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Debunked: Vegan Diets and Health

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The new year brings with it a whole variety of resolutions. Of these, some people will be taking part in Veganuary, in an attempt to practice veganism for the month of January.

One of the key aspects of veganism is adhering to an entirely plant-based diet. This means no animal products, so wave goodbye to that flame-grilled steak.

The vegan diet might seem like a relatively simple concept, but the discussion around the supposed health and nutritional benefits or disadvantages is far from. Those looking at switching may be curious as to whether, or how, it could impact their health.

People get this information in a variety of ways; the recent documentary “The Game Changers”, which explores plant-based eating and strength, has been the subject of much discussion in our Editorial office, and the internet, as ever, remains the go-to choice for information. But in an age of pseudoscience and misinformation, it can be difficult to separate fact from fiction.

We recently asked our readers what they already knew about vegan diets, health and nutrition and what they wanted to know. There were debates, strong opinions and many claims made, but what does the science say?

Is a vegan diet “healthy”?

One of the main factors swaying people towards a vegan diet is that it is supposedly “healthier”; a recent analysis found that 50% of meat-eaters surveyed perceived veganism to be healthy.1 The difficulty with this term is that “healthy” means different things to different people, and even from a medical perspective, what constitutes a healthy diet is unique to the individual.

“There are certainly balanced and optimal ways to practice a vegan diet as well as suboptimal ways,” explains Alicia Romano, a registered dietitian at Tufts Medical Center and spokesperson for the Academy of Nutrition and Dietetics.

“Ideally, when practicing a vegan diet, we want to make sure that balance exists on the plate to optimize dietary variety and nutrient intake. This means incorporating plant-based foods that provide protein, fiber, healthy fats (including omega-3 fatty acids) and fortified nutrients known to be lacking in the vegan diet.”

So, what kind of foods make up the optimal vegan diet? Romano suggests a variety of fruit and vegetables, as well as legumes, nuts and seeds, soy products and grains. “This diet becomes less balanced or optimal when the bulk of the diet contains highly processed vegan foods – processed frozen foods, packaged foods, margarines, sweets.  Processed vegan foods often contain higher amounts of saturated fats (such as palm oil), added sodium and sugars, and a number of other preservatives,” she continues.

As someone who was taught about the “Eat Well Plate” at school, this comes as no surprise; it was drummed into our impressionable young minds that a balanced diet consisted of more of the fresh foods than processed (although frankly that never stopped my teenage self from going wild at the ice cream factory in Pizza Hut). However, it’s easy to understand how, like any other diet, a vegan one can also be unbalanced, particularly without an education of how to eat in a balanced way when certain foods are taken out of the picture.

, vegetable, mineral…

The elimination of animal products from the diet also presents particular challenges when it comes to getting the right amount of vitamins and minerals. “Due to the restricted nature of the vegan diet there is a high risk of deficiency in a number of nutrients, including iron, B12, calcium, vitamin D and omega-3 fatty acids. A number of these nutrients are found in rich quantities in animal products, fatty fish and dairy,” Romano explains.

When we asked our readers about their knowledge of vegan diets, iron was one of the most frequently mentioned minerals. Why is it so important?

Iron is a key component of hemoglobin, the molecule responsible for oxygen transportation in our bodies. A lack of iron can result in reduced hemoglobin levels, leading to iron-deficiency anemia, a disorder characterized by fatigue and shortness of breath. “Vegans are prone to developing iron deficiency due to elimination of heme iron, which is found in animal meats. Heme iron is more easily absorbed by the body than non-heme iron, which is found in plants.”

This isn’t to say that deficiency is inevitable – the key appears to be in the planning.

“It is possible to achieve adequate vitamin and mineral intake on a vegan diet if it is well planned.” For example, Romano suggests that iron-rich plant foods should be consumed in conjunction with foods rich in vitamin C, as this helps to optimize iron absorption. She also notes that other nutrients that present a high risk of deficiency, such as B12, calcium and vitamin D, are often fortified in vegan food products, such as plant-based milks.

“The use of fortified foods is an important piece in optimizing intake, while additional supplementation may be necessary where fortification lacks, such as B12, vitamin D and iron.”

Does a vegan diet prevent disease?

Another popular reason for many switching to a vegan diet is that it may reduce the risk of disease. Research has revealed a number of associations between plant-based diets and prevention of disease; a 2014 meta-analysis reported that vegan diets were associated with ~15% reduced risk of cancer.2

However, the authors of this paper also acknowledge that the low number of studies investigating this relationship means that this statistic should be interpreted with caution. Furthermore, studies into the health benefits of vegan and vegetarian diets are frequently cross-sectional, meaning they are susceptible to bias.

Romano is also careful to emphasize the difference between a vegan diet and a plant-based diet when it comes to reaping health benefits. With regards to the latter, “it refers to a way of eating where we crowd out the plate with plant-based foods, meaning vegetables, fruits, legumes, nuts and seeds make up the majority of the meal (about two-thirds of the plate), leaving room for animal-based products.”

To optimize the potential for reduced disease risk, “One does not have to strictly follow a vegan diet. Instead, choose to shift the plate to include two-thirds plant-based foods.” says Romano.

The gut microbiome

Now more than ever, we are learning about the impact that our diet can have on the microbial ecosystem within our gut, and consequently, how this could affect our health. Changes in the gut microbiome have been associated with a whole host of conditions, from Type I diabetes to cancer.3

“Diet in general plays a large factor for human gut microbiota composition. Diets rich in plant foods (not necessarily just a vegan diet) may be an effective way to promote a diverse array of beneficial microbes in the gut to support overall health,” says Romano.

Nevertheless, much like other research into vegan diets and disease, the data currently available is limited.

“Areas of research in the gut microbiome are exciting.” Romano tells us. “However, due to the complexity and interindividual differences, we need further research to fully understand the interactions between diet, the microbiome and health outcomes.”

The general verdict? “Whether you follow a vegan eating plan or not, plant-based foods are good for your overall health, including the health of your gut.”

“There is not necessarily a one-size-fits-all diet approach”

Whether or not a vegan diet is successful, optimal, or “healthy”, seems very much down to the individual. It also appears that, where health benefits may exist, it might not be necessary to follow a completely vegan diet in order to achieve them.

“We are all unique individuals with unique nutritional needs.” Romano concludes.

“There is not necessarily a one-size-fits-all diet approach.”


  1. Bryant. (2020) We Can’t Keep Meating Like This: Attitudes towards Vegetarian and Vegan Diets in the United Kingdom. Sustainability. DOI: https://doi.org/10.3390/su11236844
  2. Dinu et al. (2017) Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Critical Reviews in Food Science and Nutrition. DOI:  https://doi.org/10.1080/10408398.2016.1138447
  3. Shreiner et al. (2015) The gut microbiome in health and disease. Current Opinion in Gastroenterology. DOI: https://doi.org/10.1097/MOG.0000000000000139