Do we really need meat at all?
If the horsemeat controversy has made you uneasy about eating meat, take a look at the pros and cons of vegetarian and meat diets.
As the horsemeat scandal rages, many meat eaters will be wondering exactly what they've been consuming. And if you're a vegetarian, recent events will probably leave you more convinced than ever that you made the right choice, with many celebrities leading the way, including Stella McCartney, Jessica Chastain and Madonna.
New research has shown that vegetarians are a third less likely to suffer from heart disease than meat eaters, statistics that will make a meat-free diet a more attractive proposition for some.
However, the meat industry is eager to point out that vegetarians may be low in certain essential vitamins and minerals, and that eating lean red meat is an important part of a healthy diet.
But do we really need meat to be healthy, or is the modern human better suited to a vegetarian diet?
A new study from the University of Oxford has found that the risk of heart disease, the biggest killer in the UK, is 32% lower in vegetarians than people who eat meat and fish.
The study tracked almost 45,000 volunteers from throughout the 1990s until 2009, and found that vegetarians had lower blood pressures and cholesterol levels than non-vegetarians, as well as lower body mass index (BMI) and fewer cases of diabetes.
Dr Francesca Crowe, lead author of the study, explains: "Most of the difference in risk is probably caused by effects on cholesterol and blood pressure, and shows the important role of diet in the prevention of heart disease."
The Vegetarian Society suggests horsemeat and health factors may have combined to make a meat-free diet more of a consideration for some people.
"This year hasn't started well for meat eaters," says the society's spokesperson, Liz O'Neill.
"First horsemeat is found in certain beef products, and then a new report indicates meat eaters have a much higher risk of heart disease than vegetarians.
"Throw in higher rates of obesity, high blood pressure and a number of different cancers and it's hard to see why anyone still wants to eat meat."
She says many health studies have shown positive outcomes for vegetarians, and points out: "The new study findings make it clear that relying on meat for your daily nutritional needs means taking a significant unnecessary risk with your health."
HEALTHY BALANCED DIET
Nutrition experts say that while research shows the benefits of vegetarianism, everyone should be trying to eat a healthy balanced diet, and that can include both meat and non-meat.
It is generally recommended that adults should eat no more than 70g of cooked red or processed meat a day - equivalent to three rashers of bacon or three slices of thin ham.
If a balanced diet is eaten, the risk of vitamin and mineral deficiencies should be no greater for vegetarians than for meat eaters.
Vitamin B12: Helps form red blood cells and nerve fibres, and is only found naturally in meat, fish, eggs and milk, although it's sometimes added to cereals, bread and yeast spreads.
Nutrients such as vitamin A and D, magnesium, zinc, selenium and potassium, that Government dietary surveys have shown some UK diets are low in.
Protein: Meat is high in protein, which is needed for cell growth and repair.
Iron: Sourced from animals, it's more easily absorbed than iron from plants and is important for the formation of red blood cells and the work of the body's immune system and metabolism. Not enough can lead to iron deficiency anaemia.
Fats: Meat contains saturated fat which can block the absorption of essential fats which help maintain cell structure, and increase cholesterol in the blood which can lead to heart disease. But lean red meat also contains heart-healthy nutrients and polyunsaturated and monounsaturated fats.
A VEGETARIAN DIET PROVIDES
Protein: Though typically lower in protein than non-vegetarian diets, a vegetarian can get protein through foods such as pulses, nuts, eggs, dairy foods, cereals, soya and Quorn.
Vitamins: A high intake of fruit and vegetables means more vitamins, minerals such as potassium and magnesium, and antioxidants from many important nutrients such as vitamin C, vitamin E and beta-carotene, which have been shown to reduce the risk of certain cancers and heart disease.
Fats: Vegetarians usually eat fewer saturated fats - found in meat and dairy products - and more unsaturated fats - found in vegetable oils such as olive oil, nuts, seeds and avocados. With the exception of fish, plant foods are generally higher in polyunsaturated fats than foods from animals. Such fats have been shown to prevent elevated cholesterol in the blood.
Vitamin B12: Helps form red blood cells and nerve fibres, and vegetarians can get it from eggs and milk. It may also be added to cereals, soya milk, vegetable burgers and yeast extract.
Iron: Vegetarian sources of iron include eggs, pulses, nuts, seeds, green leafy vegetables, dried fruit and fortified breakfast cereals.