Download Stephen Atkin`s presentation

Fruit & Vegetables and the prevention of
diseases – the evidence
Stephen Atkin
Professor of Endocrinology and
Metabolism
[email protected]
A balanced diet is very important
• “Five a a day”
• Change 4 life
The facts
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•
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Vitamins, minerals
Trace elements
Obesity
Cancer
Vitamins – water soluble or fat
soluble
Example of water soluble vitamin; Vitamin C
• Citrus and soft fruits, green leafy vegetables.
• Essential for collagen formation, enzyme co-factor, antioxidant prevention of damaging effects of free radicals.
Also role in iron absorption.
– deficiency – scurvy, more mild gum disease, loosening of teeth,
easy bruising and poor wound healing.
– infants (6-12 months).
•
Elderly.
•
Low income families.
Example of fat soluble vitamin; Β-carotene
• Yellow, orange and green fruit and vegetables
• Provitamin of Vit A. Vit A essential to processes
of vision, reproduction, growth and cellular
differentiati
– Deficiency - Longterm inadequate intakes
associated with night blindness, susceptibility
to infection
– Not seen in developed world as multiple
sources of vit A
• Fortification of margarines
Minerals
Magnesium
• green leafy vegetables
• cofactor for many enzymes, required for
protein synthesis and for both anaerobic and
aerobic energy synthesis
• Deficiency linked to cardiovascular,
skeletal, GI and CNS disorders
Potassium
• Almost all fruit and vegetables
• essential for the maintenance of normal
osmotic pressure within cells, enzyme
cofactor, required for secretion of insulin
• Deficiency can cause rapid/irregular heart
rhythm, muscle weakness
Trace elements
• Cobalt
• green leafy vegetables
• essential trace element, integral part of vit
B12, which is essential for folate and fatty
acid metabolism,
• molybdenum
• legumes, green leafy veg, cauliflower
• metalloenzyme function
manganese
• green veg and tea
• essential component of number of enzymes
boron
• almost all fruit and veg
• involved in metabolism of various elements
(including calcium copper and magnesium)
glucose, triglycerides, oestrogen
Who needs fruit and veg when
you have got it all in a tablet?
The biggest threat to the developed world?
Economic impact of obesity in
England
• The estimated annual cost of obesity to the
economy is:
– £3.5 billion for the UK economy
– 18 million sick days
– 40,000 lost years of working life
National Audit Office Report. Tackling Obesity in England. London, 2001.
Consequences of obesity in adults
• Associated with increased morbidity and mortality
• Risk factor for range of chronic diseases
– Cardiovascular disease (2-3 fold↑ risk)
– Type 2 diabetes, hypertension (>3 fold↑ risk)
– Some cancers e.g. colorectal, oesophageal,
breast and endometrial
• Increased likelihood of gallstones, osteoarthritis
and high blood pressure (in turn increasing risk of
stroke)
• Increased complications during childbirth
Childhood obesity: parents will
live longer than their children
Eat well plate
Fruits and vegetables
Meat, fish and
protein alternatives
Bread, cereals and potatoes
Milk and dairy products
Foods rich in sugars and fat
Reproduced with kind permission of the Food Standards Agency
Plate model (the one you actually
eat off)
Fruit
Protein
Milk/yoghurt
Vegetable
Vegetable
Starch/cereal
Relative risk of health problems
associated with obesity
Disease
Women
Men
Type 2 diabetes
12.7
5.2
Hypertension
4.2
2.6
Myocardial infarction
3.2
1.5
Colon cancer
2.7
3.0
Angina
1.8
1.8
Gall bladder disease
1.8
1.8
Ovarian Cancer
1.7
-
Osteoarthritis
1.4
1.9
Stroke
1.3
1.3
National Audit Office Report. Tackling Obesity in England. London, 2001.
Cancer
• Antioxidant effects of vitamins
• Antioxidants such as vitamins C, E and A
(in the form of carotenes): protect cells from
toxic by products formed in the body
• Free radicals
• oxidation
FSA review of antioxidants in
foods
• Disease prevention of antioxidants: lower
heart disease and cancer deaths
• Do not get these effects from supps; need
the complex of substances in fruit/veg
Heart disease
•
•
•
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Free radicals
oxidation of cholesterol
LDL
Atherosclerosis – heart disease
Stroke
• Meta analysis of 8 studies including
257 551 individuals
• Compared with individuals who had less
than three servings of fruit and vegetables
per day, showed that fruit and vegetables
had a significant protective effect on both
ischaemic and haemorrhagic stroke
The evidence
• Large well designed studies investigating
effects of supplements – no evidence of
benefit in cancer or heart disease
– 7 studies vitamin E supplementation
– 8 studies Beta carotene
dietary sources linked to lower rate of heart
disease, for example the tomato
• vitamin C
• vitamins A and B,
• potassium, iron and phosphorus.
• Lycopene
The humble apple
Vitamin A
Vitamin C
Vitamin E (Alpha Tocopherol)
Vitamin K
Niacin
Vitamin B6
Folic acid
Pantothenic Acid
Choline
67.5 IU
5.7mg
0.2mg
2.8mcg
0.1mg
0.1mg
3.8mcg
0.1mg
4.2mg
Minerals
Amounts Per Serving
Calcium
Iron
Magnesium
Phosphorus
Potassium
Sodium
Fluoride
7.5mg
0.1mg
6.3mg
13.8mg
134mg
1.3mg
4.1mcg
Fibre
• Fibre – populations with high fibre intake
tend to have low risk of colon cancer (UK’s
third most common cancer, claiming 18,000
lives in the UK each year)
• Eating plenty fresh fruit and veg thought to
prevent against this.
• Insoluble fibre – fruit and veg contain this,
keeps bowels healthy and stop constipation
Fibre
• Breast cancer
• Foods rich in this are more bulky so help
make us feel full, which means we are less
likely to eat too much.
Fibre content of fruit/veg (standard portion or one piece)
g
RDA
Carrot
4.0
14%
Broccoli
2.0
9%
Peas
4.0
14%
Spinach
2.0
7%
Apple
3.0
12%
Orange
4.0
14%
Banana
6.0
23%
Peach
3.0
12%
Strawberries
3.0
12%
White bread
1.0
4%
Wholemeal bread
2.0
8%
Pasta
2.5
10%
Rice
1.0
4%
(bread per slice approx)
Conclusion
• Robust evidence that fruit and vegetables
have added benefits globally for health that
you cannot get by replacing them with pills
and tablets