Healthy Food: the Impact of the Vegetarian Diet



In recent years, there has been a growing trend towards vegetarianism in societal dietary choices. The practice consists of excluding flesh and sometimes by-products of animals from consumption for distinct reasons. Six to eight million people in the United States are estimated to practice some form of vegetarianism (Harvard Health Publications, 2016).

In the modern world, with the availability of diverse food choices, vegetarians can uphold the nutritional needs of the body. While vegetarianism has many positive effects on human health, certain pathophysiological disorders are stemming from such long-term dietary choices that need addressing.


Vegetarianism can be practiced for a variety of moral, religious, cultural, and medical reasons. There are different patterns of the vegetarian diet revolving around the consumption of dairy and eggs, including vegan, lactovegetarian, and ovo-lacto-vegetarian.

There are evident health benefits that arise from minimal amounts of animal products as the amount of total and saturated fat is significantly lower. Consequently, the risk of chronic illnesses around heart problems, obesity, and blood pressure drops significantly.

A meta-analysis of credible clinical and observational trials shows a positive correlation regarding the effect of the vegetarian diet on blood pressure (BP). Cardiovascular disease is consistently linked to blood pressure independent from other risk factors. The analysis showed that vegetarian diets consistently lowered systolic and diastolic BP by 2-7mm Hg, thus lowering instances of hypertension (Yokoyama et al., 2014).

“Vegetarian diets can be healthful and nutritionally sound if they are carefully planned to include essential nutrients” (American Heart Association, 2016, para. 3). Due to current trends and lack of appropriate nutritional or medical supervision, people choosing vegetarianism often for the health benefits, end up causing long-term damage to their physiology.


The main instances of pathophysiology stemming from vegetarianism are based on a deficiency of basic organic compounds. These are critical to the healthy function of various systems in the human body, including the cardiovascular, nervous, digestive, and muscular systems.

Histidine-containing dipeptides (HCDs), an analog of carnosine formed through amino acid synthesis, are present throughout the body, particularly skeletal muscle and neuronal tissue. A vegetarian diet is free of HCDs, and by comparison to omnivores, long-term muscle carnosine levels are lower (Blancquaert et al., 2016). In a specific case report of a patient on a vegan diet, bloodwork showed no significant benefit based on a lipid risk profile.

Other than a reduction of high-density lipoprotein, the profile, including total cholesterol, showed poor markings. The study suggests that more research to determine if vegetarianism is indeed helpful to cholesterol levels and consequentially reduced the risk of cardiovascular disease (Koury & Bergdahl, 2016).

As might be expected, vegetarianism affects the digestive system by altering the gastrointestinal microbiota. Fiber intake increases and escalates short-chain fatty acid production by microorganisms. Consequentially, intestinal PH falls, and residential bacteria cannot grow consistently.

Dysbiosis, occurring when gut microbiota has been modified, can result in triggering of autoimmune diseases such as type-1 diabetes, rheumatoid arthritis, and Hashimoto’s thyroiditis (Colucci et al., 2015).

Perhaps the strongest argument against vegetarianism is a vitamin deficiency, particularly cobalamin (B12) and omega-3 fatty acids, a component of which is docosahexaenoic acid (DHA). While vegetarian diets are rich in Vitamin C and comparable to omnivores in zinc, there is a strong deficiency of B12 on a consistent basis. B12 serves as a key defense against oxidative stress.

Consequently, the oxidative injury will disrupt catalyst processes in the body, which correlate with elevated cardiovascular, neurological, and endothelial dysfunctions (Boancă, Colosi, & Crăciun, 2013). When the cobalamin deficiency combines with a lack of omega-3 fatty acids, found only in seafood, brain function is diminished.

Homocysteine levels increase, which can cause neuron DNA damage, apoptosis, a decrease in synaptic function. Oxidative stress causes cellular damage in the brain due impact on omega-3 levels.

The growth of homocysteine toxicity and declining DHA and B12 indicators in plasma correlate to the psychological irregularity behind schizophrenia. Also, an observed effect was noticed on maternal plasma during pregnancy leading to preeclampsia (Rathod, Kale, & Joshi, 2016).

Literature Review

All references used for research in this paper were credible and peer-reviewed scientific sources. First, pages on vegetarianism from Harvard University and American Heart Association websites were utilized to gain a coherent basis for further research. While informational, these sources were more in the realm of popular science for the general public rather than in-depth medical research.

Due to vegetarianism being such a popular lifestyle choice, there were obvious indicators that some positive dynamics in health could be noticed in such cases.

Although a whole section is dedicated to pathophysiology, research was included from JAMA Internal Medicine to show a proven benefit of the diet. This resource presented a never done before meta-analysis of data on the topic, signifying its tremendous scientific value (Yokoyama et al., 2014).

Several of the cited journals consisted directly of laboratory analyses to research phenomena surrounding molecular mechanisms. Articles, particularly from Archives of Environmental Contamination and Toxicology as well as The Journal of Physiology, were not focused on the topic of this paper, but their findings presented information that was relevant when describing the pathophysiology of vegetarianism.

With that information, a connection could be made to case studies regarding the diet. The British Journal of Medicine and Medical Research presented a case study of one patient, and while it seemed to have been written as a suggestion for future research, the authors made claims based on a cardiovascular profile of one patient. No matter how common the case may have been, there is no relevant data on a large scale at this time to support their findings.

Meanwhile, the European Journal of Clinical Nutrition published an article that described a case study done on 86 people, categorically broken down to compare results.

Also, the article included a synthesis of past research on the common vitamin B12 deficiency seen in vegetarians. The conclusions made were coherent and logical, exponentially increasing its scientific usefulness. Together, these resources helped synthesize the information presented in this essay.


Lifestyle and dietary choices stemming from vegetarianism are usually based upon admirable reasons and should be respected. There are several health benefits of this diet, which aid with symptoms and prevention of the most severe pathological conditions related to statistically common diseases in the United States. However, a vegetarian diet, not planned and balanced correctly, can cause long-term disrupting pathophysiological dysfunctions.

If people choose this lifestyle, it must be done in a sustainable way for the human body with careful medical and nutritional supervision. More research and trials are needed to determine the physiological effects of vegetarianism regarding psychology, vitamin and nutrient deficiency, as well as genetics. By identifying issues and finding appropriate solutions, the diet can be safely practiced for the positive outcomes it provides.


American Heart Association (2016). .

Blancquaert, L., Baba, S. P., Kwiatkowski, S., Stautemas, J., Stegen, S., Barbaresi, S.,… Everaert, I. (2016). Carnosine and anserine homeostasis in skeletal muscle and heart is controlled by β-alanine transamination. The Journal of Physiology, 594(17), 4849-4863. doi:10.1113/jp272050

Boancă, M. M., Colosi, H. A., & Crăciun, E. C. (2013). The impact of the lacto-ovo vegetarian diet on the erythrocyte superoxide dismutase activity: a study in the Romanian population. European Journal of Clinical Nutrition, 68(2), 184-188. doi:10.1038/ejcn.2013.179

Colucci, R., Lotti, F., Arunachalam, M., Lotti, T., Dragoni, F., Benvenga, S., & Moretti, S. (2015). Correlation of Serum Thyroid Hormones Autoantibodies with Self-Reported Exposure to Thyroid Disruptors in a Group of Nonsegmental Vitiligo Patients. Archives of Environmental Contamination and Toxicology, 69(2), 181-190. doi:10.1007/s00244-015-0138-7

Harvard Health Publications. (2016). .

Koury, O., & Bergdahl, A. (2016). Poor Cardiovascular Risk Profile Following a Vegan Diet: A Case Report. British Journal of Medicine and Medical Research, 13(8), 1-4. doi:10.9734/bjmmr/2016/23762

Rathod, R., Kale, A., & Joshi, S. (2016). Novel insights into the effect of vitamin B12 and omega-3 fatty acids on brain function. Journal of Biomedical Science, 23(1). doi:10.1186/s12929-016-0241-8

Yokoyama, Y., Nishimura, K., Barnard, N. D., Takegami, M., Watanabe, M., Sekikawa, A.,… Miyamoto, Y. (2014). Vegetarian Diets and Blood Pressure. JAMA Internal Medicine, 174(4), 577-587. doi:10.1001/jamainternmed.2013.14547

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