Vegetarianism, particularly veganism, has become increasingly popular, especially among young people in the United States. While studies suggest vegan diets (VD) can decrease the risk of cardiometabolic diseases like cardiovascular disease, type 2 diabetes, obesity, and non-alcoholic fatty liver disease, they are also linked to potential adverse health outcomes. These include nervous, skeletal, and immune system impairments, hematological disorders, and mental health problems, often stemming from micro and macronutrient deficits. This article aims to explore the existing literature on the impact and long-term consequences of veganism, particularly on vulnerable populations such as children, adolescents, pregnant and breastfeeding women, and fetal outcomes in vegan mothers.
Understanding Veganism and its Variations
Vegetarianism comes in various forms. Vegans adhere to the strictest dietary restrictions, eliminating all animal-sourced foods and their by-products. Other variations include:
- Lacto-vegetarians: Exclude meat, fish, and eggs but consume dairy products.
- Ovo-vegetarians: Exclude meat, fish, and dairy products but consume eggs.
- Lacto-ovo-vegetarians: Exclude meat but consume eggs and dairy products.
- Pescatarians: Exclude meat except for fish and shellfish.
Given the rise of obesity and related health concerns, there's growing interest in dietary habits. Obesity is a known risk factor for diabetes, which in turn, increases the risk of coronary artery disease.
Potential Benefits of a Vegan Diet
Reduced Risk of Illness
Some studies suggest that a vegan diet can lower the risk of common diseases like diabetes, hypertension, and heart disease. However, individuals who follow a vegan diet often have the resources and flexibility to control their diet, and may also have healthier lifestyles, making it difficult to attribute the reduced risk solely to the diet.
Weight Management
Adopting a vegan diet can lead to weight loss as individuals adjust to new eating habits. The reduced intake of saturated fats and high-calorie options, such as cheeses, contributes to a healthier overall diet, aiding in weight management. Plant-based meals are often naturally lower in calories and saturated fats.
Read also: Vegan Diet for Diabetes Management
Better Heart Health
Vegans often exhibit lower cholesterol and blood pressure levels, which reduces their risk of heart diseases. A diet rich in fruits, vegetables, and whole grains is generally beneficial for cardiovascular health.
Lower Cancer Risk
Research suggests that a diet high in fruits and vegetables can lower the risk of certain types of cancers. Vegans consume a variety of plant foods that contain protective antioxidants and phytonutrients.
Improved Digestive Health
Typically, a vegan diet is rich in fiber, which promotes healthy digestion and regular bowel movements. High-fiber diets are associated with a reduced risk of constipation and colon-related issues.
Environmental Impact
Veganism is often touted for its positive effect on the environment. Animal agriculture significantly contributes to greenhouse gas emissions and deforestation. By abstaining from animal products, individuals can reduce their carbon footprint.
Potential Drawbacks and Health Concerns of a Vegan Diet
Nutrient Deficiencies
Vegan diets can lack essential nutrients, including vitamin B12, iron, calcium, omega-3 fatty acids, and zinc. Plant proteins are less digestible (50-70%) than animal proteins, and food processing methods like heating may further reduce digestibility. According to the WHO, animal proteins are considered complete proteins and have higher biological value, protein efficiency ratio, net protein utilization, and a higher Protein Digestibility Corrected Amino Acid Score (PDCAAS) compared to plant proteins.
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Protein: Vegans consume less total protein compared to other diet groups, raising concerns about insufficient protein intake, especially when legume, seed, and nut consumption is limited. They also consume fewer essential amino acids than non-vegans.
Vitamin B12: Low vitamin B12 intake is a significant concern in vegan diets due to the exclusion of vitamin B12-rich foods like meat, poultry, and eggs. A lack of vitamin B12 has been linked to neurologic and hematologic problems. Inadequate B12 consumption may contribute to carcinogenesis by increasing uracil misincorporation, impairing DNA synthesis, and causing genomic instability.
Iron: Vegans have greater iron needs as non-heme iron from plant-based foods is less bioavailable, with absorption hindered by whole grains, legumes, and nuts due to their phytic acid content.
Zinc: Inadequate zinc consumption may be associated with mental health problems (e.g., depression), dermatitis, diarrhea, and alopecia, all of which are more prevalent among vegans.
Calcium and Vitamin D: Vegans often consume insufficient calcium and vitamin D due to the absence of dairy products and calcium bioavailability problems in plant-based diets. Vitamin D insufficiency exacerbates calcium shortage further owing to impaired intestinal absorption.
Read also: Lose Weight with Veganism
Omega-3 Fatty Acids: These are difficult to get from plant-based foods, so often must be supplemented alongside. This can be expensive and inconvenient.
Bone Health
Studies indicate an increased risk of hip fractures in vegetarians and vegans compared to meat-eaters. Vegans also had a greater incidence of overall fracture and leg fractures.
Mental Health
Research suggests that meat-free diets are linked with worse psychological health. Studies highlight the high incidence of mental health problems among vegans, emphasizing the crucial need of increasing awareness of these illnesses to facilitate early intervention.
Orthorexia Nervosa
Orthorexia nervosa (ON) is defined as a fixation on health-conscious eating behavior. It involves obsessive (compulsive) food decisions, self-imposed anxiety, self-punishment, and increasingly extreme limitations. Individuals develop dietary restrictions, lack of food pleasure, inflexible and rigid eating behaviors, and ritual activities surrounding food preparations.
Challenges in Eating Out
Finding suitable vegan options can be difficult, especially in non-vegan-friendly areas. Dining out may require extra effort and research to identify vegan-friendly restaurants and menu items.
Social Limitations
Being vegan might pose social challenges during gatherings or events, as not everyone may understand or accommodate dietary preferences. These situations can sometimes be uncomfortable.
Initial Learning Curve
Transitioning to a vegan diet may require learning new recipes, understanding ingredient alternatives, and familiarizing yourself with plant-based nutrition. This learning curve may feel overwhelming initially.
Potential Expense
While a plant-based diet can be affordable, specialty vegan products and substitutes can be more expensive than their non-vegan counterparts.
Not Recommended for Certain Health Conditions
Depending on the status of your health, your doctor may discourage you from following a vegan diet. Illnesses that require a lot of calcium to help maintain strength in bones, like osteoporosis, still advise you to consume dairy, as this is the number one source of calcium.
Veganism in Vulnerable Populations
Children and Adolescents
Adolescents often show a strong preference for VD. A balanced diet is critical for children and adolescents to meet their bodies' rising demands during the growth spurt, rendering the implications of VD in this vulnerable age more intriguing. Some studies show no specific nutrient concerns among vegetarian, vegan children and adolescents compared to omnivores. However, subsequent cross-sectional studies showed that vegetarian and/or vegan children had a lower bone mineral density (BMD). Vegan children had substantially lower vitamin D levels and BMD than omnivores. It is suggested to maximize childhood BMD to promote peak BMD and therefore reduce the risk of osteoporosis and fracture in adulthood. It does not seem to be ideal to start puberty, a period when bone-specific nutrition requirements are greater, with an already established BMD deficiency. If such deficiencies continue throughout adolescence as a result of a diet, they may raise the likelihood of poor bone outcomes later in life.
Pregnant and Breastfeeding Women
Optimal fetal growth requires balanced maternal nutrition during pregnancy. Mothers on rigorous VD are at risk of vitamin insufficiency, which can lead to poor fetal outcomes. Vegan diets were significantly linked with an elevated risk of small-for-gestational-age infants. Birthweight in vegans was lower compared to lacto-ovo-vegetarians and omnivores. Vegans also had a lower mean gestational weight gain compared only to omnivores. Maternal B12 status influences their offspringâs B12 levels and is an independent risk factor for neural tube defects (NTD). Studies have shown an association between low B12, low birth weight, and pre-term delivery. Vegan mothers may have poor prenatal nutritional status, resulting in low maternal fat reserves for breastfeeding. Providers should evaluate a woman's nutrition and energy consumption frequently. Women on restrictive diets may need to take supplements or eat fortified foods to meet the required needs throughout pregnancy and breastfeeding.
The Importance of a Balanced Vegan Diet
An optimal diet should be balanced, consisting of lean meat, nuts, fresh fruits and vegetables, and olive oil. A wholesome diet is essential in maintaining a healthy gut flora, which in turn is pivotal in avoiding inflammatory disorders. While some studies indicate a reduction in mortality associated with vegetarianism and VD, the larger body of evidence indicates that the health benefits associated with vegetarianism may be due to other âlifestyleâ factors associated with socioeconomic statuses, such as adequate physical activity, low alcohol, and drug consumption, or avoidance of tobacco products.
Vegans should be closely monitored and treated for nutritional deficiencies, in order to mitigate any long-term negative health outcomes. It should be noted that vegans often have better socioeconomic levels, live a healthier lifestyle with more physical exercise, and tend to smoke less compared to non-vegetarians, making it difficult to isolate the effects of veganism in observational research. Existing research is often skewed by selection bias, which is when the study sample is chosen based on prior eating patterns and such studies are often recruited in environments with a high level of health awareness.
Different Types of Vegan Diets
- Raw Vegan Diet: Consists mainly of uncooked fruits and vegetables, raw nuts and seeds, sprouted and soaked grains, cold-pressed oils, and fermented foods. It may be higher in vitamins, minerals, fiber, and antioxidants but is very restrictive and could cause nutrient deficiencies.
- Vegan Keto Diet: Very low-carb, high-fat, and moderate-protein diet. It focuses on high-fat vegan foods like avocados, nuts, seeds, and coconut and olive oils. Like a raw vegan diet, it is very restrictive and could lead to nutrient deficiencies.
- Vegan Diabetic Diet: Moderately low in carbohydrates, especially high-glycemic, refined carbs. Whole grains, beans, and legumes are high in fiber, which can help control blood sugar.
- High-Protein Vegan Diet: Focuses on higher-protein plant foods such as nuts, seeds, beans, tofu, quinoa, and seitan.
- Alkaline Vegan Diet: Prioritizes foods based on their pH value, with a focus on fruits, nonstarchy vegetables, whole grains, nuts, and seeds.
- Vegan Anti-Inflammatory Diet: Focuses on fresh, whole foods and limits sugars and highly processed foods to reduce inflammation.
- Mediterranean Vegan Diet: Rich in fruits, vegetables, grains, beans, nuts, seeds, and unsaturated oils.
- Low-Carb Vegan Diet: Includes nonstarchy vegetables, high-fat fruits, low-sugar fruits, nuts and seeds, soy foods, and olive, avocado, and coconut oils.
Vegan Foods and Alternatives
On a vegan diet, you can eat foods made from plants, including fruits and vegetables, legumes, nuts and seeds, breads, rice, and pasta, and vegetable oils. These can be consumed whole or in prepared forms like tofu, seitan, and tempeh. Vegan meats and plant-based milks, cheeses, yogurts, mayonnaise, honey, ice cream, and butter are also available.
Is Yeast Vegan?
Most vegans consider yeast to be vegan-friendly, although a small percentage of strict vegans ("level 5 vegans") avoid it.
Vegan Baking Alternatives
Plant-based milk, yogurt, and cream can stand in for dairy in baking. To replace an egg, you can use a mixture of corn starch and water, chia seeds or ground flaxseeds and water, or nut butter, applesauce, or mashed banana.