Fundamentals of Human Nutrition/Vegetarian Diets

Section 5.7 Vegetarian DietsEdit

5.7.1 Types of Vegetarian DietsEdit

Many people have different reasons for refraining from eating meat including religion, ethics, for the health benefits, or environmental concerns.

Health A study done at Oregon State University found that most people who choose a vegetarian diet are seeking a healthier lifestyle.[1] Diets rich in plant foods have been found to "lower blood cholesterol levels, lower risk of heart disease, lower blood pressure levels, and lower the risk of hypertension and type 2 diabetes" along with reducing the occurrences of obesity and overall cancer prevalence.[2] Conversely, diets involving high intakes of meat and animal products are linked to heart disease, stroke, and some types of cancer. Today, many animals are given antibiotics and hormones to keep them healthier and help them grow faster and larger. This is linked to increasing antibiotic resistance in humans.

Ethical Reasoning Many vegetarians and vegans choose to abstain from animal products due to their concern about the current practices of the meat industry – the treatment, living conditions and slaughter of the animals are specifically considered cruel and unnecessary. Beyond this, many people believe that animals should simply not be used food or killed in general. In a 2006 article of The Minnesota Daily, Peter Singer[3] states that opposition to factory farming is quickly growing. Alternatives for those who disapprove of the conventional farming practices but do not want to cut animal products from their diet include selections of free-range meats and eggs and options from local, organic farms.

Ecological Impacts Meat production is linked to excessive uses of land and water resources. For example, beef requires 100 to 300 times the amount of water as compared to vegetable crops.4 Many vegetarians argue that land used to raise livestock is wasteful and could instead be used to grow vegetable crops to directly feed and adequately nourish our current human population. Forests and woodland are most often cleared to provide land for raising cattle, accounting for up to 80 percent of deforestation and promoting land erosion.[4] Changing the average American diet to include mostly plant-based products, and less animal products, may reduce our use of fossil fuels and agricultural resources despite a growing population.

Religious Concerns Many people choose a vegetarian diet based on religion. Some religions teach that our bodies are a gift from God and therefore, individuals should treat their bodies as holy and keep them healthy. Others believe that in order to reach spiritual enlightenment, they must never kill any living animal. A belief in karma, or reincarnation may also play a role in someone’s choice to be vegetarian or vegan. Different religions have their own reasoning for avoiding animal products.[5]

• Hinduism – The Hindu god, Krishna, promoted vegetarian diets, specifically avoiding the consumption of beef, as the cow is considered sacred. In Hindu scriptures, there are many passages that recommend vegetarianism based on the idea that there is a strong link between nonviolence and spirituality.

• Jainism – Jains hold the belief that is it wrong to kill or harm any living being. Traditions respect nonviolence, non-acquision, truth, and other’s rights.

• Buddhism – The Buddha, Siddhartha Gautama, taught that following a vegetarian diet was a key component to becoming mindful and compassionate and relieving suffering.

• Judaism – Judaism teaches that humans are to love and protect all of creation, and forbids inflicting unnecessary pain on animals. Jewish people are expected to abide by kosher dietary laws and detailed laws which require that animals be treated humanely and never exploited.

• Seventh-Day Adventists – Promote a lacto-ovo vegetarian diet and most choose not eat meat in efforts to preserve the overall health of their mind, body, and spirit.[6]

Economic Reasoning Current farming practices are very expensive – raising livestock requires the use of pesticides, antibiotics, computer controlled feeding, and air circulation. Because of this, many people around the world simply cannot afford to buy and eat meat. Instead, they opt for a cheaper, plant-based, vegetarian diet to support their budget.

Most people have an idea of what it means to be a vegetarian but there is a wide array of diets that branch from vegetarianism. Because of these differences, many people disagree on what is considered a true vegetarian diet namely when it comes to semi-vegetarian diets. Vegetarian diets include: vegan, ovo-vegetarian, lacto-vegetarian, lacto-ovo vegetarian, and semi-vegetarian. There are also variations when it comes to religious based vegetarian diets. Recently, there have been implementations in society to cater to those with vegetarian diets such as Meatless Mondays in schools and businesses, and offering vegetarian meals in airlines and hospitals.[7]

There are many different diets following close to what is considered a vegetarian.

  • A vegan diet doesn’t include animals, animal byproducts such as milk and honey, and products that contain items such as gelatin which is crushed animal skin and bones that is found in some processed foods (white sugar, beer, etc).[8] The main difference between a vegan and vegetarian diet is that veganism doesn’t include eggs or dairy products namely for ethical reasons as acquiring these products may lead to harm to the animal or premature death. Many cereals are fortified with Vitamin D as well as soymilk which vegans incorporate into their diet due to elimination of dairy products.
  • An ovo-vegetarian diet include meat or dairy products but does include other animal byproducts such as eggs. However, some ovo-groups refuse to consume fertilized eggs.
  • Lacto-vegetarian diet includes dairy products but no meat or eggs.
  • Lacto-ovo vegetarian includes both eggs and dairy products but no animal flesh of any kind. This diet could be at risk with consuming too much fat if full fat dairy products are used.
  • Raw food diets consume plant based foods along with some raw dairy products without heating up foods which although some nutrients is lost by heat there’s a benefit in digestibility and destroys anti-nutrient factors [7]

Some vegetarian diets are considered semi-vegetarian and contain animal flesh in the diet:

  • Pescetarian includes eggs, dairy products, and seafood but no other meat.
  • Pollo-pescetarian includes poultry into the pescetarian diet to exclude mammals from their diet.
  • Pollotarianism includes no seafood but only poultry is incorporated into the diet for meat.

There are also variations when it comes to vegetarian diets namely for religious reasons such as jain-vegetarianism diets that do consume dairy products but avoid to hurt bugs by not consuming honey or eating vegetables rooted into the ground as you may cause damage to bugs.

5.7.2 Vegetarian Diet PlanningEdit

Though a vegetarian diet may seem to require different, more in depth dietary planning, the meal-planning task is the same as everyone else. The overall goal is to use a wide range of foods that provide all the necessary nutrients in the diet, while allowing for enough energy to maintain a healthy body weight. In fact, vegetarians who use milk, milk products and eggs in their diets are likely to meet nutrient recommendations as easily as nonvegetarians. Vegan vegetarians do not have these items in their diet, so their eating patterns must make up for this by including fortified foods or supplements. MyPlate[9] is a helpful resource that provides tips for planning vegetarian diets, by utilizing an adaptation of the USDA food patterns. MyPlate provides a variety of options to account for all types of vegetarians and vegans, including soy milk in place of milk or items such as eggs, legumes, and soy products for protein. Though most vegetarians can obtain many of their nutrients easily through plant foods, there are areas where they are prone to lack, including iron, protein, calcium, zinc, Vitamin B12, Vitamin D, and omega-3 fatty acids.


Iron is a nutrient that can be difficult for everyone to attain. However, vegetarians and vegans may have more of a problem, as they do not have meat in their diets. There is iron in plant foods, such as dark green, leafy vegetables like spinach or legumes. Further, there is iron in whole grain breads and iron-fortified cereals. The issue with these iron sources is that they are poorly absorbed, compared to iron in meat. Fortunately, the body can actually adapt to a vegetarian diet that is low in iron by decreasing iron loss and increasing iron absorption. Further, if you consume vitamin C it will increase iron absorption.


Protein may seem to be the biggest concern with a vegetarian diet, however the protein needs are usually met. In fact, the RDA for vegetarians is the same as nonvegetarians. Specific vegetarians, such as lacto-ovo-vegetarians, can acquire the recommended amount of protein easily through animal-derived foods such as eggs. Vegetarians also receive protein from plants, but they are not digested as completely. Further, there is protein in whole grains, nuts, and seeds and some vegetarians use meat replacements. Examples of meat replacements include soy proteins that are made to look and taste like meat, poultry and seafood. These products are fortified to provide the nutrients that are found in protein from animal sources.


Calcium is not a huge issue for vegetarians that still consume milk and milk products in their diets. However, vegans do not use milk or milk products and so are more at risk for low levels of calcium. Fortunately, there are other sources of calcium that vegans can use to make up for what they are missing. Examples of calcium rich sources include soy milk, calcium-fortified juices, figs, some legumes, some nuts, and some green vegetables. Calcium is especially important for children, so they should pay special attention to their calcium intake if they are on a vegan diet.[10]


Like iron and protein, meat is the richest food source for zinc. Though zinc can come from plants, it is not absorbed very well. However, vegetarian adults are not usually zinc deficient. There are plenty of foods that provide zinc in the diet, including whole grains, pinto and kidney beans, black eyed peas, and nuts. Further, zinc is found in seafood, especially oysters, if that is included in the diet.

Vitamin B12

Though the requirement for Vitamin B12 is small, it is still very important for health. A lack of vitamin B12 can result in nerve damage and health consequences such as loss of vision. Vegetarians, and especially vegans, will likely have a hard time acquiring enough vitamin B12 in their diets. There are options such as soy products and seaweeds, but some of these products present an inactive form or can lead to iodine toxicity. Thus, many vegetarians and vegans will require vitamin B12-foritfied supplements or sources.

Vitamin D

Vitamin D is another nutrient that can be difficult to acquire for both vegetarians and nonvegetarians. Thus, it is important to eat fortified foods and expose yourself to sunlight to make sure vitamin D is synthesized. Vegetarians and vegans in northern climates must pay special attention to their vitamin D levels, especially infants and children.

Omega-3 Fatty Acids

Though a vegetarian diet and a diet of someone eating meat, eggs and fish differ greatly in omega-3 fatty acids, the blood differences between the two is small. Further, vegetarians can receive omega-3 fatty acids from flaxseed, walnuts, canola oil and soy.

Making the decision to become a vegetarian differs from person to person; some become vegetarians almost instantly, while others are more cautious. Being a vegetarian is as simple or as difficult as one chooses to make it. Some people find great pleasure in the creativity needed to create awesome vegetarian meals, while others are completely turned off by the amount of thought it can take to create the perfect vegetarian meal. That being said, this decision is ultimately dependent on what is best for you.[11]. Planning anything, especially a vegetarian diet, can seem like a daunting task; however, with a proper meal plan paired with the adequate nutrition, one can create a well-planned diet that meets the guidelines to support people of all ages and stages of life. The importance is to remain cognizant of your specified nutritional needs so that you can create the perfect vegetarian diet that meets each need, as well as follows the proper health guidelines.[12]

The word "vegetarian" often yields thoughts such as "meatless", or meals lacking fish or poultry, but despite these thoughts, vegetarian diets greatly vary in what they exclude or include. The different types of vegetarian diets include: lacto-vegetarian diets, lacto-ovo vegetarian diets, ovo-vegetarian diets, and vegan diets -which will be discussed in greater detail in the following section.

In order to sustain a healthy vegetarian diet, one must remember to incorporate a variety of different nutrient rich foods because not one single food is capable of providing the amount of nutrients that your body needs to thrive. Similar to studying for an exam, creating a vegetarian diet is all about proper planning which will ensure the diet includes everything that your body needs. These four food groups: fruits, grains, legumes, and vegetables are imperative for a healthy vegetarian diet. Fill your plate with a variety of these four things to ensure an extremely healthy and refreshing diet.[13] Make sure to include these major nutrients into your vegetarian diet: iron, calcium, protein, vitamin D, vitamin B12, zinc, and omega-3 fatty acids. Each of the nutrients listed plays a special role in important factors such as: producing red blood cells, promoting strong bones, skin and muscle health, promoting healthy heart health, fighting anemia, and promoting a strong immune system.[14]

5.7.3 Benefits of a Vegetarian DietEdit

There are many reasons for someone to adopt a plant based diet. Across the globe, vegetarianism and veganism is practiced for a variety reasons. Places like India, where Buddhism is the predominant religion, people abstain from meat for religious purposes. In coastal areas, many people adopt diets low in meat consumption because of necessity and availability of meat. Here in America, many people associate vegetarians with radical groups like PETA, but in reality, vegetarianism is practiced across the country for both the reasons mentioned above and many others. Although a sometimes controversial topic, there are many benefits to a plant based diet, both for the body's health and the health of the environment.

While some vitamins and nutrients are readily and largely available in meant, a well planned vegetarian diet can offer a variety of benefits. It’s important to monitor plant based diets and eat a wide variety of foods to insure that you are getting the appropriate nutrients. Here are a few examples of the benefits one can expect from eating a diet free from meat:

● Heart- On average, vegetarians are healthier than those who eat meat. A study published in the American Society for Nutrition found that those who were on a plant based diet had less incidence of heart disease than those on a diet that contained meat.Additionally, they found that vegetarians had lower BMI’s, blood pressure, and cholesterol levels.

● Eyes- Plant based diets can help reduce incidence of disease in all areas, including eyes. A 2011 study found that those who ate diets high in meat were more likely to develop cataracts than those who identified as vegan or vegetarian. Age related cataracts are a prevalent problem in aging Americans, and a change in diet may help reduce this condition.

● Skin- Some vegetarians take their diet one step further and eliminate all animal products from their diet. While some might consider this a step too far, these people reap benefits that others don’t, like having healthier skin. According to one study, people who practice veganism have lower rates of acne, which is closely related to diet (Melnik 2012). Switching to a vegan diet can help eliminate a lot of the foods (meat and dairy) that are the main drivers of acne in older teens and adults.

● Cancer- While cancer rates continue to climb, a readily available solution may be right under our noses. Studies show that eating a diet low in meat can help contribute to lower cancer rates (dos santos Silva 2002). While there are many theories as to while a plant based diet helps protect against, scientist and researchers have yet to pinpoint the exact reason that plant based diets have such preventative properties.


  1. M. Floyd M. (2011) Why do people become vegans/vegetarians? Survey says: all of the above from Oregon State University
  2. Position of the American Dietetic Association: Vegetarian Diets: Health Implications of Vegetarian Diets, 2009, Journal of the Academy of Nutrition and Dietetics 109(7): 1266-1282
  3. Peter Singer (2006) Factory Farming: A Moral Issue, The Minnesota Daily
  4. John Barrett Our heath, our environment: the ecological footprint of what we eat
  5. G. Sager (2005) Vegetarianism and the Major World Religions from the Society of Ethical and Religious Vegetarians
  6. Living A Healthful Life rrom the Seventh-Day Adventist Church
  7. a b Mangels, R., & Messina, V. (2004) "Demographics and Definitions" in The dietitian's guide to vegetarian diets: Issues and applications (2nd ed., pp. 1–12). Sudbury, Mass.: Jones and Bartlett
  8. Breier, D. (2001) "Food Ingredients" in Vegan & vegetarian FAQ: Answers to your frequently asked questions (pp. 72–86). Baltimore: Vegetarian Resource Group
  9. My Plate from Food and Nutrition Service of the US Department of Agriculture
  10. Vegan Health
  11. Vegetarianism in a Nutshell
  12. Nutrition and Healthy Eating from Mayo Clinic
  13. Vegetarian and Vegan Diets from The Physicians Committee
  14. Vegetarian Diet: How to Get the Nutrients You Need from Family Doctor