Probiotics and prebiotics affect the bacterial flora that lives in the gut and helps to protect against infections. Probiotics are live cultures, such as yogurt, that can survive the stomach acids and change the composition of the gut flora. Prebiotics are non-digestible food ingredients that stimulate the growth of beneficial bacteria in the gut.

Long Chain Omega-3 fatty acids, from oily fish and algae, can be added to dietary supplements and functional foods (for example, yogurts and eggs). Traditionally these oils are recognised as being good for a healthy heart. Other studies have shown that depression can be linked with a lack of these fatty acids in the diet. Fatty acid supplements can improve behaviour both in children with Attention Deficit Hyperactivity Disorder (ADHD) and related disorders in adults.

Phytosterols, which occur naturally in plants, have been shown to reduce cholesterol levels, and for this reason are now incorporated in several fat spreads and dairy products, as many people’s fruit and vegetable intake is not adequate.

Minerals and vitamins can aid bone health. Osteoporosis, or the crumbling of bones, affects one in three women in the UK. It happens mainly in later life and calcium and vitamin D are often included in functional foods to combat this. It is important to build healthy bones during schooldays, so teenagers, especially girls, should try to ensure a regular intake of calcium from their diet. It is found in good quantities in milk and dairy products, and bread.

When it comes to fibre, the UK diet is generally low in fibre or “roughage”, and hence certain high fibre breakfast cereals can be regarded as functional foods. Dietary fibre has long been accepted as a beneficial component of a healthy diet, improving digestion and promoting a healthy intestinal tract. Many plant extracts , for example green tea extract and grape juice extract, are currently being evaluated for their health benefits and subsequent possible inclusion in food products.

If a healthy ingredient has not been a traditional part of the European diet, it may be evaluated for safety by the Novel Foods Committees in each European country.

A great deal of work is currently underway on substances such as lycopene which may help in the reduction in the risk of disease such as bowel cancer and other chronic illnesses. Others include lutein, from green leafy vegetables (for eye health) and green tea extract (antioxidant).

As part of a healthy lifestyle, functional foods are concerned with helping towards the prevention of ill-health or contributing to the reduction of disease risk factors. They are not to be seen as disease cures: products used in a curative, therapeutic or preventative sense are sold as medicines with a defined set of indications under the supervision of a qualified physician.