Eggs are one of the most significant sources of dietary cholesterol.
However, does dietary cholesterol have an impact on levels of cholesterol in the blood?
This article explains the topic, reviews the evidence, and answers this question.
As there are numerous types of eggs, this article will refer to typical chicken eggs when discussing nutritional data.
Table of contents
- Background on eggs and cholesterol
- What do health organizations advise about dietary cholesterol intake?
- Does dietary cholesterol in eggs raise blood cholesterol levels?
- But do eggs raise LDL cholesterol levels?
- Eggs are nutritious, and context is required
Background on eggs and cholesterol
It is common to see eggs appear in media stories every month or two. As part of these stories, their dietary cholesterol content is often a talking point.
Sometimes you’ll see claims that eggs are “bad” because they contain cholesterol. However, other times you’ll hear that dietary cholesterol does not affect blood cholesterol levels.
Seeing these contrasting media stories can be very confusing for many people. This article will try to set the record straight.
Please note: answering the question of whether the dietary cholesterol in eggs raises blood cholesterol is not judging the nutritional value of eggs. This article is focused on objectively analyzing the impact of their cholesterol content, which does not necessarily comment on their health properties. Appropriate nuances will be discussed later in the article.
What is dietary cholesterol?
Cholesterol is a waxy substance that all humans and animals make, found within cells around the body. It plays a vital role in the production of hormones. The body, specifically the liver, makes cholesterol regardless of dietary intake (1).
However, scientific consensus states that high levels of LDL cholesterol (LDL-C) in the blood are a risk factor for cardiovascular disease (2).
Since animals store cholesterol (often in fat cells), we can consume cholesterol when we eat certain animal foods. ‘Dietary cholesterol’ is the common name for this consumed cholesterol.
On this note, eggs contain substantial cholesterol at approximately 186 mg per 50-gram large egg (3). Furthermore, data from the National Health and Nutrition Examination Surveys (NHANES) 2001-2014 demonstrated that eggs contribute 25% of total dietary cholesterol intake in the average American diet (4).
However, an important point: dietary cholesterol is not the same as blood cholesterol.
These are different things; many diet and lifestyle factors can influence blood cholesterol levels.
Is dietary cholesterol intake one of them? We’ll come to this shortly.
What do health organizations advise about dietary cholesterol intake?
Before looking at the recent research on dietary cholesterol and eggs, let’s examine what public health organizations advise on dietary cholesterol intake.
Dietary Guidelines for Americans
The Dietary Guidelines for Americans, published every five years, previously advised limiting dietary cholesterol intake to 300 mg daily until the 2015-2020 iteration.
The 2015-2020 guidelines dropped this guidance while providing the following explanation:
“The Key Recommendation from the 2010 Dietary Guidelines to limit consumption of dietary cholesterol to 300 mg per day is not included in the 2015 edition, but this change does not suggest that dietary cholesaterol is no longer important to consider when building healthy eating patterns. As recommended by the Institute of Medicine, individuals should eat as little dietary cholesterol as possible while consuming a healthy eating pattern.”2015-2020 Dietary Guidelines for Americans, Chapter 1, Page 32
The most recent Dietary Guidelines for Americans, the 2020-2025 edition, mentions dietary cholesterol but still absent a target limitation:
“The National Academies recommends that trans fat and dietary cholesterol consumption to be as low as possible without compromising the nutritional adequacy of the diet.”Dietary Guidelines for Americans, 2020-2025, Chapter 1, Page 44
American Heart Association
Following the elimination of dietary cholesterol target limits in recent dietary guidelines, the American Heart Association published a science advisory in 2020.
This advisory discussed how it was difficult to ascertain the effect of dietary cholesterol on blood cholesterol for two reasons (5):
- Most foods high in cholesterol are also high in saturated fat, which tends to increase LDL-C (low-density lipoprotein cholesterol) in the blood.
- Heart-healthy dietary patterns tend to be low in cholesterol
However, the advisory also recommended that healthy adults stick to one egg per day (or equivalent). Also, the report states that older adults with normal cholesterol levels can increase this to two eggs per day.
U.S. Food and Drug Administration (FDA)
The FDA publishes a ‘daily value’ recommendation concerning the amount a consumer should consume or not exceed daily (6).
This daily value is based on a 2000-calorie diet. The FDA has set a daily value of 300 mg for dietary cholesterol.
As previously mentioned, a large 50-gram egg contains approximately 186mg of dietary cholesterol (3).
Does dietary cholesterol in eggs raise blood cholesterol levels?
A meta-regression analysis published in 2019 looked at the effects of dietary cholesterol intake on LDL cholesterol (7).
This analysis included fifty-five randomized controlled dietary intervention trials involving 2652 participants.
To summarize, here is an overview of what the analysis demonstrated:
- There was a positive relationship between dietary cholesterol intake and increased LDL cholesterol. Based on the mean predictions of the meta-regression, it suggests that a 100mg increase in dietary cholesterol would raise LDL cholesterol by 4.52 mg/dL.
- However, the effect significance of dietary cholesterol appears to reduce as intake increases. For example, a 200mg increase in dietary cholesterol would increase LDL cholesterol by 6.76 mg/dL rather than have double the effect of 100mg.
- The extent of these increases in different individuals is complex and may depend on baseline diet and current LDL cholesterol levels. In other words, there may be minimal effect or slightly more of an impact, depending on the person.
- A sensitivity analysis investigated the impact of baseline LDL cholesterol levels. This analysis found that changes in dietary cholesterol intake of 100 mg per day predict an increase in LDL cholesterol of 2.7, 3.6, 4.6, and 5.5 mg/dL for people with baseline LDL cholesterol levels of 100, 125, 150, and 175 mg/dL, respectively.
This meta-regression analysis is the most current, in-depth analysis of dietary cholesterol’s impact on blood cholesterol, specifically LDL cholesterol.
Thus, it does seem to show that dietary cholesterol will raise LDL cholesterol levels.
Context: how significantly does dietary cholesterol raise LDL cholesterol levels?
For some context, it is worth noting that the extent of the increase in LDL cholesterol from dietary cholesterol intake is relatively small compared to other nutritional and lifestyle factors that can increase it. Such factors include (8, 9, 10, 11):
- Diets high in saturated fat and refined carbohydrates
- (Lack of) fiber intake
- A lack of physical activity
- Unfiltered coffee consumption
- Overweight and obesity
Additionally, as the impact of dietary cholesterol on LDL cholesterol appears to fall as intake increases, the effect may be minimal for some people. In this regard, the mean dietary cholesterol intake in the United States stood at 293 mg per day, according to data from NHANES 2001-2014 (4).
Also, some people are hyperresponders or hyporesponders to dietary cholesterol. Thus, it may cause more (or less) of an increase in LDL cholesterol in these groups than others (12).
But do eggs raise LDL cholesterol levels?
You may wonder if eggs contain dietary cholesterol and dietary cholesterol likely impacts blood LDL cholesterol, doesn’t that mean we can assume eggs raise LDL cholesterol?
The effect of a particular nutrient or compound (in this case: dietary cholesterol) may not always be the same depending on the food.
For example, some foods may contain high amounts of a nutrient that can increase LDL-C. At the same time, they may also have other components that lower this increase.
Cheese is an excellent example to illustrate this point:
Cheese contains a milk fat globule membrane (MFGM), which encases its milk fat globules. The MFGM buffers the effect of the saturated fatty acids in cheese. As a result, cheese has a much smaller impact on LDL-C than other dairy products like butter, even when matched for equivalent saturated fat content (13, 14).
In other words, just because dietary cholesterol can slightly raise LDL cholesterol levels doesn’t automatically mean that eggs will do the same.
However, the data on egg intake and LDL cholesterol suggest that eggs increase it.
Studies on eggs and LDL-C
- A systematic review and meta-analysis published in the Journal of Food Biochemistry in 2020 looked at the response of different egg dosages on cholesterol. The meta-analysis examined fifty-three studies that evaluated the impact on LDL-C. The analysis results demonstrated that egg intake higher than one per day consistently increased LDL-C levels (15).
- A 2020 systematic review and meta-analysis published in the Nutrients journal examined the association between egg consumption and cholesterol. The analysis included thirteen randomized controlled trials with data on the impact of eggs on LDL-C. The study demonstrated that higher egg intakes increased LDL-C compared to the control groups (16).
If an individual is actively seeking to lower their LDL cholesterol, they should discuss the role of eggs and overall diet with their dietitian or doctor.
Eggs are nutritious, and context is required
As this article shows, research suggests that dietary cholesterol does have a small impact on blood cholesterol.
Furthermore, studies focusing specifically on eggs show that they raise LDL cholesterol compared to no-egg control groups.
That said, it is important to note that eggs are a good source of protein and contain a wide range of vitamins and minerals.
Eggs and nutrient adequacy
For one thing, it is worth noting that studies show eggs can make a significant contribution to nutrient adequacy in people who eat them:
Based on data from the National Health and Nutrition Examination Survey (NHANES) 2001-2016, eggs (and dietary patterns containing them) significantly contributed to nutrient intake.
For instance, egg consumers had higher intakes of fiber, calcium, magnesium, potassium, choline, vitamin A, vitamin C, vitamin D, and vitamin E than non-consumers. Most notably, 24.4% of egg consumers were above the ‘adequate intake’ level for choline compared to only 4.3% of non-consumers (17).
Context, comparative foods, and overall diet
It is also worth noting that all foods will impact a specific health marker (in this case: LDL-C) relative to a comparison food.
For example, a meal of eggs and vegetables would likely impact LDL-C less than a fatty cut of beef cooked in butter. In contrast, it would have a more significant impact than a meal of tofu or chicken breast with vegetables.
However, eggs contain higher amounts of specific vitamins and minerals like choline, iodine, selenium, and vitamin D than chicken breast and tofu. For an individual with an insufficient intake of these nutrients, it would be reasonable to argue that eggs are a beneficial dietary inclusion (3, 18, 19).
In other words, nutrition is complex, and the overall dietary pattern and combination of foods and nutrients consumed matter most.
The Dietary Guidelines for Americans 2020-2020 state that eggs are a ‘nutrient-dense food’ that can be part of a ‘healthy dietary pattern’ (20).