A Nutritionist Reviews: Veganuary

What’s the verdict on plant-based and vegan diets

Veganism is big news – so much so that between 2014-19 the number of people in the UK embracing a vegan lifestyle quadrupled.

For the first time much of the mainstream population are having conversations about plant-based diets and that is particularly true in January.

According to veganuary.com, more than half a million people went plant based for January in 2021 and The Observer reported that “it’s boom time for Veganuary as… thousands sign up to stick to a plant-based diet next month, while hundreds of vegan food launches are in the pipeline”.

For many, the choice to become vegan is a moral and environmental one, but what really grabs the headlines is the touted health benefits. With such a media storm around veganism, it can be difficult to decide fact from fiction.

Registered nutritionists are the most qualified people to discuss nutrition advice. So let’s take a look at the burning question:

is going vegan good for you?

The Pros

For the vast majority of people, introducing more plant-based foods into their daily diet is extremely beneficial.

Plants tend to be comparatively high in fibre compared to other food sources so increasing the amount of plant matter you consume will help you to reach the NHS recommended 30g daily fiber intake.

Fibre plays a key role in gut health with research linking diets rich in fruit and vegetables with a highly diverse microbiota and greater abundance of Prevotella and Faecalibacterium prausnitzii type micro-organisms. Healthy levels of Prevotella have been linked with good blood glucose management and low levels of F. prausnitzii in the gut microbiome are common in conditions of inflammation, obesity and intestinal disorders.

Switching from an omnivore to a vegan diet can alter the gut microbiome in just 5 days, but there is not enough evidence yet to establish if vegan diets can be used therapeutically for this purpose.

Vegan diets also tend to be low in cholesterol and saturated fat and are associated with the increased health benefits of high intakes of folate, antioxidant vitamins C and E, magnesium and phytonutrients, all important factors in preventing chronic diseases.

A 2017 study even concluded that vegans have a significantly reduced frequency of total cancers (-15%), as well as a 25% lower incidence and/or mortality from ischemic heart disease and increased insulin sensitivity.

However, this is where things start to become a little more ambiguous.

Studies such as the one cited above typically compare participants who follow a vegan diet with a randomised sample of the general population. The problem with this is that vegans are significantly more likely to be health conscious than the general population and are therefore far less likely to smoke, drink alcohol or eat junk food. It is therefore often difficult to reliably conclude the health benefits of veganism BUT what is for sure is that there are undoubtedly drawbacks as well.

The cons

Completely eliminating animal food sources from the diet can lead to vitamin B12, D, calcium and omega 3 fats deficiency, with lower serum levels already detectable after 4 weeks of no supplemented or properly planned vegan diet.

But what does this all mean? Why are these nutrients so important?


Vitamin B12 can only be found in animal sources, and for this reason it is essential that vegans follow a supplementation protocol.

B12 is essential for DNA synthesis, gene expression, production of some neurotransmitters, and prevention of megaloblastic anaemia. Deficiency could manifest as anemia, extreme tiredness, palpitations, mouth ulcers, pins and needles or low mood.

Vitamin D

Vitamin D is produced by the body when exposed to sunlight and is involved in calcium and phosphorus balance, having an impact on bone health, muscle contraction and teeth health.

There are vegan sources of vitamin D, for example mushrooms, and of course sun exposure during summer months but the main dietary sources are red meat, egg yolks, liver and oily fish.

Vegans should be mindful of a potential deficiency and work alongside a trained professional to assess the best supplemental regime dosage, considering that the NHS recommends 10mg (40IU) supplementation in winter months for adults following an omnivorous diet.


Calcium is essential for bone and teeth health, muscle contraction and nervous cell signalling. The main dietary source of calcium for most people is dairy so a vegan diet can be low in this mineral. Vegetable sources of calcium are green leafy vegetables and brassicas, so it is important that those are abundant in a vegan diet to avoid deficiency.

Omega 3 fats

Omega3 fatty acids are considered essential fats, meaning our body can’t manufacture them so they should need to come from our diet. Essential fatty acids are an essential part of cell membranes and regulate cell to cell communication and dictate how substances enter the cells.

They also have anti-inflammatory properties, can modulate lipid profile (percentage of HDL and LDL cholesterol), are involved in nervous system signalling and blood sugar levels regulations – just to name a few functions!

Omega 3 fatty acids can be found in nuts and seeds, but the quantity in those foods is not comparable to oily fish – the main dietary source for omega 3 fatty acids EPA and DHA.


Another risk for vegan diets is not reaching enough protein intake, as many unbalanced vegan diets can heavily focus on carbohydrates. Introducing pulses on a daily basis is very important, as well as occasional soy produce such as tofu and tempeh. Protein deficiency can have an impact on muscle mass, cellular repair, hormone’s production and impair liver detoxification.

It is important to note that plant proteins tend not to be as digestible as most animal proteins, as plant cell walls can lower digestibility. High quality proteins have all the 8 essential amino acids – a feature of animal proteins.

Plant based protein sources can lack one or more essential amino acids, so it is important to combine different sources to obtain all essential amino acids throughout the day (doesn’t need to be in the same meal).

Some vegan “meat” products can be very processed, featuring high levels of salt, added sugar and preservatives – it is important to read labels carefully or rely on less processed vegetable protein sources such as legumes, tofu and tempeh.


When following a vegan diet, it is also important to ensure there are plenty of iron sources – mainly green leafy vegetables. No-heam iron (form of iron found in vegetable sources) is not as easily absorbed by the body as heam-iron (form of iron found in animal sources).

A way to overcome this issue, is to have sources of vitamin C alongside sources of no-heam iron (for example adding lemon juice to a spinach salad), and having tea and coffee at least 2 hours prior from meals in order to increase iron absorption.

Our recommendation

From a purely nutritional perspective, increasing your intake of healthy, whole, plant-based foods is an absolute no-brainer.

However, for the vast majority of people, cutting animal products out altogether could have adverse health effects.

The reason for this is that following a purely plant-based diet makes it much more difficult to consume all the essential nutrients our bodies need to function. It’s not impossible but it requires a lot of knowledge and discipline to get right.

For most people we recommend following a balanced diet, high in plant-based foods (try to get at least 30 different types into your diet each week) which is supplemented by healthy, whole-food animal products to provide you with the full range of nutrients your body needs.

If you are interested in following a vegan diet for reasons other than health then we recommend that you do so under the guidance of a registered nutritionist online who can help you to ensure that you are supplementing your diet correctly, using verified products and food sources whilst building your own understanding over time.


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