Recommended energy and nutrient intakes

A healthy diet should be nutritionally balanced, with energy and nutrient levels in adequate quality and quantity, sufficient to cover all human needs, but without excesses, to achieve an optimal state of health.

The requirements of each nutrient are quantitatively very different, the macronutrients, which provide us with energy, should be consumed in amounts of several grams daily, while the rest, vitamins and minerals are needed in much smaller amounts, some in the order of milligrams and others just a few micrograms daily.

In order to know the approximate quantities of nutrients, capable of satisfying the daily necessities, diverse standards or reference values have been established that can be classified in two great categories that complement each other:

• Recommended intakes.

• Nutritional targets and dietary guidelines.

Recommended Intakes (RI): are defined as the amount of energy and nutrients that the diet should contain for the maintenance of health in healthy people. They are included in the tables that the competent bodies of each country prepare according to the conditions and requirements of their populations.

Recommended energy intakes: the recommended energy intakes are made considering an average level, taking into account that recommending high levels, in order to cover variations among individuals, could cause obesity in a large number of people.

For this reason, people who do not perform an average level of physical activity should adapt the figures that reflect the energy needs, according to the recommendations provided in the tables. Example: in the tables of recommended daily intakes of energy and nutrients for the Spanish population, the following is stated:

• Energy needs are calculated for moderate activity. For light activity reduce by 10% and for high activity increase by 20%.

Recommended intakes of the rest of the nutrients: recommended intakes of vitamins and minerals are taken as equivalent values to the average requirement of the population, plus twice the standard deviation of the requirement, to take into account the following factors:

• Possible losses, from the time the nutrient is in the food until it reaches the organism.

• Individual variability in the processes of digestion, absorption and metabolism. For example, in the case of iron, only 10 to 15% of the total amount ingested is absorbed, so it is necessary to ingest around 10 milligrams of iron daily to cover an approximate real demand of only 1 milligram.

• Modifications due to the action of culinary processes. For example, vitamin C is more sensitive to the action of heat, so if we cook foods that contain it, we receive it in smaller proportions.

• Differences in age, sex, and periods of life.

Examples:

• Children need additional calcium and protein to support organ and tissue growth.

• Women need higher iron intakes during the fertile period, to cover losses during menstruation.

Applications of recommended intakes:

• They can be used as a guide, to program and nutritionally assess diets.

• To plan and develop nutritional education programs, guiding people on how to make better food selection.

• They should be taken into account for estimating standards in nutrition labeling and for the development of new products in the food industry.

Dietary reference intakes: are a set of standards, based on updated scientific concepts, that provide a reference on the content of each nutrient that the diet should contain, to avoid health disorders caused by nutritional problems and to reduce the risks of contracting chronic diseases.

Dietary reference intakes include four types of reference values:

• Estimated Average Requirement (EAR): is an average daily intake value, of a nutrient that covers the needs of 50% of a homogeneous population group.

• New Recommended Intake (RDA): is the amount of a nutrient that is judged appropriate to cover the nutritional requirements of nearly all persons in a homogeneous population group.

• Adequate intake (AI): these are estimates used when there is insufficient scientific evidence to establish the value of the estimated average requirement (EAR) or to calculate the amount of new recommended intakes (RDA).

• Tolerable Upper Intake (UL): is defined as the highest level of daily intake of a nutrient that, although consumed over a long period of time, does not pose a risk to the health of the majority of individuals in a population group.

• Nutritional Objectives (NO): these are dietary recommendations, framed in the country's nutritional policy, which provide qualitative and quantitative information on nutrients, aimed at the entire population, with the objective of preventing chronic degenerative diseases,

For their establishment, it is necessary to take into account eating habits, as well as nutritional or health problems affecting the population.

Nutritional objectives include limits for those nutrients whose favorable or detrimental action on health is scientifically substantiated. For example, in the nutritional objectives for the Spanish population, in the case of lipids it is recommended:

• Intake ranges between 25% and 35% of kilocalories, if high proportion monounsaturated oils (olive oil) are consumed.

• This recommendation, which includes quantitative and qualitative aspects of fats, is made in order to guarantee essential fatty acids and energy intake, but establishes limits in terms of quality and quantity of fat to avoid damage to health by overconsumption.

Dietary guidelines: To achieve the nutritional objectives (ON), food-based dietary guidelines (FBG) are prepared to provide the population with simple and easy-to-implement messages to achieve a balanced and prudent diet.

Characteristics of food-based dietary guidelines (FBPGs):

• They should address qualitative and quantitative aspects of foods in a simple manner and taking into account the cultural aspects of the region or country.

• Their content should include adequate energy and nutrient intakes to improve overall dietary habits.

• Their recommendations should cover the entire diet, but using mainly foods that are common for the community.

• They should be attractive, using colors and graphic representations such as wheels and pyramids, among many others.

• They should be prepared using the most recent scientific information and should be updated periodically.