Nutritional needs in adults

At Phytocea , we don't just design and distribute food supplements . We believe that to make informed choices about your food or supplements, you need to understand the key concepts. We created this article with that goal in mind.

A few reminders about nutrition

Nutrition is a science that studies the impact of food on physiology and health.

It is a much more complex discipline than it appears and involves taking into account many parameters.

Nutritional studies have established the nutritional needs of individuals. These needs and the resulting recommendations vary depending on age , sex , health status , and other factors.

Recommendations are also subject to change, but this time it stems from evolving knowledge: over time, studies refine our understanding of nutritional needs and also dispel certain long-held beliefs. This is why recommendations issued by health authorities are subject to change. This is particularly true of the recommendations of the National Nutrition and Health Program (PNNS), which are regularly updated.

What is nutritional need?

Nutritional needs are defined as:

" the average amount of nutrients needed daily to ensure the development of the body, the renewal of tissues, the maintenance of good physical and mental health, and physical activity in accordance with one's living conditions ."

How can I determine my energy needs?

For energy expenditure , there are several different parameters and calculation methods. It is important to remember that there are differences:

• Male / Female (energy expenditure is lower in women).
• Dependent on age : infants, young children, adolescents, adults, seniors . Energy requirements, as a general rule, decrease with age.
• In women, needs vary during pregnancy and the breastfeeding period.
• Physical activity increases energy expenditure; a sedentary person has a much lower energy expenditure than someone who is very physically active.

Specifically, the average energy requirement for an adult (18-60 years old) falls within a range of:

• 1800 to 2200 kcal per day (7536 to 9211 kJ per day) for women
• 2400 to 2700 kcal per day (10048 to 11304 kJ per day) for men

The calorie is a unit of energy. It represents the amount of energy needed to raise the temperature of one gram of water by 1°C.

The calorie is an old unit; the true international unit for the quantification of energy is the joule (J).

Note that there is an older variant of the calorie: the “large calorie” (Cal) which is equivalent to 1000 calories (cal).

Normally, only the calorie (cal) and the joule (J) are used today.

1 calorie (cal) = 4.18 joules (average value)

1kcal = 1000 cal = 1 Cal = 4180 J = 4,180 kJ

What are the differences between calories and nutrients?

We now know the energy expenditure of adults. But this tells us nothing about what constitutes a food intake: providing calories is good, but they must also be of quality, allowing the body to function properly.

Calories have a variable nutritional value; in particular, there is a concept of "empty" calories which helps to better understand the nutritional value of a food.

An empty calorie corresponds to the energy value of a food whose consumption provides no essential nutrients for health .

The perfect example is alcohol. 1g of alcohol has a high energy value (7 kcal/g), but provides NO essential nutrients for the functioning of the body: no vitamins, no minerals, no essential amino acids, etc.

Alcohol consumption therefore has no benefit for health and only provides energy (which in this case will tend to be stored as lipids).

The calories provided by alcohol are therefore “empty” calories ; alcohol is a food with no nutritional value .

Nutrients are the components of food; the body uses them to maintain homeostasis . A distinction must be made between:

• The essential nutrients (certain amino acids, certain fatty acids, certain vitamins, etc.) must necessarily be provided by food, because the body cannot synthesize them.

• Conditionally essential nutrients : the body can synthesize them if it has sufficient quantities of the necessary precursors. They can become essential in certain specific situations (diseases, malabsorption, deficiency, enzymatic deficiency, etc.).

• Non-essential nutrients : the body can synthesize them if needed.

What are the recommended daily allowances and nutritional reference intakes?

In France, it is ANSES which, thanks to expert committees and EFSA recommendations, defines nutritional references.

Nutritional references evolve over time based on knowledge acquired through various studies (basic, interventional, observational, etc.).

Several concepts exist and provide different information.

The average nutritional requirement or NRV

Defined as “ the average requirement within the population, as estimated from individual intake data in relation to a nutritional adequacy criterion in experimental studies ”.

The nutritional reference intake for the population or RNI

Defined as “ the intake which in theory covers the needs of almost the entire population considered (97.5% in most cases), as estimated from experimental data ”.

The satisfactory contribution or AS

Defined as “ the average intake of a population or subgroup for which nutritional status is considered satisfactory ”.

When the BNM and the RNP cannot be estimated correctly or are considered insufficient, the AS is retained as the nutritional reference.

The upper safety limit or LSS

In addition to these concepts, there are safety values ​​for certain nutrients, these are the upper safety limits or USLs.

The LSS is defined as “ the maximum chronic daily intake of a vitamin or mineral considered unlikely to present a risk of adverse health effects for the entire population ”.

What are the recommended nutritional intakes for adults?

In conclusion

Nutritional needs are a concept that goes beyond simply needing calories.

It is not enough to simply provide the body with energy, but also to provide it with the nutrients it needs to function by consuming a simple, varied, balanced diet.

As a general rule, highly processed foods should be avoided and a diet with plenty of plant-based products should be favoured, while limiting meat consumption.

Finally, the nutritional information presented in this fact sheet only covers the calorie, vitamin, and mineral requirements for adults. It does not include the needs for other essential elements such as certain fatty acids and amino acids . The nutritional requirements for fatty acids are detailed in another article .

Nutritional needs other than those of adults will be presented in dedicated fact sheets.

Sources

National Nutrition and Health Program (PNNS)

ANSES

EFSA