Nutrition-Based Pros and Cons of Vegetarian Diets

by Kirsten Chesney | Oct 1, 2020 | Diets

Today is World Vegetarian Day! Every day seems to be celebrating something, right? Well, in honor of World Vegetarian Day, I want to talk about some pros and cons of following a vegetarian diet. This will help guide you in whether or not a vegetarian diet is right for you. It will also serve as a resource for current vegetarians to be aware of potential drawbacks and how to correct them. Although there are environmental and ethical aspects related to vegetarian diets, I will only be focusing on nutrition-based aspects with this blog. Let’s check them out!

Pros of Vegetarian Diets:

Vegetarian diets avoid some of the harmful compounds found in meat products while increasing the beneficial compounds found in whole, plant-based foods. Of course, a person can eat Oreos and ravioli every day and technically still be vegetarian, but this version of avoiding meat will not support health. The pros of vegetarian diets listed here assumes a person is focused on whole plant foods from a variety of sources. This also includes animal products such as fish, dairy, and eggs, which are eaten by many vegetarians.

Reduced Disease Risk

A vegetarian diet means you’ll likely be eating more whole foods as you must find a suitable replacement for protein. The very act of eating whole foods will nourish your body with the vitamins, minerals, and enzymes it needs to promote health. In fact, studies have shown that vegetarian and vegan diets can reduce the risk of cardiovascular diseases, diabetes, and even some cancers as compared to their meat-eating counterparts.

Wider Variety of Food

Statistically, there’s a higher likelihood that vegetarians eat a wider variety of foods than omnivores. While they may still get into the habit of eating similar foods each day (as humans, we seek patterns and are creatures of habit), those foods will be more varied and from a wider selection of food groups. Eating a wider, more colorful variety of whole foods means you’re getting consistent amounts of phytonutrients and antioxidants with every meal. These compounds promote system-wide health, ward off infections and illnesses, as well as prevent chronic diseases.

Protection From Growth Hormones in Meat

Furthermore, eating a high-protein diet (specifically animal protein) is associated with accelerated aging and disease progression. This is because animal protein controls growth hormone pathways, such as IGF-1, which enters our bloodstream. This hormone is necessary for fetal development and childhood growth but is known to promote cancer, chronic diseases, and tumor growth by stimulating cell proliferation in adulthood. Keep in mind that these results were seen in those who eat animal protein in excess of recommended guidelines. Further, IGF-1 is also found in dairy products (even if cows are not treated with RBST). Limiting dairy will thus decrease IGF-1 levels in the bloodstream. IGF-1 levels should be low in adults but never zero. This hormone continues to preserve bone and muscle throughout life so we do need small but adequate amounts of it. IGF-1 is also found in soy products and normal servings will provide small amounts. A person has to eat over 10 servings per day of soy foods before their IGF-1 levels resemble those of meat-eaters.

Protection From Carcinogenic Chemicals

In 2015, the World Health Organization (WHO) labeled red meat as “probably carcinogenic to humans” and processed meat as, “carcinogenic to humans.” Much of this has to do with the way in which processed meat is made as well as how meat is cooked. Meat that is processed or cooked over a flame produces carcinogenic chemicals. Another reason for WHO’s statements is due to research showing that high consumption of red meat can increase the risk of some cancers, heart disease, diabetes, and other chronic diseases. Note that WHO’s findings are limited to red meat and processed meat only. Increased disease risk was not associated with other meats such as poultry and fish.

Cons of Vegetarian Diets:

While vegetarian diets help you avoid harmful compounds and reduce your risk of disease, they are not without flaw. One of the main arguments against a vegetarian diet is the potential for deficiencies in some vitamins, minerals, and other compounds. This may be especially true for those who do not eat fish, dairy, and/or eggs. In addition to nutrient deficiencies, harmful exposure to certain toxins and chemicals can be a concern for vegetarians. Let’s explore each of these.

Possible Nutrient Deficiencies

Vitamin B12

Perhaps the most common vitamin people get concerned about is vitamin B12. This is found in meat, fish and shellfish in adequate quantities, making vegetarians and vegans at higher risk for a vitamin B12 deficiency. However, this vitamin is also found in dairy products and in eggs. Those who eat two eggs per day get about 46% of the recommended daily value of this vitamin. Those who are vegan, however, are at a higher risk for deficiency (about 92%). Sometimes a vitamin B12 supplement is recommended.

Calcium

Another nutrient of concern is calcium. Some vegetarians choose to limit their intake of dairy products as well as meat. This eliminates some of the main sources of calcium. People in this camp should be extra mindful about getting enough calcium from plants: green leafy vegetables, white beans, sesame seeds, sweet potatoes, broccoli, kale, and bok choy are all great sources of calcium. However, the antinutrient oxalate can interfere with the absorption of calcium (among other nutrients). Antinutrients are present in plant foods to varying degrees. Eating low-oxylate foods that are high in calcium will offset this problem. Broccoli, kale, and bok choy are low in oxylates.

Iron and Zinc

Iron and zinc are other minerals that tend to be lower in vegetarians and vegans. However, when it comes to zinc, studies have shown that vegetarians and vegans actually learn to adapt to a lower intake by increasing their absorption and retention of this mineral. Cool eh? Zinc can be found in shiitake mushrooms, green peas, spinach, lima beans, lentils, asparagus, beet greens, broccoli, and sweet corn.

Iron is unique in that there are two forms of it: heme and non-heme. Heme iron is found in animal protein whereas non-heme is found in plant-based foods. Heme iron is better absorbed than non-heme, meaning that a vegetarian would have to eat more iron than those who eat meat, specifically 1.8 times more iron per day. High iron foods include beans, lentils, tofu, cashews, green leafy vegetables, and whole grains.

Similar to calcium, there is an antinutrient that inhibits the absorption of both zinc and iron. It’s called phytate and it’s found in grains, nuts, and legumes. Eating high-phytate foods can raise the risk for zinc and iron deficiency over time. In general, those who eat a wide variety of whole foods should not be concerned about these deficiencies. This is because iron and zinc can be obtained from other low-phytate foods and will offset the times when high-phytate foods are eaten. Nevertheless, a person can lower the phytate content in whole grains and legumes by soaking them in water overnight or by sprouting them. Quinoa seeds for example have 98% less phytate content after being soaked overnight!

Omega-3 Fatty Acids

Some vegetarians eat fish and so get enough omega-3 fatty acids. Those who do not eat fish can find themselves deficient in omega-3’s. Some plant foods do contain a precursor of omega 3 fats. This precursor is called alpha-linolenic acid (ALA) and our bodies must convert it to omega-3 before we can reap the benefits of this oil. Walnuts, flaxseeds, and chia seeds are good sources of ALA, however most people have a hard time converting ALA to omega-3. Our bodies are simply not efficient at this. It is often recommended to take a plant-based fish oil supplement, which comes from marine microalgae or algal oil. Fish get omega 3’s from eating algae (or from eating other fish who eat algae), making an algal oil supplement a good source of omega 3 fatty acid.

Vitamin A

If you’ve ever heard your mom say that eating carrots helps you see better, then you know a little bit about vitamin A. However, there’s much more to the story here (as with any topic explored deeply enough). Vitamin A comes in two forms: preformed vitamin A and provitamin A. Preformed vitamin A is only found in animal products (meat, fish, liver, eggs, and dairy) and is easily broken down into its usable form called retinol. On the other hand, provitamin A is only found in some plant foods in the form of carotenoids. Carotenoids are the pigments of plants, specifically those that are orange, yellow, red, and some green (fun fact: there are over 750 types of carotenoids! However, our human diet only contains about 40 types).

Perhaps you’ve heard of beta-carotene. This is the carotenoid your mom was talking about when she told you to eat your carrots. The problem with carotenoids is that they are less easily absorbed by our body. Even once they are absorbed, they must then be converted into retinol before it is usable. This conversion is a less efficient process than it is for animal products. This means many vegetarians and vegans have two hurdles to jump before they can reap the benefits of vitamin A. Let’s talk about how to get over these hurdles:

• Absorption of carotenoids: As stated, carotenoids are the plant version of vitamin A and they can be difficult for our bodies to absorb. In general, absorption will increase if you cook or juice the food first, which will breakdown the complex matrix of the food. For example, only 2% of the beta-carotene in raw carrots are absorbed by our bodies, but if you juiced that carrot you’d be absorbing about 14% of its beta-carotene. Likewise, cooked spinach releases more beta-carotene than raw spinach. Lastly, vitamin A is a fat-soluble vitamin. This means it will always be best absorbed if eaten in conjunction with a healthy fat.

• Conversion of carotenoids: Recall that carotenoids must be converted into the usable form of vitamin A, called retinol. This conversion is cumbersome and less efficient than for preformed vitamin A from animal products. Why so difficult? Well, for a number of reasons: body composition, age, smoking status, gut microbiome health, statin medication, alcohol intake, and genetic variation all determine how well your body converts carotenoids. Research shows as many as 50% of people have trouble converting carotenoids into vitamin A! You can increase your conversion by ensuring you have good health in all areas, avoid unnecessary medications, improve gut health, quit smoking, and limit alcohol intake. Further, increasing your absorption of carotenoids, discussed above, will increase the amount of available carotenoids that your body can convert. Lastly, focusing on foods with a simpler food matrix, such as certain oils and algae, is a much more efficient way to absorb and convert carotenoids. Red palm oil and spirulina are excellent sources of readily available carotenoids. Be careful with spirulina though, as it can be contaminated with toxic metals and harmful bacteria if it’s grown in unsafe conditions. It is important to purchase responsibly sourced and pure versions of spirulina. There are vitamin A supplements available, called retinyl palmitate, although most of them are derived from animal products.

• Eating preformed vitamin A: Perhaps the easiest way to easily absorb and convert vitamin A into its usable form is to get them from non-meat animal products, eggs and dairy. This is available for vegetarians who choose to eat these products.

Nutrients Only Found in Fish, Dairy, or Eggs

This section may only apply to vegans, however some vegetarians additionally choose to avoid fish, dairy, and/or eggs. We have already discussed some of the nutrients found in these animal products: vitamin B12, omega-3 fatty acids, and vitamin A. These nutrients are found in fish, dairy, and eggs, however if you avoid these foods, then here’s a quick recap: vitamin B12 should be supplemented. Omega-3 fatty acids are poorly converted by nuts and seeds and should be supplemented. Vitamin A is also poorly converted (by carotenoid-containing foods) and can be supplemented with red palm oil or spirulina.

In addition to these nutrients, there are other compounds that are only found in fish, dairy, and/or eggs:

• Carnosine: this antioxidant is only found in meat, including fish. Although fish contain very small amounts of it. Carnosine is well known for increasing muscle function, reducing muscle fatigue, and improving performance. It may also minimize oxidation, improve blood glucose levels, fight inflammation, bind to metal ions, improve cataracts, and be neuroprotective after spinal cord injuries. Carnosine is made by our bodies in small amounts but research suggests we may need more of it through our diet. If you are vegetarian your best source of carnosine will be in beta-alanine supplements. Beta-alanine is an amino acid that helps form carnosine in the body.

• Vitamin D: truth be told, vitamin D is a very common vitamin that most people are low in, whether or not they are vegetarian. The active form of this vitamin (D3) is only found in animal products whereas the inactive form (D2) is found in plants. Similar to omega-3’s and vitamin A, vitamin D2 (from plants) is less efficient at converting to its active form. Vitamin D3 is found in fish and eggs, so if you avoid both, you may be at higher risk of deficiency than our already deficient general population. The best source of vitamin D3 for you would come from vegetarian supplements made from lichen. Most vitamin D3 supplements are made from lanolin which is oil from sheep’s wool (odd, I know). So be sure to read the ingredients to ensure you’re getting a vegetarian version.

• Taurine: this is a sulfur compound that helps with muscle function, formation of bile salts, antioxidant activity, and the detoxification of xenobiotics. Taurine is found in fish, dairy, and eggs, although it is also made in small amounts by our bodies. Taking taurine supplements may be helpful for you if you avoid these foods. Supplementing with taurine can be effective against congestive heart failure, high blood pressure, high cholesterol, and plaque build-up in the arteries.

• Creatine: is found in dairy and some fish. It is also produced by our bodies, however vegetarians have been found to have lower amounts of this compound. A person needs between 1-3 grams of creatine per day. Creatine is best known for providing energy for our muscles and increasing strength and endurance. It may also slow down the build-up of lactic acid, boost protein synthesis, and improve brain function and memory. Not all vegetarians choose to take creatine supplements, and they’re not recommended for those with diabetes or blood sugar issues. Creatine supplements are most commonly taken by athletes. If you do supplement, it is best to take it with a lot of water so as not to strain your kidneys. Creatine supplements are safe at appropriate doses and for up to 5 years. They should not be taken long term and high doses could damage the liver, kidneys, and heart.

Increased Pesticide Exposure

If vegetarians and vegans aren’t diligent about sourcing their food, they may be trading the harms of meat (hormones, antibiotics, and carcinogenic compounds) for the harms of fresh produce (pesticides). Eating more whole foods, particularly fruits and vegetables, naturally means greater exposure to pesticides. Any discussion on the harmful effects of pesticides would fill a thick book. Suffice it to say that pesticides exposure has been linked to cancer, Alzheimer’s, Parkinson’s disease, ADHD, hormone disruption, reproduction issues, nervous system issues, and much more. Your best bet to avoiding pesticides is to purchase organic produce whenever possible. Check out the Environmental Working Group to get a list of the Dirty Dozen, updated each year. The Dirty Dozen is a list of fresh produce found to be most contaminated by pesticides and thus should be bought organic. Common produce on the Dirty Dozen list include kale, spinach, strawberries, and peaches. See the complete list here.

Aside from fresh fruits and vegetables, there are three other foods that are commonly eaten by vegetarians and vegans that can contain harmful compounds:

• Soybeans are one of the most heavily sprayed crops in the US and are thus a high source of pesticide exposure. Tofu and any other soy-based product should be bought organic.

• Dried seaweed snacks should also be mentioned. They are not sprayed with pesticides but they can contain heavy metals including arsenic, mercury, lead, and cadmium depending on the region in which they are grown. The FDA does regulate the level of these toxins in dried seaweed, however it is good practice to purchase organic versions.

• Certain types of rice contain high levels of inorganic arsenic. This form of arsenic is found in soil and groundwater and is more toxic than organic arsenic. Inorganic arsenic is often found in the irrigation water used in the paddy fields that grow rice. Rice is also great at absorbing arsenic compared to other types of crops. Arsenic can be significantly reduced by washing the rice and then cooking it in plenty of water, however be sure your water source is not also contaminated with arsenic! Arsenic is a common contaminant found in well water and can also be found in some city water. Well water is not regulated by the city and therefore can contain arsenic levels over and above the standard set by the EPA. It is wise to get your water tested and to install a filter designed to remove arsenic. Rinsing and cooking rice (or anything) in arsenic-laden water will only increase your exposure. The good news is that some types of rice contain less arsenic than others. These include white, basmati, jasmine, or any rice from California, India, or Pakistan. Interestingly, brown rice contains more arsenic than white rice. Since brown rice confers more health benefits than white, be sure to rinse and cook brown rice in arsenic-free water. Lastly, organically grown rice sill absorbs arsenic in the same way as conventional rice, so purchasing organic rice will not solve the problem.

Vegetarian diets can be a very healthy upgrade compared to a standard American diet. Vegetarians enjoy a wider variety of food meaning that they reap the benefits of the myriad of nutrients that whole foods bring. These nutrients help reduce the risk of several chronic diseases. Lower protein intake is also a benefit among vegetarians, as high protein diets can stimulate disease progression. Furthermore, vegetarian diets avoid the added hormones, antibiotics, and carcinogenic compounds associated with meat products.

With all that said, some vegetarians may have to supplement their diet with specific vitamins, minerals, and other compounds, especially if they avoid fish, dairy, and eggs. Lastly, harmful toxins and metals are often present in plant-based foods and require extra vigilance to avoid these compounds. Overall, it is best to monitor your health and any new symptoms while following a vegetarian diet. Eliminating the source of your symptoms will prevent serious health issues later on. Our team at CustomCare Nutrition will help you determine the best eating plan for your needs, based on any health conditions or symptoms. Contact us today!