What You Should Know Before Going Vegan
The VITL Nutrition Team
A record 500,000 people have signed up for Veganuary this year, so we asked the Vitl Nutrition Team: “What are the health benefits and challenges of a plant-based diet?”
With 4x as many vegans in Britain, as there were in 2014, veganism has become one of Britain’s fastest-growing lifestyle movements. Over half a million people in the UK follow a plant-based vegan diet, avoiding all animal foods including meat, fish, dairy, eggs, and honey 1.
Historically, veganism stemmed from moral, religious and spiritual ideas. It was (and still is) believed that a diet free from animal products cleanses the body, allowing humans to live in harmony with the Earth 2. Vegans often follow a plant-based diet for ethical reasons, avoiding animal products out of a concern for the environmental and social impacts of raising livestock for food.
Often argued as a ‘cleaner’ way of eating, people are more recently turning to a vegan diet for health reasons, avoiding animal products that might contain contaminants such as antibiotics, hormones and other pollutants.
What are the health benefits of a vegan diet?
High in fibre
A plant-based diet which is high in vegetable fibre has been shown to help prevent chronic disease 3. Fibre can dilute possible carcinogens in faeces and increase their elimination speed, reducing exposure time and protecting against bowel cancer. Undigested fibre improves bulking and satiety, short-chain fatty acid production and reduces glycaemic responses - both important for digestion. The viscous fibre in starchy vegetables and beta-glucans in oats, barley and whole grains, can contribute to lower cholesterol and, therefore, reduced rates of cardiovascular disease (CVD) 4.
Low in saturated fats
Saturated fats found mainly in animal products have been linked to increasing the risk for CVD and the associated risk factors, such as obesity and high cholesterol. Research in this area is controversial as there is some evidence to show that in moderation, saturated fat can contribute to a healthy diet 5.
Rich in unsaturated (‘good’) fats
Vegan diets are often rich in healthy fats such as the monounsaturated fats found in nuts and avocados.
High in antioxidants
Antioxidants are found in abundance in fruit and vegetables, which are prominent in a vegan diet. Vitamin C, E and beta-carotene are antioxidants that help defend against free radicals, which are highly reactive molecules which may cause a number of diseases including Type 2 diabetes 6.
What are the main problems with a vegan diet?
Obtaining enough essential fatty acids
Essential fatty acids, omega-3, and omega-6 are chiefly obtained from fish and are not easily found in plant foods. They are crucial for growth and have lipid-lowering and blood clot-reducing properties to protect against CVD 7. It’s also argued that meat-eaters do not consume enough essential fatty acids either and would also benefit from supplementation 8.
Animal-derived proteins are termed ‘first-class’ as they are high in good quality amino acids. Vegetable proteins, however, are incomplete meaning that no individual vegetable protein contains all the nine essential amino acids that we need. Different vegetable proteins need to be combined to get a complete protein. Consuming enough protein is absolutely essential for optimal health. This is something vegans need to be aware of by including a variety of legumes, whole grains, nuts, and seeds into their diet.
Risk of zinc, iron & calcium deficiencies
Fish, dairy products and eggs are the major sources of zinc. Zinc absorption is a concern amongst vegans, even if their intake is similar to omnivores. Increased levels of phytates and polyphenols, which are high in vegan diets, bind to zinc and prevent its absorption 9.
Iron deficiency can be a problem for those following a vegan diet, with links to anaemia and a compromised immune function. There are two main sources of iron: haem iron found in animal-based products, and non-haem from vegetable sources. Haem iron is much more easily absorbed by the body, compared to non-haem.
Calcium is most commonly found in dairy products, so a diet which restricts these will need to compensate with green vegetables, nuts, seeds, seaweeds, soy foods and other legumes.
Risk of vitamin B12 & vitamin D deficiencies
B12 is only found in animal products and so needs to be supplemented in a vegan diet. Low energy, impaired memory and permanent nerve damage are just a few of the symptoms of low B12 levels.
Vitamin D is found in fish, meat, eggs and fortified milk, which are all absent from a vegan diet. This vitamin is synthesized from cholesterol when the skin is exposed to sunlight, hence vitamin D deficiency is common amongst both vegans and omnivores due to lack of sunlight exposure (especially in the winter).
A vegan diet certainly has its benefits. It’s rich in antioxidants, folates, phytonutrients and fibre; and low in calories, saturated fats and cholesterol. A plant-based diet can offer protection against high blood pressure, heart disease, diabetes and other degenerative diseases. There is an absence of certain essential fatty acids, zinc, B12 and low levels of calcium and vitamin D, however, which can cause health problems.
Supplementation is required to help prevent vitamin and mineral deficiencies in a solely plant-based diet and it’s important to seek advice from a qualified health practitioner if you are thinking about becoming a vegan.