Adopting a vegan diet – a GP’s perspective

vegan diet - Thrive Nutrition and Health Magazine

Vegan GP Josh Cullimore guides us through some of the key things to think about if you’re adopting a vegan diet. From making sure that you get the recommended daily amount of B12 and iron to the old question of “Where do you get your protein from”?

As a vegan GP, I recommend wholefood plant-based diets to my patients, as the evidence shows such diets are associated with lower rates of any array of chronic conditions. I have seen some amazing success stories with patients who follow this advice, with obese patients losing significant weight, hypertensive patients dropping their blood pressure, patients with ischaemic heart disease having less angina attacks, and even patients reversing their type 2 diabetes. I also get asked about three nutrients more than any other: protein, vitamin B12 and iron. But, how valid are these concerns?

The B12 question

To start with the most valid, it is essential that all patients following plant-based diets ensure they are obtaining an adequate source of B12, as this is the only nutrient that is not found ‘naturally’ in a modern vegan diet. I put ‘naturally’ in inverted commas, as B12 was previously found in the soil as it is synthesised by bacteria, but with the advent of the sanitation revolution, in addition to no longer getting cholera and dysentery, we also no longer get sufficient B12 from our soil-covered vegetables.

In addition, the concept of ‘natural’ is often used to try and discredit the idea of taking supplements, but it is such a vague and meaningless concept. The whole of modern medicine could be deemed to be ‘unnatural’, including the advice that all pregnant women take folic acid to prevent spina bifida, but most sensible people would agree that folic acid, contraception, life-saving brain surgery, etc are all positive steps forward, as are modern inventions such as electricity. I would argue that there are other unnatural practices such as factory farming that are not positive, and yet go unquestioned by the vast majority.

It is worth pointing out that cattle are often injected with vitamin B12 themselves, so omnivores are receiving their B12 from an ‘unnatural’ second-hand source anyway.

It is true however that obtaining adequate B12 is vital, as deficiencies can lead to a multitude of health problems such as depression, memory loss, anaemia, heart disease, pins and needles, and even irreversible paralysis and coma. These symptoms can take up to 5 years to develop.

There have been claims that there are some natural vegan sources of B12 such as spirulina, but this is not true. Everyone following a vegan diet should either ensure they are eating enough fortified foods or take a B12 supplement Fortified foods include breakfast cereals, nutritional yeast, Marmite, and some vegan spreads and milks. If you are relying on fortified foods you need to make sure you are eating at least 3 micrograms a day, split between at least 2 meals. Alternatively, it is simpler to take a supplement of at least 10 micrograms a day or 2000 micrograms a week. You can aid absorption by chewing the tablets or allowing them to dissolve on your tongue.

If you have any significant malabsorption issues such as pernicious anaemia, Coeliac disease or inflammatory bowel disease, you will either need to use a sublingual spray or tablet (that is absorbed directly from under the tongue into the bloodstream) or have B12 injections. It is also worth pointing out that there is much debate about which of the two types of B12 is better – cyanocobalamin or methylcobalamin – but essentially the differences are minimal, and either are absolutely fine.

The iron question
Patients are often worried about obtaining enough iron on a vegan diet, but there are many plant based foods that are abundant in iron, including legumes, tofu, nuts, seeds, green leafy vegetables and dried fruits. In fact, iron deficiency anaemia is no more common in vegans than in omnivores. The vast majority of iron deficient patients are meat eaters, and this is usually due to menorrhagia (particularly heavy periods). These patients all require iron supplements, no matter what their diet. In fact, there is considerable evidence that it is the type of iron found in animal products – haem iron- that is partly responsible for the greater rates of bowel cancer, type 2 diabetes and heart disease in omnivores. Although it is better absorbed than plant iron (non-haem iron), it is not a compound that you want in your body.

In order to increase the absorption of plant iron there are various things you can do, such as eating vitamin C rich foods (which increases absorption by up to 5-fold), and avoiding tea, coffee, calcium supplements and PPI medications (such as omeprazole) with your meals.

The protein question
The final nutrient is one that vegans gets asked about so much, it makes our heart sink! “Where do you get your protein?” In the UK, on average people eat 55% more protein than they need, and yet people are still concerned that they are not getting enough.

A much more valid concern is the fibre deficiency epidemic- 90% of people do not get the recommended 30g a day.

In addition, there have been many observational studies showing that high animal protein intake leads to higher death rates than plant based protein. The recommended daily intake is 0.8g of protein per kg of bodyweight, which is easily obtained through plant-based sources such as legumes, nuts, and grains. It is worth bearing in mind that some of the biggest and strongest animals on the planet such as elephants, hippos and gorillas are vegan, and yet no one questions their protein intake!

For people trying to gain muscle, the guidance is to eat higher amounts – 1.5 to 1.8g of protein per kg of bodyweight.

There are many plant-based athletes who have shown this is not only possible but have excelled in their careers, including tennis star Venus Williams and powerlifter Patrik Baboumian (who has won the title of World’s Strongest Man).

Feature from inside our Thrive Health Magazine Summer issue article written by: Josh Cullimore – Vegan GP. @vegandoctorjosh