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Objectif Nutrition N°59 (July 2001)
The "Apports nutritionnels conseillés"
Geneviève POTIER de COURCY
Recommendations regarding recommended nutrient intakes (ANC) have changed
since the previous version published in 1992. Applicable on a population-wide
scale to evaluate risks of deficiencies or excess these recommendations
are modulated according to different age groups.
However, to date, it is still not possible to formulate individual recommendations.
The ANC ( "Apports Nutritionnels Conseillés" for the French
population) or recommended nutrient intakes are reference values for a given
population adapted to gender, to each age category and to specific physiological
conditions: pregnancy, lactation, or intensive and regular physical exercise.
Since there are statistical values, the ANC are used to evaluate the risks
of deficiency or excess intake in a given population: they are intended
to cover the needs of 97.5% of the population. Based on physiological requirement
values measured in a group of subjects, ANC are calculated by adding two
standard deviations to the value obtained from the group.
Thus, inter-individual variability is taken into account, in particular,
variability associated with differences in energy expenditure, stature,
basal metabolism, etc. Thus, if the optimum level for a given population
is to range within a value close to that of the ANCs, for an individual
subject, intake of a nutrient ranging between 0.8 and 1 time ANC value
can be considered as satisfactory (figure 1).
The ANCs for 2001 represent optimum intakes and, in this regard, incorporate
preventive measures against certain diseases (i.e. cancers, cardiovascular
disorders, diabetes, osteoporosis). They are based on clinical, epidemiological
and experimental data.
Energy: How much and why?
The energy balance is attained when energy intake (obtained from proteins,
carbohydrates and lipids) is equal to energy expenditures. And yet, such
expenditures depend on several factors: physical activity, thermoregulation,
gender, height, age (the decrease in energy expenditure may reach 30% in
subjects between 20 and 75 years of age, largely exceeding the simple decrease
in muscle mass), body composition (an excess in fatty tissue results in
a relative decrease in energy expenditures) and basal metabolism.
The change in lifestyle over the last few decades has given rise to a sedentary
lifestyle, automation in the workplace, and heated offices and residences.
All of these factors have resulted in a definite decrease in energy expenditures
and therefore in energy requirements. Furthermore, there is a wide variability
between subjects of the same height, gender and age in basal metabolic expenditures,
in those associated with physical activity, in the energy needed for the
formation of a given quantity of stored fat, or in the regulation of food
intake.These variability parameters, which to a large extent, are genetically-related
and the result of thousands of years of adaptation to nutrient shortages,
have been survival factors for most humans. With the advent of Western societies
enjoying nutrient abundance, and allowing a sedentary lifestyle, these parameters
have become factors of dietary excess and obesity with all of the potential
associated disorders. This large variability in basal metabolism is easy
to illustrate: for example, calculations show that a 22-yea-old man, 1.80
m high and weighing 90 kg has a basal metabolism nearly twice that of a
58-year old woman weighing 45 kg and 1.60 m high (2014 kcal versus 1068
kcal). Considering current average physical activity of adults in France,
total energy expenditures and requirements amount to approximately 2200
kcal/day for men and 1800 kcal/day for women.
Proteins: excessive intake
Recommended nutritional intake of proteins is clearly less than 1 g/kg/day:
for a young adult, it is currently estimated at 0.8 g/kg/day. This intake
is largely covered, both quantitatively and qualitatively (essential amino
acids), by a diversified and balanced diet including meat and fish. In Western
countries, mean intake of protein is currently between two and five times
greater than the requirements!
A balance is required between animal and vegetable proteins, in particular
because of their associated nutrients: calcium, iron, zinc, vitamins A and
B12 for animal proteins, unsaturated fatty acids and antioxidant substances
(vitamins C, B9, carotenoids, polyphenols) for plant proteins.
Lipids: taking into account the qualitative aspects
The proportion of lipids in the diet should not exceed one third of total
daily energy intake, i.e. about 80g/day for a man and 67 g/day for a woman.
These quantitative recommendations mainly result from three characteristics
of dietary lipids: their high energy density, the lesser adaptation of their
oxidation to the quantity ingested (compared to carbohydrates), and the
rise in postprandial serum lipid levels when lipid intake exceeds 30% of
total daily energy intakes.
Qualitatively, lipids are the major components of cell membranes and of
many compounds such as steroid hormones. Among lipids, some polyunsaturated
fatty acids (PUFA) are essential: linoleic acid (n-6) and a-linolenic acid
(n-3), (the latter can be converted into long chain PUFA (LC-PUFA) by the
tissues), which are essential to the formation of biological membranes,
prostaglandins and leukotrienes. On a population-wide scale, a-linolenic
acid is associated with a decrease in coronary risk and LC-PUFA which, derived
from it, may decrease the frequency of some types of cancer (breast, colon,
prostate). High amounts of linoleic acid promote the growth of tumors: this
is why linoleic acid should not exceed 1/8th of lipid intake with an n-6/n-3
ratio which should not exceed 5.
Saturated fatty acids (SFA), the natural components of phospholipids, sphingolipids
and stored triglycerides, are essential to the formation of certain nervous
membranes, in particular myelin. Since high intake of SFA has been linked
to coronary mortality, SFA intake should not exceed one fourth of lipid
intake.
Carbohydrates: rehabilitating complex carbohydrates
Carbohydrate intake should account for at least half of the energy ration.
The recommendations suggest increasing the proportion of complex carbohydrates
and decreasing that of simple carbohydrates. Among complex carbohydrates,
fibers appear to play a major role: their intake in sufficient quantity
appears to decrease the risk of colon cancer and may have a preventive effect
on coronary mortality (in particular by decreasing LDL cholesterol). Yet
the regular decrease in legumes intake in the French population since the
early 20th century has resulted in a decrease of fiber intake by half, which
is currently well below recommended values (20 to 30 g/day). Thus, eating
food high in fiber (fruits and vegetables, cereals, pulses, etc.) should
be encouraged.
The recommended limitation regarding simple carbohydrate intake varies is
mostly based on the characteristics of foods rich in simple carbohydrates:
i.e. food high in fat, low in fiber, and often eaten as snacks ("empty
calories"). .
Vitamins and Minerals: the recommendations are changing
Changes regarding these micronutrients (summarized in Table 2) are
justified with regard to vitamins either because of the decrease in metabolic
needs (vitamins B1, B2, B3, B5, B8 and A), or based on new epidemiological
data (folates and vitamins B6, B12 and C).
Conclusion
Recommended nutrient intakes necessarily change in order to incorporate
new data. While these ANCs were especially viewed as a reference to be used
in nutritional surveys, which up to now had been too few, future advances
will focus on the accuracy and relevance concerning the evaluation of nutrient
needs in individual subjects, while taking their diversity into account.
Geneviève POTIER de COURCY
CNRS - ISTA/CNAM
Specific Recommendations
Children : A sufficient lipid intake
is necessary in young children for the formation of nervous
structures. On the contrary, excessive protein intake is suggested
in the pathogenesis of obesity. Relative iron deficiency is
the only type which has been documented in France.
Recommended nutrient intakes (ANCs) in children and adolescents,
except for energy and constitutional nutrients such as calcium,
are extrapolated from adult needs, most often referring to energy
needs. The only at-risk group in these age categories, which
often are overly- and sometimes inadequately nourished is that
of adolescents who frequently eat a diet which is not balanced.
Pregnant women : The adaptation
mechanisms are sufficient in most cases to ensure the pregnancy
and lactation needs without any problem. The risks of a deficiency
in vitamin D, iron, calcium and iodine in pregnant women are
known and are usually taken into account, but folate deficiency
continues to be the parameter of most concern because of the
fetal abnormalities it may cause (spina bifida). Very young
women (15 to 24 years of age) are the main at-risk group for
insufficient folate intake.
The elderly : An increase in calcium
intake in men and women over 50 years of age may help to prevent
osteoporosis. Starting at 75 years of age, it is necessary to
maintain a sufficient intake of vitamin D (whose endogenous
synthesis decreases with age at the same time as exposure to
the sun), proteins (1g/kg/day) and antioxidant vitamins (vitamins
C and E) whose needs increase. Adequate intake, without being
excessive, of folates, vitamins B1 and B6, water and fiber (non-irritant),
often insufficient, should also be provided.
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ANC 2001
ANC 1992 |
ANC 2001
ANC 1992 |
| |
Adult men
|
Adult women
|
| Vitamin A
(Retinol equivalent) |
800
1000 |
600
800 |
| -
b carotene (mg) |
2.4 |
1.8 |
| Vitamin
D (µg) |
510 |
510 |
| Vitamin
E (mg) |
12 |
12 |
| Vitamin
K (µg) |
45 |
45 |
| Vitamin
B1 (thiamine) (mg) |
1.3
1.5 |
1.1
1.3 |
| Vitamin
PP (niacin) (mg) |
14
18 |
11
15 |
| Vitamin
B6 (mg) |
1.8
2.2 |
1.5
2 |
| Folic
Acid (µg) |
330
300 |
300 |
| Vitamin
B12 (µg) |
2.43 |
2.43 |
| Vitamin
C (mg) |
110
80 |
110
80 |
| Calcium
(mg) |
900 |
900 |
| Phosphorus
(mg) |
750
800 |
750
800 |
| Magnesium
(mg) |
420 |
360
330 |
| Iron
(mg) |
910 |
16(<55
years of age)
18 |
| Iodine
(µg) |
150 |
150 |
| Fluoride
(mg) |
2.5 |
2 |
|
 |
Recommended nutrient intakes (ANC 2001) in vitamins
and minerals.
The previous ANCs (1992) are listed below the most recent values whenever
different.
Figure 1 (from the ANC 2001, as modified)
Bibliography
ANC 2001 : Apports nutritionnels conseillés pour la population française.
3e édition
CNRS/CNERNA/AFSSA. Tec et Doc Lavoisier, Paris, 2001, 605 pp.
The "Apports Nutritionnels Conseillés (ANC)" for the French population.
Sci. Alim 2001, 21(4) : 307-448
Hercberg S., Galan P., Preziosi P., Roussel A.M., Arnaud J., Richard M.J.,
Paul-Dauphin A., Briançon S., Favier A. .
Background and rationale behind the SU.VI.MAX study, a prevention trial
using nutritional doses of a combination of antioxidant vitamins and minerals
to reduce cardiovascular diseases and cancers.
Internat J Nutr Res. 1998, 68 (1): 3-20.
Conseil supérieur d'hygiène publique de France. Avis du 12 septembre 1995.
Les limites de sécurité dans les consommations alimentaires des vitamines
et des minéraux.
Tec et Doc Lavoisier. Paris. 1996, 172 pp.
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