes a notoriously unreliable. There was no validation to test if the self-reported dietary intakes match the actual intakes.
Second major issue is that the CSIRO’s test for validity simply compared self-reported surveys. The claim that the “validity analysis showed moderate correlation between SFS#1 [Short Food Survey #1] and 24-hour recalls (ICC = 0.43 [. . .]).” is misleading. According to the paper, “the survey overestimated the diet index score by an average of 12.7 points out of 100 [-20.11:42.94] in comparison to recalls”.
A 43% correlation is not a moderate correlation—stating that it is even a fair correlation is somewhat optimistic. Note that the average difference was 13 points with that range of differences being -20 to 43 out of a possible score of 100. Deriving consistent results from the Healthy Diet Score survey is obviously difficult.
The only health outcome that is recorded in the Health Diet Score is the weight status which is based on the BMI. The weight status can be one of the following: underweight; normal weight, overweight, obese.
The third major issue is that the survey does not address the only question that really counts—that is, which food intakes are correlated to healthy outcomes.
The Healthy Diet Survey was used to justify the “Eggs are OK every day” campaign.
This is despite the fact that, at the most optimistic, we can only state that there is a fair correlation between two different self-reported dietary survey and despite the fact that the Health Diet Score only measures compliance to dietary guidelines and not actual health outcomes.
|Daily Egg Consumption||HDS|
|High consumption (> 1.0)||61.3|
Daily egg consumption compared with average HDS
The justification for “Eggs are OK everyday”, is that the as the egg consumption increases, so does the Healthy Diet Score. However, the Healthy Diet Score has not been shown to be associated with an increase in health outcomes.
If the weight status is compared with the egg consumption and Healthy Diet Score, a different observation is shown.
|Weight Status||Eggs per day - male||Eggs per day - female||Mean Diet Score|
|Underweight||1.04 (2.24)||0.62 (1.20)||59.6 (14.4)|
|Normal weight||0.83 (1.34)||0.77 (1.28)||60.5 (12.6)|
|Overweight||0.89 (1.65)||0.83 (1.45)||58.1 (12.5)|
|Obese||0.98 (1.84)||0.88 (1.58)||55.7 (13.2)|
The mean egg consumption and mean HDS compared with weight status.
The standard deviation is shown in brackets.
There is an increase in body weight as the number of eggs consumed increases and a decrease in the mean of the Healthy Diet Score. This clearly contradicts the observation that egg consumption is associated with an increase in healthy outcomes.
There are a number of dietary indices that attempt to measure the quality of dietary intake. A number of different version for most of these indices. Examples include:
- Diet Quality Index
- Healthy Eating Index
- Mediterranean Diet Score
- Overall Nutritional Quality Index
- Plant Diet Indices such as Plant Diet Index, Healthy Plant Diet Index and Unhealthy Plant Diet Index
- Healthy Diet Score from the CSIRO
A challenging problem is to determine how accurately these indices reflect healthy outcomes.
The Healthy Diet Score’s discretionary food items consists of alcohol, cakes and biscuits, chocolate and confectionery, fried potato products, ice-cream, muesli and snack bars, processed meat and products, savoury pies and pastries, savoury snacks, sugar sweetened beverages and takeaway foods. These items have no nutritional value and are not beneficial. A person is allocated zero points or 20 points for this category.
Below are three examples where a choice of two food items generate the same number of points. Do the two choices create the same health outcomes?
- Consuming either no discretionary or consuming two servings of discretionary each and every day will both add 20 points to your score.
- Does eating 3 servings of fruit and 6 servings of vegetables have the same health outcomes as eating 2 servings of discretionary items a day? Both will add 20 points to your Health Diet Score.
- Always trimming your meat of fat and always eating wholegrain breads will both add 5 points to your score.
- Eating 3 servings a day of red meat, poultry and fish adds 10 points to your score which is the same as consuming 3 servings of legumes, tofu, nuts and seeds.
Dairy, meat, fish, poultry are given positive ratings in the Health Diet Score despite Seventh-day Adventists’ studies consistently showing an improvement in health status as the diet becomes more vegan. The Odds Ratio in the following table relates to Type 2 diabetes.
|Category||%||BMI||Type 2 diabetes
No red meat, fish, poultry, dairy, eggs
Vegan with eggs and milk
Vegan with fish, milk and eggs
Red meat, poultry less than once a week plus fish, milk, and eggs
Red meat, poultry more than once a week plus fish, milk, and eggs
(*) After adjustment for age, sex, ethnicity, education, income, physical activity, television watching, sleep habits, alcohol use and BMI
These figures are after adjustment for BMI, physical activity and television watching which not independent variables.
Note that the comparisons are with Californian Adventists who are much healthier that the average Californian who are also much healthier than the average American.
The life expectancies of vegan Californian Adventist men and women are higher than those of any population studied.
The Physicians’ Health Study commenced in 1981. As well as examining the role of aspirin and a beta-carotene supplement, on heart disease and cancer, it also examined the role of egg consumption on health. The result from a 20-year follow-up showed a significant correlation between egg consumption and all-cause mortality. A key finding is that physicians consuming 7 or more eggs per week had a 31% increase in all-cause mortality compared with those consuming less than 1 egg per week. For diabetic physicians, the association was much higher with the increase in mortality slightly more than doubled.
A British study reported a 2.7 times greater risk of cardiac deaths for those consuming 6 or more eggs per week.
Based on the above observations, the recommendation for “one egg a day” does not appear to be justified.
- Hendrie, G., Baird, D., & Noakes, M. (2016, October). Australians’ usual egg consumption. CSIRO Publications.
- Le, L. & Sabate, J. (2014) Beyond Meatless, the Health Effects of Vegan Diets: Findings from the Adventist Cohorts. Nutrients. 6 (6), 2131–2147.
- Fraser, G. E., & Shavlik, D. J. (2001). Ten Years of Life – Is It a Matter of Choice? Archives of Internal Medicine, 161(13), 1645–1652. https://doi.org/10.1001/archinte.161.13.1645
- Djoussé, L. & Gaziano, J. M. (2008) Egg consumption in relation to cardiovascular disease and mortality: the Physicians’ Health Study. American Journal of Clinical Nutrition. 87 (4), 964–969.
- Mann, J. I. et al. (1997) Dietary determinants of ischaemic heart disease in health conscious individuals. Heart. 78 (5), 450–455.