Transcript Nutrition and Health - The Institute of Chinese Medicine

Nutrition and health
 The importance of nutrition in the primary prevention
of disease has long been recognised in the public
sector.
 The influence of food intake on health and wellbeing
has drawn many research interests and continues to
develop.
Good Food v.s. Bad Food?
 A food that is beneficial to
the body is regarded as a
Functional Food, in that, it
is one claiming to have
additional benefits other
than nutritional value.
 Foods may also contain
substances that are
harmful to health, these
are regarded as Naturally
Occurring Toxicants.
Functional foods
 There are two different types of claim that are specific for
functional foods:
 Type A – relates to a positive contribution to health or to a
condition linked to health, to the improvement of a
function or to modifying or preserving health.
 Type B – relates to the consumption of a food that might
help reduce the risk of a specific disease or condition.
1. Cholesterol lowering functional foods
 Dietary Fibre – has been shown to play an important role
in cholesterol metabolism by decreasing plasma
cholesterol and low-density lipoprotein cholesterol (LDLC) levels.
 In general, most soluble fibres lower plasma cholesterol
more efficiently than water insoluble fibres by decreasing
LDL cholesterol without significantly affecting the HDLC and triaclyglycerol levels.
Water soluble fibres
Water insoluble fibres
 peas
 whole grains
 soybeans
 corn
 broccoli
 bran
 carrots
 wheat
 sweet potatoes
 flax seeds
 onions
 cabbage
 Phytosterols – are cholesterol-like molecules found in all
plant foods, with the highest concentrations found in
vegetable oil.
 They function to inhibit the absorption of intestinal
cholesterol, a key step in lowering plasma cholesterol.
 It has been suggested that the daily intake of 2g of
phytosterols can effectively lower the cholesterol by 914% in humans with little or no effect on HDL-C and
triacylglycerol levels (Law, 2000).
 Tea catechins – are a group of antioxidant plant
metabolites found predominately in green tea.
 Epidemiological observations indicate that tea
consumption is associated with reduced levels of plasma
cholesterol and LDL-C.
 In addition, the consumption of 375mg of tea theaflavin a
day effectively reduced cholesterol and LDL-C in mild
and moderate hypercholesterolemia subjects.
 Soya proteins – the Food and Drug Administration (FDA)
suggested that incorporating soya proteins in a diet low in
saturates and cholesterowering cholesterol levels.
 In 2002, the UK Joint Health Claims Initiative (JHCI)
approved the health claim on the association between soya
protein and cholesterol reduction.
 The inclusion of at least 25g of soya protein per day, as
part of a diet low in saturated fat can help reduce blood
cholesterol levels.
2. Obesity management with functional food
 Obesity arises from an energy imbalance whereby energy
intake exceeds energy expenditure.
Energy Output
Energy Input
 Dealing with obesity requires modification of one or both
components of energy balance.
 Energy intake – one promising avenue to reduce energy
intake using functional foods is through increased satiety.
 The goal is to provide foods that increase the sense of
fullness and encourage the individual to stop eating sooner,
thereby reducing total energy intake.
 High protein diets are currently popular for weight loss
and are based on the idea that high-protein diets promote
satiety.
 Energy expenditure – Recently, it
has been demonstrated that diets high
in calcium maybe protective against
weight gain and that part of the
mechanism maybe an increase in
energy expenditure.
 Oolong tea is another food that may
have some impact on increasing
energy expenditure, perhaps by its
catechin content.
 In a study by Rumper et al 2001, it
was reported that resting metabolic
rate has increased by 3-4% during
three days of oolong tea consumption
at 5 cups per day.
 Energy storage – if some of the energy ingested is not
absorbed completely, this can reduce net energy available
to meet metabolic demands and can lead to weight loss.
 Olestra is a non-absorbable fat substitute that has been
shown to reduce energy intake. Olestra was approved by
the FDA in 1996 for use in savoury snack products.
 Olibra, which is a 95.5% mixture of fractional palm oil
and oat oil, has been reported to inhibit appetite.
3. Diabetes and functional foods
 Diabetes mellitus is a disease in which the body cannot
regulate the amount of sugar in the blood. There are two
types of diabetes:
 Type 1 diabetes is when the pancreas stops or produces
too little insulin, a hormone that regulates blood sugar
levels.
 Type 2 diabetes is when the pancreas produces insulin, but
the body is partially or completely unresponsive to react to
the insulin.
 Pumpkins – a study carried
out in China revealed that a
compound found in Asian
pumpkins acted to regenerate
damaged pancreatic cells
amongst rats with diabetes.
This may suggest that the
increased insulin levels may
reduce the need for insulin
injections or other diabetes
management drugs.
 Bitter melon (karela) – a study has isolated four
compounds in bitter melon and revealed that these
compounds may activate an enzyme that is responsible for
regulating metabolism and transporting glucose from the
blood into the cells.
 The bitter melon extract may be useful in treating diabetes
by helping the body to digest sugar molecules in the blood,
thereby lowering blood sugar.
Naturally occurring toxicants
 Naturally occurring toxicants may cause toxic effects
within hours, days or weeks of consumption of food, or
they may have mutagenic or carcinogenic effects in
which an inheritable change in the genetic
information of a cell may lead to cancer or other
disease states over a period of time.
 Diarrhoatic shellfish poisoning (DSP) – belongs to the
marine toxin group. It has been reported throughout the
world, with most incidents recognised in Europe and
Japan.
 Diarrhoea, nausea, vomiting and abdominal pain occur
within 30 minutes to a few hours of consumption of
contaminated shellfish and last for up to 3 days.
 Bioaccumulation occurs commonly in mussels, clams and
scallops, which concentrate DSP toxins.
 Paralytic shellfish poisoning (PSP) – is also a marine
toxin. It is caused by the consumption of contaminated
bivalve molluscs (i.e. clams, cockles, mussels).
 The onset of illness occurs within 15 minutes to 10 hours
after consumption. Symptoms vary depending on the toxin
involved and the amount ingested, which includes
paralysis of the mouth, throat and extremities, dizziness
and muscular and respiratory paralysis.
Vitamins and minerals
 Vitamins are organic compounds that cannot be
synthesised in the body and so it is required in small
amounts from the diet.
 Minerals are elements other than carbon, hydrogen,
oxygen and nitrogen that are found in the body. Both
vitamins and minerals are essential in the diet in small
quantities and so they are often grouped together as
micronutrients.
Vitamin A
 Also known as retinol plays an
important role in vision, bone
growth and reproduction. It also
functions to regulate the immune
system, which helps prevent or
fight off infections.
 Rich sources of vitamin A comes
from beef liver, some dairy
products (i.e. milk, cheese and
butter), oily fish (i.e. tuna and
sardines) and colourful
vegetables (i.e. carrots, spinach,
apricots, papaya and yellow
squash).
Vitamin A Requirements
 Diets low in fat intake can result in vitamin A deficiency,
especially in children between the ages of 1 – 5 years.
 People living in developing countries are also at risk due
to the lack of dietary diversity and the prevalent infectious
intestinal disease.
 To prevent vitamin A deficiency, a diverse diet is
recommended.
Vitamin B1
 Also known as thiamin plays an
important role in carbohydrate
metabolism by converting
glucose into the usable energy in
the body. It also stimulates action
in the brain and promotes
general growth.
 Main sources of thiamine can be
found in unrefined cereals and
rice, legumes, apricots, melons
and many leafy vegetables.
Vitamin B1 Requirements
Males 15 – 50+
years (mg/day)
Females 15 – 50+ Pregnancy - last
years (mg/day)
trimester
only(mg/day)
Lactation
(mg/day)
0.9
0.8
1.0
0.9
 Thiamin deficiency is common in chronic binge
drinking alcoholics (particularly in those with liver
disease).
 Thiamin deficiency is also found in those undergoing
renal dialysis.
Vitamin B2
 Also known as riboflavin, helps to
metabolise fat, protein and
carbohydrate. It also helps to create
red blood cells and antibodies and
is especially important during
periods of rapid growth as with
young children and babies.
 Rich sources of riboflavin can be
found in cow’s milk, as well as
some fruits such as papaya, apples,
currants and apricots. It can also be
found in some nuts and whole
grains, especially almonds and
walnuts.
Vitamin B2 Requirements
Males 15 – 50+
years (mg/day)
Females 15 – 50+
years (mg/day)
Pregnancy
(mg/day)
Lactation
(mg/day)
1.3
1.1
1.4
1.6
 For pregnant and lactating women and infants,
riboflavin requirements are higher.
 This is because concentrations of riboflavin in breast
milk is lower than in cows milk.
 Riboflavin supplementations maybe required.
Vitamin C
 Also known as ascorbate acid is required for
the growth and repair of tissues in the body.
 Vitamin C is one of many antioxidants,
nutrients that block the damage caused by
free radicals. Free radicals are by-products
produced in the body during the
transformation of food into energy. The build
up of these by-products over time is largely
responsible for the ageing process and can
contribute to the development of various
health conditions such as cancer and heart
disease.
 All fruits and vegetables contain some
amounts of vitamin C. Foods that contain the
highest sources of vitamin C include green
pepper, Brussels sprouts, broccoli, citrus
fruits and juices, strawberries, cranberries,
blueberries, papaya and mango.
Vitamin C Requirements
Males 15 – 50+
years (mg/day)
Females 15-50+
years (mg/day)
Pregnancy
(mg/day)
Lactating
(mg/day)
40
40
50
70
 In order to meet increased foetal demands, pregnant
woman are recommended to increase their vitamin C
intake.
 Vitamin C concentration in lactating women should also
increase vitamin intake in order to maintain sufficient
levels in breast milk.
Vitamin D
 Is essential for the promotion of calcium
absorption in the gut and so is needed for
adequate bone growth.
 Without sufficient levels of vitamin D, bones
can become brittle and thin. In addition,
vitamin D also helps to promote the immune
system and the reduction of inflammation.
 Very few foods in nature contain vitamin D.
the flesh of oily fish such as salmon, tuna
and mackerel and fish liver oils are among
the best sources.
 Small amounts of vitamin D can also be
found in beef liver, cheese and egg yolks.
Most people, however, meet their vitamin D
needs through exposure to sunlight.
Vitamin D Requirements
 Elderly people are at higher risk of vitamin D
deficiency. As people age, the skin cannot synthesize
vitamin D efficiently and so its requirements are made
higher.
 People with limited sun exposure are also at risk of
vitamin D deficiency.
 It is suggested that at risk groups should increase their
sunlight exposure. Fish oil supplements may also be
recommended.
Vitamin E
 Is also an important antioxidant
that helps to reduce the damage
caused by free radicals.
 This may help to prevent or limit
the chronic diseases associated
with free radicals.
 In addition, vitamin E is involved
in immune function and other
metabolic processes.
 Numerous foods provide vitamin E.
Nuts, seeds, and vegetable oils are
among the best sources, and
significant amounts are available in
green leafy vegetables and fortified
cereals.
Vitamin E Requirements
Males (mg/day)
Females (mg/day)
3.5 – 19.5
2.5 – 15.2
 Patients with heart disease and lung cancer are at high risk
for vitamin E deficiency.
 This is due to the fact the tobacco smoke is rich in free
radicals, which leads to the depletion of vitamin E.
Iron
 Almost two-thirds of iron in the body
is found in hemoglobin, the protein in
red blood cells that carries oxygen to
tissues.
 Smaller amounts of iron are found in
myoglobin, a protein that helps supply
oxygen to muscle, and in enzymes that
assist biochemical reactions.
 A deficiency of iron limits oxygen
delivery to cells, resulting in fatigue,
poor work performance, and decreased
immunity.
 Iron can be derived from red meats,
fish and poultry. Iron can also be
found in plants such as lentils and
beans.
Calcium
 Is one of the most important minerals for growth, maintenance
and reproduction. It helps to form and maintain healthy teeth
and bones.
 In addition, calcium helps with blood clotting, nerve signalling,
muscle contraction and the release of certain hormones. It is
also needed for a normal heartbeat.
 Dairy products are the most significant sources of calcium,
such as yoghurt, cheese and buttermilk. Other sources come
from broccoli, turnip greens and other green leafy vegetables.
Zinc
 Is needed for the body’s defensive system. It plays a role in
cell division, cell growth and wound healing.
 It is also needed for senses of smell and taste.
 Rich sources of zinc can be found in high protein foods
such as beef, pork and lamb. The dark meat of chicken
contains more zinc than light meat. Peanuts and legumes
are also good sources of zinc.
Magnesium
 Plays an important role in muscle contraction and
relaxation. It also promotes the function of certain
enzymes in the body.
 Most dietary magnesium comes from green leafy
vegetables. Other good sources include bananas, apricots,
avocadoes, legumes and nuts.