The Components of the human diet By Demetra and Raphael
Dec 24, 2015
The main components:Food Energy
Fats/lipids
Sodium
Carbohydrates
Fibres
Proteins
Vitamins
Minerals
They are also called Nutrients
A Nutrient It is a chemical substance found in food that is used by the body
Essential Nutriments cannot be formed by the body:
Water
Vitamins
Proteins (polymers of amino acids)
Some unsaturated fatty acids -> Proteins are polymers of amino acids
Some amino acids
Some Minerals
A Nutrient It is a chemical substance found in food that is used by the body
Non-essential Nutrients can be replaced or formed by the body:
Carbohydrates / Sugars
Other minerals
Saturated fatty acids / fats
Other amino acids
Efficient Energy StorersWe also know that the Plasma membrane of
cells is made of a phospholipid bilayer. There is another use of fatty acids: They are used for cholesterol, building the hydrophobic part of the layer, giving it stability.
They are also used as lipid hormones such as steroids
Omega 3 FatsThe Omega number tells us the position of the
double bond of the unsaturated fatty acid:
Omega 3:
A large intake can prevent the blood from clotting, preventing heart attacks and strokes
Cis and Trans:
Trans fats can be dangeous since the body thinks they are saturated acids, but then it doesnt know what do do with them
Fatty Acid Sources Possible effects
Omega-3Fish, Nuts, Vegetable oils
Reduces blood pressure /clotting and tryglicerides
Trans FatsPartially hyrdogenated oils, marrgarines, deep fried foods
Reduces helpful Cholesterol, increases blood pressure
Saturated Fats
Meat, Seafood, Diary products, Coconut oil
Can lead atheroscleriosis and to strokes and heart attacks
Vitamin Function Sources
Vitamin A Eye function, vision, hair, skin
Dairy, Meat, Fish
Vitamin B Nervous system, control, digestion, coenzymes (enzyme assistants)
Dairy, meat, spinach, Brocoli, Salads,
Vitamin C Immune system, healing, anti.oxidants
Fruits (especially citrus)
Vitamin D Calcium absorption: Bones and teeth
Seaweeds, seafood, fish, dairy
The RDIIt is the recommended daily intake of a
nutrient and is set by government health bodies and the world health organisation
A lack of vitamin C in your diet can lead to pale skin, a slow scurvy healing process and sunken eyes
Vitamin C The RDI for Vitamin C is 40-60 ml per day, this is
explained below:
Vitamin CExcessive doses of Vit C are usually just
excreted by the body,
However, An excessive intake of vitamin C can „spoil“ the body so it starts getting used to high levels of a nutrient, the body adapts by making the absorbing of the nutriment less efficient
Vitamin DIt is produced by the skin
Paler skin produces more vitamin d than darker skin. Therefore, darker skinned people need more vit d in their diet, especially in colder countries
Paler skin has a higher risk of developing skin cancer, so in very hot countries, these poeple need to eat extra vit do to prevent this risk.
MineralsIodine is used by the thyroid gland to produce
hormones which are responsible for monitoring metabolism and body temperature
Calcium is essential for cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bones and shells, calcium is the most abundant metal by mass in many animals.
Dietary fibreFibre itself is not absorbed into the blood and it is
not digested
However, many high-fibre foods (including vegetables) are packed with other useful nutrients
It mainly works for the stomach, but it also helps regulating blood sugar and can reduce blood cholesterol by blocking uptake of lipids in the diet
Phenylketonuria (PKU)PKU is a genetic disease caused by a mutated gene on
chromosome 12.
Normally, phenylalanine is converted into tyrosine by an enzyme, allowing normal brain development.
People with PKU cannot convert phenylalanine. When the body tries to get rid of the excess, toxins are produced which affect brain development. It can lead to severe mental problems and learning difficulties.
Roughly 1/18000 babies is born with the recessive gene.
Children with PKU should follow a special diet low in protein to avoid excessive phenylalanine.