Nutrition is an incredibly complex and sometimes contentious area of science, and a very important one to understand for the sake of human health and well-being. The nutritional benefits and drawbacks of various diets have long been compared and contrasted. Plant-based diets have received particular attention in recent years, as more young people have been turning to vegetarianism and veganism in the United States. One of the most common concerns accompanying this rise in popularity is the question of the nutritional quality offered by a plant-based diet. Some have raised an alarm, asserting that a plant-based diet is both unnatural and unsustainable and invariably leads to health consequences. However, scientific studies show that a vegan diet is both manageable and sustainable, and can even have some unique benefits to human health, as long as one is aware of the basic science behind it.
Lack of protein on a plant-based diet is a very commonly raised concern about plant-based diets. While some claim that getting enough protein as a vegan is a challenge, others go so far as to say that it is a completely impossible task. In reality, however, plant-based sources of protein are abundant and provide the same benefits as animal-based sources; the same essential amino acids that make up protein are present in both animal and plant foods. As an added bonus, plant protein also tends to contain more fiber and less saturated fat than animal protein.
Good plant-based sources of protein include legumes, nuts and seeds, whole grains, and soy. In fact, despite the United States’ current fixation on protein as the single most important indicator of health, evidence suggests that most people in the United States meet or even exceed the recommended amount of protein. This is especially true for males ages 19-59 consuming meat, poultry, and eggs. An excess of protein, particularly animal protein, is often accompanied by an excess of saturated fat, a problem we will return to later on.
In contrast to protein, fiber is an important component of nutrition that is often neglected; gastrointestinal health is a more important indicator of overall health than it is often given credit for. Fiber is a powerful booster of gastrointestinal health, an area often negatively impacted by a diet rich in animal foods. Fiber boosts the strength of the gut’s microbiome, reducing inflammation associated with the development of disease. It is common knowledge that whole foods, especially fruits and vegetables, contain more fiber than animal-based foods, but the importance of fiber and the benefits it provides are not as widely known. Great sources of fiber besides whole fruits and vegetables include whole grains, legumes, and nuts.
Several micronutrients have also been raised as points of concern for the feasibility of a plant-based diet. The most common of these include calcium, iron, vitamin D, and vitamin B12. We have all heard the phrase “milk builds strong bones,” but animal milk is far from the only rich source of calcium available to us. Calcium is found in many plant-based foods, especially in leafy greens, (spinach, kale, broccoli, rhubarb, bok choy, etc.). Regular and varied consumption of greens is important to meet one’s calcium needs. Calcium fortified plant-based foods, including fortified plant milks, are also widely available and are an option to supplement direct calcium consumption through leafy greens.
Iron is another essential micronutrient that can be a challenge to maintain on a plant-based diet without careful planning. Maintaining healthy iron levels is even more of a concern for premenopausal females than for other vegetarians and vegans, but it is nonetheless a problem faced by many who stick to a plant-based or plant predominant diet. Interestingly, rates of iron deficiency anemia are actually similar among vegetarian and meat-eating males, while anemia is more common among vegetarian females than meat-eating females. To oversimplify a meta analysis of previous studies for the sake of brevity, iron levels may not drastically differ between vegetarians and vegans. In any case, low iron is caused both by lack of availability of iron and low iron bioavailability in plant foods. Getting enough iron on a vegan diet is very possible, however: Beans, including soybeans, lentils, and garbanzo beans, are all great sources of iron. Again, fortified foods are also an option. It is important to note that iron supplements can be detrimental to health when used on a regular basis; sparse use of supplements, however, can serve as a convenient failsafe addition to directly consumed iron.
Vitamin B12 is another common concern for those considering going plant-based. B12 is an essential nutrient that does not originate in plant foods or animal-based foods, but vitamin B12 deficiency is a more common problem in vegans due to the fact that B12 becomes concentrated in animal flesh after animals consume feed containing the microorganisms from which B12 originates. Nutritional yeast is a common and efficient source of B12 for vegans and vegetarians; it is also popular for its ability to mimic the taste of dairy cheese. Besides supplements, B12 fortified foods are again the most surefire way to make sure you are meeting your vitamin B12 needs. Common examples of B12 fortified foods include plant milks and cereals.
Finally, we come to vitamin D. Vegetarians and vegans may indeed be at a higher risk of vitamin D deficiency than meat-eaters due to the fact that animal-based foods naturally contain more vitamin D than plant sources. However, vitamin D is actually not widely available in any foods, and thus dietary consumption of vitamin D is low across the spectrum. According to a study on vitamin D levels in vegetarians versus meat-eaters, the differences in levels of vitamin D between these groups may have to do with more variables than just diet. The same plant foods often fortified with vitamin B12 are also often fortified with vitamin D. Further, while it is true that vitamin D is not widely available in foods, ultraviolet treated mushrooms are a great natural source of the vitamin.
As has been alluded to thus far, the plant-based diet boasts many disease prevention properties, especially when compared to the standard American diet. According to the CDC, heart disease and cancers are the two most common causes of death in the United States. Research shows that a plant-based diet can lower a person’s risk for several diseases, including heart disease and certain cancers, as well as diabetes. A whole foods plant-based diet, in particular, has been shown to not only prevent but also treat coronary heart disease and Type 2 diabetes.
The disease prevention associated with a plant-based diet can likely be attributed to both plant-based foods’ tendency to contain various important compounds, and also a lack of exposure to harmful compounds often present in an omnivorous diet. As previously mentioned, saturated fat is present to a much higher extent in animal foods than in plant foods, and an excess of saturated fat puts one at an elevated risk of heart disease. Cholesterol also increases risk for developing heart disease and is found exclusively in animal foods (UCSF). Even methods of preparing animal food have an effect on its health-compromising properties. The process of grilling and frying animal foods causes them to form toxins that accelerate the aging process, accompanied by inflammation that leads to the formation of disease.
In sum, plant-based diets can be healthier than diets containing animal products as long as one is careful to monitor their intake of certain key nutrients. However, even small reductions in meat and other animal products make a difference, so don’t feel discouraged if you aren’t ready to go fully plant-based just yet. The most important thing is that you do what is best for you at this stage in your nutrition journey!
Shae Stokes is an FFAC fellow and a college senior studying philosophy, sociology, and animals & society.