Do eggs raise your cholesterol or heart-disease risk?

Why eggs were blamed. Eggs are a major source of dietary cholesterol, and in controlled feeding studies each extra 100 mg of it a day raised total cholesterol by about 2.2 mg/dL and nudged the ratio of total to HDL cholesterol up⁹. A 2025 umbrella review found LDL about 7 mg/dL higher on average with egg intake, but rated the evidence very weak³. Responses differ: roughly two-thirds of people change little, and those who do respond tend to raise both LDL and HDL².

What long-term studies find. Three US cohorts of 215,618 people found that eating at least one egg a day was not linked to cardiovascular disease, and a meta-analysis found no association per egg per day, with possibly lower risk in Asian cohorts¹. In three international studies (PURE, ONTARGET and TRANSCEND) covering about 177,000 people in 50 countries, egg intake was unrelated to lipids, death or major cardiovascular events⁷. The dissent: pooled US data tied each extra half egg a day to 6% more cardiovascular disease and 8% higher mortality, but the egg link vanished after adjusting for dietary cholesterol⁸, and a cohort of 521,120 older Americans found 7% higher all-cause mortality per half egg¹⁰.

Why studies disagree. People who eat more eggs tend to eat more red meat, have a higher BMI and use fewer statins¹, so what eggs are eaten with may matter as much as the eggs. The American Heart Association says dietary guidance should focus on healthy patterns such as Mediterranean-style and DASH-style diets, which are inherently relatively low in cholesterol¹¹.

Diabetes. A meta-analysis linked higher egg intake to more type 2 diabetes and to more cardiovascular disease among people who already had diabetes⁴. Yet in a randomized trial of 128 people with prediabetes or type 2 diabetes, 12 or more eggs a week caused no adverse changes in cholesterol, blood sugar control or inflammation compared with fewer than two⁵.

TMAO and choline. Gut bacteria can turn choline in eggs into TMAO, a compound associated with cardiovascular risk. In a crossover trial, two eggs a day for four weeks raised blood choline and betaine but not TMAO¹². See TMAO and choline.

In practice. About one egg a day fits most healthy diets. For nutrition, see eggs: the perfect food; for pasture-raised and organic eggs, see organic meat, dairy and eggs.

Large analyses that disagree

The Zhong analysis pooled individual data from six US cohorts (29,615 adults, median follow-up 17.5 years, 5,400 cardiovascular events, 6,132 deaths). Each extra 300 mg of dietary cholesterol a day went with higher cardiovascular risk (HR 1.17, 1.09 to 1.26) and mortality (HR 1.18, 1.10 to 1.26); each extra half egg a day went with HR 1.06 (1.03 to 1.10) for cardiovascular disease, an absolute increase of 1.11%, and 1.08 for mortality. After adjusting for dietary cholesterol, egg associations were no longer significant (HR 0.99 for cardiovascular disease, 1.03 for mortality)⁸. The Harvard analysis followed 215,618 US nurses and health professionals for up to 32 years (14,806 events): at least one egg a day versus less than one a month gave HR 0.93 (0.82 to 1.05). Its meta-analysis of 33 estimates (1.72 million people, 139,195 events) found RR 0.98 (0.93 to 1.03) per daily egg, with US 1.01, European 1.05 and Asian 0.92 (0.85 to 0.99)¹. The NIH-AARP cohort (521,120 people, 129,328 deaths over a median 16 years) found HR 1.07 per half egg for all-cause, cardiovascular and cancer mortality, with cholesterol mediating about 62% of the cardiovascular figure¹⁰. In PURE (146,011 people in 21 countries), seven or more eggs a week versus less than one gave HR 0.96 (0.89 to 1.04) for the composite outcome, 1.04 for mortality and 0.92 (0.83 to 1.01) for major cardiovascular disease, with similar results in 31,544 people with vascular disease⁷.

Cholesterol and lipid evidence

A meta-analysis of 17 controlled feeding studies (556 people) found each 100 mg of added dietary cholesterol raised total cholesterol 0.056 mmol/L (2.2 mg/dL), HDL 0.3 mg/dL and the total-to-HDL ratio by 0.020 (0.010 to 0.030), and concluded that advice to limit cholesterol may still be valid⁹. The 2025 umbrella review covered 14 meta-analyses since 2020 and found LDL higher by 7.39 mg/dL (5.82 to 8.95) and total cholesterol by 9.12 mg/dL (7.35 to 10.89) with egg intake, but no association with cardiovascular outcomes or all-cause mortality. It rated evidence quality critically low and concluded there was insufficient evidence to discourage eggs³. A review by researchers who report prior funding from the Egg Nutrition Center describes variable responses, with about two-thirds of people minimally affected, and an LDL-to-HDL ratio that is typically maintained in responders². The AHA advisory judged observational data generally unrelated to cardiovascular risk, while most trial meta-analyses link intakes above the current average to higher total or LDL cholesterol¹¹.

Diabetes and TMAO

A meta-analysis of 22 cohorts found no link between at least one egg a day and cardiovascular disease overall (HR 0.96, 0.88 to 1.05), but higher type 2 diabetes incidence (HR 1.42, 1.09 to 1.86) and, in people with diabetes, higher cardiovascular disease (HR 1.69, 1.09 to 2.62)⁴. The DIABEGG trial randomized 128 people with prediabetes or type 2 diabetes to a high-egg (12 or more a week) or low-egg (under two) diet through 3 months of weight loss and 6 months of follow-up. Weight loss was the same (about 3.1 kg), and there were no differences in glycemia, lipids, inflammation, oxidative stress or adiponectin⁵. In a crossover trial of 20 overweight postmenopausal women with mildly raised cholesterol, two whole eggs a day versus a yolk-free substitute for four weeks raised plasma choline and betaine, yet TMAO and gut microbiome composition did not change¹².

Where the evidence conflicts

Egg intake in cohorts relies on food-frequency questionnaires, and egg eaters differ in diet and habits. US analyses disagree with one another, and Asian cohorts point the other way. Trials measure risk markers, not heart attacks. Safety is separate from heart health: shell eggs were the main vehicle of a Salmonella Enteritidis epidemic from the 1970s, which fell after farm, refrigeration and consumer-education measures, though outbreaks persist⁶.

Bottom line

Confidence is 4 of 5 for the general population: about an egg a day is not clearly harmful, and may nudge LDL up in some. Confidence is lower for people with diabetes or high LDL, where individual advice is warranted.