• Hazel Wallace

TheFoodMedic's Guide to Making the Vegan Transition

The question is, why should someone go vegan?

The reason for opting to go vegan could be one of many such as; ethical or environmental issues, cultural or religious beliefs, or for the perceived health benefits. 

The debate as to whether a plant-based diet is healthier than an omnivorous diet inclusive of both meat and plant products is extremely complex and very strong arguments can be made by advocates of either diet. We know that dietary patterns that include plenty of plant foods have many associated health benefits. A largely plant-based diet tends to be higher in fruit and vegetables, wholegrains and fibre, while also being lower in saturated fat and added sugars .The evidence specifically for vegan diets and health is limited, although some evidence suggests a reduced risk of some diseases, such as cancer. However, we also know that people who follow plant-based diets are often more health conscious overall and generally follow healthier lifestyles.

Nevertheless, eating more plants is always a good thing – just please don’t feel pressured by anyone or anything to label your diet or conform to any specific dietary pattern, if that is not something you genuinely want to do. 

The purpose of this blog post, however,  is to help those who are planning to go adopt a vegan diet for the next month, or forever more, and offer some advice on what nutrients to be a bit more mindful of.

The main nutrients which are a bit more tricky to obtain from a vegan diet include are; iron, zinc, calcium, vitamin B12, Vitamin D, iodine, selenium, and omega 3 fatty acids.  


I’m going to tackle this nutrient first as there is still an assumption that a vegan diet is devoid of protein – it’s a myth, there is protein in plants too!

Those who follow a plant-based diet are generally not at risk of a protein deficiency, however, adequate intake of complete protein sources (i.e. proteins which all 9 essential amino acids*) is slightly more difficult through the consumption of plants alone. Complete sources of protein are mainly animal foods (meat, fish, and dairy) but also include plant-based foods such as soya, quinoa, hemp and chia seed. Most other plant proteins provide some, but not all, essential amino acids, with each plant providing a different combination. So, as long as you’re eating a mixture of different plant proteins you’ll be getting all the essential amino acids your body needs. Remember protein is not just important for those looking to build or maintain muscle – protein is a crucial component of every cell in the body! It is used to build and repair muscles, cartilage, ligaments, skin, hair and lots of other tissues, as well as making important enzymes, hormones, and antibodies, or defence cells, for our immune system.

*essential = those of which we can’t make ourselves and must be obtained from the body

Protein rich plant-based sources; Pulses (beans, lentils, chickpeas), tofu and soya products, nuts, seeds, and nut butters, whole grains, and vegan protein blends (e.g.hemp/pea/brown rice).


Iron is needed to make haemoglobin, which is a protein that transports oxygen around the body in the bloodstream. Low iron levels result in iron deficiency anaemia which manifests as the following signs and symptoms*; tiredness (all the time), shortness of breath, pale skin or dark circles around the eyes, headache or dizziness/lightheadedness, weakness and poor appetite.

There are two forms of dietary iron; Heme iron which is found animal foods and non-heme iron which is found in plant foods such as grains, legumes, nuts and seeds. Heme iron is easily absorbed by the body, but non-heme iron must undergo a chemical change before it is absorbed. So although iron is abundant in plants, our body finds it slightly more difficult to absorb iron from plant sources compared to animal sources.

The absorption of non-haem iron is also affected by other foods in the diet including tea and coffee, and plant chemicals called oxalates and phytates. Phytates are found in plants such as nuts, legumes and grains which bind to and block the absorption of certain nutrients, in particular; iron, zinc and calcium. They’re certainly not “bad” for you, and in well-balanced diets, are rarely a concern. However we can reduce the phytic acid content of food through several preparation methods such as; soaking, sprouting, and fermenting. The absorption of iron is also increased when vitamin C is consumed during the same meal because the vitamin C converts it to a more bioavailable chemical form – so boost your meal by adding a lemon or lime to your salad dressing, or bell peppers to your curries and stews.

Plant based sources of iron: Pulses (beans, lentils, and chickpeas), green leafy veg (spinach and kale), fortified cereals and bread, nuts and seeds, and dried fruit.

*NOTE: If you have some of these symptoms it would be worth speaking to your GP who can do a simple blood test to check your iron levels.


Zinc is an essential trace element. It plays a number of important roles in the body from supporting the body’s immune system, assisting in wound healing, hormone production and fertility, and the formation of important proteins. Similar to iron, phytates found in plant foods such as beans, whole- grains, nuts and seeds, can reduce zinc absorption. 

Good plant-based sources of zinc include; fermented soya such as tempeh and miso; beans (soak dried beans then rinse before cooking to increase zinc absorption); whole grains, nuts and seeds and certain fortified breakfast cereals.


This essential mineral acts as an antioxidant to help prevent cell damage in our body and support our immune system. Selenium is usually found in animal based products such as meats, eggs and fish. The amount of selenium in a plant food varies depending on how much is in the soil the plant is grown in. Brazil nuts are famous for their high levels but selenium, but keep in mind that just two nuts a day may meet your daily requirements. Excessive intake of selenium can also be harmful so you may wish to take a supplement instead.

Plant based sources of selenium – brazil nuts, cereals, grains and supplements.


Calcium is probably best known for its role in bone and teeth formation, but it is also involved in the nervous system, blood clotting, and muscle contraction.

Calcium absorption from plant foods is also affected by molecules in plants called oxalates. So while leafy greens like spinach have a relatively high calcium content, the calcium is not efficiently absorbed during digestion. One study comparing calcium in plant foods to calcium in milk, suggested that it would take 16 servings of spinach to achieve the same amount of absorbable calcium that is in a 240ml glass of milk. However, there are plenty of other good plant-based sources of calcium.

Plant-based sources of calcium include; fortified plant milk-alternatives*, nuts and seeds, tofu and tempeh (and other soya products), and leafy green vegetables such as kale.

*Check the label to ensure fortification. 

Vitamin D

Vitamin D regulates the amount of calcium in the body so it is vital for strong bones and teeth. Research also suggests that sufficient intake of this vitamin may provide protection from, and decrease an individual’s risk, of various diseases including; osteoporosis, hypertension, type 2 diabetes, and cancer.

Vitamin D is made in the skin by the action of sunlight and this is the main source of vitamin D for most people. During the autumn and winter, PHE recommended that everyone living in the UK takes a supplement of 10 microgram per day – regardless of you’re vegan or not. Furthermore, certain groups of people may need to take vitamin D supplementation all year round. For more information see here.

Plant-based foods which are rich in vitamin D include; fortified margarines, breakfast cereals and soya milk. Mushrooms can also be a good source – but pop them in the sunlight or leave them on the windowsill for 1-2 hours to boost their nutrient value.

Vitamin B12

The l that everyone asks about. This vitamin is not something you want to be deficient in as it is involved in the production of red blood cells and is also essential for the proper functioning and development of the brain and nerve cells.

Vitamin B12 is only available from animal products, so if you are following a vegan diet, you will need to supplement your diet. However, vitamin B12 stores last for 2-4 years so if you’re going into veganuary with a good diet anyway, you don’t need to worry about becoming deficient within a month. However, if you decide the vegan life is for you, I would advise you consider getting yourself a supplement. Speak to your local pharmacist for advice on what supplement is best to take. 

Omega 3 fatty acids

The omega 3 fatty acids include; Docosahexaenoic acid (DHA), Eicosapentaenoic acid (EPA), and alpha linolenic acid (ALA). DHA and EPA are found in oily fish such as salmon and mackerel. Obviously vegan diets exclude fish, but ALA, which is found in plant foods such as flaxseeds and chia seeds, can be used by the body to make EPA and DHA. However, the amount produced from the conversion of ALA, would not be the same as consuming it directly through the diet so some people choose to supplement. To read more on omega 3 fatty acids see here.

Plant-based sources of omega 3; flaxseed, chia seeds, hemp seed, nuts e.g. walnuts, and vegetable oils e.g. rapeseed and linseed.


Although iodine tends not to be the first nutrient that comes to mind as a concern for those who follow a vegan diet, most dietary iodine comes from animal sources such as; fish and shellfish, milk and other dairy products. Iodine is crucial for the formation of thyroid hormones, which play an important role in metabolism and growth, and can therefore lead to hypothyroidism and the development of a goitre (a swelling of the thyroid gland in the neck). If fetuses and neonates do not get sufficient iodine, brain development can be impaired.

In some countries, there is mandatory iodisation of salt to prevent and control iodine deficiency, but iodised salt is not generally available in the UK. Plant-based sources of iodine include seaweed and foods which are fortified, such as bread and certain plant milk-alternatives. Seaweed, however, often has very high concentrations of iodine so is therefore not recommended to be consumed regularly as it can result in excessive iodine intake – which also leads to thyroid problems. So again, if you are considering continuing a vegan diet beyond veganuary, you may wish to consider a supplement – particularly if you are pregnant or breastfeeding. Speak to your GP, pharmacist, or a registered nutritionist or dietician for further advice on supplementation.

Plant-based sources of iodine: fortified foods and supplements.


How do I know if I’m meeting my nutrient requirements?

One way to check if your diet is lacking anywhere is checking out a free dietary self-assessment app called VNutrition developed by the vegan society.

Can a vegan diet be unhealthy?

Not all plant-based diets are equal! Well-planned vegetarian and vegan diets can be nutritious and healthy, but it is also possible to follow an unhealthy vegan diet. Foods that are suitable for vegans can also be high in saturated fat, salt and sugars, such as deep fried foods, biscuits, crisps and sweets. The same healthy eating principles apply regardless if you are vegan or not – lots of fruit + vegetables, high fibre foods such as wholegrains and pulses, healthy fats from plant oils, nuts and seeds, protein rich foods such as beans and pulses or soya products, and lesser amounts of sugar and saturated fat.

Is a vegan diet expensive?

If you plan and shop carefully, it is possible to eat a healthy, vegan diet on a budget. For example, fruit and vegetables don’t just have to be fresh – dried, canned and frozen varieties, which tend to be cheaper or more value for money, all count towards your minimum 5 A DAY and often have a longer shelf life and can be stored more easily. However, it does require a little more thought and a little more preparation. 

What is the best way to transition into a vegan diet?

(1) Start slow! Remember that you don’t have to label your diet and simply being more plant focused is a positive thing and you don’t need to rush it.

(2) If you are not ready for a fully plant based diet, start by having 1-2 meat free days per week.

(3) Collect plant-based recipes to try at home – maybe invest in a few cookbooks.

 (4) Eat veggie or vegan when you’re out for dinner and opt for dishes that you have not tried before.

(5) Have a read about the vegan diet and make sure you’re prepared in terms of how and what to cook, any supplements you may need and get some inspiration from some vegan chefs online (check out Gaz Oakley and BOSH!).

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