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© Livestock & Meat Commission for Northern Ireland 2015
Dietary Fibre and Water
Learning objectivesTo know the functions, sources and health benefits of dietary fibre.
To know the functions and sources of water.
To understand the principles of fluid balance.
© Livestock & Meat Commission for Northern Ireland 2015
Dietary fibre
Dietary fibre was known as ‘roughage’.
It comprises groups of substances in plant foods which cannot be completely broken down by human digestive enzymes, including lignin, polysaccharides such as cellulose and pectin.
It was originally thought that dietary fibre was not digestible and did not provide any energy. It is now known fibre is fermented in the large intestine by gut bacteria to provide a small amount of energy (2kcal/8kJ per gram).
© Livestock & Meat Commission for Northern Ireland 2015
Sources of dietary fibre
The components of dietary fibre are found in different proportions in fibre containing foods and have different properties.
It is therefore important to eat a range of fibre containing foods.
Sources include wholegrain cereals and cereal products, vegetables, fruits, nuts, beans, lentils, potatoes.
© Livestock & Meat Commission for Northern Ireland 2015
Fibre in the dietThe different types of dietary fibre have different functions in the body, which include:• Helping to prevent constipation (with an
increased water intake) which reduces the risk of diverticulitis and bowel cancer;
• The maintenance of normal blood cholesterol levels;
• The reduction of the rise of blood glucose after a meal;
• The association with feelings of fullness to help control food intake, as foods which are high in fibre often are low in energy density.
© Livestock & Meat Commission for Northern Ireland 2015
How much fibre do we need?
In July 2015, the Scientific Advisory Committee on Nutrition (SACN) recommended an increase in the population’s fibre intake to an average of 30g AOAC fibre per day for adults. No age group in the UK is achieving this; average intakes in adults are around 18g AOAC fibre.
For children, SACN provided the following recommended intakes: 15g/day (age 2-5); 20g/day (age 5-11); 25g/day (age 11-16); 30g/day (age 16-18).
© Livestock & Meat Commission for Northern Ireland 2015
Fibre on food labels
The European regulations on nutrition and health claims states that for a product to claim to be a ‘source’ of fibre it must contain a minimum of 3g of fibre per 100g, or a minimum of 1.5g of fibre per 100kcal.
For a product to claim to be ‘high fibre’ it must contain at least 6g of fibre per 100g, or at least 3g of fibre per 100kcal.
© Livestock & Meat Commission for Northern Ireland 2015
How many ways can you think of to increase fibre in your diet?Some examples include:• Have a bowl of wholegrain breakfast
cereals, served with a handful of dried fruit.
• Switch from white to wholemeal or granary bread.
• Add oats to fruit or vegetable crumble toppings.
• Serve a side salad with a sandwich or pasta dish.
• Add beans and pulses to casseroles and soups.
© Livestock & Meat Commission for Northern Ireland 2015
Water
Water is essential for life, and although humans can survive for a number of weeks without food, they cannot go without fluids for more than two to three days.
Water makes up an average of 60% of body weight, and is essential for the correct function of all the cells in the body.
© Livestock & Meat Commission for Northern Ireland 2015
Water
Water has many functions in the body:
• Acts as a lubricant for joints and eyes;• Main component of saliva, which helps us
to swallow;• Provides a medium in which most
reactions in the body occur;• Acts as a cushion for the nervous system
and helps get rid of waste;• Help to regulate body temperature.
If we do not consume enough water, we become dehydrated.
© Livestock & Meat Commission for Northern Ireland 2015
Water
The body cannot produce enough water to meet all of its needs, so most of the water needed must be provided by food and drink.
Our bodies lose water all the time, when we go to the toilet, from sweat and also through respiration. We need to replace this water by drinking regularly to prevent dehydration.
Even mild dehydration can lead to headaches, irritability and loss of concentration.
© Livestock & Meat Commission for Northern Ireland 2015
Sources of water
Around 20% of water consumed is from food, and the remaining 80% from beverages.
The water content of food varies widely; <40% in cereal products, 40-70% in hot meals, >80% in fruits and vegetables, and approximately 90% in cows’ milk.
We can get our fluid requirements from a number of sources as water is contained in most foods and all drinks consumed.
It is not necessary to drink only ‘pure’ water, although this is a good choice as it hydrates without the provision of energy.
© Livestock & Meat Commission for Northern Ireland 2015
How much water do we need?
The amount of water and other fluids we need to drink each day varies from person to person, depending on age, time of year, climate, diet, and the amount of physical activity.
Children are recommended to have 6-8 drinks each day. European recommendations for adults suggest 1.6L of fluid per day for women (about 8 200ml glasses) and 2L of fluid per day for men (about 10 200ml glasses). This is in addition to the fluid we get from food.
We need to drink more when the weather is hot or when we are active.
© Livestock & Meat Commission for Northern Ireland 2015
What is thirst?
When dehydration is detected, the body’s first response is to signal the kidneys to conserve water.
When 1-2% of body mass is lost due to dehydration, the thirst response is initiated, so it is important to drink if we are thirsty.
Headaches and tiredness are also symptoms of not getting enough water.
What ways can you think of to check if you are getting enough water or not?
© Livestock & Meat Commission for Northern Ireland 2015
Which population groups might be at risk of dehydration?Older adultsMay have a weaker sense of thirst, so may need help and encouragement to drink plenty throughout the day.
ChildrenNeed plenty of fluid and should be encouraged to drink regularly, particularly if they are very active.
People who are very physically activeShould be encouraged to drink lots to replace the water lost through sweating.
© Livestock & Meat Commission for Northern Ireland 2015
What happens if we drink too much water?Can lead to water intoxication, with potentially life threatening hyponatraemia (as the sodium concentration will get too low).
Severe cases can result in brain swelling, headache, fatigue, confusion, and vomiting.
© Livestock & Meat Commission for Northern Ireland 2015
Summary
Dietary fibre can be found in cereal foods, including bread, beans, lentils, fruit & vegetables.
It cannot be broken down by human digestive enzymes.
SACN have recommended average intake for adults is 30g (AOAC) per day, but average intakes are much lower.
A low fibre intake is associated with constipation and some gut diseases.A high fibre diet can help reduce cholesterol, reduce the risk of diabetes and can help protect against becoming overweight.
© Livestock & Meat Commission for Northern Ireland 2015
Summary
Water makes up about 60% of our bodyweight, and regular fluid intake is essential for our bodies to function properly.
The amount of fluid needed varies between people.
Dehydration can impair physiological and performance responses, and in extreme cases can be fatal.
© Livestock & Meat Commission for Northern Ireland 2015
Summary
Drinking too must water can result in water intoxication, which can lead to hyponatraemia.
We have sensitive mechanisms to maintain our body water but attention should be given to those who may not recognise the sensation of thirst so easily, to ensure they consume enough fluids.
It is essential to replace water before, during and after exercise.
© Livestock & Meat Commission for Northern Ireland 2015
Acknowledgement
For further information, go to: www.food4life.org.uk © LMC 2015
© Livestock & Meat Commission for Northern Ireland 2015
