How Going Vegan Affected My Body

By Diana Licalzi, MS, RD, CDCES, November 8, 2021

iStock_000061701414_Large-697455-edited.jpgSome people hesitate to pursue a vegan diet because they fear not getting adequate amounts of protein. This, however, should not be the case as beans, nuts, seeds, quinoa, edamame, and peas all provide sufficient amounts when consumed as part of a balanced vegan diet. As a nutrition graduate student at Tufts University, I recently completed a course called Nutritional Biochemistry: Micronutrients. In this class, we rigorously analyzed the metabolism of vitamins and minerals and their requirement for the functioning of the human body. Along the way, I discovered that despite popular opinion, a more pertinent concern for vegans revolves around micronutrients rather than protein.

This left me asking the question, "Does a plant-based diet provide sufficient amounts of vitamins and minerals?" Well, I decided to find the answer on my own, and thus began my two-month vegan challenge. In this blog post, I share a recap of my results and the important lessons learned.


Blood DNA Fitness tracking ebookUsing personalized blood analysis from InsideTracker, I monitored three key biomarkers – iron, calcium, and vitamin B12 – micronutrients difficult to obtain from a plant-based diet, and three measures of metabolism and weight control – glucose, cholesterol and triglycerides.


Iron's effect and importance

Our bodies need iron to perform many physiological functions. Iron is required for the formation of hemoglobin and myoglobin, proteins that carry oxygen around the entire body. It is found in both animals and plants; however, our bodies absorb animal-sourced iron much more efficiently than plant-sourced iron.

The recommended daily intake of iron is 8mg for adult men and 18mg for premenopausal adult women. Some rich sources of iron (high/low absorption)2 include the following:

  • 3oz clams - 12mg (high)
  • 1 cup raw spinach – 7.4mg (low)
  • 1 cup cooked lentils – 6.5mg (low)
  • 3oz liver – 5mg (high)
  • 1 cup beans (such as navy, lima & black) – 2.0-4.4mg (low)
  • 3oz hamburger – 2mg (high)

Since I was testing a vegan diet, I relied only on plant-based sources of iron. When I started this "experiment," my iron levels were "low" at 17ng/mL, and fell closer to deficient levels (14ng/mL) at the end of the two months. An iron deficiency, categorized as less than 12ng/mL, can cause fatigue, decreased physical and intellectual performance, lower levels of immunity and resistance to infection, and may even cause complications during pregnancy.2 If I were a lifelong vegan, I would strongly consider taking an iron supplement; alternatively, I would abstain from supplements and more actively monitor my plant-based iron intake.  



Fortify your body with vitamin B12

Vitamin B12 is an essential vitamin that primarily comes from animal products. Some animals, cows for example, produce B12 from bacteria in their intestines, which then passes into their byproducts (eggs, milk, cheese, etc.). Edible algae and some fermented foods/drinks like fermented soybeans, contain varying traces of B12, making them plant based but difficult to reach your daily needs. However, fortified cereals and non-dairy milks are readily available vegan products containing 25-100% of your daily B12 requirement.  

I relied on fortified almond milk as my main source of vitamin B12 consuming about a cup a day, equaling around 50% of my daily need. Although still in the optimized zone, my levels decreased after two months. Levels below your optimized zone can lead to fatigue, diarrhea, poor memory, and loss of appetite. More serious deficiencies may damage the brain and nervous system.2 Had I continued the experiment, I would have either increased my almond milk consumption, or considered taking a B12 supplement. 


Keeping up with calcium

Calcium contributes to healthy bones and teeth, but did you know it also increases muscle mass while promoting healthy blood pressure and normal blood clotting? Adults need 1,000mg of calcium a day, and milk and dairy products are the best sources. Milk and yogurt contain anywhere from 200-400mg of calcium per cup, while cheese provides 100-200mg of calcium per ounce. The best plant-based sources of calcium – turnips and mustard greens, broccoli, cauliflower, and kale – provide only 20-65mg per one cup serving, far below the daily requirement. You would need to consume 32 cups of kale a day to obtain enough calcium! To complicate matters, many factors hinder calcium absorption. For example, oxalic acid, found in many vegetables, binds to calcium preventing its absorption. Spinach contains a fair amount of calcium for a vegetable (32mg) but because of its oxalic content, it is not considered a reliable source.2

One cup of fortified almond milk, however, contains 45% of your daily calcium needs. I relied on almond milk, broccoli, and kale for my calcium during my two-month experiment, but unfortunately, the result at the end of the diet indicated a deterioration in bone health. Similar to B12, if I remained a vegan, I would begin a calcium supplementation routine or increase my almond milk consumption to reach my daily needs. 


Good for my glucose

My blood glucose showed the most significant improvement of all my biomarkers. Glucose is the body’s main source of energy, and must be carefully regulated in the blood to maintain good health. Proper regulation helps stabilize energy levels, improves blood pressure, and helps control weight. Glucose levels above 85 mg/dL can increase your risk for cardiovascular disease and cancer, and levels reaching 100-125mg/dL may lead to pre-diabetes.3,4,5

With an initial, borderline-high, glucose level of 97mg/dL, InsideTracker recommended that I increase my consumption of avocados, chia seeds, and old-fashioned oats. I took their advice, ate almost an avocado a day, and happily saw my glucose level drop sharply.


A key to cholesterol?

Interestingly, my total cholesterol and LDL or ‘bad’ cholesterol remained unchanged while my HDL or ‘good’ cholesterol improved significantly. HDL cholesterol acts as a scavenger by gathering excess plasma cholesterol and depositing it in the liver, where it’s then broken down and excreted. Low levels of HDL cholesterol can increase your risk of poor heart health. Replacing saturated fats, such as fatty beef, cream, and cheese with unsaturated fats like avocados, nuts, and vegetable oils has been shown to improve cholesterol.6 As a vegan, my consumption of healthy fats increased significantly as I relied more on these foods to keep me full.


Triumphant triglycerides

Triglycerides are a form of fat found in both our blood and food. After we consume a meal, any excess calories we don’t use for energy are converted to triglycerides and are utilized later in times of energy need. Like cholesterol, normal levels are important to sustain energy, improve metabolism, and promote heart health. Vegan diets have been associated with lower levels of triglycerides6. My results agreed with current research findings as my levels declined into my optimized zone.



The top takeaways 

So, would I recommend a vegan diet? It depends. Veganism emphasizes a diet rich in fruits, vegetables, and whole grains – foods that should comprise the majority of everyone's diet. Research shows that plant-based diets may lower body mass index, blood pressure, cholesterol levels, and heart disease mortality rates. They also reduce the need for medications to treat chronic diseases7. Plus, plant-based diets cause less harm to the environment! So, if you suffer from any of the aforementioned illnesses, a plant-based diet may help you significantly. However, it may also put you at greater risk of experiencing certain deficiencies. 

I prefer a diet that consists of natural, whole foods and avoids supplements and processed food products. My regular diet consists of mainly plants (fruits, veggies, whole grains, legumes, nuts, and seeds) occasionally eggs, fish, yogurt, and limited chicken, meat, and cheese. I plan to continue to incorporate the extra servings of healthy fats into my diet, and look forward to seeing how my biomarkers change once again. As for my role in helping the environment? I will limit my organic and grass-fed meat and dairy consumption, and choose organic, local foods as often as possible! Of course, anyone who chooses to switch to a vegan diet should first consult a Registered Dietitian to develop a proper nutrition plan and should test their blood regularly. (See below for a chance to win a consultation with ours...)



[1] Oppenlander, Richard A. Less Meat, and Taking Baby Steps Won’t Work. Minneapolis, MN : Langdon Street, 2013. Print.

[2] Gropper, SAS., Smith JL, and Groff JL. Advanced Nutrition and Human Metabolism. Australia: Wadsworth/Cengage Learning, 2013. Print. 

[3] Bjornholt, J.V., Erikssen, G., Aaser, E., Sandvik, L., Nitter-Hauge, S., Jervell, J. et al. Fasting blood glucose: an underestimated risk factor for cardiovascular death. Results from a 22-year follow-up of healthy nondiabetic men. Diabetes Care. 199;22:45-49.  

[4] The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care.2002;25(1):s5-s20. 

[5] Levitan, E.B., Song, Y., Ford, E.S., Liu, S. Is nondiabetic hyperglycemia a risk factor for cardiovascular disease? A meta-analysis of prospective studies. Arch Intern Med.2004;164(19):2147-55.

[6] Dinu M, Abbate R, Gensini GF, Casini A, Sofi F. Vegetarian, vegan diets and multiple health outcomes: a systematic review with meta-analysis of observational studies. Crit Rev Food Sci Nutr. 2016 Feb 6:0.

[7] Tuso, P. Ismail, M. et al. Nutritional Update for Physicians: Plant-Based Diet. The Permanente Journal. Spring 2013; 17(2)61


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