DIETARY REQUIREMENTS

 

The first thing to remember is that nutrient needs vary enormously between individuals. Energy needs are dependent on gender, age, weight and activity levels but if you are muscular, muscle tissue needs more energy than fat tissue so that can also make a difference. Vitamin and mineral needs also vary slightly depending on these factors but whilst protein, fat and carbohydrate absorption in the gut is normally pretty efficient, vitamin and mineral absorption can be affected by the type of foods eaten and the chemical form of the nutrient in the food.

 

 

For example; iron absorption can be enhanced if the meal also contains
vitamin C (Have a glass of orange juice with your meal!) but if the meal
has high zinc content, the zinc may be absorbed instead of the iron!

 

Although spinach is known for being a good source of iron, most of it is
actually unavailable so it’s better to eat fortified cereals, baked beans or
dried fruit if you are trying to increase your iron intake.

 

How are dietary requirements measured? The Terminology!

 

In the UK, Dietary Reference Values (DRVs) or Reference Nutrient Intakes (RNIs) are used by Nutritionists to compare nutrient intakes and to provide information about average intakes but they are not GUIDELINE amounts. DRVs & RNIs are available according to gender and age. Some groups may require extra nutrients- for example during pregnancy or breastfeeding, so these groups have a separate set of DRVs.

 

If your intake is equal to or above the RNI, then your diet will be adequate (for 97.5% of the population) to prevent any signs of deficiency. That is why we use these figures as a basis for nutritional analysis but this doesn’t mean you will necessarily be getting the right nutrients for optimal health. Unfortunately there is not yet enough knowledge about their role to make clear guidelines for intake of specific nutrients, although much research is being done! This is why it is not recommended to take large doses of vitamins and minerals in supplement form until the long term effects can be fully understood.

 

DRVs & RDAs

 

To confuse matters further, in the UK product labels show information based on Recommended Daily Amounts (RDAs). The DRVs were published in 1991, over 20 years ago but RDAs are even older as they were published 30 years ago in 1979! Most of the RDAs shown on food labels are the same as the DRVs but there are some small differences. The DRVs are being reviewed and it is hoped a new publication in 2010 will give us more information about our bodies’ needs for specific nutrients. For more information about food labelling click here