With ethical credentials, vegan diets are growing in popularity. But just how healthy are they? Nutritionist Kerry Torrens explores the health pros and cons of a vegan diet.
For more on vegan diets, we've collaborated with BBC Future – read more below:
The health benefits of going vegan – BBC Future
Why vegan junk food might be even worse for your health – BBC Future
How a vegan diet could affect your intelligence – BBC Future
The hidden biases that drive anti-vegan hatred – BBC Future
The mystery of why there are more women vegans – BBC Future
Why the vegan diet is not always green – BBC Future
Which milk alternative should we be drinking? – BBC Future
What is a vegan diet?
A vegan diet is a plant-based diet that includes vegetables, grains, nuts, seeds and fruits. Vegans do not eat foods that come from animals, including meat and meat-derived products like gelatine and rennet, as well as fish, shellfish, dairy, eggs and foods containing them, such as non-vegan Quorn products. Vegans also avoid honey.
What are the health benefits of a vegan diet?
Research has linked a vegan diet with lower blood pressure and cholesterol, and as a result, a lower rate of heart disease. This may be explained by the fact that a vegan diet is likely to be low in fat and rich in dietary fibre, as well as a good source of heart-friendly nutrients such as folate, vitamins C and E, potassium, magnesium and unsaturated fats. Staple foods of a vegan diet, such as nuts and wholegrains, also confer heart benefits.
In general, vegans are more likely to have a lower body mass index (BMI), thanks, in part, to this fibre-rich and naturally satiating way of eating. As a consequence, vegan diets tend to be lower calorie and, therefore, effective for weight management.
Following a balanced, whole-food vegan diet may reduce the risk of developing type 2 diabetes, while studies also demonstrate the value of a low-fat vegan diet for those with type 2 diabetes, including improved glycaemic response and lipid management.
Generally, vegans eat considerably more legumes, vegetables and fruit than non-vegans, and this may, in part, explain the findings that a vegan diet confers a reduced risk of total cancers.
A plant-based diet is naturally high in fibre, which is a crucial food source for beneficial gut bacteria. A fibre-rich diet promotes a diverse and stable microbiome, which in turn creates compounds, known as Short Chain Fatty Acids (SCFA). These support the immune system, improve the integrity of the gut barrier and regulate digestive function.
Top tips for eating a balanced vegan diet
Whether you are a long-term vegan or just starting out, obtaining a balanced diet is achievable with the right planning and a little knowledge. In summary:
- Eat a wide and varied selection of vegetables and fruit (a minimum of 5 portions, with the emphasis on vegetables) every day.
- Base your meals on wholegrains, such as wholegrain wheat, rye, barley, rice, quinoa, buckwheat or starchy vegetables, like potatoes.
- Choose fortified plant milks, yogurts and spreads and include them daily, to support your intake of nutrients like vitamin B12.
- Include beans, peas and lentils for their protein contribution.
- Choose unsaturated oils and spreads and consider cooking with cold-pressed rapeseed oil for its omega 3 contribution.
- Drink 6-8 glasses of water or other hydrating fluid daily.
Which nutrients may be missing from a vegan diet?
Vegan diets are often criticised as being lacking in key nutrients. These may include vitamin B12 and omega-3 fatty acids because vegan foods are naturally low in these nutrients. However, it is feasible to obtain all the nutrients you need from a varied vegan diet. If you are concerned about deficiency or experiencing symptoms, speak to your GP.
Key nutrients to focus on include:
This macronutrient is one that people starting a plant-based diet are often concerned about, however, peas, lentils and beans are good sources of plant-based protein. Anyone starting a vegan diet can take comfort from the fact that there is no evidence to suggest vegans eating a varied, plant-based diet are likely to be deficient in protein.
Plant foods do not supply vitamin B12, so vegans are at risk of deficiency unless they include fortified foods or take a supplement. Recommendations for vegans include eating fortified foods such as fortified plant milks, yogurts and spreads as well as fortified breakfast cereals at least two or three times a day to achieve at least 3mcg of vitamin B12 per day.
Very low intakes may lead to anaemia and impair the nervous system. Most vegans obtain adequate amounts of vitamin B12, although there are a few groups who may be at greater risk – these include the elderly whose absorption may be compromised, long-term vegans who avoid fortified foods, such as raw or macrobiotic vegans, and breastfed infants of vegan mothers whose own intake of B12 is low.
Vitamin D plays an important role in the health of our bones, teeth and muscles. As well as being found in a limited number of foods, vitamin D can be made by the action of sunlight on the skin. A daily intake of 10mcg is recommended, although this is difficult to achieve through diet alone, and may be a particular issue in the winter months when we are exposed to less sunlight. When considering a supplement, its worth remembering that some products are not vegan-friendly – look for vitamin D derived from lichen or vitamin D2.
We typically associate calcium with bone health but it’s also necessary for nerve and muscle function and blood clotting. A vegan diet can adequately provide your calcium requirements. Vegan food sources include calcium-set tofu, fortified plant milks and yogurt alternatives as well as leafy greens, including kale and pak choi and nuts and seeds such as chia seeds and almonds.
Iron deficiency is common for meat-eaters and vegans alike, especially among women of reproductive age. However, there are plenty of vegan food sources – these include lentils, chickpeas, beans, nuts, seeds and dried apricots and fortified breakfast cereals.
We need iodine for thyroid hormones – these hormones control our metabolism and, as such, determine how fast our cells work. Plant foods, with the exception of sea vegetables, tend to vary in content and on the whole contain very low levels of iodine. Sea vegetables may not be appropriate because they may be contaminated or contain elevated levels. This means a non-seaweed supplement may be the most reliable source.
Omega-3 fatty acids
These important fatty acids are referred to as essential because we have to obtain them from our diet. They're crucial for the brain, hormonal balance, nerves, eyes and the immune system. There are three main types of omega-3 fats, which are known as ALA, EPA and DHA. The most active forms EPA and DHA are typically found in fatty varieties of fish. It is possible to obtain omega 3 fats in the form of ALA from plant foods, however, this form of omega-3 needs to be converted by the body to EPA and DHA. The conversion rate is influenced by a number of factors including gender, with women enjoying a better conversion efficiency. It is possible to supplement a vegan diet with EPA and DHA from microalgae and this may be useful for infants, expectant mums and those who are breastfeeding.
Vegan food sources which supply ALA include chia, hemp and flaxseeds as well as walnuts. Rapeseed oil is a useful omega-3 option for cooking.
What about processed vegan foods?
A vegan diet is not always a healthy one, along with the growth in veganism's popularity comes a market of vegan-friendly ready meals and junk foods. Some processed foods have salt, sugar and fat added in an attempt to improve their palatability. Of particular note are trans fats or hydrogenated fats, which are commonly present in processed ready meals and have been linked with heart disease. Moreover, processed foods, may include additives such as emulsifiers. Emerging science suggests that such additives may have a negative impact on our beneficial gut bacteria and as a consequence may promote intestinal inflammation.
That said, it’s important to remember that not all processing is bad. Fortification, for example, is important for some vegan foods. Fortifying foods with vitamins like B12 and D increases the accessibility of these nutrients to vegans and facilitates a balanced and nutritionally adequate vegan diet.
Is a vegan diet healthy while pregnant or breastfeeding?
Although plant-based diets may be low in certain nutrients, evidence shows that a well-planned vegan diet is considered safe during pregnancy and breastfeeding. One important nutrient to consider during pregnancy is choline, which is richest in animal foods like egg yolks. Choline is essential for the brain chemical acetylcholine, which helps sharpen our memory, and plays a key role in liver function, muscle development and even cholesterol management. Expectant mums are thought to have a greater need for this nutrient because it may be important for the baby’s brain development. Mums will also need it for their own livers and placental function. Vegans won’t fall short of this nutrient as long as their diet includes a wide variety of foods, such as beans, soya and quinoa, as well as green veggies, nuts, seeds and grains, including wheat. It's worth bearing in mind that choline is a water-soluble nutrient, so if you are boiling green vegetables, make use of the cooking liquid in sauces and soups.
Find more information on the NHS website.
Who can I speak to for advice?
If you have concerns about the nutritional adequacy of your diet, you are pregnant, breast-feeding, are young or elderly or have an underlying medical condition, refer to your GP or a registered dietitian for advice and guidance.
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This article was reviewed on 31st January 2022.
Kerry Torrens BSc. (Hons) PgCert MBANT is a Registered Nutritionist with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.
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