What are aspartame and saccharin, and are they safe?

Aspartame and saccharin are sweeteners and they are used in soft drinks and other reduced-calorie or sugar-free foods. As with all food additives, aspartame and saccharin have undergone rigorous safety assessments before approval and are only allowed to be used in a limited range of products.

The use of additives is carefully monitored, and surveys are routinely carried out to make sure that people do not regularly consume more than the Acceptable Daily Intake (ADI). This is the amount of an additive that a person may eat or drink each day for an entire lifetime without causing any known harm to health.

The Sweeteners in Food Regulations 1995 (as amended) control the use of sweeteners in Great Britain. These regulations set out the maximum levels permitted in specific food categories and take into account the ADI for each sweetener. Once an additive is approved, its safety is also kept under review.

In the case of aspartame, the ADI is set at 0-40 milligrams (mg) per kilogram (kg) of body weight. This is equivalent to 2.8 grams (g) for an average British adult. For saccharin, the ADI is 0-5 mg per kg of body weight, which is 0.35g for the average British adult.

Many scientific papers regarding aspartame have been published over the past few years. The Scientific Committee on Food (SCF), an independent group that advised on the authorisation of food additives, reviewed aspartame in 1988. Between then and 2000, more than 500 papers were published on aspartame. A significant number of these papers were new studies that directly addressed questions of safety. Some of these studies support the safety of aspartame, while others point to potential adverse health effects.

Therefore, in April 2001, the Food Standards Agency requested that the Scientific Committee on Food review aspartame again. The SCF published its updated opinion on the safety of aspartame in December 2002. The Committee concluded that there was no evidence to suggest a need to revise the outcome of its earlier risk assessment that the sweetener is safe for use, or change the ADI previously established for aspartame.

The European Commission asked the European Food Safety Authority (EFSA), which took on the SCF's role in advising the Commission, to review further research that claimed to have shown that rats given aspartame in doses equivalent to the ADI may develop tumours. This research was from the Ramazzini Institute in Bologna.

EFSA reviewed the research and, in May 2006, concluded on the basis of all the evidence currently available that there is no need to further review the safety of aspartame or to change the ADI.

What does 'vegetarian' or 'suitable for vegetarians' mean?

There isn't a single legal definition of the word 'vegetarian', either in the UK or in Europe. This means there isn't one set of rules about when a food can be called vegetarian. So what a 'vegetarian' food does or doesn't contain could vary from product to product.

If a food is labelled vegetarian, this usually means that the food doesn't contain any meat or animal-derived additives such as gelatine (a gelling agent derived from animal ligaments, skins, tendons, bones etc.) In the case of cheese, it usually means that animal-derived rennet hasn't been used to make it.

Some vegetarians are stricter about what foods they avoid than others. Remember, if you want to avoid a particular ingredient, you can check the ingredients list on a food's label.

Manufacturers aren't required to label foods as 'suitable for vegetarians' because this is a voluntary practice. This means there are many foods without the 'suitable for vegetarians' logo that don't contain meat or animal-derived additives.

Foods approved by the Vegetarian Society can display the Society's 'Seedling Symbol'. To be approved, the food must meet a number of conditions, not just be free of meat and animal-derived additives. For example, foods containing eggs will only be approved if the eggs used are free-range.

Even though there isn't one set of rules about when a food can be called vegetarian, general labelling laws prohibit manufacturers and retailers from describing a food in a misleading way.

What do 'use by', 'best before' and 'display until' mean?

'Use by' means exactly that. You shouldn't use any food or drink after the end of the 'use by' date shown on the label. Even if it looks and smells fine, using it after this date could put your health at risk and cause food poisoning.

You will usually find a 'use by' date on food that goes off quickly, such as milk, soft cheese, ready-prepared salads and smoked fish.

It's also important to follow any storage instructions given on food labels, otherwise the food might not last until the 'use by' date. Usually food with a 'use by' date needs to be kept in the fridge.

'Best before' dates are usually used on foods that last longer, such as frozen, dried or canned foods. It should be safe to eat food after the 'best before' date, but the food will no longer be at its best. After this date, the food might begin to lose its flavour and texture.

However, you shouldn't eat eggs after the 'best before' date. This is because eggs can contain salmonella bacteria, which could start to multiply after this date.

Some food labels also give instructions such as 'eat within a week of opening' and it's important to follow these instructions. But remember, if the 'use by' date is tomorrow, then you must use the food by the end of tomorrow, even if the label says 'eat within a week of opening' and you have only opened the food today.

'Display until' and 'sell by' dates are instructions for shop staff to tell them when they should take a product off the shelves.