Samenvatting Voedingsleer
Les 1; Linking food, function and health
Science of nutrition
Food refers to the plants and animals we consume. It contains the energy and nutrients our body
needs to maintain life support growth and health. Nutrition is a science. The science that studies food
and how food nourishes our body and influences our health.
The cultivation, preservation and preparation of food have played a critical role in the lives of humans
for millennia, but in the west, the recognition of nutrition as an important contributor to health was
developed slowly only during the past 400 years. In the mid-1700s researchers started to make a link
between diet and illness. They discovered that vitamin C-deficiency disease scurvy (scheurbuik) can
be prevented by consuming citrus fruits. By the mid-1800s, the three energy-providing nutrients –
carbohydrates, lipids (vetten) and proteins – had been identified, as well as a number of essential
minerals. Then, as the higher standard of living after Wold War II led to an improvement in the diet,
nutrition research began pursuing a new objective: supporting wellness and preventing and treating
chronic disease. The ones of particular interest include obesity, cardiovascular disease, type 2
diabetes and various cancers. In the closing decade of the 20 th century, an exciting new area of
nutrition research began to emerge. Reflecting our growing and understanding of genetic,
nutrigenomics seeks to uncover links among our genes, our environment and our diet.
How does nutrition contribute to our health?
Nutrition is one of several factors supporting wellness
Wellness is considered to be a multidimensional process, one that includes physical, emotional and
spiritual health. Wellness is not an end point in our lives but rather is an active process we work with
every day. Two crucial components of wellness; nutrition and physical activity; our overall state of
nutrition is influenced by how much energy we expend doing daily activities, and our level of physical
activity has a major impact on how we use our the nutrients in our food.
A healthful diet can prevent some diseases and reduce your risk for others
Nutrition appears to play a role in the development of many diseases. These discoveries led nutrition
experts to develop guidelines for nutrient intakes that are high enough to prevent deficiency diseases
and to lobby for the fortification (versterking) of foods with nutrients of concern. These measures,
along with a more abundant (overvloedig) and reliable food supply, have ensured that most nutrient-
deficiency diseases are no longer of concern in developed countries.
Obesity is fundamentally a consequence of consuming more energy than is expended. Obesity is
defined as a body mass index greater than or equeal to 30.
What are nutrients?
,Foods are composed of many chemical substance, some of which are not useful to the body and
others of which are critical to human growth and function. These latter chemicals are referred to as
nutrients. The six groups of nutrients found in foods are:
Carbyhydrates
Lipids
Proteins
Vitamins
Minerals
Water
Organic these nutrients contain the elements of carbon (koolstof) and hydrogen (waterstof)
(carbohydrates, lipids, proteins and vitamins)
Inorganic minerals and water
Koolhydraten en vetten kunnen in ons lichaam worden opgeslagen. Eiwitten, vitamines en mineralen
kunnen niet of beperkt worden opgeslagen.
Koolhydraten en vetten kunnen in elkaar worden omgezet en je kunt enige tijd zonder.
Eiwitten, vitaminen en mineralen moet je dagelijks opnieuw innemen.
Carbohydrates, lipids and proteins provide energy
The energy nutrients are also referred to as Macronutrients. Macronutrients are needed in relatively
large amounts to support normal function and health. We express energy in kilocalories (kcal). Both
carbohydrates and proteins provide 4 kcal per gram and lipids provide 9 kcal per gram.
Energy is defined as the capacity to do work
A kilocalorie (kcal) is the amount of heat required to raise the temperature of 1 kilogram (kg) of water
by 1 degree Celcius.
Rust stofwisseling = basis stofwisseling
Gemiddeld 4 kj / min
1 calorie = 4,2 kj
Ons lichaam gaat naarmate we ouder worden minder energie verbruiken.
Carbohydrates are a primary fuel source
Carbohydrates are the primary source of fuel for the human body, particularly for neurologic
functioning and physical exercise. Carb- refers to carbon and –hydrate refers to water. Water is made
up of hydrogen and oxygen.
Lipids provide energy and other essential nutrients
Lipids are a diverse group of organic substances that are largely insoluble in water. Lipids are
composed mainly of carbon, hydrogen and oxygen. They contain much less oxygen and water than
carbohydrates. This quality explains why they yield more energy per gram than either carbohydrates
or proteins.
Triglycerides (more commonly known as fats) are by far the most common lipid in foods. They are
composed of an alcohol molecule called glycerol attached to three acid molecules called fatty acids.
Triglycerides are an important energy source when we are at rest and during low- to moderate-
intensity exercise. The human body is capable of storing large amounts of triglycerides as adipose
,tissue (vetweefsel) or body fat. These fat stores can be broken down for energy during periods of
fasting, such as while we are asleep.
Phopholipids are a type of lipid that contains phosphate. The body synthesizes phospholipids and
they are found in a few foods. Cholesterol is a form of lipid that is synthesized in the liver and other
body tissues.
Proteins support tissue growth, repair and maintenance
Protein also contain carbon, hydrogen and oxygen, but they differ from carbohydrates and lipids in
that they contain the element nitrogen (stikstof). Within proteins these four elements assemble into
small building blocks known as amino acids. Although protein can provide energy, they are not
usually a primary energy source. Proteins play a major role in building new cells and tissues,
maintaining and strength of bone, repairing damaged structures and assisting in regulating
metabolism and fluid balance.
Vitamins assist the regulation of physiologic processes
Vitamins do not contain energy, however they do play an important role in the release and utilization
of the energy found in carbohydrates, lipids and proteins. Because we need relatively small amounts
of these nutrients to support normal health and body functions, we call them micronutrients.
Vitamins are classified according their solubility in water as either fat-soluble or water-soluble
vitamins.
Minerals assist in the regulation of many body functions
Minerals already exist in the simplest possible chemical form; thus they can’t be broken down during
digestion or when the body uses them to promote normal function; and unlike certain vitamins they
can’t be destroyed by heat of light. Minerals assist in fluid regulation and energy production, are
essential to the health of our bone and blood and help rid the body of harmful by-products of
metabolism. The two categories minerals in our diet and body are the major minerals (consume at
least 100 gr per day, total amount in our body at least 5 gr) and the trace minerals (spoorelementen)
(consume less than 100 gr per day and total amount in our body less than 5 gr).
Water supports all body functions
Adequate water in take ensures the proper fluid both inside and outside of our cells and
assist in the regulation of nerve impulses and body temperature, muscle contractions,
nutrient transport and excretion (uitscheiding) of waste products.
What are the current dietary recommendations and how are they used?
The dietary reference intakes identify a healthy person’s nutrient needs
Dietary reference intakes (DRIs)
They do not apply to people with diseases or those who are suffering from nutrient difeciencies.
The DRIs for most nutrients consist of four values:
Estimated Average Requirement (EAR)
The first step in determining our nutrient requirements is to calculate the EAR. It represents the daily
nutrient intake level estimated to meet the requirement of half of the healthy individuals in a
particular life stage or gender group.
, Recommended Dietary Allowance (RDA)
Represents the average daily nutrient intake level that meet the nutrient requirements of 97% to 98%
of healthy individuals in a particular life stage and gender group. Scientist use the EAR to establish the
RDA. If an EAR cannot be determined for a nutrient, then this nutrient cannot have an RDA.
Adequate Intake (AI)
A recommended average daily nutrient intake level based on observed or experimentally determined
estimates of nutrient intake by a group of healthy of healthy people. These estimates are assumed to
be adequate and are used when the evidence necessary to determine an RDA is not available.
Tolerable Upper Intake Level (UL)
The highest average daily nutrient intake level likely to pose no risk of adverse health effects to
almost all individuals in a particular life stage and gender group.
The standards for energy and the macronutrients also include:
Estimated Energy Requirement (EER)
Defined as the average dietary energy intake that is predicted to maintain energy balance in a healthy
individual. This dietary intake is defined by a person’s age, gender, weight, height and level of physical
activity that is consistent with good health.
Acceptable Macronutrient Distribution Range (AMDR)
A range of intakes for a particular energy source that is associated with reduced risk of chronic
disease while providing adequate intakes of essential nutrients. The AMDR is expressed as a
percentage of total kcal. The AMDR also has a lower and upper boundary; if we consume nutrients
above or below this range, there is potential for increasing our risk.
In Nederland worden de volgende twee gebruikt:
ADH, aanbevolen dagelijkse hoeveelheid; heeft betrekking op de gemiddelde behoefte van
97,5% van de Nederlandse bevolking met een ruime marge om rekening te houden met de
spreiding van de behoefte van de bevolking. 2,5% heeft mogelijk meer nodig, terwijl het
merendeel aan minder ook al voldoende heeft.
AI, adequate inname; niveau van inneming dat voldoende is voor vrijwel alle personen in een
bepaalde bevolkingsgroep. Er is dan voldoende informatie beschikbaar om de gemiddelde
behoefte te bepalen.
Gemiddelde behoefte niveau van inneming dat bij een normale verdeling van de behoefte
toereikend is voor de helft van de populatie.
Aanvaardbare bovengrens van inneming niveau van inneming waarboven de kans bestaat dat
ongewenste effecten optreden.
Diets based on the DRIs promote wellness
The primary goal of the dietary planning is to develop an eating plan that is nutritionally adequate,
meaning that the chances of consuming too little or too much of any nutrients are very low.
How do nutrition professionals assess the nutritional status of clients?
Before nutrition professionals can make valid recommendations about a client’s diet, they need to
have a thorough understanding of the client’s current nutritional status, including his or her weight,
ration of lean body tissue to body fat and intake of energy and nutrients. They will become the
