Fruit & Vegetables and the prevention of diseases – the evidence Stephen Atkin Professor of Endocrinology and Metabolism [email protected].

Fruit & Vegetables and the prevention of diseases – the evidence

Stephen AtkinProfessor of Endocrinology and

[email protected]

A balanced diet is very important

• “Five a a day”

• Change 4 life   

The facts

• 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, anti-oxidant 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

Bread, cereals and potatoes

Milk and dairy products

Foods rich in sugars and fat

Meat, fish and protein alternatives

Fruits and vegetables

Reproduced with kind permission of the Food Standards Agency

Plate model (the one you actually eat off)

Vegetable

Milk/yoghurt

Fruit

Vegetable

Protein

Starch/cereal

Relative risk of health problems associated with obesity

National Audit Office Report. Tackling Obesity in England. London, 2001.

Disease Women Men

Type 2 diabetes

Hypertension

Myocardial infarction

Colon cancer

Angina

Gall bladder disease

Ovarian Cancer

Osteoarthritis

Stroke

12.7

4.2

3.2

2.7

1.8

1.8

1.7

1.4

1.3

5.2

2.6

1.5

3.0

1.8

1.8

-

1.9

1.3

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

• 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 67.5 IUVitamin C 5.7mgVitamin E (Alpha Tocopherol) 0.2mgVitamin K 2.8mcgNiacin 0.1mgVitamin B6 0.1mgFolic acid 3.8mcgPantothenic Acid 0.1mgCholine 4.2mg

MineralsAmounts Per ServingCalcium 7.5mgIron 0.1mgMagnesium 6.3mgPhosphorus 13.8mgPotassium 134mgSodium 1.3mgFluoride 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