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Week 3: Phytochemicals: compounds in plant-derived food :check: (Purposes…
Week 3: Phytochemicals: compounds in plant-derived food :check:
Purposes in
Body
Suppressing inflammation
Interfering with DNA replication
Protecting from cancer
2 examples
(LIMITED EVIDENCE) Lycopene (a carotenoid) from tomatoes
Properties
Provide red pigment
Powerful antioxidant that may seems to inhibit cancer cells growth
Beneficial if obtain through dietary sources instead of through supplementation
Supplements may interfere cancer treatments
Phytoestrogen from soy products (MOST effective when consumed in moderation early & throughout life)
Properties
Chemical structure is similar to the hormone estrogens
Have antioxidant properties that appears to slow down the growth of some cancers
May protect against breast and prostate cancers
(BUT) NOT advisable to obtain soy extracts & phyoestrogen supplements
Especially for women with breast cancer & other high risk factors
Stimulating enzymes
Destroying bacteria
Mimics hormones
Binding to cell walls
Might have adverse effects if consume in excessive amounts
Protect from Heart Disease
(example) Flavonoids
Purified ones may be harmful
Properties
Minimize inflammation
Reduce blood platelets stickiness
Slow down the progression of atherosclerosis, hence reducing the possibility of blood clotting
Protect LDL against oxidation
Food
Colours
Aromas
Tastes
2 more examples needed more research
Orange-Yellow pigment, Curcumin
Reverse insulin resistance
Inflammation
Other symptoms associated with obesity
Lutein and zeaxanthin
Protect eyes and skin from UV light damage
Protect bones from mineral loss
(Found in) Functional groups:foods that are used to maintain health and prevent disease
rich in phytochemcials
Easily available in supermarkets
Fluid & Electrolyte Balance
Week 3: Water :check:
Water Intake
Water balance: Maintaining water input and output
:check:
Functiions :check:
Body temperature regulation
Maintains the structure of large molecules such as protein and glycogen
Maintains blood volume
& Influences blood pressure
Transports nutrients and waste products throughout the body
Serves as solvent for minerals, vitamins, AA, glucose etc.
Acts as a lubricate & cushions joints, inside the eyes, spinal cord, womb
Participates in metabolic reactions
How?
When the body has an excess of water, the kidneys excrete a large volume of dilute urine
Water intoxication: Excessive water intake (1 hour --> 2/3L )
Kidney disorders, reducing urine production
Symptoms
Confusions
Death
(in extreme cases)
Hyponatremia:
Dilution of sodium concentration of the blood
Caused by ingestion of large amount of water ( 10 – 20L) within a few hours
Convulsions
When water intake is low, the kidneys conserve water and only excrete a small volume of concentrated urine
(influenced by) 1st Stage of Dehydration, Thirst: Mouth turns dry
Hypothalamus initiates drinking behavior
Concentrated blood
Dehydration: Lack of water/ Too much water lost and is not replaced
(Unable to get water) Symptoms of Dehydration progress from thirst to delibrium
Eventually death
Water Recommendation: include drinking water, other beverages and foods
Adequate Intake (AI) for total water intake
Adult men : 3.7 L/day
Adult women : 2.7 L/day
Pregnancy : 3.0 L/day
Lactation : 3.8 L/day
People who are physically active or who live in hot environments may need more
In the body,50-70 % total body weight :check:
2 types of fluid
(65%, Inside cells) Intracellular fluid
(35%,Outside cells) Extracellular fluid
intravascular fluid is within the blood vessels
intercellular fluid between or surrounding the cells
Compositions of fluids differ
Events of imbalances
Body responds rapidly by adjusting both water intake and output, per necessarily
Thereafter, the entire system of cells and fluids remains in a delicate controlled state of homeostasis
Under normal conditons
Fluids from both compartments lose and replace their components
But the composition in each compartment remains relatively constant
Amount of water present in females, obese people and the elderly is usually lower due to the smaller proportion of lean tissue
Water losses
Minimum amount excreted: 500 ml (about 2 cups) of water each day
If higher than this amount, excretion adjusts to balance intake
Amount of fluid loss from each sources varies according to:
Environment (such as heat or humidity)
Body’s physical condition (such as exercise or fever)
Via 3 ways called Insensible Water Losses
faces
lungs as vapour
skin as sweat
Water Balance: Require healthy kidneys and sufficient fluid intake
helps to maintain healthy kidneys and prevent kidney stone formation
Kidneys :check:
functions :check:
Adjust the volume and concentration of the urine
Reabsorb required body substances
Accommodate the changes in the body
Excrete wastes with some water in the urine
Works with :check:
Renin
(released by) Decreased blood pressure in kidney
Renin and Angiotensin work together to give off Angiotensin I, primarily in the lungs
( Angiotensin I) Forms Angiotensin II
(Stimulates) Adrenal gland
Releases
Constricts blood vessels
Angiotensin from liver
Antidiuretic Hormone (ADH)
(Released by) Posterior Pituitary gland
Hypothalamus receives signals of increased blood osmolality from receptors, stimulates
Increases water retention in kidneys
Increases blood pressure
Aldosterone
Increases sodium retention in kidney
Minerals affecting the movement of water in the cells
:check:
Calcium
Sulfur
Potassium
Magnesium
Chloride
Phosphorus
Sodium
Dissociation of salt in water :check:
In electrolyte solutions
Cation (+) and anion (-) concentration are balanced
If anion enters the fluid, a cation must accompany it or another anion must leave to maintain electrical neutrality
Transport protein in the cell membranes regulate the movement of positive ions and other substance from one side of the cell membrane to the other
:check:
Negative ions follow positive ions, and water moves towards the more concentrated solution
(Protein) When leaked out of blood vessels into spaces between cells
Fluids follow
Cause swelling of edema
2 sites that ensure that there is a constant amount of various minerals in the body :check:
Gastrointestinal (GI) tract
Minerals in digestive juices and those present in foods are absorbed in the large intestines or excreted as needed
8 litres of fluids and associated minerals are recycled this way
Enables ample opportunity for the regulation of electrolyte balance
Kidneys
Control body’s water content by hormone ADH
Regulate electrolyte content by hormone aldosterone
While sodium (positive ions) is being reabsorbed, potassium (another positive ions) is excreted to ensure that the total positive charge = total negative charge
Imbalances :check:
Loses ability to compensate
Traumatic wounds
Heavy sweating
Burns
Severe diarrhea
Vomitting
Causing
Over-secretion of aldosterone from adrenal glands due to:
Tumor growth, losing potassium
Uncontrolled diabetes, losing glucose
Vomiting or Diarrhea, losing sodium
Replacing
Oral rehydration therapy (ORT): simple solution of sugar, salt, and water
Do not need hospitalization
Can be prepared from ingredients available locally
consuming plain water and regular diet
Support Activity
Using fluids as temperature regulation
Body routes its blood supply through capillaries just under the skin
Sweat is secreted to evaporate
Cool the skin and underlying blood
Blood flows back to cool the deep chambers
but Sweat doesn’t evaporate well in hot, humid weather because the surrounding air is already laden with water
heat stroke/ hyperthermia
symptoms
Clumsiness, stumbling
Confusion, dizziness, other mental changes, loss of consciousness
Flushed skin (skin may turn red as body temp rises)
Muscle cramping (early symptom)
Nausea and vomiting
Rapid breathing
Rapid heart rate
Sudden cessation of sweating (hot, dry skin)
Throbbing headache
Preventations
Drink enough fluid before and during the activity
Rest in the shade when tired
Wear lightweight clothing that allows sweat to evaporate
(temp regulation) in cold weather, active body still sweats
(May face)hypothermia
Inexperience, slow runners participating in long races on cold or wet, chilly days
Slow runners who produce little heat can become too cold if clothing is inadequate
symptoms
Clumsiness, loss of coordination
Confusion, disorientation, other mental changes, loss of consciousness
Drowsiness
Shivering (early symptom)
Cessation of shivering (late symptom)
Slurred speech
Slow breathing
Slow heart rate
Fluids should be warm or at room temperature to prevent hypothermia
Fluid Replacement via Hydration
:check:
Endurance athletes can easily lose 1.5L or more fluid during each hour of activity
To prepare fluid losses, a person must hydrate:
Before activity
During activity
After activity
In hot weather, GI tract may not be able to absorb water fast enough to catch up with the sweat losses
Therefore, dehydration is inevitable
Athletes preparing for competition are advised to drink extra fluid in the days immediately before the event
Excess water is not stored in the body, but drinking extra will maximize hydration at the start of the event
Athletes who are slightly dehydrated at the start of the event begins with a disadvantage
Electrolyte Losses and Replacement
:check:
Hyponatremia
Causes by
Endurance athletes drink large amounts of water over the course of a long event that overhydrate dilute the body’s fluids to an extent of causing low sodium concentration
Athletes sweat profusely over long period of time and do not replace sodium
Symptoms
Vomiting
Severe headache
confusion
seizure
Bloating, puffiness from water retention (shoes tight, rings tight)
Preventions
Other dietary sources of sodium during long competitions
Some may need beverages with higher sodium concentrations than commercial sports drink
Salty pretzels
Do not restrict salt intake days before the event, especially an event in the heat
Sports drink:
beverages that contain carbohydrates and electrolytes in specific concentrations
Offers
Glucose
Provides simple sugars or glucose polymers that help to maintain hydration and blood glucose
Enhance performances
Fluid: Help to offset the loss of fluids during physical activity
Sodium and Other Electrolytes
Help to replace sodium and electrolytes losses during physical activity
Sodium helps to increase the rate of fluid absorption in GI tract and maintain plasma volume during activity and recovery
Meals eaten within hours of competition are able to replace these minerals
Most sports drink contains relatively low in sodium, hence those who choose these beverages may pose a lower risk of excessive intake
Good Taste: people will drink more, hence ensuring adequate hydration
Beneficial for athletes who
Exercise on an empty stomach
Don’t eat enough carbohydrate
Want to load carbohydrates
Want to gain weight
Train at altitude or in extreme weather
Had diarrhoea (or vomiting recently)
Refuse to drink adequate amounts of water
Enhanced Water:
Lightly flavoured waters with added sugars, vitamins, minerals and in some cases, protein
Neither natural nor healthy, as marketing ads claim
In fact, most enhanced water contain small amount of a few minerals, some vitamin B, and sometimes vitamin C or vitamin E
These vitamins and minerals in these drink do not add much to daily needs
Not a substitute for eating nutrient-rich fruits and vegetables
(UNLIKE) Poor Beverage choices
Caffeine: A stimulant
Excess caffeine or in combination with other unregulated substances may hinder performance and be potentially dangerous
Carbonated soft drinks (with or without caffeine): Makes a person feels full due to bubbles, hence limit fluid intake
Energy Drink: very high carbohydrate concentrations for optimal fluid absorption
Alcohol
breaks down into heat, but not fuel muscle work because alcohol is metabolised in the liver
Has diuretic effect, which impairs body’s fluid balance, causing dehydration
Impairs body’s ability to regulate its temperature, increasing the chance of hypothermia or heat stroke
Alters perceptions; slow reaction time; reduces strength, power, and endurance
Hinders accuracy, balance, eye-hand coordination and coordination in general
Do not drink alcohol before exercise
Drink plenty of water after exercising, before drinking alcohol
Acid- Base Balance:Ions are also used to regulate the acidity (pH) of its fluids within the narrow range :check:
Slight changes in either directions can lead to denaturing of proteins, hence affecting its properties
Ways Body Prevent Fluctuations in pH
Respiration
in Lungs
Excretion in Kidneys
Buffers in blood
H+ ions that are generated during normal energy metabolism and other acids must be neutralized
Purpose of Electrolytes :check:
Water follows whenever the electrolytes move across the membrane
via osmosis
