Committee on Medical Aspects of Food & Nutrition Policy.

The Committee on Medical Aspects of Food and Nutrition Policy (1991) recommended:

• Eating more starchy foods such as bread, potatoes, rice and pasta. Assuming these replace fat-containing foods, this will help to reduce the amount of fat and increase the amount of fibre in the diet. Adding fat to these foods should be avoided or kept to a minimum.
• Eating more fruit and vegetables. It has been suggested that individuals aim for at least 5 portions of different fruits and vegetables a day (excluding potatoes). As long as extra fat is not added to these foods, these changes will help to reduce fat intake, and increase intakes of fibre and important nutrients such as vitamin C.
• Choosing leaner cuts of meat and lower fat versions of dairy products will help to reduce the amount of fat, particularly saturated fatty acids in the diet. Trimming fat, choosing cooking methods that do not require added fat and eating smaller portions of high fat foods can all be helpful.

People who are overweight should lose weight by using their fat stores to provide energy and increasing their energy output. This means eating less and increasing their physical activity. They should aim to reduce their weight by no more than 1 kg a week. To do this they need to reduce their energy intake by about 1,000 kcal (4.184 MJ) a day. In this way they will lose fat rather than muscle.

A well-balanced diet is the most important requirement for healthy living. Good nutrition helps reduce our risk of getting a large number of diseases, from diabetes to heart disease.

From the point of view of activity, a recent report by the Chief Medical Officer made the following recommendations:

• Adults should participate in at least 30 minutes of at least moderate intensity activity on five or more days a week.
• This does not have to be taken all at once – 3 brisk walks each of 10 minutes duration would be equally beneficial.

CARBOHYDRATES

The Department of Health recommends that men should not consume more than 3-4 units of alcohol/day and women not more than 2-3 units. A standard unit is typically half a pint of beer, a small glass of wine or a single measure of spirits.

The two main types of carbohydrate are sugars and starch. Sugars and starch provide energy. At least half the energy in our diets should come from carbohydrate, mostly as starchy carbohydrates.

FATS

Fat has many important functions as a nutrient:

• It provides more than twice as much energy as protein or carbohydrate. However, no more than one third of our energy intake should come from fat. Fat is needed for health but only in small amounts.
• It is a carrier for fat-soluble vitamins A, D, E and K.
• It contains the essential fatty acids (EFAs) linoleic acid (omega-6) and alpha linolenic acid (omega-3). These - and fatty acids synthesised from them - are important in the formation of cell membranes particularly in nerve tissue. At least 1.2% of energy intake should come from EFAs. Although the fatty acids EPA and DHA are synthesised in the body, they can also be obtained pre-formed from oily fish in particular and fish oil supplements. They are also present in the meat or eggs of animals fed omega 3 enriched diets.

PROTEIN

• Protein is needed for growth and repair of the body.
• Protein provides energy.
• Different foods contain different amounts and combinations of amino acids (the building blocks of proteins). Vegans and vegetarians can get all the protein they need by combining different plant sources of protein, e.g. pulses and cereals.
• The amount of protein we need changes during a lifetime.

MINERALS

• Minerals are nutrients that are needed in the body in tiny amounts.
• Minerals have many roles in the body.
• They form the architecture of bones, they are constituents of body fluids, they help enzymes to work, they help nerves to send signals.
• The amount of each mineral we need changes during our lifetime.

Some minerals are needed in larger amounts than others, e.g. calcium, phosphorus, magnesium, sodium, potassium and chloride. Others are required in smaller quantities and are sometimes called trace minerals, e.g. iron, zinc, iodine, fluoride, selenium and copper. Despite being required in smaller amounts, trace minerals are no less important than other minerals.

Calcium
Calcium is the main constituent of hydroxyapatite, the principal mineral in bones and teeth. Calcium also plays an essential role in intracellular signaling and is therefore necessary for nerve and muscle function. It is also involved in blood clotting.

Foods that are particularly rich in calcium are milk, cheese and other dairy products (but not butter). White and brown flour, but not wholemeal is fortified with calcium by law so bread and other products made from this are important sources of calcium in the UK diet. Calcium is most readily absorbed from milk and dairy products.

Magnesium
Magnesium is present in all tissues including bone. It is present in all foods, but because magnesium is found in chlorophyll, it is abundant in dark green leafy vegetables. However much of this is bound and not readily available for absorption. Grains and nuts are also rich in magnesium, providing about a quarter of total intake among UK adults. Although deficiency is rare, low intakes have been observed in some groups.

Iron

Iron is required for the formation of haemoglobin in red blood cells, which transport oxygen around the body. Iron is also required for normal energy metabolism, and for metabolism of drugs and foreign substances that need to be removed from the body. The immune system also requires iron for normal function. A lack of iron leads to low iron stores in the body and eventually to iron deficiency anaemia. Loss of blood due to injury or large menstrual losses increases iron requirements. Women of child bearing age and teenage girls, in particular, need to ensure their diet supplies enough iron as their requirements are higher than those of men of the same age. Data indicates that iron intake is to low in some groups of women.

Iron is found in animal and plant sources. Iron from animal sources (haem iron) is better absorbed than iron from plant sources (non-haem iron). Absorption of non-haem iron is affected by various factors in food. Phytate (in cereals and pulses), fibre, tannins (in tea) and calcium can all bind non-haem iron in the intestine, which reduces absorption. On the other hand vitamin C, present in fruit and vegetables, aids the absorption of this kind of iron when eaten at the same time. The same applies to meat, fish and poultry. Bread and many breakfast cereals are fortified with iron in the UK, and make a valuable contribution to iron intake.

WHY is water good for us?

Water is essential for our bodies to work properly. Water (and fluid in general) has many functions in the body.
• It acts as a lubricant for joints and eyes
• It helps us swallow
• It provides the medium in which most reactions in the body occur
• It acts as a cushion for the nervous system and helps get rid of waste
• It helps to regulate body temperature.

Caffeine

Caffeine is a mild diuretic (i.e. it increases urine output to a small extent), but drinks that contain caffeine (e.g. tea, coffee, cola) also contribute to fluid intake. You do not need to drink more water to compensate for consuming these drinks, provided you are achieving the 6-8 cups required.

Alcohol

With alcoholic drinks, the dehydrating effect can be greater. Drinking water alongside alcoholic drinks will minimise any dehydrating effects.

Bottled, filtered or tap water?

There are few nutritional differences between bottled and tap water in the UK, and regulations are often tighter for tap than bottled water.

Filtering water reduces problems with limescale build-up and scum on hot drinks by decreasing the hardness of the water and also reduces chlorine and impurities in the water, which may affect taste, but filtered water offers no special benefits in terms of nutrition.

Tap water in the UK is safe to drink. Boiled and cooled tap water is recommended when making up infant formula milk.