The energy requirement of a person depends on many factors such as e.g. gender, height, weight, body composition and naturally on physical activity. A balanced, sufficient energy supply is demonstrated by a stable body weight.
The daily energy requirement of a women average in age, height and weight lies between 1800 kcal (sedentary lifestyle) and 2400 kcal (active lifestyle). A man of average age, height and weight requires between 2300 kcal (sedentary lifestyle) and 3000 kcal (active lifestyle).
The energy content of a food which is utilisable by man cannot be exactly determined, but is calculated by means of factors. The factors take into account that the human organism can only make use of a part of the energy present in a food.
In the Swiss Food Composition Database the energy content is given both in calories (kcal) as well as in kilojoules (kJ). The values are calculated using the conversion factors from the Swiss Ordinance on the labelling and advertising of foodstuffs (SR 817.022.21, dated 1.1.2012):
|Carbohydrates||4 kcal or 17 kJ per gramme|
|Protein (albumin)||4 kcal or 17 kJ per gramme|
|Fat||9 kcal or 37 kJ per gramme|
|Alcohol||7 kcal or 29 kJ per gramme|
|Dietary fibres||2 kcal or 8 kJ per gramme|
The carbohydrates are a large group of nutrients that are mainly found in vegetal foodstuffs, but also in dairy products. Quantitatively, vegetal starch is the most important carbohydrate. Other carbohydrates are glucose, dextrose, fructose), lactose, maltose and saccharose.
The daily energy requirement should be limited to 45-55% of carbohydrates.
Information on the available carbohydrates and on starch and sugar* can be found in the Swiss Food Composition Database. Starch and sugar make up the major part of the available carbohydrates. The available carbohydrates are generally calculated using the following formula: Carbohydrates, available (g/100g) = 100 – protein (g/100g) – fat, total (g/100g) – water (g/100g) – ash (g/100g) – dietary fibres (g/100g)
* The term “sugar” includes all mono and disaccharides, e.g. glucose, fructose, lactose, saccharose.
Dietary fibres (also known as roughage) are indigestible, vegetal nutrients that inter alia have a positive effect on digestion. One differentiates between soluble and insoluble dietary fibres. Soluble dietary fibres are for example beta-glucan (e.g. in yeast) and pectin (e.g. in apples). Nuts and wholemeal grain provide principally insoluble dietary fibres (e.g. cellulose). Refined products, such as e.g. white flour, contain almost no dietary fibres.
Adults should eat at least 30 g of dietary fibres per day. An adequate intake of liquid optimises the positive effect on digestion. In contrast, not enough liquid intake coupled with a high dietary fibre intake can lead to constipation.
Fats are found in vegetal as well as in animal foodstuffs and are a nutritional source of energy and essential fatty acids*. Moreover, fat-containing foodstuffs are an important source of fat-soluble vitamins (A, D, E, K).
The daily fat intake should represent 30-40% of the energy intake. From experience at least half of the fat intake is met by “hidden” fats (such as e.g. from dairy products, eggs, meat, nuts etc.).
The data on fat in the Swiss Food Composition Database correspond to the total fat content (incl. triglycerides, cholesterol, phospholipids etc.). The sum of the three fatty acid groups (saturated, mono-unsaturated and poly-unsaturated) is consequently less than the total fat content.
* Fatty acids are the most important components of fats. They can be subdivided into three groups: saturated, mono-unsaturated and poly-unsaturated fatty acids. The various fatty acids and fatty acid groups exhibit different effects and functions in metabolism.
Cholesterol is a fat-related substance which is found only in animal foodstuffs (e.g. offal, egg yolk, butter) and can itself be produced by the human organism. Cholesterol fulfils a number of important tasks, e.g. the synthesis of vitamin D and of various hormones.
Cholesterol from the diet plays only a minor role in influencing the blood cholesterol level. Cholesterol in the blood originates mainly from the body’s own production and not from the diet. From today’s scientific viewpoint, limiting the intake of cholesterol is therefore no longer justified.
The intake should be ca. 300 mg per day.
Protein, also known as albumin, supplies the body with amino acids* that are required for the synthesis of the body’s own proteins (e.g. muscle protein, hormones etc.). Proteins from animal foodstuffs such as meat, fish, eggs, milk and dairy products tend to be of higher value than vegetal proteins (e.g. from cereals, potatoes, nuts), as they contain a more optimal spectrum of amino acids. However, vegetal proteins can be greatly enhanced by combining them or in combination with animal proteins.
The protein intake should contribute 10-20% of the total energy. The minimum daily protein requirement is 0.8 g per kilogramme body weight. The intake should not exceed 2 g per kilogramme per day because health disadvantages cannot be excluded with a higher protein intake.
Pursuant to the Swiss Ordinance on the labelling and advertising of foodstuffs (LKV, SR 817.022.21, dated 1.1.2012) the protein content is calculated in the Swiss Food Composition Database by using the formula “nitrogen content x 6.25”. The use of a uniform factor of 6.25, however, means that for some foodstuffs the actual protein content is either overestimated or underestimated. Data on the specific conversion factors of nitrogen to protein can be found inter alia in FAO/WHO publications, e.g. Food energy – methods of analysis and conversion factors, 2003 (see Table 2.1).
* Amino acids are the building blocks of the proteins. They are strung together into long chains. The sequence and type of the amino acids determines the function of the protein.
Alcohol is an energy-supplying nutrient that is present in exceedingly small amounts in natural foodstuffs. The major sources of alcohol are alcoholic drinks and products prepared from them.
Recommendations for alcohol intake do not exist. Acceptable daily quantities are considered to be 10 g for women and 20 g for men. Children, adolescents, pregnant women and breast-feeding women should dispense completely with alcohol.
The alcohol content is listed in the Swiss Food Composition Database in grammes per 100 ml or 100 g. These values are lower than the volume per cent figures for alcoholic drinks. A schnapps with 40 vol % contains about 32 g alcohol per decilitre.
Water is present not only in drinks and soups but also in most foodstuffs. Fruit and vegetables in particular have a high liquid content (up to 95%).
Water makes up more than half of the human body and the daily losses of water (mainly from the kidneys, skin, lungs) have to be regularly replenished. An inadequate supply of liquid can lead to reduced physical and mental capacity as well as to constipation.
Daily requirements for water are ca. 2.5 litres. However, 1 to 2 litres per day of fluid intake suffice. The remainder is covered by the food intake.
Vitamin A is a fat-soluble vitamin which is present only in animal foodstuffs. Vegetal foodstuffs contain the vitamin A precursor (provitamin A) beta carotene that the body can partially convert into vitamin A.
Women require 0.8 mg, men 1.0 mg vitamin A per day. The tolerable upper intake level is considered to be 3 mg per day.
The Swiss Food Composition Database lists the content of all-trans-retinol as well as the total vitamin A activity (incl. contributions from provitamins such as e.g. beta carotene) in equivalents.
The equivalents are calculated as follows:
Vitamin A values are occasionally also listed in International Units (IU). The following conversion factors then apply: 1 IU ≙ 0.3 μg-RE or 1 μg-RE ≙ 3.3 IU
Beta carotene is a fat-soluble vitamin which is found in almost all plants. Principally in yellow, orange and green fruits and vegetables. In the body it can be converted into vitamin A.
The daily requirement is estimated to be 2-4 mg. The tolerable upper intake level is considered to be 10 mg per day.
The Swiss Food Composition Database lists the content of beta carotene as well as the beta carotene activity (incl. contributions from other provitamin A carotenoids if data is available) in beta carotene equivalents.
The beta carotene equivalents are calculated as follows: Beta carotene-Equivalent (BCE) = 1 x beta carotene (µg) + 0.5 x other provitamin A carotenoids (µg)
Vitamin B1 (Thiamine)
Vitamin B1 is a water-soluble vitamin and is found in animal as well as vegetal foodstuffs.
Women require 1.0 mg, men 1.2 to 1.3 mg per day. There are no known risks of an overdose.
Vitamin B2 (Riboflavin)
Vitamin B2 is a water-soluble vitamin and is found in animal as well as vegetal foodstuffs. As a result of its intensive colour, Riboflavin is added to many foodstuffs as a colorant – declared as E101 colorant.
Women require 1.0 to 1.1 mg, men 1.3 to 1.4 mg per day. There are no known risks of an overdose.
Vitamin B6 (Pyridoxine)
Vitamin B6 is a water-soluble vitamin and is found in animal as well as vegetal foodstuffs.
Women require 1.2 mg, men 1.5 mg per day. The tolerable upper intake level is considered to be 25 mg per day.
Vitamin B12 (Cobalamine)
Vitamin B12 is a water-soluble vitamin and is found only in animal foodstuffs. A specific glycoprotein of the stomach, the “Intrinsic Factor” is required for its absorption in the intestines.
The daily requirement is 3 μg for both men and women. There are no known risks of an overdose.
Niacin (previously also known as vitamin B3 or PP) includes nicotinic acid and nicotinamide. Niacin is a water-soluble vitamin of the B-group and is found both in vegetal as well as animal foodstuffs.
Women require 11 to 13 mg, men 15 to 16 mg per day. The tolerable upper intake level for adults is 35 mg.
The niacin requirement is supplied not only from the intake of niacin but also from the body’s own synthesis (in the liver and kidneys) from the essential amino acid tryptophan. 1 mg of niacin can be formed from ca. 60 mg tryptophan (= 1 mg Niacin Equivalent). The contribution from the amino acid tryptophan to meet the niacin requirement is not considered in the Swiss Food Composition Database.
Folate is a water-soluble vitamin of the B-group and is found both in vegetal as well as animal foodstuffs. Folate is ingested considerably better from animal foodstuffs than from vegetal sources.
Folic acid is the name for the synthetic form of this vitamin and is used for manufacturing fortified foodstuffs or for vitamin supplements.
Women as well as men require 300 μg per day. There are no known risks of an overdose.
Pantothenic acid (previously known as B5) is a water-soluble vitamin of the B-group and exists in virtually all foodstuffs.
Women as well as men require 6 mg per day. There are no known risks of an overdose.
Vitamin C (ascorbic acid)
Vitamin C is a water-soluble vitamin and is found exclusively in vegetal foodstuffs.
Women require 95 mg, men 110 mg per day. The tolerable upper intake level is considered to be 1000 mg per day.
Vitamin D (Calciferol)
Vitamin D is a fat-soluble vitamin and includes the forms vitamin D2, vitamin D3, 25(OH) vitamin D3 and 1,25(OH)2 vitamin D3. The most important representative is vitamin D3 (= cholecalciferol) that is found only in animal foods. Humans are themselves able to synthesise vitamin D3 with the aid of UV-B light.
Women, like men, require 15-20 μg (600-800 IU) per day (from food, supplements and/or endogenous production). The tolerable upper intake level for adults is 100 μg (4000 IU) per day.
In the Swiss Food Composition Database the total value for the vitamin D activity is listed, wherein the fraction originating from the 25(OH) vitamin D3 is practically not taken into account due to the paucity of data. This leads to an underestimation of the total vitamin D activity, in particular because 25(OH) vitamin D3 is five times more active than vitamin D3.
|1 μg Vitamin D =||1 μg Vitamin D2 (ergocalciferol)|
1 μg Vitamin D3 (cholecalciferol)
0.2 μg 25(OH) Vitamin D3
Vitamin D values are occasionally also listed in International Units (IU). The following conversion factors then apply: 1 IU ≙ 0.025 μg or 1 μg ≙ 40 IU
Vitamin E is a fat-soluble vitamin which is mainly found in vegetal foods.
Women require 12 mg, men 13 to 15 mg per day. The tolerable upper intake level for adults is 300 mg per day.
Vitamin E includes eight forms: alpha-, beta-, gamma-, delta-tocopherol as well as alpha-, beta-, gamma-, delta-tocotrienol. The activity of the various forms is set as a ratio to the activity of alpha-tocopherol and expressed as alpha-Tocopherol Equivalents (aTE). The activity of the individual forms has not yet been conclusively researched, particularly in the case of the tocotrienols.
The values for vitamin E are listed in the Swiss Food Composition Database as mg aTE. However, which of the eight forms were used to calculate the aTE is not known for all of the foodstuffs. Consequently, an underestimation of the total vitamin E activity is probably possible.
Vitamin E values are occasionally also listed in International Units (IU). The following conversion factors then apply: 1 IU ≙ 0.67 mg or 1 mg ≙ 1.49 IU
Sodium is a mineral substance. Sodium is naturally occurring in almost all foods and is frequently artificially added – mainly due to the addition of sodium chloride (table salt or cooking salt).
An adequate intake of sodium for men and women equates to 1500 mg per day. This corresponds to about 3.8 g of salt and could easily be met without the use of table salt. No advantages are expected from an intake exceeding more than 2300 mg (equivalent to 5.8 g of salt), which could possibly even lead to disadvantages.
Potassium is a mineral substance. Vegetal foods are the main sources.
An adequate intake of potassium for men and women equates to 4000 mg per day.
Chloride is a mineral substance, which is a constituent of table salt or cooking salt (= sodium chloride).
An adequate intake of chloride for men and women equates to 2300 mg per day.
Calcium is a mineral substance. Prevalent sources in our cultural area are dairy products and some mineral waters.
Women, like men, require 1000 mg per day. The tolerable upper intake level is considered to be 2.5 g per day.
Magnesium is a mineral substance.
Women require 300 to 310 mg, men 350 to 400 mg per day. The tolerable upper intake level from supplements or fortified foodstuffs is considered to be 250 mg per day (in addition to the natural magnesium levels from food).
Phosphorus is a mineral substance.
Women, like men, require 700 mg per day. The tolerable upper intake level is considered to be 3.5 g per day.
Iron is a trace element and exists in two forms: haeme-iron and non-haeme-iron, wherein haeme-iron can be more efficiently assimilated. The principle sources for haeme-iron are meat and fish. Eggs and dairy products contain mainly haeme-iron and vegetal foodstuffs contain exclusively non-haeme-iron.
Women require 10 to 15 mg, men 10 mg per day.
Iodine is a trace element that is present only in very minor quantities in the majority of foodstuffs. The supply of iodine for the Swiss population cannot be ensured through nutrition, which is the reason why the use of iodised table salt (20 mg/kg) is recommended.
Women, like men, require 150 μg per day. The tolerable upper intake level is considered to be 500 μg per day.
The iodine content of a processed foodstuff such as e.g. cheese, bread and sausages and cold meat depends strongly on whether iodised table salt has been added or not. The individual iodine content of a salted product can therefore vary from the indications in this database.
Zinc is a trace element.
Women require 7 mg, men 10 mg per day. The tolerable upper intake level is considered to be 25 mg per day.