Eggs

What it is

Eggs are a whole food. A whole egg provides protein, choline, antioxidants, vitamins and minerals [1]. Lutein, a yellow pigment that also sits in the eye, is found in egg yolk [2].

Some studies compare whole eggs with egg whites [3].

How it might work

Proposed: eggs are a source of high-quality protein, and whole eggs may stimulate muscle repair more than egg whites with the same protein, possibly because of nutrients in the yolk [4].

Proposed: lutein and zeaxanthin may build up in the macula, which would link egg yolk lutein to eye pigment and possibly eye health [5].

Proposed: egg protein is digested slowly, so amino acids reach the blood more slowly than after cottage cheese, although the feeling of fullness was similar [6].

What the research says

Egg allergy in babies. A meta-analysis of nine trials (4,811 infants) found that introducing egg at 3 to 6 months of age lowered the risk of egg allergy (risk ratio 0.60) [7]. In a trial of 147 infants with eczema, early egg powder reduced egg allergy at 12 months: 5 of 60 (8%) in the egg group and 23 of 61 (38%) in the placebo group in the primary analysis [8]. Two larger trials in infants without eczema found no significant reduction [9][10].

Heart disease and stroke. In large US cohorts pooled in a 2020 BMJ analysis, eating up to one egg a day was not associated with cardiovascular disease (pooled relative risk 0.98 per extra egg a day, 0.93 to 1.03) [11]. A 2013 meta-analysis of cohort studies found no link to coronary heart disease per egg a day (0.99, 0.85 to 1.15) [12]. The 2020 analysis also found a lower risk in Asian cohorts (0.92, 0.85 to 0.99) [11].

Stroke results differ. A 2016 meta-analysis of seven cohort studies found 12% lower stroke risk for high versus low egg intake (0.88, 0.81 to 0.97) [1]. Other pooled analyses found no significant link: 0.91 per egg a day (0.81 to 1.02) [12] and 0.99 (0.91 to 1.07) [11].

Feeling full. In 21 men, an egg breakfast led to fewer calories over the next 24 hours than an isocaloric bagel breakfast [13]. In 140 adults with prediabetes or type 2 diabetes, the high-egg group reported less hunger and more satiety after breakfast than the low-egg group [14]. Not every trial agrees: in children and adolescents, an egg breakfast did not change lunchtime eating compared with a bagel [15].

Weight loss. In a 12-month trial of 128 adults with prediabetes or type 2 diabetes, weight loss from month 3 to month 12 was similar on a high-egg diet (-3.1 kg) and a low-egg diet (-3.1 kg) [16]. This shows eggs did not get in the way of weight loss; it does not show that eggs cause extra weight loss [16].

Muscle recovery and strength. In 10 resistance-trained young men, whole eggs eaten right after exercise produced more muscle protein synthesis than the same amount of protein from egg whites [4]. In 30 resistance-trained young men over 12 weeks of training, the whole-egg group (three eggs after each session) gained more knee-extension and grip strength and lost more body fat than the egg-white group (six egg whites), although muscle mass did not differ between the groups [17]. A second 12-week trial of 30 trained men found similar gains in muscle and body composition with whole eggs and with egg whites [3].

Eye pigment. A meta-analysis of five trials (296 people) found that eating eggs raised macular pigment optical density, a measure of the yellow pigment in the macula, and raised blood lutein [5]. In a 90-day trial of 100 people, blood lutein rose by 76% and 77% with lutein-enriched eggs or an egg-yolk drink, but macular pigment did not change [18]. That trial measured pigment and blood levels, not vision or macular degeneration [18].

Blood pressure. A review of 15 trials (748 adults) found no significant effect of egg consumption on systolic or diastolic blood pressure [19].

Breastfeeding. In a US cohort of 1,039 mother-infant pairs, mothers who ate eggs three or more times a week were more likely to start breastfeeding (93.8% versus 81.1%; adjusted odds ratio 3.34) [20]. This is an association from one observational study, which was funded by the American Egg Board's Egg Nutrition Center [20].

Memory and thinking. A 2025 systematic review of 11 mostly observational studies (over 38,000 people) found improvements in memory and processing speed with moderate, but not high, egg intake in several studies [21]. Two studies linked about 0.5 to 1 egg a day with a reduced risk of dementia or cognitive impairment, but results were inconsistent and the review did not pool them [21]. Eggs contain choline: in 20 overweight postmenopausal women, two whole eggs a day for four weeks raised plasma choline and betaine [22].

Blood sugar in type 2 diabetes. In a 12-month trial of people with prediabetes or type 2 diabetes, a high-egg diet did not change glycaemic control compared with a low-egg diet [16]. A 3-month trial of 140 people found no between-group difference in glycaemic control either [14].

Cholesterol. Trials show a small rise in blood fats with eggs. A meta-analysis of 28 trials found that egg intake raised total cholesterol by 5.6 mg/dL, LDL cholesterol by 5.55 mg/dL and HDL cholesterol by 2.13 mg/dL, compared with low-egg diets [23]. Other trials found no difference: eating more than four whole eggs a week did not change blood lipids compared with four or fewer [24], and in 140 people with type 2 diabetes a high-egg diet did not change LDL or HDL cholesterol [14]. In a cross-sectional analysis of 728 adults, the highest egg-eating quartile had lower LDL cholesterol overall, but no link was found in people with obesity, diabetes, hypertension or high cholesterol [25].

Type 2 diabetes. Findings differ by region. Pooling three large US cohorts found a 14% higher type 2 diabetes risk for each extra egg a day [26]. Across 16 cohorts worldwide the pooled result was not significant (1.07, 0.99 to 1.15), and the link appeared in US studies but not in European or Asian ones [26]. A pooling of nine US cohorts found 27% higher risk with seven or more eggs a week than with none (95% CI 16% to 37%), with no clear link below two eggs a week [27]. A 2016 meta-analysis found a modest higher risk only at three or more eggs a week, restricted to US studies [28].

Death from any cause. Results are mixed. In 27,078 men in the ATBC study, each additional 50 g of egg a day was linked to higher overall death (hazard ratio 1.06) and cardiovascular death (1.09) [29]. A 2022 meta-analysis of 33 cohorts found no link between the highest and lowest egg intake and death from all causes (relative risk 1.02) [30]. A global study of about 177,000 people in 50 countries found no significant link between egg intake and death or major cardiovascular events [31].

Doses used in studies

Examples from the trials: two whole eggs a day for four weeks [22]; two eggs a day on six days a week for three months [14]; 12 or more eggs a week in a 12-month weight-loss trial [16]; three whole eggs straight after each training session, three sessions a week, for 12 weeks [17]; and 50 mg a day of heated egg powder, rising to 250 mg a day, in infants with eczema [8]. Cohort studies report risk per egg a day or by weekly intake categories [11][27].

Safety and interactions

Common side effects: egg is one of the most common causes of food allergy in early childhood [10]. In the trial of infants with eczema, six infants were admitted to hospital in the egg-powder group and none in the placebo group [8]. People with egg allergy: in a trial of 55 children, 55% of those given egg-white immunotherapy passed a food challenge after 10 months (none on placebo), and 28% of the treated group kept their tolerance at 24 months [32].

Upper limits: no upper limit for eggs was set in the studies we read. The authors of one cohort analysis advised restricting dietary cholesterol [29].

Medicines: none of the studies we read tested interactions between eggs and medicines, so this is not covered.

Pregnancy and breastfeeding: the one pregnancy study we read was observational and linked maternal egg intake to breastfeeding; it did not test safety [20]. We found no trial of egg intake safety in pregnancy and no data on raw or undercooked eggs in pregnancy.

Kidney, liver and bleeding disorders: none of the studies we read covered these conditions.

People with type 2 diabetes: one cohort subgroup linked high egg intake to higher coronary heart disease risk [12]. People with high LDL cholesterol: trials show a small rise in LDL with eggs [23].

Caveats and open questions

The overall evidence is of critically low quality: a 2025 umbrella review of 14 meta-analyses judged the evidence too weak to discourage egg consumption [33]. Most findings come from observational cohorts, which show associations but cannot prove that eggs cause the outcome.

Cancer death: two meta-analyses of cohort studies linked more eggs with higher cancer death: relative risk 1.20 for the highest versus lowest intake [30], and 1.16 per extra egg a day [34]. The certainty of evidence was low to moderate in one [30] and very low in the other [34].

Heart disease in people with diabetes: one subgroup analysis of cohort studies found a higher coronary heart disease risk with the highest versus lowest egg intake (relative risk 1.54, 1.14 to 2.09) [12]. The two diabetes trials measured blood markers, not heart events [16][14].

Results conflict by region and outcome. Heart and diabetes results differ between US, European and Asian cohorts [26][11].

Several muscle trials compared whole eggs with egg whites rather than with no eggs [4][17].

The muscle, eye and blood sugar findings come from small or short trials, and the muscle and eye results are short-term markers rather than vision or long-term muscle outcomes [4][18].

Funding: the American Egg Board funded an investigator grant behind the US diabetes pooling [27]; the Egg Nutrition Center funded the breastfeeding study [20]; the British Egg Industry Council funded the authors of a 2023 egg review [35]; and a commercial sponsor funded the 2014 lutein trial, whose authors include patent holders [18]. The lutein meta-analysis [5] has no competing-interests or funding statement in its abstract or PubMed record, so its funding and author ties are unknown.

Open questions: the cognitive review called for well-controlled intervention studies to test whether eggs help thinking [21]. The 2025 umbrella review found the cardiovascular evidence weak [33].