Should you go vegan for your health?
With supermarket shelves packed with oat milk, coconut yoghurt and meat alternatives, there has never been a better time to be vegan.
Many give up meat and dairy to reduce their carbon footprint or for ethical values, while others believe a plant-based diet is good for their health.
But while some say ditching animal products has given them an extra spring in their step, others complain of feeling tired and run down.
This World Vegan Day, we look at the evidence for – and against – a plant-based diet, and how you can do it healthily.
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Is a vegan diet nutritional?
The vegan diet is based on plants like vegetables, grains, nuts, fruits and foods made from plants, and doesn't consist of any foods that come from animals, including dairy and eggs (veganism is also a way of life too, with many steering clear of certain clothes and products too).
Vegans can get all the nutrients they need from eating a varied and balanced diet including fortified foods and supplements, the NHS claims.
To maintain a healthy vegan diet, this includes:
eating at least five portions of different fruit and veg a day
basing meals on potatoes, bread, rice, pasta or other starchy carbs (wholegrain are better, if possible)
having fortified (with extra vitamins and minerals) dairy alternatives, like soya drinks and yoghurts
filling up on beans, pulses and other proteins
eating nuts and seeds rich in omega-3 fatty acids every day
opting for unsaturated oils and spreads, and eating in small amounts
having fortified food or supplements with nutrients more difficult to get in the vegan diet (like vitamin D, B12, iodine, selenium, calcium and iron)
drinking plenty of fluids (six-eight cups a day as standard)
So, essentially, it just means sourcing the same nutrients elsewhere, which is possible.
Without dairy to keep bones and teeth healthy, for example, vegans have to turn to calcium found in foods like broccoli, sesame seeds and dried fruit.
Unable to indulge in a rare steak, they also have to get their iron from lentils, watercress and nuts.
It seems with a bit of planning, vegans can have a healthy diet.
But whether cutting out meat and dairy is actually better for you is less clear cut.
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Are vegan diets healthier?
The benefits, and drawbacks, of a vegan diet is a hot area of research.
While the jury is still out, it seems cutting out meat and dairy could do you the world of good.
Scientists from the Cleveland Clinic in Ohio, for example, had a group of children with high cholesterol, and their parents, adopt a vegan diet with no added fat.
After just four weeks, the youngsters’ health improved across nine 'wellbeing parameters'.
These included BMI, blood pressure, cholesterol and markers of inflammation.
The parents also benefited, but to a lesser extent.
While it sounds positive, these children consumed less vitamin D and B12 than those in a group told to eat according to the American Heart Association (AHA) guidelines, the results show.
The AHA recommends a variety of fruit and vegetables every day, as well as fish twice a week.
Vitamin B12 is only found naturally in meat, fish and dairy.
Vegans therefore rely on fortified cereals, drinks and yeast extract, like Marmite (or supplements).
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It is also worth noting that as well as cutting out meat and dairy, the children also had no added-fat in their diet.
'Added' fat includes a smear of butter on bread or oils to cook with, as opposed to fat found naturally in meat or fish.
Too much fat, particularly the saturated kind, has repeatedly been linked to weight gain and high cholesterol.
It is therefore difficult to gauge how much of the benefits came from the vegan diet and how much was due to cutting down on fat.
Watch: Eight thing you need to know about veganism
Can a vegan diet help with weight loss?
In a separate study, a team from the George Washington University in DC looked at 64 women who were put on a low-fat, vegan diet.
After 14 weeks, they lost up to 12lbs (5.8kg), compared to a maximum 8lb (3.8kg) loss in those who just cut their fat intake.
This is despite calorie consumption being the same between both groups of women.
All the women saw their insulin sensitivity – a marker of diabetes risk – improve, with meat and dairy consumption not coming into it.
The 'vegan group' were also found to consume less protein, which is essential for growth and repair.
The same scientists later suggested going vegan may improve heart health.
Some 99 type 2 diabetics were told to follow a low-fat, vegan diet or an AHA approved plan for 22 weeks.
At the end, 43% of the vegans were able to reduce their diabetes medication, compared to 26% in the AHA group.
The vegans also had larger reductions to their blood sugar, weight and cholesterol.
Heart health aside, Dr Winston Craig from Andrews University in Michigan suggested vegans may eat more antioxidant-rich vegetables, cutting their cancer risk.
By eliminating red and processed meat, their risk of bowel cancer also goes down, the professor of nutrition added.
While it all sounds positive, going vegan may take some serious willpower.
Scientists from the Institute for Clinical and Experimental Medicine in Prague found the 'hunger hormone' called ghrelin was significantly lower in people who had recently eaten a hamburger than after a 'vegan meal rich in carbohydrates'.
By cutting out oily fish, vegans also tend to have lower levels of healthy fatty acids, which are important for heart, brain and eye health.
Found in salmon and mackerel, vegans rely on supplements or hard-to-find alternatives – like seaweed – for their 'good oils'.
Dr Craig also warned vegans typically have around a quarter the vitamin D levels of meat eaters.
The sun is the main source of vitamin D. However, with UV rays being hard to find in the UK, non-vegans often rely on oily fish to up their amount.
Public Health England recommends everyone take 10 micrograms of vitamin D a day.
Read more: Vitamin D supplements: When and why you should take them
And with iron being easier to absorb from meat than plant-based sources, like seeds, vegans may also be at a higher risk of anaemia.
Dr Craig added, however, they tend to eat lots of fruits and vegetables. These are rich in vitamin C, which improves iron absorption from plant-based sources.
While there is no definitive answer, it seems that with a little planning and supplements, going vegan could seriously benefit our health this World Vegan Day and any day.
If you have any health conditions or are pregnant, talk to your doctor before changing your diet.