Nutrients ABC

Use this site to discover more about the nutrients and active ingredients that keep our organism running. By clicking on the different ingredients, you can find out interesting information about the importance of these for the human body, as well as the recommended daily dosage. This site is made possible by the friendly support of the Institute for Nutritional Science and Food Chemistry of the University of Bonn.

To maintain its functions, the human body has to be supplied with enough energy through the intake of food. Important nutrients that the body needs for energy are carbohydrates, fats and proteins. The ideal intake of these per day is as follows:

• 50 to 55 % carbohydrates
• 20 % proteins
• <30 % fats

These nutrients used by the body differ greatly in how much energy they contain: Fat has the highest fuel value with 9kcal per gram.

• 1 g of protein: 17 KJ / 4 kcal
• 1 g of carbohydrates: 17 KJ / 4 kcal
• 1 g of fat: 37 KJ / 9 kcal
• 1 g of alcohol: 29 KJ / 7 kcal

Carbohydrates like sugar, starch and cellulose are not essential like vitamins, but serve as one of the most easily available sources of energy (its energy content is, like every protein, 17,2 kJ/g or 4,1 kcal/g). Depending on the number of sugar „building blocks“, it differs between simple sugars (monosaccharides), and component sugars (oligosaccharides) which have between two and nine simple sugar units and complex sugars (polysaccharides). Among the compound sugars, disaccharides are especially important for nutrition.

The average daily dosage of carbohydrates is 5g per kg of body weight. Too little intake of carbohydrates can be balanced out somewhat by nutritional fats. If fats and carbohydrates are missing as energy sources, protein is metabolized. Long-term deficiencies can lead to loss of muscle mass, whereas a sufficient suppliment of carbohydrates can have a protein-saving effect.

Simple sugars like glucose, fructose and galactose can be found in fruit and honey. Important compound sugars in foods are milk sugar (lactose), malt sugar (maltose) found in beer, and cane and beet sugar (saccharose) which can be purchased as regular household sugar. Complex sugars can be found in the form of starch in all potatoes, rice, and grains.

Nutritional fats are the number one energy source, because of their high energy content of 37 kJ/g (= 9 kcal/g) – twice as much as carbohydrates or protein. Direct energy needs are usually covered by carbohydrates, because burning fat is, despite the high energy gains, more difficult for the organism. Fat deposits are usually seized after 30 minutes of continous bodily strain. The body stores extra energy from nutrition in deposits. Weight gain is the result. Nutritional fats are usually triglycerides (reserve fat) and in the case of animal fats, cholesterol.

Trygliceride

The difference in triglycerides depends on the number of double bonds in the chain of fatty acids. Saturated fats have no double bonds (like stearic acid and palmitic acid) and mono or polyunsaturated fats have either one (oelic acid) or multiple (linolic acid) double bonds. With the unsaturated fats, there is a difference depending on the position of the double bond in the molecule – omega-3, omega-6 and omega-9 fatty acids. Omega-3 and omega-6 fatty acids are essential for humans and have to be consumed through food. Omega-3 fatty acids include linseed oil, soy oil and rapseed oil; omega-6 fatty acids include safflower oil and sunflower oil. The more double bonds there are, the more reactive and sensitive the fats are to oxygen and heat. Because of this, Safflower oil should not be used for frying because of its high linolic acid content. For the human body, it's important to remember that the unreactive saturated fats usually end up in deposits, whereas the reactive unsaturated fats are used for organic building processes. Besides its role as an energy carrier, nutritional fats absorb vitamins A, D, E, and K into the organism. Polyunsaturated fats also have a protective effect for the cardiovascular system and a positive effect on skin appearance.

The importance of Fat for health is dependant upon its saturated, monounsaturated, and polyunsaturated fat content. Many plant fats have a high polyunsaturated fat content that is essential for the body, whereas animal fats contain mostly saturated fats and monounsaturated fats that the body can also produce itself. Consuming mono or polyunsaturated fats in the place of saturated fats has a positive effect, because it helps the liver absorb more dangerous LDL cholesterol. More dangerous LDL cholesterol can therefore be taken out of the blood stream and lower cholesterol levels. Monounsaturated fats (olive oil, rapseed oil) are especially important concerning heart disease and should (like in mediterranean kitchens) be on the menu every day. Ideal proportions are as follows:

• At least 1/3 monounsaturated fats
• At least 1/3 polyunsaturated fats
• At most 1/3 saturated fats

About 25-30% of your energy intake should be covered by fats. This means a daily fat intake of about 0,7 - 0,9 g / kg body weight, whereby the fat intake naturally depends on total energy needs, which varies depending on age, body weight, bodily strain and climate.

Generally, the use of fat in western industrial societies is too high – because of this, fatty food consumption should be reduced. Too much consumption of fat with high unsaturated fatty acid content can lead to strong development of deposits and obesity, which can bring on many health problems (mechanical overload in standing and moving, low physical ability, psychological problems as well as libido or potency disfunction and a high risk for many diseases such as diabetes, high blood pressure, heart attack, etc). Too little fat, which could come from a long-term fat free diet or fat-free artificial nutrition is dangerous because of the lack of essential fat oils. Consequences include for example changes in skin, hair loss or growth problems.

Cholesterol

Next to Triglycerides, cholesterol is also one of the nutritional fats. It is non-essential because the liver and other peripheral tissue cells can synthesize it. 66% of the cholesterol in the human body is produced in this way, and about 34% is ingested through food products from animals (food products from plants are practically cholesterol-free)

Cholesterol serves to build steroid hormones (ex. estrogen, progestagens and androgens) in the human body, as well as producing bile acids in the liver and helping build new tissue. Cholesterol is not soluble in water. In order for it to be better transported though the blood stream, it is encased in a layer of Lipoprotein. Lipoprotiens differ depending on the thickness of the layer. Most important are the thin lipoproteins (Low Density Lipoproteins or LDL) and the thicker Lipoproteins (High Density Lipoproteins or HDL).

Too much LDL cholesterol can be dangerous, because it increases the risk of clogged arteries (atherosclerosis). This leads to a narrowing of the blood passages that puts the circulatory system in danger, or even to a complete closure of the artery (many times this can lead to a heart attack). HDL cholesterols, on the other hand, are a „useful“ cholesterol. It has the special ability to remove the LDL cholesterols that are attached to the blood vessel walls and transport them to the liver. There, it can be made into bile acid and can be expelled with the bile in the intestines. Because of this, HDL cholesterol protects you from atherosclerosis.

Often, a poor diet (too much fat and cholesterol) is the reason for higher cholesterol levels, but also genetic disorders of the metabolism, thyroid, kidneys or liver could be at fault. Through a healthy diet, the risk on atherosclerosis can be actively decreased.

Proteins are essential building and repair materials for human cells and are utilized in very diverse ways for the human metabolism. They occur in the human body, among other things, as a component of diverse hormones and enzymes and are made of different building blocks, the so-called amino acids, whose number of proteins varies greatly (Oligopeptides have, for example, less than 10 amino acids, polypeptides 10-100). To maintain its structure and function, the human body needs 20 differnt kinds of amino acids, from which it produces its own proteins to carry out certein functions (this production is also known as protein synthesis). Half of these amino acids must be included in the diet because the body cannot produce these alone.

Protiens are not all the same – there are strong differences in „quality“. Proteins differ depending on their biological value, or by how much of the body's proteins can be synthesized through the intake of 100 grams of this particular type. Animal proteins are usually better in this respect (value 80-100, that means that from animal protein, 80-100g of body protein can be synthesized) than plant proteins (60-80).

For the transfer of energy, proteins are secondary: with an energy density of 17 kJ/g (= 4 kcal/g), proteins are about as „energetic“ as carbohydrates and only about half as much as fats. They are only taken as an energy source if the body's carbohydrate and fat resources are used up.

A daily protein intake of about 0,8-1g/kg body weight is recommended (that means a protein proportion of about 12-15%). Young people, pregnant women and professional sportspersons are recommended a higher protein intake. Because the essential amino acids are taken in through the diet and cannot be produced by the body, not only the amount but the different types for proteins are important – what amounts of the necessary amino acids are ingested.

Symptoms of a protein deficiency could be:

• lowered physical and mental ability
• fertility problems or problems with the immune system (a larger risk for infections)
• speeding up of the bodily aging process
• noticible adema (stored liquid in the tissue) with massive protein deficiency

Too much protein in the diet can stress the liver and kidneys and can disrupt the calcium content of the body.

Plant proteins can be found in grains, soy and legumes; animal proteins are in eggs, dairy products, meat and fish. The requirement for amino acids can also be attained through purely plant-based (vegan) diets, but it is important to mix different plant protein sources. A mix of the same proportion of beans and corn contains a biological value of about 100. This is even simpler for vegetarians who can also incorporate milk products into their diet.

Vitamins

vitamins, like minerals, are essential substancesthat must be regularly added to the diet because they are, with few exceptions, not produced by the body or produced in very little amounts. They are not used as building materials for bodily substances or as energy souces, but are needed to keep certain body processes running, whereby each vitamin has a special role in the organism. In this way, they influence this production of body tissue, the immune system, the production of hormones or even enzymes, which play an important role in countless life processes.

Man unterscheidet Vitamine gemäß ihrer Lösungseigenschaften in zwei Gruppen: Fettlösliche Vitamine (Vitamin A , Vitamin D , Vitamin E und Vitamin K ) und wasserlösliche Vitamine (Vitamin C und die B-Vitamine). Fettlösliche Vitamine können sich ohne Hilfsstoffe (quasi eine Hülle) nicht in wässrigen Gebieten des Körpers (z.B. im Blut) fortbewegen und halten sich daher in einigen Organen und Geweben (z.B. Zellmembran) auf. Wasserlösliche Vitamine hingegen verteilen sich auf alle wasserhaltigen Bereiche des Körpers, also quasi fast überall (zwischen den Zellen, im Blut, etc.). Während fettlösliche Vitamine in der Leber gespeichert werden können, werden überflüssige waserlösliche Vtaimine einfach wieder ausgeschieden (Ausnahme bildet das Vitamin B12).

The differences in the solubility of the vitamins categorizes them in one of two groups: the fat soluble vitamins (Vitamins A, D, E, and K) and the water soluble vitamins (vitamin C and the B vitamins). Fat soluble vitamins can't move in liquid areas of the body (ex. In the bloodstream) without helper substances and therefore remain in a few organs and tissues (ex. Cell membranes). Water soluble vitamins, on the other hand, can spread freely in all parts of the body that contain water; practically everywhere (between the cells, in the blood stream etc.). While fat soluble vitamins can be stored in the liver, extara water soluble vitamins are simply expelled from the body (discluding the exception of B12). Vitamins are sensitive to other influences such as heat, air, or even light. Too much cooking, intensive peeling or washing, cooking at too-high temperatures or long storage should be avoided to preserve the maximum vitamin content. Deep freezing or steaming are harmless for the vitamin content.

Through a balanced diet, the vitamin and mineral needs of the body can be covered naturally without problems. Extra vitamin suppliments are not necessary.

Fat soluble vitamins

Vitamin A

The fat-soluble vitamin A and its precursor, beta-carotene, (provitamin A, which is transformed into vitamin A by the body when necessary) carry out many important functions for the human organism. The following functions it carries out are especially important:

• Vision (vitamin A, in combination with the protein opsin, forms visual purple, also known as rhodopsin)
• Growth and formation of skin, mucus membranes and cartilage tissue (Vitamin A is responsible for the function and dispersion of epithelial cells)
• Activation of natural cell protection (provitamin A binds itself to oxygen and works as an antoxidant to deactivate aggressive free radicals and other oxidizing particles, which prevents the oxidization of important substances such as proteins, fatty acids and nucleic acids. This protects damage to cells, cell walls and cell nuclei, and likely protects from cancer)
• Growth
• Normal reproduction (vitamin A is necessary for the development of the placenta and the foetus, as well as the production of testosterone)

Symptoms of deficiency, sometimes only noticeable after months, include the following:

• Vision impairment (vision disturbances such as night blindness, quick „tiredness“ of the eyes, and sensitivity to light)
• Dryness and flakiness of the skin or mucus membranes
• Tissue damage
• Growth disorders in children
• Weakened immune system
• Respiratory problems, diarrhea
• Fertility and reproductive problems

Vitamin A deficiency could be one possible catalyst for the outbreak of cancer, heart disease or cataracts.

The recommended daily dose of Vitamin A is about 0.9 mg and can be directly found in food products from animals (fish, liver, eggs, dairy) or through the provitamin A in plant products (ex. Carrots, peppers, apricots, cherries, spinach, cabbage and broccoli).

Vitamin A can be stored in the liver and transported to cells through the blood. Because an overdose cannot simply be expelled like water soluble vitamins, too much vitamin A (more than 30 mg a day) can cause damage (short term pain, dizzyness or vomiting or long term symptoms such as weakness, exhaustion, dry skin, hair loss, etc). With provitamin A, there is no risk of overdose.

Vitamin D

In contrast to all other vitamins, vitamin D (one of the fat soluble vitamins) can be produced by the human body. Under UV light, cholesterol materials located in the skin transform into vitamin D, which can them be transported to the necessary locations through the blood stream. In addition, large amounts of vitamin D can be absorbed through the intestinal walls as a result of proper nutrition.

Important functions are:

• Cooperation in the mineralization of teeth and bones (together with calcium, vitamin D helps keep bones and teeth healthy and stable)
• Directs the intake (resorption) of calcium and phosphate from the intestines, their transport through the blood stream and their installation into the bones and teeth.
• Disorders in the production of bones can lead in the worst case to rickets (weakening and deformation of the bones because of problems in bone metabolism or an imbalance of calcium and phosphates and poor mineralization) in children and osteomalacia (softening and bending of the bones through poor mineralization) or osteoporosis (slow deterioration of the bones, where they become porous and fragile) in adults.

Older people especially lean toward a vitamin D deficiency, because the human organism synthesizes less vitamin D with old age. Here, it is important to increase vitamin D intake.

Up to 90% of the necessary vitamin D can be produced by the body itself, as long as UV light shines on the skin. Through the diet, relatively little vitamin D is ingested. The German Society for Nutrition e.V. recommends 5 µg Vitamin D daily, for infants and people older than 65, twice the amount – 10 µg. Vitamin D can only be found in high concentration in the liver fat of sea fish, but it is added during the production of many different foods (ex. Margarine or baby food).

An overdose of Vitamin D through light exposure or through diet is hardly possible, because the human organism regulates the production of the vitamin, and relatively low amounts of vitamin D in foods prevent too much vitamin D in the diet.

Vitamin E

Vitamin E, which can be found only in plants, contain many different types of chemical bonds (tocopherols) which the body can utilize better or worse, depending. Because of this, different sources of E vitamins have very different in their biological effectivity. The natural D-alpha-Tocopherol is the most effective in humans. About 70% of the vitamin E ingested is expelled from the body, about 30 percent is absorbed through the intestines and dispersed throughout almost all tissues in the body. The function of tocopherols are not completely known. They do protect organs from dangerous oxidation and stabilize the cell membranes. Vitamin E is also an important antoxidant, that sits on the cell membrane and protects the cell from free radicals and oxygen radicals which are a possible catalyst for cancer. Vitamin E is also involved in fat metabolism: together with other antoxidants, it prevents the deterioration of storage fat, membrane fat and fat proteins through lipidperoxidation. Other functions include supporting the immune system and prevention of clumping in blood platelets.

Deficiency symptoms could include:

• Tiredness and lack of concentration
• Inefficiency and muscle weakness
• Weakening of the immune system
• Nervousness, irritability
• Limp skin
• Age spots
• Weakness of vision

In healthy people, a deficiency in vitamin E rarely occurs because it is found in many different foods, and the recommended daily dose of 6-8 mg is easily covered (if many unsaturated fats are ingested in the diet which impair the absorption of vitamin E in the intestines, the daily dose raises to about 12-14 mg). Smokers, people under heavy stress and people with weakened immune systems also have a higher need for vitamin E. Because the vitamin is stored in body fat, these reserves are utilized next of the intake of vitamin E stops. Because of this, deficiencies only occur after a long period of time.

Vitamin E can be found in large concentrations in all types of plant oils (wheat germ oil, soy oil, corn oil, sunflower oil, etc.) but also in butter, nuts, and vegetables (beans, cabbage, asparagus).

Vitamin K

Vitamin K is a fat soluble vitamin that is involved with the production of bodily proteins and the synthesis of blood clotting factors. Because of this, a deficiency of vitamin K can lead to an increased tendency to bleed. Together with proteins and calcium, it also has a positive effect on the formation and maintenance of bones.

The bacteria of the intestinal flora are able to produce large amounts of vitamin K2 (Menachinon), which covers half of the daily requirement. The rest is ingested as part of the diet. Plants produce vitamin K1 (Phyllochinon) – high content can be found in all green parts of plants (ex. green vegetables, head lettuce, broccoli, spinach) in different types of cabbage (cauliflower, brussel sprouts, red and green cabbage) as well as in soy and rapseed oil. A vitamin K deficiency is practically unknown and if they do occur, it not a result of poor diet, but of illness or as a side effect of certain medications (e.x. Antibiotics).

Water soluble vitamins

Vitamin B1

The water soluble thiamin belongs to the B-vitamin group and is dispersed throughout the entire healthy human body, in the major organs as well as in the tissues and muscles. It is a co-enzyme with many different uses for carbohydrate and fat metabolism, it helps produce energy from ingested food, and helps with specific functions of the nervous system.

Deficiency symptoms could include:

• Low appetite and weight loss
• Sleep and concentration disorders
• Psychological lability (poor concentration, irritablity, depression)
• With long-term deficieny: muscle weakness and heart/circulatory disorders
• With heavy deficiency: Beriberi (neurological disorders, muscle atrophy and heart insufficiency)

A light deficiency of vitamin B1 also occurs occasionally in the central European diet (ex. through avoidance of whole wheat products) – heavy deficiencies mostly occur in third-world countries, in combination with alcoholism or through extremely poor diet.

The German Society of Nutrition e.V. recommends a daily dose of 1.0 – 1.3 mg for adults. When under stress, in pregnancy or nursing, or competitive sports players, the requirement could be between 5 – 10 mg. An overdose is hardly possible because unused vitamin B1 is expelled through the kidneys.

Vitamin B1 is only found in small amounts in most foods. The highest concentrations, as with the other B-vitamins, can be found primarily in whole grains and rice. Other plant sources include legumes, potatoes, fruit and vegetables. With animal products, thiamins can be found in low-fat pork. If the vitamin is ingested from a plant source, the body can utilize it directly; if it is from an animal source, it must first be broken down by enzymes.

Vitamin B2

Vitamin B2-- Riboflavin and its bioactive variants (different flavins) can only be produced by plants and microorganisms. In nature, it occurs as yellow plant material, but is also accumulated in animal tissue. As a co-enzyme, Vitamin B2 plays an important role in the entire metabolism of carbohydrates, fats, and amino acids, and controls certain hormones in the nervous system. Vitamin B2 is good for the skin and eyes.

Deficiency symptoms could include:

• Inflammatory skin changes (particularly with Niacin deficiency)
• Diarrhea (particularly with Niacin deficiency)
• Inflamation of the mucus membranes
• Vision disorders
• Neurological disorders
• Tiredness
• Growth inhibition
• In worse cases: anemia

Deficiencies primarily occur in the third world. In middle europe, children are primarily effected by a light vitamin B2 deficiency (symptoms include inertness, skin problems or infection of the gums).

The daily requirement for adults is between 1.2 and 1.5 mg (children, pregnant or nursing women and alcoholics have a higher requirement), whereas the vitamin must be supplied by the diet because the body's reserves can only last for about 2-4 weeks. Because an overdose of vitamin B2 can be expelled through the liver, a high intake of B2 does not cause any damage. Important sources of vitamin B2 include meat, milk and dairy products, as well as grains and vegetables like cabbage, broccoli, peas and beans.

Important sources of vitamin B2 include meat, milk and dairy products, as well as grains and vegetables like cabbage, broccoli, peas and beans.

Niacin

Niacin is also part of the B-vitamin group and was also known earlier as vitamin B3. It can be found in many different foods and can by extracted from tryptophan (a protein component) by the body. Niacin contributes to energy extraction and carries out important functions in protein, fat, and carbohydrate metabolism. It is involved in many enzyme functions and has an antioxidating effect. Niacin is important for the regeneration of skin, muscles, nerves and DNS.

The recommended dosage of Nicacin that should be ingested daily in the diet is between 10 and 15 mg (the rest is produced out of protein by the body). Deficiencies, that usually appear in combination with other vitamin B deficiencies, are skin changes, diarrhea or even depression.

Good sources of Niacin are protein-rich foods like meat and fish. Whole grain products as well as different types of fruits and vegetables also contain Niacin, although animal sources can be better utilized by the body.

Vitamin B6

Many plants and microorganisms produce vitamin B6. It is absorbed through the intestines in animals and humans and transported to many organs and to the muscle structure through the blood stream. The term vitamin B6 includes a number of related chemical bonds. Vitamin B6 occurs in plants primarily as pyridoxin, and in animal bodies as pyridoxal and pyridoxamin. Vitamin B6 is involved many different reactions in all cells of the body. Especially important is its role in the metabolism of amino acids and in the production of body proteins from ingested proteins. It supports the immune system and helps with blood coagulation.

Deficiency symptoms could include:

• Skin changes
• Infections
• Disorders of the immune and nervous systems (overexcitability, sleep disorders)
• Cramps and
• In worst cases, anemia

B6 is found in many plant and animal sources, so a deficiency is unlikely. The average requirement for vitamin B6 is about 1.6-2.1 mg a day (other studies say that women need a dose of 1.2 mg per day, whereas men need 1.5 mg. Up to 3 mg can be used if necessary to prevent heart and circulatory diseases. The need for vitamin B6 grows as more protein is ingested.

Pyridoxin can be found in green cabbage, beans, spinach, broccoli, potatoes, legumes, whole wheat products, nuts, bananas, pork, poultry, and liver.

Vitamin B12

B12 is almost exclusively produced by microorganisms. In ruminant animals, large amounts vitamin B12 produced by these microorganisms end up in the meat of the animal. It is seldom found in plants. The amount of B12 produced by the intestinal flora of humans is not nearly enough to cover the daily requirement, because it is hardly absorbed into the body. Small amounts of B12 can be found in some plant products like sauer kraut or even beer, because microorganisms play a part in their production.

Vitamin B12 is soluble in water and even though it is only needed by the body in very small amounts, it still carries out important functions. It is a component in some enzymes and therefore needed, among other things, for the production of red blood cells (Erythrozyten). In addition, it supports cell growth and effects the regeneration of mucus membranes. Also, it is important for the forming and decomposition of amino acids in the context of protein metabolism and for the nervous system. Because it helps transform protentially dangerous homocystein into methionin in the circulatory system, B12 can help to decrease the risk of heart disease.

An advanced deficiency of vitamin B12 can lead to anemia with charachteristically overlarge blood cells and damage to the nervous system (memory weakness or even dementia). Because B12 can be stored in the liver and to some degree in the muscles, a deficiency only appears after a long period of time. In central Europe, there is usually enough B12 in the diet, although vegans, older people, and alcoholics are at risk.

The human body uses about 2,5 µg Vitamin B12 per day, and about this much should be ingested through the diet. In special cases, for example during pregnancy or breastfeeding, an amount of 3,5 bis 4 µg per day is recommended.

The largest B12 content can be found in liver and kidney, and in addition, Cyanocobalamin can be found in fish, eggs, milk and cheese.

Vitamin C

The water soluble vitamin C (the most prominent of all vitamins) is produced by many plant organisms and is therefore naturally prevalent. Because the human body cannot produce vitamin C, it must be ingested as part of the diet daily.

Vitamin C has many important functions for the human organism:

• As a water soluble antioxidant, it can react in liquid areas of the cells with agressive substances and through this, help the cells' ability to function. Vitamin C also inhibits the cancer catalyst Nitrosamine.
• Strengthening of the immune system
• Cooperation as a co-enzyme during the production of the components of ligament tissue, cartilage, teeth, gums and bones
• Improvement on the absorption of iron from the diet (important for blood production, ligament tissue and wound healing)

Typical symptoms of deficiency include:

• Drowsiness
• Susceptability to infection
• Lowered productivity
• Difficulty concentrating
• Poor wound healing.

Vitamin C cannot be stored by the body and must be ingested as part of the diet. The German Society for Nutrition recommends 100 mg per day for healthy adults. This reduces the risk of catching a cold, as well as the risk for cancer. With a balanced diet, this requirement is easily filled. Pregnant or nursing women, alcoholics, smokers, professional sportspersons and people under stress need more vitamin C per day (150 mg). An overdose in vitamin C is not dangerous, because it is expelled through the kidneys.

Vitamin C can be found in almost all fruits and vegetables. Especially rich sources of vitamin C include acerola, sea-buckthorn, currents, kiwi, tomato, pepper, and citrus fruits. Meat and fish have hardly any vitamin C content, and if any, in the liver and kidney.

Next to the main nutrients (carbohydrates, proteins and fat), the body needs other nutrient components in order to maintain certain functions. The body either cannot produce these components itself or only in very small amounts. These include the vitamins described above as well as certain minerals.

Minerals are essential non-organic nutritional substances which must be ingested as part of the diet. Like vitamins, minerals are not an energy source, which means they are not involved (or only seldomly) in energy metabolism. They are, however, used in many different functions in the human organism. These minerals can be placed into two categories depending on their function: Nutrients (ex. Calcium, phosphorus and magnesium) and regulating minerals (ex. Iodine, sodium, potassium, iron and chloride), although some minerals carry out both functions.

Depending upon the proportion of minerals in the body, they can also be separated into macrominerals, which are found in relatively large amoungs (> 50 mg per kg body weight) and trace minerals, which are found in smaller amounts (< 50 mg per kg body weight).

The macrominerals that are essential for the body include sodium, potassium, calcium, magnesium, chloride, phosphorus and sulfur. The trace minerals include manganese, chromium, molybdenum, cobalt, selenium, fluorine, iodine and iron (although iron lies between macro and trace mineral because of it's proportion in the body).

Calcium

Calcium is without a doubt the most important mineral for the human body and must be found in relatively high amounts in the diet. A grown man has about 1 kg of calcium stored (mostly) in his bones and teeth (only about 1% in the blood and tissue).

Calcium is necessary for the formation and preservation of bones, teeth and collagen fibers, and plays a role in blood coagulation (as coagulation factor IV), muscle contraction and in the saltatory conduction of the nerves (calcium controls the electrical action potential of muscles and nerves).

Because of its significance for the human skeletal system, an adequate calcium level in the body is of utmost importance. The daily requirement for children is 1200 mg Calcium per day, for adults, 1000 mg. Pregnant and nursing women have a requirement of 50% more.

Even in industrial nations, where many people have a more than satisfactory diet, the daily requirement for calcium is often not met. Food or drinks with a high phosphate content bind to calcium which lead to the calcium being expelled from the body.

A deficiency in calcium causes the decalcification of bones and teeth and increases the risk for osteoporosis in adults or rickets in children. Even a light deficiency in calcium can cause muscle problems in sportspersons such as shaking or cramping. Too much calcium is usually expelled and is therefore not harmful (exceptions are dialysis patients, whose calcium levels must be regularly checked).

The most important sources of calcium are milk and dairy products. Cabbage, broccoli, whole grains and legumes also have calcium in small amounts.

Chloride

Chloride, which is found together with sodium in regular kitchen salt, is an important component of stomach acids, which is responsible for the breakdown of nutrient proteins. Together with sodium and potassium, chloride helps in the regulation of the water supply in the body. It is located – like sodium – mostly in liquids outside of the body cells (ex. Blood liquid, but not in the blood cells) and regulates the osmosis, or liquid transfer, between cells. Chloride and sodium are also responsible for the formation and transfer of nerve impulses.

The German Society for Nutrition estimates the chloride requirement for adults at about 830 mg per day. Chloride is primarily ingested in the form of salt-containing foods. About 50% of salt intake comes from bread and baked goods, about 30% from meat and sausages. Fruits and vegetables, legumes, unsalted nuts and plant oils have very little chloride.

A chloride deficiency, which could lead to disorders in the acid-bases balance, is very rare. Mostly, the chloride content is over the requirement because of the large number of salt-containing foods. Extra chloride is expelled through the urine and sweat.

Potassium

Potassium is an important elektrolyte in the body that is almost exclusively found on the inside of cells. It is responsible for water balance between cells together with sodium and chloride, and takes part in the biosynthesis of protein (protein production) and in the utilization of carbohydrates. Together with sodium, calcium and chloride, potassium helps in heart muscle activity and is responsible for the excitability of muscle cells, or for muscle movement, but also for nerve cells.

Need for potassium depends on many parameters and an adiquate dosage for adults is estimated at about 2 g per day or more. For children and young people, the German Society for Nutrition recommends 1 or 2 grams. Potassium occurs in many foods, so that the daily requirement is usually filled. Causes of a potassium deficiency could include vomiting or diarrhea, alcohol abuse, too high salt intake or dehydration because of too little water intake.

A potassium deficiency can bring about a variety of problems including:

• Disorders in elektrolyte balance
• Muscle weakness, cramping or atrophy
• Circulatory disorders
• Drowsiness
• Headaches
• Dizzyness

Important sources of potassium include especially plant based foods (grain, potatoes, green vegetables, fruits like banana, apricots, and plums) but also milk and dairy products as well as meat and fish.

Magnesium

The average adult has about 25 grams of magnesium stored up in his body, more than half of which is located in the bones, and other large amounts in the interior of cells (only about 1% is in the blood).

Magnesium doesn't just play a large role in the formation and preservation of our bones and teeth, but also in the metabolism of proteins, fat, and carbohydrates, as well as in processing energy sources. Furthermore, it helps control muscle and nerve function. A deficiency in magnesium can primarily be noticed through muscle spasms or cramps.

The daily recommended dose of magnesium for adults, says the German Society for Nutrition, between 300-400mg. A higher dosage is recommended for sportspersons, diabetics, alcoholics and older people, who often do not drink enough liquids. It is almost certain that the daily requirement of magnesium is covered by a normal diet, but with illness, poor nutrition, or in older people, a deficiency could appear.

Symptoms of a magnesium deficiency could include:

• Muscle and calf cramps
• Uneasiness, dizziness, concentration problems, headaches
• Heart disruptions such as racing heartbeat or cramps of the heart muscles
• Digestive problems (nausea, vomiting, diarrhea)

In healthy people, an overdose in magnesium is usually not possible because extra magnesium is expelled from the body.

Magnesium can be found in plant and animal products, although whole grain products, raw foods, nuts, legumes and green vegetables are especially rich in magnesium. Mineral water is also an important source of magnesium, and can contain up to 80 mg per liter.

Sodium

Sodium is found in normal kitchen salt together with chloride. The human body has about 80-100g of sodium stored up, mostly in bodily fluids outside of the cells and about 1/3 in the bones.

Sodium regulates the balance of water in the organs, the osmotic pressure and the balance of acids and bases. Furthermore, it plays an important role in transferring electrical impulses in nerves and muscles, and supports many different enzymes.

The German Society for Nutrition reccomends a daily dose of about 550 mg for young people and adults. Usually more is consumed, because sodium in the form of sodium chloride (table salt) is present in almost all foods. Because of this, a deficiency in sodium plays practically no role, but can be present because of diarrhea or vomiting. Symptoms include confusion and in extreme cases unconsciousness, but also nausea, loss of appetite, headaches or muscle cramps.

Too much sodium in a daily diet has negative effects on high blood pressure and is therefore a risk factor with diseases of the heart and the circulatory system.

Phosphorus

In the human organism, phosphor can be found as phosphate, mostly in the bones and teeth. Phosphor supports the formation of bones and teeth, similar to calcium. It also is necessary for processing energy sources in the body, and is a component in DNA and RNA.

In childhood, a deficiency in phosphorus can lead to delayed growth, poor bone and tooth formation or rickets. Symptoms in adulthood could be weight loss, drowsyness or abnormal appetite. When too much phosphate is present in the diet, it can lead to a disfunctional absorption of other minerals and trace minerals.

The German Society for Nutrition estimates the daily requirement for adults at about 700-800 mg or 900 mg for pregnant and breastfeeding women. Young people who are growing also have a higher requirement for phosphorus. The daily dose of phosphorus is usually covered by a balanced diet. Deficiencies in phosphorus only occur in the case of certain diseases or alcoholism. The quotient of calcium to phosphorus in the diet should be about 1 to 1. In current eating habits, the tendancy is to have too much phosphorus in the diet in proportion to calcium. Sources especially rich in phosphorus include milk and dairy, eggs, meat, and fish. It can also be found in legumes, potatoes, wheat, soy flour and bread.

Der Quotient von Calcium zu Phosphat sollte in der Nahrung ca. 1 betragen. Bei den heutigen Ernährungsgewohnheiten besteht die Tendenz zu einer überhöhten Phosphataufnahme zuungunsten des Calciums. Besonders reich an Phosphat sind eiweißreiche Lebensmittel wie Milch und Milchprodukte, Eier, Fleisch und Fisch; enthalten ist es auch in Hülsenfrüchten, Kartoffeln, Weizen, Sojamehl und Brot.

Iron

Iron has a position between the macrominerals and the trace minerals because of the relatively large proportion of iron found in the body (it is the most important of the trace elements). Iron is important for the transport of oxygen through the blood: it is a component of red blood cells and binds oxygen to these so that it can be transported to other cells. In addition, iron is a component of many enzymes and is important for growth and the immune system's defenses against bacterial infection.

Symptoms of iron deficiency include:

• low mental and physical productivity
• drowsyness
• headaches
• meteorological sensitivity
• nervousness and irritability
• paleness
• rough, raw skin
• increased risk of infection

Light to moderate iron deficiencies as well as iodine deficiencies are the most common mineral deficits present in industrial countries. Heavy iron deficiency is very rare. It could become present in the case of a one-sided diet (via extreme dieting, no meat in the diet), but is mostly caused by heavy bleeding, for example during menstruation or injury.

The German Society for Nutrition recommends a daily dose of 10-12 mg of iron for healthy people older than 8 years. During menstruation, women are recommended about 15 mg of iron per day; pregnant or breastfeeding women are recommended 30 or 20 mg respectively. Iron is present in animal products (liver, meat, and sausages) as well as plant products (bread is an important source of iron).

The absorption rate of iron into the body differs greatly: Iron from meat is more easily absorbed by the body than iron from pland sources. Vegetarians must include larger amounts of iron in their diet for this reason. Vitamin C, citric acid, some amino acids and possibly also fructose can improve the intake of iron. An overdose of iron is very rare, because extra minerals are expelled from the body.

Chromium

Chromium stimulates the enzyme from fatty acid formation and of carbohydrate metabolism. In this way, it is important for the utilization of glucose. If too little chromium is present in the body, the tolerance for glucose sinks. Chromium can be found in potatoes, nuts, vegetables, whole grain products and fruit.

Iodine

Iodine is important for thyroid gland function. It is built into the thyroid gland hormones, which are responsible for the regulation of metabolism and body temperature. A minor deficiency in iodine is common in Germany, especially in the southern regions. Pregnant and nursing women are especially at risk because the requirement for iodine is much higher.

Important sources of iodine include sea fish, milk and dairy products. Iodine supplements and also table salt with iodine can help prevent a deficit.

Manganese

Manganese is an enzyme activator and takes part in carbohydrate and fat metabolism. It is important for normal bone development. Manganese can be found in soy beans, bananas, green vegetables, nuts (especially walnuts) whole grain products and tea.

Selenium

Selenium is a component of an enzyme that is specialized to capture free radicals and therefore helps prevent cancer and heart disease. Also, it is responsible for tissue elasticity and can support the physiological effects of vitamin E. Selenium is found in nuts, grains, liver, fish, meat, milk, and eggs. The intake of selenium in adults is reccomended to be 30 µg/ day.

Silicon

Silicon is essential for the maintenence of connective tissue, cartilage, bones, hair, nails and teeth. The main source of silicum is grain products. It is also found in green beans, cucumber and tomato.

Zinc

Zinc is a component in over 200 enzymes and in many cases an activator: it plays a large role in hair growth and hair structure and is essential for growth. High zinc content can be found in meat, milk and grain (especially in the husks – when processed to flower, 80% of the zinc is removed). Other sources include sunflower and pumpkin seeds, nuts, eggs, shellfish, milk and dairy products.

Secondary plant compounds are, as the name implies, compounds that are exclusively produced by plants. They protect plants from illness, damage and UV light and regulate the growth of plants or act as a coloring agent. They cause positive or negative reactions in humans and animals.

They belong to many material groups including:

• Lektins
• Protease inhibitors
• Saponines
• Carotinoides
• Glucosinolates
• Phytosterines
• Polyphenoles, including Flavonoides
• Sulfides
• Phenol acids
• Phytin acids
• Monoterpenes
• Phytoestrogenes

For many years, the primary interest in secondary plant compounds laid in those which have poisonous effects, for example Lectins and protease inhibitors, which are responsible for the non-digestability of uncooked legumes. Currently it is being debated whether some secondary plant compounds have a positive effect on health. They have a wide range of effects, although exactly what these are is not 100% certain. There are differences between those with an:

• Anticancerogenic effect (lowers risk of cancer)
• Antimicrobial effect (fights against bacterial, viral and fungal infections)
• Antoxidant effect (protects against free radicals, which oxidize and damage cells)
• Immunomodulating effect (strengthening of the immune system)

Certain secondary plant compounds have a positive effect on the immune system as well as the blood sugar and blood pressure, help prevent cancer and protect the body from cardiovascular disease.

Secondary plant compounds are never found alone in nature but act in groups of different compositions. In order for them to reach full potential, the diet should include many diverse fruits and vegetables.

Fiber is the framework and support for plant cell structures that scientifically (apart from lignin) belong to the carbohydrate group, which means they are built from single sugar particles. Their composition is so complex that they cannot be broken down by digestive fluids and are therefore not utilizable as nutrients in the digestive system. It is expelled, undigested, with the stool and was earlier considered to be useless. Today it is seen as an important part of a healthy diet because of the effects it has in digestion.

Fiber is made of many different substances; they differ depending on their solublilty or non-solubility.

Soluble fibers (guar, pectin, agar) lower cholesterol levels in the blood by binding themselves to bile acid in the large intestine. Through this, the choleserol is expelled instead of being absorbed by the body. With the necessary production of bile acid, more LDL cholesterol is used which lowers cholesterol levels. In addition, decomposition products are created in the large intestine when bacteria break down this type of fiber, which prevents cholesterol synthesis in the liver. Soluable fibers are therefore very important for diabetic people.

Non-Soluble fibers (Lignin, cellulose, hemicellulose) are not soluble in water but can bind themselves to water and increase the volume of stool. This stimulates bowel movement and shortens the amount of time that stool remains in the large intestine. Stool is generally passed easier and faster.

A fiber-rich diet promotes regular digestion and decreases the risk for intestinal cancer (through the shortened amount of time stool remains in the large intestine, cancer catalysts have limited contact time with the large intestine). It also protects against a variety of gastrointestinal illnesses (ex. Hemorrhoids). Drawbacks could include hindering the intake of minerals through the large intestine.

The German Society for Nutrition recommends a daily dose of at least 30g of fiber to help normal intestinal function. Most people in industrial countries have much too little fiber in their diets (in Germany, the average is 20g/day). The cause is the excessive consumption of foods with high sugar and fat content as well as white breads that are low in fiber.

Grain and whole grain products are the most important source of fiber in the diet, but also some legumes (peas, lentils, beans) potatos and fruit (apples, pears, berries or kiwi) are rich in fiber.