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Micro- and macro-nutrients

Definitions

Micro-nutrients: They are substances which are required by the body in small amounts and are co-factor of enzymes. They include vitamins and trace minerals such as Cu, Zn, Cr, Fe

Macro-nutrients: They are substance required in large amounts and include proteins, fats, carbohydrates and minerals (Na, Ca, S, Cl)

VITAMINS

Vitamins are known as fat soluble or water soluble

Fat soluble vitamins (A, D,E, K) are long with a non-polar hydrocarbon chain or ringThey are able to accumulate in the fatty tissue of the body

Water soluble vitamins (C and the eight B-group vitamins) contain hydrogen which is attached to an electronegative oxygen or nitrogen which can form hydrogen bonds with water moleculesThey cannot be stored. They must be consumed every day.

Vitamins containing C=C double bonds and –OH groups are easily oxidised and keeping food refrigerated slows down this process

TYPES OF VITAMINS

VITAMIN A (RETINOL)

It contains only one –OH group

It is fat soluble due to its long non-polar hydrocarbon chain

It is not easily broken down by cooking

Required for the production of rhodopsin>light changes its conformation> creation of nerve impulse> vision

VITAMIN C (ASCORBIC ACID)

Due to the number of –OH groups this vitamin is soluble in water

It is not retained for long in the body

A disease known as scorbutus (scurvy) is associated with the lack of this vitamin

The symptoms are: swollen legs, rotten gums

It was most commonly noticed in sailors who spent long periods of time without fresh food

VITAMIN D (CALCIFEROL)

It is a large hydrocarbon with one –OH group and it is fat soluble

A deficiency of vitamin D leads to: bone softening and malformation which is known as rickets

MALNUTRITION

This occurs when either too much food is consumed leading to obesity or the diet is lacking in certain micro- or macro- nutrients

MICRO-NUTRIENT DEFICIENCIES

Fe anaemia > fatigue

I goiter > swallen thyroid gland

Vitamin A xerophthalmia & night blindness

Vitamin B3 pellagra > diarrhea, dementia, dermatitis

Vitamin B1 beriberi > muscles, heart, nerves

Vitamin C scurvy > rotten gums

Vitamin D rickets > malformation/softening of bones

MACRO-NUTRIENT DEFICIENCIES

Deficiency in macronutrient such as proteins cause marasmus (growth retardation) and kwashiorkor (fatigue, weight loss)

Deficiency in Ca produces osteoporosis

Deficiency in Na produces cramps

CAUSES OF NUTRIENT DEFICIENCIES

Developed world- low income- poor eating habits

Developing world- poverty- famine

SOLUTIONS TO COMBAT MALNUTRITION

Eating fresh food rich in vitamins and minerals

Adding nutrient which that are missing in commonly consumed foods

Genetic modification of foods

Providing nutritional supplements