Are all plant-based diets healthy?
Food-based dietary guidelines recommend that plant foods (for example fruit and vegetables and wholegrains such as oats, wholemeal bread, brown rice, wholewheat pasta) should make up a large part of what we eat. We should also include sources of healthy fats in our diets – such as nuts, seeds, oily fish, unsaturated oils and spreads made from them, as well as including good choices of protein – for example, beans, peas and lentils.
Nutritional adequacy in any dietary pattern is important, and can be provided by a plant-based diet. Plant foods provide important nutrients including fibre, vitamins and minerals, protein and unsaturated fats. However, it is important to note that animal food sources make an important contribution to some nutrients in the UK diet. For example, vitamin B12 and vitamin D are naturally absent from most plant foods, although they may be present in fortified foods such as breakfast cereals, fat spreads and alternative dairy products; long chain omega-3 fatty acids are found in highest amounts in oily fish (vegetarian supplements made from algae are available) and iodine is found in highest amounts in seafood, dairy foods and eggs. Dairy foods are also important contributors to most people’s calcium intake, particularly in children. Furthermore, iron and zinc are more easily absorbed from animal than plant foods. For example, phytates found in plant foods, such as wholegrains and beans, reduce zinc absorption.
Importantly, we should bear in mind that exclusion of animal products per se does not necessarily equate to a healthy diet. Poor choices, with a large inclusion of foods high in saturated fat, salt and free sugars (for example savoury snacks, deep fried foods, cakes, biscuits, confectionary and sweet spreads) can be made within any dietary pattern. In addition, very restrictive plant-based diets can lack balance and variety.
A healthy, balanced plant-based diet would typically include wholegrains, fruits and vegetables, nuts, legumes and unsaturated oils, whereas less healthy plant-based diets may include more sugars – sweetened beverages, refined grains, fried potato crisps or chips and sweets. In addition, despite their health halos some plant foods may not be healthy if consumed in high amounts such as coconut oil (high in saturated fats) and agave or maple syrups (high in free sugars).