Science Centre

The Sugar Bureau aims to improve understanding of the role of carbohydrates, including sugar, in a healthy diet.

One means of achieving this is to provide researchers and writers with up-to-date information on recently-published research.

Also in this section are articles about the major lifestyle diseases, citing the latest references from academics worldwide.


Carbohydrates are all the sugars and starches in the diet and they can be divided into three basic groups:


These are single molecules of sugar. The monosaccharides are:

  • Glucose
  • Fructose
  • Galactose

Glucose is found free in fruits and as part of the starch molecule in a wide variety of staple foods, such as bread, potatoes, rice, pasta. Most carbohydrates are eventually digested or converted into glucose by the body for energy (fuel). Fructose is also known as fruit sugar and is found in fruits, vegetables and honey (along with other sugars). It is mostly converted into glucose by the liver. Galactose is part of lactose, the sugar found in milk.


These are molecules containing two linked monosaccharides They are broken down into the monosaccharides by digestion.

The disaccharides are:

  • Sucrose which is made up of glucose + fructose
  • Lactose = glucose + galactose
  • Maltose = glucose + glucose

Sucrose (table sugar) normally comes from sugar beet and cane, as these are rich plants sources but sucrose can also be found naturally in all fruits and vegetables, and even most herbs and spices. Lactose is found in milk and milk products. Maltose is formed when starch is broken down.


Starches are simply hundreds of molecules of glucose sugar joined together. When starches are digested, they are first broken down into maltose and then into glucose. So, the only difference between sugars and starch is the size of the molecule. Ultimately, most carbohydrates will end up as glucose to provide that vital fuel to supply the body with energy.

Coronary Heart Disease

CHD affects more than 2.5 million people in the UK and comes in two main forms – angina and heart attack. Angina is a pain in the chest and is caused by a narrowing of the blood vessels that supply the heart (atheroscelerosis). If one of these vessels becomes blocked by a blood clot (thrombosis) a heart attack results.

CHD, although largely preventable, remains the single most common cause of death in the UK. Every year, one in six female and one in four male deaths are due to CHD. A number of factors are associated with an increased risk of developing CHD – the main ones are smoking, high blood pressure, high blood cholesterol, and obesity. However, other lifestyle factors – particularly diet and exercise – also have an important role to play.

Diet and CHD

Eating for heart health simply follows the principles of a healthy balanced diet. There is extremely good evidence that moderately low-fat diets, especially low in saturated fats, but high in carbohydrates, reduce the risk of CHD by inducing favourable blood lipid (fat) profiles.

Furthermore, despite the speculation in the media, it is important to add that there is no persuasive scientific evidence that sugary sources of carbohydrates – including sugar – behave any differently to starchy carbohydrates in terms of CHD risk. In fact the old idea that sugar causes CHD was dismissed as long ago as 1989 by the UK government’s COMA Committee (Committee on Medical Aspects of Food) and the scientific evidence, both clinical and epidemiological, available since that date has been thoroughly assessed but does not merit any revision of that opinion.

The key dietary component to focus on in terms of CHD is fat. However, we do need some fat in our diet to provide us with our essential fatty acids and the fat soluble vitamins – A, D, E, and K. The official guideline daily amounts (GDAs) for fat are 95g for men and 70g for women per day. The GDAs for saturated fat are 30g and 20g for men and women respectively.

Reducing dietary fat intake – particularly saturated fats – improves the levels of fats in the blood, promotes weight loss, and so reduces CHD risk. Although high blood cholesterol is a risk factor for CHD, it in-turn is more affected by the amount and type of fat in the diet than the amount of dietary cholesterol eaten. So, for most people, it is much more important to monitor the intake of saturated fat than cholesterol.

The cornerstone of dietary advice concerning reducing CHD risk is to increase the intake of carbohydrate-rich foods as this will help reduce fat intake. Plus many fruits and vegetables rich in carbohydrates are also rich in antioxidants and soluble fibre, and so consumption should be encouraged.

Eating fish – especially oily fish like salmon, mackerel, and sardines – at least twice a week is also recommended. This is mainly because oily fish are a good source of an essential fatty acid – omega-3. Omega-3 fatty acids have been shown to be beneficial for the heart by helping to improve blood fat levels and reducing blood clotting. Other sources of omega-3 fatty acids are: rapeseed oil; pumpkin seeds; and walnuts.

Moderate alcohol consumption, about one or two drinks per day, is associated with reduced risk of CHD. But, high intakes – particularly ‘binge drinking’ – increases CHD risk.

Eating lots of salt can increase blood pressure in people who are susceptible to high salt intakes, so it’s also wise to keep an eye on salt intake.