Vegan diet: is it nutritionally complete

In a nutshell (no pun intended), the vegan diet can contain all the nutrients your body needs, but you need to plan very carefully, have as wide a range of vegan foods as you can (including more unusual foods!) and be prepared to take the odd supplement and some fortified foods.


Nutrients of concern

  • Vitamin D: Vitamin D is hard to get in sufficient quantities even in a non-vegan diet and it’s often hard to get sufficient sunlight to make up for that (vitamin D is made under the skin when sunlight falls on exposed skin). Certain sun-dried or UV irradiated mushrooms contain vitamin D but they are not a reliable source. Fortified-milks and some cereals also contain it.
  • Vitamin B12: There is no reliable plant source of vitamin B12 and it appears 50-50% of vegans in the UK and US are deficient in this vitamin. Look for foods fortified with B12 and consume daily and/or take a supplement. It’s easier to prevent B12 deficiency than to correct it once it happens.
  • Calcium: If milk is not consumed on a regular basis, calcium deficiency could be an issue, compromising bone health. Most milk alternatives are fortified with calcium (don’t go for organic as these will probably not be fortified). Calcium can also be found in green vegetables, beans, tofu, pulses and dried fruits. However, these don’t form such a consistent or high source as milks.
  • Iodine: Even non-vegans are increasingly found to be short of iodine which is concerning in pre, peri and postnatal women. In non-vegans the main source of iodine is cows milk. Iodized salt is not recommended due to the health concerns of consuming too much salt. Iodine supplements are therefore recommended but not the ‘natural’ kelp or seaweed supplements as the amount of iodine in these is excessive.
  • Iron and Zinc: These minerals are normally associated with meat and meat products. However, they can be found in pulses, grains, nuts and seeds, but have a lower absorption rate due to substances in the plant that bind these minerals preventing maximum absorption. Avoiding drinking tea or coffee with meals but having a vitamin C source with it can improve absorption.
  • Omega 3: The useful, long chain versions of these is often lower in vegans. An algal-based supplement of this is therefore advisable.
  • Protein: Protein requirements can be met (providing all the essential amino acids in the right balance) providing a wide range of vegan protein sources in consumed e.g. beans, quinoa, nuts and seeds.



Those eating a plant-based diet should focus on vegetables, fruit, legumes and whole grains and add some nuts and seeds and take a good vitamin B12 supplement daily. Also consider taking an omega 3, vitamin D and iodine supplement as a safeguard.

Provided the above considerations are made, a vegan diet can be very healthy; often providing more antioxidants and phytochemicals, potassium and magnesium. It also tends to be lower in fat, and higher in fibre, thus resulting in a healthy gut.