In a world where "meat-free meat" sits next to the beef sausages in the supermarket and ordering an almond milk latte brings nary a flicker to a barista's eye, the once-fringe vegan movement seems to have gone mainstream.

For the uninitiated, followers of a vegan diet eschew all animal products, including dairy, eggs, honey and, of course, meat.

So for an eating pattern that cuts out so many foods traditionally considered essential, is it possible for a vegan diet to meet all your nutritional needs?

Yes, says Clare Collins, professor of nutrition at the University of Newcastle — but it requires you to understand food better than the average omnivore, or even vegetarian.

Here are four main nutrients to look out for.

Vitamin B12

Let's start with this one, because vitamin B12 is something we humans can really only get via animal foods — such as meat, fish, dairy and eggs — or in the form of supplements.

It's an important vitamin too, essential for making DNA, fatty acids, red blood cells and chemicals called neurotransmitters which help to pass signals around the brain.

"That's the really big one. You don't want to end up with a B12 deficiency," Professor Collins said.

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B12 deficiency manifests at first as vague but unpleasant symptoms like heart palpitations, light-headedness, tiredness and bowel or bladder changes, so it's important to keep on top of it.

In severe cases, it can progress to mood changes like depression and paranoia, and nerve problems like numbness, pain and loss of taste and smell.

While trace amounts of B12 have been found in some plant foods such as mushrooms, fermented soybeans and things that have been contaminated by soil or insects, if you're following a vegan diet you should be looking to supplements or fortified foods to ensure you're getting enough.

It's often added to non-dairy milks, but not all, so check the label.

Calcium

Most people know about the importance of calcium for your bones, but it also plays a role in other parts of your body, including your heart, muscles and nerves.

What's more, your bones actually act as a calcium bank, so if you're not getting enough from your diet, your body will make withdrawals from that bank, which can affect your bone health.

Almonds are a dairy-free source of calcium. ( Unsplash: Juan Jose Valencia Antía )

Dairy is often touted as being an important source of calcium, but it's by no means the only source. Plenty of plant-based foods contain it, including some tofu and some nuts, legumes and seeds.

But interestingly, vegans and vegetarians often need even more calcium than omnivores, because some plant foods have chemicals that make it harder for your body to access it.

For example, spinach and beans contain oxalic acid, and some grains, nuts and legumes contain phytic acid, which both interfere with calcium absorption.

You can bolster your calcium intake with fortified plant milks and fortified breakfast cereals — again, check the label to make sure the product you are choosing is actually fortified, because not all are.

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Iron

Iron is used inside your red blood cells to carry oxygen around the body, so a deficiency can leave you feeling lethargic and tired, as well as lowering your immunity.

While omnivores usually get their iron delivered ready-to-use, via red meat, plant-based sources of iron require your body to do a bit more work.

You can help your body absorb your plant-based iron, found in foods like legumes and beans, by eating it at the same time as vitamin C.

That can be as simple as putting veggies like red capsicum and broccoli next to the lentils on your dinner plate.

"The other thing you can do is not have any cups of tea straight after meals because the tannins and the phytates in the tea actually interfere with the absorption of the iron," Professor Collins said.

Combining plant-based iron sources like chickpeas with vitamin C-containing veggies like capsicum helps your body better absorb the iron. ( Unsplash: Edgar Castrejon )

Iodine

Iodine helps your thyroid to function — that little gland in your neck that controls your metabolism, among other things.

Seafood is a source of iodine, and it's also found in some dairy products in Australia, but the main source of iodine for people who avoid animal products is via iodised salt, which is used in commercial breads and some breakfast cereals.

As for some of the other essential nutrients, the symptoms of deficiency can be vague but hint at something serious, Professor Collins said.

"How do you know if you're iodine deficient? It's things like tiredness, weakness, lethargy, and then other things like constipation, heartbeat [changes], facial puffiness and so on."

Iodine deficiency is a particularly big deal for women of childbearing age, as it can affect the brain development of babies during pregnancy and increase the risk of miscarriage and stillbirth.

Pregnant women have other specific nutritional needs beyond the four mentioned here, and so do children. So talk to your doctor if your kids are on a vegan diet or you're planning to become pregnant.

And for people who follow vegan diets for a very long time, there are other nutrients, such as omega-3 fatty acids, that can become an issue.

If you're following a vegan diet, its worth mentioning it to your doctor so they can check for deficiencies.

Is veganism the optimal diet for health?

Meals based around plant-based whole foods aren't just for vegans. ( Unsplash: Maddi Bazzocco )

While most people who choose vegan diets do so because they want to minimise harm to animals or cut down on their environmental impact, others talk about the potential health benefits of being entirely plant-based.

The recent documentary The Game Changers promotes a diet free of animal products as performance-enhancing and implies it might even be the optimal diet for humans.

So ... could a vegan diet be even better for you than a healthy omnivorous one?

It's not as simple as that, Professor Collins explained.

There are plenty of animal-free products that are highly processed, high in salt and fat and low in other essential nutrients.

"People are getting a message that, hey, you're supposed to be a little bit vegan now, and they're just buying these products that are appearing … without thinking through what it has really taken to manufacture those things.

"The lazy way to be a vegan is to just leave the meat out and leave the dairy products out and make no effort to bring back in the foods that you need to replace the nutrients that you're missing out on."

So while it's certainly possible to have a healthy, complete vegan diet, it's not the only healthy way to eat, Professor Collins said.

If you're looking for a guide, she recommends the Australian Government's Eat For Health website.

"I know it's boring but it actually does outline how many serves of the five food groups you need, based on age and sex, to meet your nutrient requirements.

"You do not have to be a vegan to eat healthy.

"You can have a normal, healthy vegetarian pattern and unhealthy vegan eating pattern and you can have an unhealthy omnivore eating pattern."

More veggies, less junk would benefit us all

There are definitely things that most of us could learn from veganism though, especially when it comes to plant-based "whole foods".

Many vegan protein sources, such as pulses and nuts, do double time by also being rich sources of fibre and healthy fats.

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"One of the movements that I think can benefit everyone is what's called flexitarian, which is like being a part-time vegetarian or even a part-time vegan," Professor Collins said.

"So a few days a week, you are consciously trying to boost your intake of vegetable sources of nutrients."

Swapping out a few meals a week with whole-food vegan protein sources is not going to do you harm and will probably do you good.

"It's really about stepping back and saying, hey, what are the things I'm eating? Am I eating nutrient rich foods? And am I not going overboard on ultra-processed junk food?"

Plus, if your impact on animals and the environment is important to you — goals that motivate many people to go vegan in the first place — then going some of the way is arguably better than going none of the way.