JAMA Letter to the Editor rejected

I found an article in JAMA“Associations of Dietary Cholesterol or Egg Consumption With Incident Cardiovascular Disease and Mortality” by Victor W. Zhong et al [1]

That article is just an observational study with a lot of flaws.

So we sent a Letter to the editor of JAMA.

Other factors than egg consumption gives higher risk of incident CVD and all-cause mortality

The article is an observational study.

The article is proposing that dietary cholesterol or egg consumption increases the risk of incident CVD and all-cause mortality.

The basic sciences of mathematics, physics and biochemistry tell another story.

The fact is that an egg contains about 200 mg of cholesterol [2]. The body mass of a standard person is assumed to be 70 kg/154 lb. Normal blood volume is 8 % of body mass or 5.6 L or 56 dL and plasma volume 3 L or 30 dL

The total amount of cholesterol in the blood can be calculated as 200 mg/dL*30 dL=6 000 mg of cholesterol or in SI units 5.17 mmol/L*3.0 L*386.6 g/mol=6 000 mg.

As an egg contains 200 mg cholesterol, it would theoretically increase the total cholesterol amount in the blood from 6 000 to 6 200 mg.

The concentration would theoretically increase from 200 mg/dL to 207 mg/dL or from 5.17 mmol/L to 5.34 mmol/L. The increase is less than 3.3 % of the total blood content of cholesterol and is immeasurable in clinical laboratories.

The total amount of cholesterol in the body is about ten times greater than in the blood. The egg-caused increase of cholesterol in the body is less than 0.3 %. Maintenance of the cholesterol utilised and damaged in neurotransmission, myelin sheathing, cellular maintenance and lipid circulation requires the body to produce about 2-5 grams of neo-cholesterol-genesis daily [3].

Conclusion: The amount of cholesterol in an egg gives an insignificant and immeasurable increase of the cholesterol concentration in the blood. See also a case report from 1991 3 where 25 eggs a day showed no increase in the cholesterol level in the body.

The data above implies that there are factors other than egg consumption that give rise to the “higher risk of incident COD and all-cause mortality in a dose-response manner” proposed by Victor W. Zhong et al in their article.

Lipid profiles within blood plasma cholesterol are improved when HbA1c is well controlled and may point the way to a better understanding of lipid dysfunction, being lipid receptor damage by sugar rather than the over-production of cholesterol in the liver [4].

These results should be considered in the development of dietary guidelines and updates.

Björn Hammarskjöld                                                          Glyn Wainwright
Assistant professor in Pediatrics at Strömstad Academy      MSc MBCS CITP CEng
M.D., Ph.D. (Biochemistry)                                                 Independent Reader of Research
Former Senior Chief in Pediatrics                                               
Independent Senior Scientist in Nutrition                                     

E-mail: bjorn@hammarskjold.nu

Funding: The authors received no funding for this work.

Competing interests: The authors have no competing interests

Provenance: Written by authors not externally peer reviewed.


[1] Victor W. Zhong et al “Associations of Dietary Cholesterol or Egg Consumption With Incident Cardiovascular Disease and Mortality” JAMA. 2019;321(11):1081-1095. https://jamanetwork.com/journals/jama/article-abstract/2728487

[2] Nutrient Data for Whole, Large Eggs from a USDA Nationwide Sampling Nutrition Facts, Shell Eggs

[3] Fred Kern, Jr., M.D. “Normal Plasma Cholesterol in an 88-Year-Old Man Who Eats 25 Eggs a Day — Mechanisms of Adaptation”

N Engl J Med 1991; 324:896-899 DOI: 10.1056/NEJM199103283241306  https://www.nejm.org/doi/full/10.1056/NEJM199103283241306?

[4] Voloshyna I, Godoy JG. , Littlefield, MJ, Leon JD, Magana MC, et al. Advanced Glycation End Products Promote Pro-Atherogenic Changes in Cholesterol Transport: A Possible Mechanism for Cardiovascular Risk in Diabetes. (2014) Intern Med S11: 005. doi:10.4172/2165-8048.S11-005

That letter was rejected

Dear Prof Hammarskjöld:

Thank you for your recent letter to the editor. Unfortunately, because of the many submissions we receive and our space limitations in the Letters section, we are unable to publish your letter in JAMA.

After considering the opinions of our editorial staff, we determined your letter did not receive a high enough priority rating for publication in JAMA. We are able to publish only a small fraction of the letters submitted to us each year, which means that published letters must have an extremely high rating.

But my coauthor Glyn Wainwright commented.

I guess they unleashed quite a storm with the article and will defend the original editorial decision to publish.

Björn Hammarskjöld and Glyn Wainwright