What are the possible health benefits of a vegetarian diet? On the downside might you be missing out on important nutrients?
What healthy nutrients does a vegetarian diet contain?
Vegetables and fruits contain fibre, as well as vitamins such as A, C and E. Eating more fruit and vegetables is associated with a lower risk of death from all causes, in particular cardiovascular (e.g. heart attack and stroke) and cancer. That’s according to a review of 95 different studies published in 2017.
Pulses are a good source of protein, fibre and minerals such as iron, zinc and magnesium.
Wholegrain products contain vitamin B, potassium, magnesium and zinc. They are associated with a range of health benefits, including a reduced risk of heart disease, cancer and type 2 diabetes.
Is what a vegetarian diet excludes also important?
The UK Department of Health has advised those consuming large quantities of red and processed meat to cut back – as this probably increases the risk of bowel cancer.
Cutting out saturated animal fat may have other health benefits, as saturated fats are believed to increase the risk of cardiovascular disease. However, this is currently being debated. Some countries like France consume quite a lot of saturated fat but have low levels of cardiovascular disease. They also consume quite a lot of fruit and vegetables though, which may be protective.
According to the Harvard School of Public Health, on balance fish and moderate egg consumption (provided the eggs are stored and cooked properly) can form part of a healthy diet. However, its Healthy Eating Plate suggests that we limit dairy products like milk, cheese and butter.
What is the evidence for health benefits?
Factors believed to increase the risk of heart conditions, stroke and diabetes include high blood pressure, high blood glucose levels, high LDL (‘bad’) cholesterol, and being overweight. An analysis of 96 different studies, published in 2017, showed significantly reduced levels of LDL cholesterol, blood glucose and BMI (Body Mass Index) in vegetarians and vegans, as well as a reduced risk of heart disease and cancer.
Research from the USA suggests that vegetarian diets are associated with lower deaths from all causes - particularly from heart attack and stroke, kidney failure and diabetes. These reductions were larger and more significant in men than in women. This research aimed to take account of other potential factors, like smoking, alcohol, exercise, education and sleep – to specifically identify the effect of diet.
A long term study of over 130,000 nurses in the USA, published in 2016, found that plant protein was associated with lower death rates from all causes where participants had at least one health risk factor (like smoking, high alcohol consumption, obesity and physical inactivity). And three long term studies in the US, with collectively over 200,000 health professional participants, suggested that plant based diets (especially when rich in high quality plant foods like whole grains, vegetables, fruits, nuts and pulses) were associated with a substantially lower risk of developing type 2 Diabetes.
Are all vegetarian diets the same?
There are four main types of vegetarian diet:
The strictest is vegan i.e no food of any kind which has animal origin, including honey. Some vegetarians eat dairy products (lacto – vegetarians), some eat eggs (ovo-vegetarians) and some eat both (lacto – ovo vegetarians).
These different vegetarian diets have different nutritional consequences (see below):
Are there possible deficiencies in a vegetarian diet?
Yes. Animal protein (from eggs, dairy products, fish and meat) tends to provide all the amino acids we need. In contrast each type of plant based protein (from pulses, seeds, nuts, grains, fruit and vegetables) typically lacks one or more of the essential amino acids.
The stricter the vegetarian diet the more important it is to have a good mix of different types of plant protein, to optimise nutrient intake. For example beans on toast provides pulses (beans) and cereals (bread). Adding a glass of soya milk, some nuts and a banana would add soya, nuts and fruit i.e. three additional and different types of plant based protein. Soya and quinoa are said to be the best plant based sources of essential amino acids.
The main nutrients vegetarians and vegans need to ensure they get enough of are iron, selenium, vitamin B12 and omega-3 fatty acids. Potential sources are:
- Pulses, green vegetables, wholemeal bread, dried fruit, nuts, seeds and eggs (for iron) – ideally with fruit, to help increase the absorption of iron.
- Brazil nuts, cashew nuts and pecans (for selenium)
- Yeast extract and some fortified breakfast cereals (for Vitamin B12)
- Tofu, flaxseed, eggs, walnuts and walnut oil (for omega – 3)
Vegetarian diets from around the world provide interesting alternatives – like tortillas, beans, avocado and salsa (from Mexico) or Chana Masala (chickpeas stewed with onions, tomatoes and spices and eaten with rice), from India.
- Vegetables, fruit, pulses, whole grains, nuts and seeds contain a range of health enhancing nutrients.
- Most research suggests a vegetarian diet reduces the risk of heart attack, stroke and diabetes – and the risk of becoming overweight.
- However, there are different types of vegetarian diet.
- The stricter the vegetarian diet the more important it is to eat a wide range of sources of plant based protein to get all the nutrients needed (which non vegetarians get through meat, fish, eggs and dairy products).
Reviewed and updated by Viktoria Sekamov, January 2018 Next Review date, December 2020