Should you stop being vegan when pregnant for the sake of your baby's health?

The number of vegan converts is soaring – more than 600,000 of us turning to a plant-based diet in the UK, according to the Vegan society – so perhaps it was only a matter of time before the question of plant-based diets and pregnancy raised its head. Inevitably, the ever-opinionated Mumsnet community has duly taken the bait.

The site's message boards lit up after a user named ElizabethForever posted a message about her other half trying to get her to drop her vegan diet during pregnancy.

Cue 230 (and counting) responses, with users hungrily arguing the toss over the pros and cons of growing a human while eating only plants.

ElizabethForeveris not alone in wishing to remain vegan while pregnant. Scores of celebrities have led the way, from health blogger Ella Mills, founder of Deliciously Ella, who is currently pregnant, to Alicia Silverstone.

All look impossibly glowing and healthy – but as ever with famous names, it's tempting to bemoan their privileged position. Isn't it part of Deliciously Ella's job to know how to eat a nutritious diet? Might Alicia Silverstone have a home chef to make sure she gets everything she needs?

For the rest of us, is a vegan diet during pregnancy – a time when you need more nutritional building blocks to support your growing baby as well as yourself – as safe as eating animal products?

Many assume not, pointing to evidence that the vegan population as a whole is at an increased risk of vitamin B12 and iron deficiency, which are common deficiencies in pregnancy, too. It’s also assumed that it can be challenging to get enough protein on a vegan diet.

But actually, studies suggest otherwise. A systematic review of 22 studies assessing the effects of vegan and vegetarian diets on maternal-foetal outcomes published in BJOG: An International Journal of Obstetrics and Gynaecology found that while “the evidence on vegan–vegetarian diets in pregnancy is heterogeneous and scant... vegan–vegetarian diets may be considered safe in pregnancy, provided that attention is paid to vitamin and trace element requirements."

In fact, registered Nutritionist Sophie Thurner says, “following a plant-based diet can be beneficial. Basing a diet on wholesome plant-based products, including vegetables, fruits, whole grains, nuts, seeds and legumes, has a vast array of reported benefits.

Not only do these foods provide ample micronutrients, including vitamins, minerals and phytonutrients, they are also fantastic sources of fibre and are low in saturated fats.” Studies show that pregnant women who are vegan can have higher levels of folate and magnesium than their meat-eating NCT buddies.

Gabriela Peacock, nutritionist and founder of GP Nutrition, adds: “If you are a really conscious vegan, by which I mean eating lots of vegetables, whole grains, and beans/pulses, you will naturally have a higher intake of fibre which is great for gut flora, hence it helps balance immunity and improves digestion.”

But, Thurner warns, you have to be prepared. “Like any diet, veganism can be approached in a healthy or a non-healthy way. Including more crisps, doughnuts and sugar drinks will not be beneficial for mother or baby.”

Swerving deficiencies

So how to plan a vegan pregnancy? Thurner says the second trimester in particular is critical. “During this stage, the growing baby has low energy needs (approximately 100 more calories in a day), but the mineral and vitamin needs are high,” she says. Some nutrients are more difficult to obtain from a vegan diet, including iron and calcium.

“Sufficient iron stores are imperative leading up to and during pregnancy – remember that mothers grow a whole circulatory system, including thousands of blood vessels. The baby will take all the nutrients it needs for this, and mother is left with the rest.” Several studies show that caffeine can reduce iron absorption by up to 39pc – although pregnant women on the whole are advised to cut back on caffeine.

Both iron and calcium are more easily obtained from an omnivorous diet, she says, but adds that our “bodies are smart and adapt to pregnancy. For instance, absorption of both iron and calcium increase and the lack of a period during pregnancy further increases the amount of iron available in the body.” She advises pregnant women to eat a varied diet with an array of different coloured vegetables and fruits and different legumes and grains.

Protein, essential for building new tissue, making enzymes, hormones and antibodies, is another nutrient that is less readily available in a vegan diet. “Mothers should eat a lot more protein when pregnant – twice as much protein a day,” Peacock says, “which is a much higher intake compared to when they are not pregnant. For vegan mothers, I advise focusing on lots of beans, pulses, nuts and seeds, quinoa, mushrooms and tofu.” Sprouted brown rice is another source of vegan protein.

Perfect diets

While it’s possible in theory to have a healthy vegan pregnancy, is it actually achievable if you don’t have a personal chef on hand? Humans are, after all, imperfect beasts. We all – pregnant or not – know we should eat our five a day, but new government stats show that 90pc of adults and 80pc of children don’t manage it.

“It is absolutely fine and healthy to be vegan and pregnant,” acknowledges Peacock, “but it is just not always the easiest diet to manage.”

Particularly when cravings and aversions kick in. The actress Natalie Portman relaxed her vegan diet to include eggs and dairy, as she said she was listening to her body. “Personally I don’t like to restrict too much, but think it’s up to every mother’s individual choice,” Peacock says. “We all know that stress is very harmful for mothers and babies. I advise to do everything in moderation, so that strict rules don’t result in the mum feeling stressed.”

Supplements for a vegan pregnancy

Most pregnant women – vegan or not –are advised to take a vitamin D,, but vegan pregnancies could benefit from extra supplements. Peacock advises vitamin C to increase the absorption of iron, as well as a B12 supplement. While Thurner says omega-3 fatty acids are worth considering, to aid development of baby’s brain and eyes. All supplements should be checked to make sure they are suitable for pregnancy.

• The GP Nutrition x My Baba Guide for New Mums and GP Nutrition New Mum Gift Boxes will be available to read and buy online at gputrition.com from April.