Vegans avoid all animal products, including dairy, eggs and all meats and fish. Some also avoid honey and other products made from animal-derived ingredients such as gelatine. For many, this choice stems from religious or ethical considerations, their belief in the environmental impact of industrialised livestock and dairy production, and/or a belief in the perceived health benefits of a plant-based diet.
A typical vegan diet would generally be rich in fruits and vegetables, and non-animal protein sources such as tofu, and beans, chickpeas, lentils and other legumes. Those following a vegan diet also tend to avoid highly processed foods, such as refined carbohydrates and added sugars, instead choosing whole grains and unprocessed carbohydrate-containing foods.
So is ‘Veganuary’ simply another New Year’s fad diet, or a sensible, long-term, healthy eating plan?
Health benefits of a vegan diet
Vegan (and vegetarian) diets are associated with lower BMI and obesity rates, and lower risk of coronary heart disease, high blood pressure, Type 2 diabetes, Metabolic syndrome and some cancers, than meat-containing diets.
In fact, a recent review of the evidence concluded that a vegan diet was more closely associated with lower BMI and lower risk of Type 2 diabetes and heart and metabolic diseases, than a vegetarian diet.
So what are the reasons for this? A number of health-related mechanisms are proposed, including:
- Vegan diets are inevitably lower in saturated fat, the type of fat found in animal and dairy products, which has been linked to cardiovascular disease. These fats can increase levels of triglycerides (the form in which fat is stored in the human body), which can adversely affect the health of our arteries, a key step in the development of cardiovascular disease.
Saturated fats can also make our cell membranes (the ‘walls’ of our cells) more rigid, which can reduce our ability to remove glucose from the bloodstream, possibly increasing the risk of Type 2 diabetes.
- Vegan diets tend to be higher in dietary fibre (the parts of plants our bodies cannot break down and absorb). Dietary fibre is food for our gut bacteria, which are increasingly recognised as essential for numerous aspects of health including strong immunity, healthy brain function, and efficient metabolism, as well as gut health. Dietary fibre has also been shown to help lower cholesterol levels, another key factor in the development of cardiovascular disease, and to increase satiety (the feeling of ‘fullness’ after a meal), which can reduce the risk of obesity.
Vegan diets tend to be higher in many essential nutrients,including:
magnesium, a mineral (found in e.g. nuts, legumes, wholegrains and green, leafy vegetables), which is essential for healthy glucose uptake into cells, and for energy production
folic acid, a B vitamin (found in e.g. leafy, green vegetables such as kale and spinach) which is essential for DNA synthesis and foetal health
Vegan diets tend to be higher in dietary antioxidants including vitamin C (found in e.g. fruits, peppers and broccoli) and vitamin E (found in e.g. seeds, nuts and their oils, and avocados), andphytochemicals, compounds found in fruit and vegetables which give them their colour. Antioxidants help protect our bodies against environmental toxins and other stressors, which can overwhelm the body’s natural antioxidant defences. This can contribute to a state of chronic inflammation, which is linked to many chronic diseases, including cancer, heart disease and metabolic diseases such as Type 2 diabetes.
Vegan diets tend to be rich in whole grains and nuts, which are associated with lower cholesterol levels (substances in these foods can help bind cholesterol in the gut, increasing its excretion from the body)
Vegan diets may (although this is not always the case) involve fewer calories than a non-vegan diet
And what about the environment?
A review paper published in the middle of last year concluded that omnivorous diets generate worse carbon, water and ecological footprints than both vegetarian and vegan diets (these three indexes account for greenhouse gas emissions, the consumption of water resources and the amount of biologically productive land/sea needed to produce a unit of food product). (One additional interesting point that arose from this study was that the vegan approach was not associated with a significantly lower environmental footprint than the vegetarian approach – the study authors suggest this may be due to vegans choosing industrially highly-processed plant-based meat and dairy substitutes.) Those advocating a vegan diet also argue that eating animal products causes cruelty and suffering to animals (an argument largely blamed on industrialised factory farming).
So is it all win-win? Not necessarily …
Health risks of a vegan diet
The key risk in adhering to a vegan diet relates to possible nutritional deficiencies. These can include:
Protein – although it is possible to ensure adequate protein intake on a vegan diet, it is important to ensure that the diet includes all the ‘essential’ amino acids (the building blocks of protein which we cannot synthesise in the body). These are abundant in animal products, but harder to find in plant-based diets. Suitable protein sources for vegans include soy, quinoa, amaranth, avocado and combinations of grains and beans, or grains and nuts/seeds (although it is important to be aware that some of these foods (e.g. quinoa) are not high in protein per se)
Vitamin B12 (found almost exclusively in animal foods), which is essential for the formation of red blood cells and for cell reproduction. Vegans will need either to ensure adequate fortified sources (e.g. yeast extract, breakfast cereals, margarine, soy milk – but how many of these are healthy foods?) or, better still, to supplement this essential nutrient.
Calcium – as the richest source of calcium is dairy foods, vegans will need to ensure adequate intake of other calcium-containing foods, such as tofu, tempeh and green leafy vegetables such as broccoli and kale. (Spinach contains high levels of calcium but is bound to a substance called oxalic acid, which can reduce its absorption when the spinach is eaten raw)
Vitamin D – although sunlight is the main source of vitamin D, some is found in oily fish, so it is recommended that vegans supplement this nutrient too, as it is essential for many aspects of health, including healthy immunity and bones
EPA / DHA – these health-boosting omega-3 fatty acids are found most abundantly in oily fish, increasing the risk of deficiency for vegans. Plant sources of other omega-3 fatty acids include flaxseed and walnuts, but the conversion of these to EPA and DHA is poor, so vegans should consider a vegan supplement containing these fatty acids
Iron – vegan diets can be rich in iron (e.g. beans, legumes, tofu, dried fruit, broccoli) but the form of iron in plants (‘non-haem iron’) is less available to the body than the form of iron found in meat (‘haem iron’). In addition, many vegetarian foods contain anti-nutrients which can inhibit the absorption of ‘non-haem iron’
Zinc – although wholegrains are a good source of zinc, this mineral is more readily absorbed from animal foods, increasing the risk of deficiency for vegans. Key functions of zinc include healthy immunity, thyroid health and reproductive health
Iodine – found mainly in fish and dairy products, and also in iodised salt, iodine is particularly important for energy production, and for foetal growth and development
Other possible drawbacks of a vegan diet include:
Higher intake of anti-nutrients such as phytates (found in nuts, seeds and grains) and oxalates (found in e.g. spinach and rhubarb), both of which, when the vegetable is eaten raw, can bind to minerals in food, reducing their absorption and increasing the risk of deficiencies.
The risk of over-consumption of carbohydrates, in order to ensure adequate overall calorie intake. This may make weight loss harder
The risk of excess consumption of soy products to ensure adequate protein intake. While soy can be healthy, as it contains fibre, B vitamins and several minerals as well as all essential amino acids, and has been shown to be help in management of menopausal symptoms, and to lower cholesterol, it also contains compounds than mimic the action of oestrogen in the body (phytoestrogens) and some research suggests this may impact on breast cancer risk. Soy also contains a number of anti-nutrients including phytates
The risk of inadvertently consuming oxidised (damaged) vegetable or seed oils, in the form of vegan burgers, sausages etc. Consumption of damaged oils has been linked to increased risk of inflammation in the body
How to make sure your Veganuary is healthy
Include plenty of quality, vegan protein sources, such as nuts, seeds, beans, and higher-protein grains (such as quinoa)
Talk to a Nutrition Practitioner to discuss supplementation with vitamin B12 and possibly other nutrients including zinc, iron and (vegan) omega-3 fatty acids
Keep your energy levels up by choosing unrefined sources of carbohydrates (e.g. whole grains), and ensuring you eat protein and good fats with every meal – good fats can be found in e.g. avocado, olive oil, nuts and seeds
Be aware of how you are feeling – monitor your energy and concentration levels, sleep patterns, digestion and mood, and consider including a good quality multi-vitamin and mineral to ensure healthy levels of all nutrients
The key point is, perhaps, that a vegan diet can be healthy for most people, provided it is carefully planned and executed, and may be of particular benefit for those suffering from type 2 diabetes, high blood pressure, cardiovascular disease or obesity.
A vegan diet may not be the most appropriate dietary choice for vulnerable groups, such as infants and toddlers, menstruating and pregnant women, and/or adolescents.
Food choices should be tailored to what is important to you as an individual – if you are choosing Veganuary because of its perceived health benefits, be aware of the nutritional risks involved!
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