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Veganalysis 2021

Find out how the health of our vegan customers weighed up against the health of our non-vegan customers in our 2021 veganalysis.

Vegan diets have been around for a long time, with evidence of people choosing to avoid animal products being traced back over 2,000 years.  

But, with greater awareness of the health and environmental impacts avoiding animal products can have, it seems more people are talking about or turning to a vegan diet.  

What is Veganuary?  

Veganuary is a campaign to inspire and support people to try veganism, drive corporate change, and create a global mass movement to champion compassionate food choices.  

Veganuary is an annual challenge that encourages people to follow a vegan lifestyle for January. In 2021, Veganuary inspired more than half a million people to try vegan, with 580,000 people signing up from 209 countries and territories [1].  

Why go vegan? 

There are many reasons why a person may choose to try a vegan diet, including environmental and animal welfare causes.  

A well-planned vegan diet tends to be lower in saturated fat and higher in fibre, fruit, and vegetables, and therefore may reduce the risk of type 2 diabetes and cardiovascular disease [2].  

Since 2018, we have analysed the data of our vegan and non-vegan customers, excluding people who follow a vegetarian diet, to see how a vegan diet impacts their health and which nutrients to watch out for when following a vegan diet.  

Veganalysis 2021 

We analysed the data of over 10,000 Medichecks customers to reveal how a vegan diet shapes up against other diets. Let’s look at the results.  


Ferritin is the body’s iron storage protein and a reliable indicator of iron levels within the body. We assess levels of iron within the body by looking at the ferritin biomarker. 

In line with previous years, iron levels were 31.4% lower in vegans than people who follow an omnivorous diet. However, it is worth noting that the mean ferritin level in vegans was still well within the optimal range and that high iron levels can be as harmful as low iron levels. 

Cholesterol and cardiovascular health  

Our results show that, on average, people following a vegan diet have 15% lower non-HDL cholesterol (the more harmful stuff) and lower total cholesterol levels (9.93%) than people following an omnivorous diet. Non-HDL cholesterol levels in early middle age are associated with heart disease in later life. No significant difference was found for HDL cholesterol. 

Unhealthy cholesterol profiles are a risk factor for developing cardiovascular disease, such as heart disease and stroke. The differences may be because a healthy vegan diet typically contains fewer calories, with lower levels of saturated fats. Vegan diets may contain higher amounts of nutrients that protect against high cholesterol, such as fibre and plant sterols. 


HbA1c is a long-term measure of the body’s ability to control blood glucose. Factors like being overweight can impair the body’s ability to control glucose. With time, this can lead to insulin resistance and type 2 diabetes, which is characterised by a raised HbA1c. Like our 2019 and 2020 results, 2021 revealed that the average HbA1c levels were almost 4% lower in vegans. 


Vegans’ folate levels were a third higher compared to those following a non-vegan diet. Folate-rich foods include broccoli, brussels sprouts, leafy green veg and beans. So, it is not surprising that the vegans outdo their fellow meat-eaters in this area. However, both groups had average folate levels within the healthy range. 

Vitamin D 

In 2020, the average blood levels of vitamin D between vegans and non-vegans were very similar. That is not so surprising when we consider that food sources of vitamin D are relatively unimportant compared to supplemental vitamin D and the vitamin D we produce in our skin upon exposure to sunlight [3]. 

Our 2021 data shows that vegans’ vitamin D levels are around 4.87% lower than non-vegans. The mean vitamin D in vegans was 75.8 nmol/L - just above the optimal level of 75 nmol/L (defined by the National Osteoporosis Society). This was slightly below the level for the comparison group who had a mean of 79.7 nmol/L. 

Omega-6 to omega-3 ratio  

The omega-6 to omega-3 ratio could be an important determinant of inflammation in the body [4]. The optimal ratio is considered below 3:1 approximately, and both groups exceed this. 

In line with previous years, our 2021 data shows that vegans' omega-6 to omega-3 ratio was markedly higher, possibly reflecting an increased reliance on vegetable oils with higher omega-6 content. Although, it could also relate to vegans having a lower omega-3 intake.  

Omega-3 fats, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are predominantly found in fish, and our ability to convert a-linolenic acid is not very efficient.  

Omega-6 is considered pro-inflammatory, although there is evidence that omega-6 rich foods, such as nuts, can decrease the risk of some diseases. Omega-6 fats are unsaturated, and the foods we find them in are typically very healthy, so we would not recommend cutting down on these.  

It may be better for our vegan customers to increase their intake of omega-3 a-linolenic containing foods such as chia seeds, flax, and walnuts, and perhaps consider microalgae supplements to provide a daily dose of EPA and DHA.  


Markers of inflammation, such as CRP-HS, were marginally lower in our vegan population. 

A lower CRP-HS level may reflect the influence of a lower-calorie diet and lower body fat in vegans. CRP can also rise in illness, so it may also be that vegans were experiencing fewer illnesses at the time of blood testing. 

In both groups, the mean level of CRP-HS was within the reference range and below the level that may indicate raised cardiovascular risk. There was also an accompanying 8.29% reduction in total white cell count in vegans. 

Liver inflammation 

In agreement with our findings from previous years, in 2021, gamma-glutamyl transferase, a marker of liver health, was 30.4% lower for vegans. Alanine transferase was also 22.3% lower. These findings may be due to less obesity leading to less fat deposition within the liver or healthier attitudes to alcohol consumption. 

Vegan analysis 2021 

Our Veganalysis results have remained remarkably consistent over the years. Vegans have lower levels of the metabolic markers HbA1c and non-HDL cholesterol, which means that they will have a lower likelihood of their blood vessels being damaged and causing cardiovascular disease.

A common concern about the vegan diet is that vegans struggle to maintain levels of vitamins and minerals, but we found that even where vegans had a significantly lower level (e.g. ferritin), the mean level was still within the optimal range. 

Are you thinking of going vegan or would you like more information on how to optimise your health and nutrition when eating a plant-based diet? Have a look at our guide to vegan and plant-based health.  

Extra comments 

It is important to note that these values represent averages and cannot predict how an individual will respond to a particular diet. Any significant changes in your diet should be supported by a health professional such as a doctor, AfN-registered nutritionist, or dietitian. 

In addition, this study represents observational data, which means that many other factors, such as lifestyle, age, gender, income, and overall health, are likely to influence the findings. 

Markers where we expected a statistically significant difference between vegans and non-vegans were analysed. Vegetarians were excluded from the other comparison group. The Wilcoxon rank-sum test was used to assess whether a statistically significant difference between groups existed. All biomarkers were restricted to 2021 values. 

Are you thinking of trying Veganuary? Look at our top 10 tips for getting through veganuary as a new (or returning) vegan. 


  3. Geissler, C. and Powers, H.J. eds., 2017. Human nutrition. Oxford University Press. 
  4. Ajabnoor, S.M., Thorpe, G., Abdelhamid, A. and Hooper, L., 2020. Long-term effects of increasing omega-3, omega-6 and total polyunsaturated fats on inflammatory bowel disease and markers of inflammation: a systematic review and meta-analysis of randomized controlled trials. European Journal of Nutrition, pp.1-24.