Biology Diet and Food
- Created by: Henna
- Created on: 14-01-13 17:51
Biology Diet and Food
We need to have a BALANCED DIET to get enough NUTRIENTS which, provide us with energy.
Nutrition allows us to make ENERGY, GROW and REPAIR.
Benefits of a BALANCED DIET:
- Better health
- Stronger immune system
- Ill less often
- Learn better
- Stronger
- More productive
Carbohydrates = main source of ENERGY (pasta, rice, breads)
Fats = energy, cell membranes, water proofing, fat soluble vitamin absorption (cakes, crips)
Vitamins = some water soluble others fat soluble (B3 B6)
Proteins = source of AMINO ACIDS for cell repair and growth (1st class - meat) (eggs, fish)
Minerals = INORGANIC essential for normal function (calcium, iron)
Water = Transport around the body and 60% of the body is made up of water
Fiber or Roughage = INDIGESTIBLE needed to keep the digestive system healthy, helps move food through the gut. (bran, wholemeal bread)
Different people need different amounts of food.
57% = CARBOHYDRATES = bread, pasta, wheat, potatoes
30% = FATS = cakes, sweets, butter
13% PROTEINS = 1st class = Meat, fish
Weight gain occurs when a person eats more food energy than needed to live
The energy that is not needed is DISPOSITED as FAT in the ADIPOSE TISSUES
Obesity
Form of malnutrition = unbalanced diet (too much energy)
BMI
BMI = Body mass index
It can be calculated by:
mass/height (metres^2)
- less than 18.25 = underweight
- 18.25 - 25 = average weight
- 25 - 30 = overweight
- 30 - 35 = obese class 1
- 35 - 40 = obese class 2
- 40+ = obese class 3
A growing problem of Obesity
- - 1980 = 6% men 8% women
- - 2000 = 25% men 20% women
- - 1995 - 2004 boys & girls (children 11-15)
15% - 26% = girls
14% - 24% = boys
Reasons for increase
- Availability of food
- Cheaper food
- Less exercise
- Bad parenting
- Availability in markets
Health risks caused by obesity
- - 3000 deaths
- - Cancer
- - Cardiovascular disease
- - Type 2 diabetes linked to
- - Gallstones
- - Osteoarthritis
- - Hypertension (high blood pressure)
Atherosclerosis
This is the NARROWING and HARDENING of the coronary arteries (blood vessels supply the heart)
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Avoiding this problem
- Eating fibre
- Moderate alcohol consumption
- Eating oily fish
Salt
- Decreases water potential of blood
- Water moves into blood (OSMOSIS) and pressure INCREASES
- High blood pressure (HYPERTENSION) leads to damage in the INNER LINING of the arteries which makes way for ATHEROSCLEROSIS
Lipids
- Essential to diet
- Animals = saturated
- plants = unsaturated
- Saturated = harmful
- Poly and Mono = unsaturated fats eg,Olive oil = beneficial
c-c-c-c-c-c-c-c SATURATED
c-c-c-c-c-c=c-c UNSATURATED (contains double bond)
Cholesterol
- is not a Triglyceride
- found in SATURATED FATS
- found in liver from SATURATED FATS
- 45-47% deaths from Coronary heart diseases are linked to high cholesterol levels of 5.2mmol dm-3
Why is Cholesterol in the blood
- essential for good health
- cell membranes
- making steroid based…
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