Module 1 Basic principles of micronutrients
1.1 Introduction
Door huisartsen en ‘experts’ worden veel vitaminen en mineralen supplementen voorgeschreven, bijvoorbeeld als
iemand klaagt over vermoeidheid. In de meeste gevallen ligt dat helemaal niet aan een vitaminen en mineralen
tekort, maar door een placebo effect kan dit alsnog werken.
Maar, zeker in derde wereld landen, komen dit soort tekorten toch nog best vaak voor. Deze tekorten veroorzaken
grote problemen (zoals ijzertekort anaemia veroorzaakt)
1.2 Basic principles of vitamins and minerals
1.2.1 Overview of micronutrients
Micronutrient = voedingsstof waarvan we maar 1 gram (of minder) per dag van nodig hebben
Vitamin = organic molecule (molecule with carbon atoms)
Mineral = inorganic molecule (molecule without carbon atoms)
1.2.2 Overview of vitamins
Many vitamins, for example vitamin E, are actually a family of molecules which comparable metabolic activities.
Vitamins are not produced by the human body (or in insufficient amounts), therefore we must consume them
Vitamers = molecules which belong to the same vitamin family
Provitamin = molecule which can be converted to a vitamin in the human body
Fat-soluble vitamins:
- Vitamin A
- Vitamin D
- Vitamin E
- Vitamin K
Water-soluble vitamins:
- Vitamin C
- 8 Vitamin B’s (vitamin B1, B2, B3, B6, folate, B12, biotin and pantothenic acid)
Differences between fat and water soluble vitamins:
- Fat soluble vitamins are more stable to heat (not lost to the cooking of food)
- Fat soluble vitamins are absorbed together with fats in food
- Fat soluble vitamins are first absorbed into the lymph system and then into the blood
- Fat soluble vitamins cannot just travel through blood, they need a carrier protein
- Fat soluble vitamins can be stored in fatty parts of the body (water soluble are excreted in urine, so they
need to eaten regularly). That means that fat soluble vitamins can reach a toxic amount.
1.2.3 Discovery of vitamins
Pas aan het einde van de 19e eeuw zijn vitamines ontdekt, dat verklaarde een hoop ziektes.
1.2.4 Name of vitamins
De naam vitamine kwam van vitale (=essentieel) amine (molecuul met stikstof), maar later werden er ook vitamines
ontdekt die geen amine waren.
1.2.5 Chemistry of minerals
Mineral = element which is essential to the human body
Of the 118 elements, 21 are essential. 4 (carbon, hydrogen, nitrogen and oxygen) are present in common organic
molecules, so 17 elements comprise the dietary minerals.
Major mineral = more than 5 grams of this mineral is present in the body: calcium, phosphorus, potassium, sulfur,
sodium, chloride and magnesium
Trace element = less than 5 grams in of this mineral is present in the body: iron, zinc, copper, manganese
molybdenum, fluoride, cobalt, iodine, selenium and chromium
1.2.6 Mineral bioavailability and food content
Not all minerals in food can be absorbed by the body, because for instance the minerals are bound to compounds
that limit absorption. In general, bioavailability of minerals is lower in plant foods than in animal foods.
1.3 Micronutrient requirements
1.3.1 Dietary reference intakes: the basics
Dietary reference intakes (DRI’s):
, - Estimated average requirement (EAR) = level of intake of nutrient at which the requirement of half of the
healthy people are met
- Recommended dietary allowance (RDA) = level of intake of nutrient at which the requirement of almost all
(98%) healthy people are met = used as a recommendation
- Adequate intake = recommended intake if RDA is unknown
- Tolerable upper intake = highest level of daily intake that is safe
DRI’s are calculated for healthy people. If you have a disease which affects nutrient needs, the DRI is probably
wrong.
1.4 Micronutrient supplements
1.4.2 Who needs extra vitamins and/or minerals?
After birth, babies receive vitamin K to prevent bleeding. They should get supplemental vitamin K in the first 3
months of their life. Also, babies need vitamin D supplements until the age of 4.
Vitamin D is also recommended (by the Dutch Health Council) for:
- Males older than 70
- Females older than 50
- Pregnant woman
- People that rarely get outside or cover their skin
- Dark-skinned people
Elderly people can take supplemental calcium (not a very strong recommendation though)
People older than 50 are recommended to take supplemental vitamin B12
Vegans should take vitamin B12. Vegans and vegetarians should consider taking iron tablets (especially if pregnant).
Pregnant woman should take folate (between 4 weeks before conception to 8 weeks after conception), vitamin D
and calcium in populations where calcium intake is low.
1.4.3 Potential harmful effects of extra vitamins and/or minerals
Valt wel mee, als je niet te gek doet
, Module 2 Water, minerals, trace elements
2.2 The role of water in the body
2.2.1 The role of water in the body
Functions of water (50-60% of body is water):
- Water makes life possible. Cells consists of a lot of water and nearly all proteins in the cells are dissolved in water
(and wouldn’t function otherwise)
- Water is the main component of blood
- Water participates in a lot of biochemical reactions in cells
- Water has a high heat capacity, it takes a lot of energy to raise the temperature of water (this makes is easier to
keep body temperature consistent)
- Water plays a big role in ion balances
2.2.2 Water balance
Water intake = amount of water a person takes in per day (not only pure water, but also in foods)
Water loss = amount of water a pe-rson loses per day (by urine, sweat, air and stools)
2.2.4 Dehydration and water intoxication
Dehydration = life-threatening if water reaches 10% of body weight (most often related to vomiting, diarrhea, use of
drugs that increase urine production, sweating and decreased water intake). Mostly prevalent amoung young
children and elderly.
Water intoxication = life-threatening if water is consumed too much within a short time span. This leads to
disturbances in ion balances and neurological symptoms. Mostly prevalent among athletes who over-consume water
with low concentrations of ions.
2.3 Water and health
2.3.1 Health effects of water
Low water intake -> increases long-term risk of kidney dysfunction + increases development of high blood sugar
But more research is needed to confirm this
2.3.2 Bottled water
Bottled water = water in a bottle (nothing more than that)
Mineral water = water bottled at the source (and minimal treatment)
Some mineral water contains more minerals than normal bottled water. These can help reach the daily
recommended intake of certain minerals.
2.3.3 Tap water
In developing countries, a lot of people do not have access to safe tap water. This can cause diarrhea.
In developed countries, tap water is just as healthy to drink as bottled/mineral water (it even contains more minerals
than some mineral waters).
2.4 Sodium and potassium
2.4.1 Sodium and potassium content in foods
40% of the weight of salt (sodium chloride) is sodium
Processed foods contain most salt we intake
Potassium is present in large amounts in a lot of foods (not only processed foods)
WHO: mean intake of <2g of sodium (so <5g of salt) is optimal. But the mean global sodium intake is more than 4g
2.4.2 Function of sodium and potassium in the body
Edema = excessive fluid build-up in tissue, because of a high concentration of sodium/potassium
2.4.3 Health effect of sodium
Lower sodium intake results in a lower blood pressure. High blood pressure is a large risk factor for cardiovascular
diseases, so lowering sodium intake will lower the risk.
2.4.5 Salt restriction programs
Lowering salt intake of a population is difficult, because people like salt so when you are the only one who leaves salt
out of your product people won’t buy it anymore. So salt restriction programs are conformed to lower salt intake.
2.5 Calcium
2.5.1 Calcium content in foods
Calcium is mostly found in dairy products, nuts, green leafy vegetables and beans. Some foods have added calcium,
like cereals, soy milk and orange juice.
