Ovo-vegetarianism is a branch of vegetarianism.
Vegetarians follow a predominantly plant-based diet, abundant in fruits, vegetables, whole grains, legumes and nuts; and do not allow the intake of animal-origin foods.
Ovo-vegetarians – on the other hand – are vegetarians who allow the consumption of eggs in their diet.
Eggs are an affordable, highly nutritious food source, containing a high source of digestible protein, and the essential micronutrients vitamin A, vitamin B12, selenium, choline, biotin and vitamin D (Ruxton et al., 2010).
According to Melough et al. (2019) “Egg consumption was associated with a higher likelihood of meeting or exceeding recommendations for several micronutrients” when compared to non-egg consumers.
Eggs contain approximately 12.5 g protein per 100 g of raw fresh egg.
According to a research paper by Rehault-Godbert et al. (2019), “Eating two eggs per day covers 10% to 30% of the vitamin requirements for humans”.
Eggs contain the essential micronutrient, Vitamin B12.
Vitamin B12 is commonly found in animal sources and rarely found in plant-based foods; strict vegetarians are generally at risk of low intakes of this nutrient (Applegate, 2000).
Eggs also contain important bioavailable forms of the carotenoids, lutein and zeaxanthin. These antioxidant compounds are critical for healthy eyes and prevention of macular degeneration (Applegate, 2000).
Although containing some omega-3 fatty acids and vitamin D, these nutrients can be increased in the egg product via modification of the chicken feed.
There are many reasons for a person to choose to follow an ovo-vegetarian diet.
An ovo-vegetarian diet may interest a person who wants to reduce their meat intake – for health or environmental concerns – and would like to increase the amount of plant-based foods in their diet, while still allowing the intake of eggs which offer a very nutritious, alternative protein source to meat (beef, pork, and lamb).
Eggs are also extremely versatile and easy to prepare: they can be boiled, fried, scrambled, poached or incorporated into a delicious omelette containing vegetables like mushrooms, spinach, and tomatoes.
In this article we explain (in plain English!) the conclusions of scientific studies that have looked at ovo-vegetarianism.
Drawbacks of Ovo-Vegetarianism
In this section, we will discuss the drawbacks of an ovo-vegetarian diet.
Before starting a new diet, it is important to speak with your doctor or a registered dietitian to make sure this diet is the right fit for you.
Eggs: Good or Bad for Your Health?
The high dietary cholesterol content of eggs and its impact on human healthhas been a topic of debate for decades (Rosenson & Song, 2019).
Cholesterol, a type of waxy fat, is associated with heart disease and negative health outcomes (Wadhera et al., 2016).
Are eggs good or bad for our health?
Let’s take a look at the evidence.
A study published in the Journal of the American College of Nutrition, investigated the relationship between egg consumption and serum cholesterol levels in a population of 27 378 individuals.
They reported that those who ate more than 4 eggs/week had reduced serum cholesterol levels, compared to individuals who ate less than 1 egg/week “People who reported eating ≥ 4 eggs/wk had a significantly lower mean serum cholesterol concentration than those who reported eating ≤ 1 egg/wk” (Song & Kerver, 2000).
According to a 2018 study published in the journal, Nutrients, a potential explanation for the low serum cholesterol levels in egg consumers, could be due to the fact that dietary cholesterol found in egg is not easily absorbed by the body and does not impact blood cholesterol levels “These results suggest that the dietary cholesterol in whole egg was not well absorbed, which may provide mechanistic insight for why it does not acutely influence plasma total-cholesterol concentration and is not associated with longer-term plasma cholesterol control” (Kim & Campbell, 2018).
An ovo-vegetarian diet is not suitable for those who have an egg allergy.
Eggs are among some of the most common foods causing allergic reaction (FDA, 2022).
Younger children are more likely to develop an egg allergy, although it generally disappears after the age of 5 years.
Infants, aged 6 months or younger, are advised not to consume eggs (Caballerro, 2005).
Food Safety Concerns
Poultry meat and eggs, can contain harmful, pathogenic bacteria that can cause food poisoning.
The pathogenic bacteria, Salmonellae, E. coli, Staphylococcus aureus, and Campylobacter are the main culprits associated with food poisoning from poultry meat and egg consumption (Khalafalla et al., 2015).
Always ensure that your eggs have been properly washed and correctly prepared (cooked).
Always avoid consuming raw egg, and make sure surfaces are properly cleaned after cooking with raw egg.
Benefits of Ovo-Vegetarianism
Although an ovo-vegetarian diet may pose some drawbacks to certain individuals, in the sections that follow we will look at several studies which have linked ovo-vegetarianism with health benefits such as:
Lowered Blood Glucose Levels
An ovo-vegetarian diet may aid in controlling blood sugar levels.
A study published in the journal, Annals of Nutrition and Metabolism, evaluated the effectiveness of egg intake on controlling blood glucose levels and insulin regulation in healthy individuals.
The study consisted of 12 healthy men (aged 18-29 years) from the University of Nancy, France.
To analyse the influence of egg intake on blood glucose levels, participants were asked to consume a breakfast consisting of white wheat bread with butter, black coffee with 10 g sugar, and one of the four below options:
Four tests were run, with a week between each breakfast option.
The findings indicate that when consuming the standard breakfast without eggs, the participants blood glucose levels spiked the highest, however when consuming the breakfast with eggs, especially egg yolk the blood glucose levels were the lowest.
The authors of the study suggest that the addition of egg to the breakfast meal delays gastric emptying and prevents a spike in blood sugar levels.
Eggs are able to help maintain healthy blood sugar levels and regulate insulin levels “The results indicate that egg ingestion, especially yolk ingestion, may be of interest in regulating metabolic variables of glucose metabolism” (Pelletier et al., 1996).
Lowered Blood Pressure
An ovo-vegetarian diet may help lower your blood pressure, and keep it within a normal, healthy range.
According to a 2017 study published in the journal, Public Health, “an ovo-vegetarian diet is beneficial for long-term blood pressure control and prevention of hypertension in females” (Ho et al., 2017).
Scientists from the present study examined the effect of three different eating styles, namely: vegan, ovo-vegetarian, and omnivorous (meat eaters) on the blood pressure levels of Taiwanese women, aged 40 years and older.
They reported that participants following an ovo-vegetarian diet displayed the lowest systolic (SBP) and diastolic blood pressure (DBP) of the three eating styles “In particular, the SBP and DBP of ovo-vegetarians are the lowest among the values observed for all dietary patterns” (Ho et al., 2017).
Protection Against Heart Disease
An ovo-vegetarian diet may lower your risk of heart disease.
A 2018 study published in the journal, Heart, investigated the relationship between dietary egg intake and cardiovascular disease (CVD).
More than half a million Chinese adults, between the ages of 30-79 years were included in this study.
According to the findings of the study, individuals who ate eggs daily were less likely to develop cardiovascular disease, versus those who did not eat eggs “Compared with non-consumers, daily egg consumption was associated with lower risk of CVD” (Qin et al., 2018).
The authors also reported that daily egg consumption was associated with an 18 % reduced risk of dying from CVD “Daily consumers also had an 18% lower risk of CVD death and a 28% lower risk of haemorrhagic stroke death compared to non-consumers” (Qin et al., 2018).
Aside from the benefits to cardiovascular health, eggs are also able to make you feel fuller for longer.
A 2017 study published in the journal, Nutrients, examined the influence of egg intake in comparison to an oatmeal breakfast on cardiovascular risk factors and satiety (the feeling of fullness after a meal), in a group of young, healthy individuals.
A total of fifty individuals participated in this study. Participants were randomly chosen to consume an oatmeal breakfast or a breakfast consisting of 2 eggs for a 4-week period. Following each diet, participants were given a 3-week break-period before commencing the alternative breakfast meal.
Cholesterol levels, ratio of low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and satiety were analysed after each dietary intervention.
The results indicate that the consumption of 2 eggs for breakfast did not negatively impact cholesterol levels or LDL/HDL ratios. They also reported that participants felt more full and satisfied after eating eggs for breakfast in comparison to an oatmeal breakfast “These results demonstrate that compared to an oatmeal breakfast, two eggs per day do not adversely affect the biomarkers associated with CVD risk, but increase satiety throughout the day in a young healthy population” (Missimer et al., 2017).
Good Bone Mineral Density
An ovo-vegetarian diet may assist in keeping your bones strong and healthy as you age.
Choline – a compound found mainly in eggs – is an important nutrient needed for healthy strong bones.
According to research by Wallace & Fulgoni (2017), those who do not consume eggs generally struggle to meet their daily intake requirement for choline “This research illustrates that it is extremely difficult to achieve the adequate intake (AI) for choline without consuming eggs or taking a dietary supplement”.
A 2017 study published in the Journal of Nutrition, aimed to determine the relationship between dietary choline and bone mineral density (BMD).
Data from the Hordaland Health Study consisting of over 4500 men and women, aged 46 to 49 or 71 to 74 years was analysed.
They reported that those who consumed the lowest amount of dietary choline were more prone to have low-femoral neck bone mineral densities, than those who consumed the highest amount of dietary choline.
Their findings highlight the important role choline plays in the BMD of adults and elderly individuals “Dietary choline was positively associated with BMD in middle-aged and elderly participants” (Øyen et al., 2017).
Protection Against Age-Related Macular Degeneration
An ovo-vegetarian diet may protect you from age-related macular degeneration (AMD) and cataracts.
Age-related macular degeneration is an eye disease that can affect your vision and lead to blindness.
The carotenoids, lutein and zeaxanthin – found in eggs, leafy greens and broccoli – play an important role in preventing age-related macular degeneration (Eisenhauer et al., 2017).
A 2020 study published in the journal, Clinical Nutrition, examined the relationship between egg consumption and incidence of age-related macular degeneration.
Over 3500 individuals over the age of 49 years of age were included in this study, with a follow-up time of 15 years.
The authors reported that those who consumed 2-4 and 5-6 eggs/week decreased their chances of developing late-stage AMD by 54% and 65%, respectively, versus those who consumed less than 1 egg/week “Our findings suggest that moderate consumption of eggs significantly reduces the risk of developing incident late-stage AMD over 15 years” (Gopinath et al., 2019).
According to another study published in the Journal of the American College of Nutrition, “generous intakes of lutein and zeaxanthin, particularly from certain xanthophyll-rich foods like spinach, broccoli and eggs, are associated with a significant reduction in the risk for cataract (up to 20%) and for age-related macular degeneration (up to 40%)” (Moeller et al., 2000).
Numerous studies highlight the beneficial health effects of an ovo-vegetarian diet.
While a vegetarian diet may be lacking in certain essential nutrients, eggs provide an affordable, nutrient dense food source for vegetarians and individuals who are looking to reduce their meat intake.
To follow an ovo-vegetarian diet, aim to consume a varied, balanced plant-based diet containing plenty of nutritious fruits, vegetables, legumes, whole grains, nuts, seeds, and eggs, while avoiding meat, sweetened beverages, refined carbohydrates like white bread and pasta, and sweets.
Try to purchase eggs from reputable, ethically produced farms where hens have been free roaming and not confined to cages.
Always ensure that you wash your eggs of debris, and properly cook your eggs to destroy any harmful, pathogenic bacteria that could lead to food-poisoning.
Finally, an ovo-vegetarian diet is not suitable for individuals who have an egg allergy.
Eggs should not be fed to infants and caution should be taken when introducing eggs into your toddler’s diet.