Eat for Your Lives!

MargaretThatcher · Thu Apr 07, 2005 10:05 pm

http://www.newscientist.com/channel/opinion/mg18624943.400

As a child in Blackpool, Clare Shaw loved fish and chips, and her mother's good old-fashioned cooking. Her first degree was in nutrition and dietetics at the University of London. And she stayed in London for her first job at St Bartholomew's Hospital, working in general dietetics. She joined the Royal Marsden cancer hospital in 1987, and went on to become chief dietitian there in 1992. Her book Cancer: The power of food has just been published by Hamlyn

Has science needed some persuading of the relationship between diet and cancer?

Yes. Conclusive evidence has been very hard to get, which made them cautious about false messages or easy sound bites. As a result they have been rather behind in talking to the public.

What do you think about the quality of advice out there about food and cancer?

A lot of the information that is aimed at the general public is not necessarily based on good scientific evidence. People find it difficult to know what is reliable and what is really just someone's idea, just spin. Lots of people think they know about diet, so they're all jumping on the bandwagon. Often messages about healthy eating do not fit politically with what everyone wants, whether that be the food industry, government or whomever.
What's your message?

Mine is that if we're talking about nutrition, it should be backed up by some investigation into what we are saying. It is very difficult to get the right evidence and to deal with the fact that the evidence can change over time. The public often loses confidence because we might say one thing in one decade and another in the next. As new studies are done and new evidence emerges, we can see that people haven't necessarily got it right. But that's the nature of science, isn't it?

Do you see it as your responsibility to help people understand the complexities of the link between diet and cancer?

In part. I think people have got the message about heart disease and food, but I worry about food and cancer.

A recent questionnaire from Cancer Research UK asked people which types of cancer they thought were related to the environment, which included things like exposure to smoking and sunlight, eating fruit and vegetables, and so on. It showed people were not aware that a number of cancers are related to the environment, of which diet is a very important component.

What kinds of cancers are linked to diet? Is there a clear message?

It is very complex. The fact that diet is linked only to certain types of cancer is important. For some cancers, such as sarcomas, leukaemias and the majority of childhood cancers, there is no dietary link at all. Ovarian cancer, at a best guess, seems much less likely to be linked. Cancers of the gastrointestinal tract, particularly oesophageal, stomach and bowel cancers are most strongly linked to diet. Then there's a middle ground with some of the cancers that are hormone-related, such as breast and prostate cancers.

What about cervical cancer?

This is thought to be viral, but if you look at the studies, the risks may possibly be altered by the amount of fruit and vegetables you eat. Likewise with lung cancer: while smoking is the main environmental factor, some studies have shown that a poor fruit and vegetable intake may predispose smokers to it. And we know that an environmental factor in the shape of body weight has an influence on the incidence of post-menopausal breast cancer.

Does susceptibility vary between individuals? Could people with some sorts of genome get away with a lot more in terms of poor food and other environmental factors?

Absolutely. We need lots more research that follows those variations. With my book I wanted people to appreciate to that our knowledge is mainly based on looking at what people have eaten in the past and then looking at their risk of developing cancer. What we really need now is to understand the information coming out from studies like the European Prospective Investigation into Cancer and Nutrition, which follows large numbers of people into the future and looking at diet, other risk factors and possibly individual susceptibility.
“It's hard to see how you can substitute for home cooking... we have to get back in the kitchen”

Does it matter that we cook less and less?

It is very hard to see how you can substitute for home cooking. You have to cook the starchy foods, and many vegetables need cooking to get the best out of them. Even things that look raw, like oats, have been cooked beforehand, steamed and rolled. But healthy eating can be quite quick: a piece of fish, a jacket potato, some steamed vegetables. That doesn't take a lot of cooking. We have got to get back into the kitchen, which is why I made my book a practical cookery book, to show people that it is not too complicated.

What do your family think of the recipes in the book?

They like them. I've cooked them for friends as well and they've been very pleased. I don't think I've had a bad comment from anyone I have fed the recipes to.
“We are not hinting that following a diet like that can cure cancer patients”

Do you give them to your cancer patients?

The recipes are not on our menu at the moment, and obviously in a public hospital we have to think about cost. I think we've also got to be a bit careful, because the recommendations are for the general public: we are not hinting that following a diet like that can cure cancer patients. What we are saying is that food is important for everybody, but the emphasis is different when patients are in the middle of treatment and perhaps struggling to eat.

Presuming you follow your own advice, is there anything you miss eating?

I do eat chocolate, but not in large quantities, more for a taste. Probably also balsamic vinegar crisps. I like a glass of wine in moderation, but having alcohol-free days is very important.

But there have been lots of reports recently that wine and chocolate are good for you in moderation...

Unfortunately there is evidence that even one drink a day does increase the risk of breast cancer. The mechanisms are not known but even light drinkers do have an increased risk of breast cancer compared with people who don't drink at all.

OK, forget the wine. How about cold spaghetti out of a tin, then? Am I on my own with that?
Yes, I'm afraid so.
From issue 2494 of New Scientist magazine, 09 April 2005, page 42
A clearer message

In 1981, two of the world's top cancer researchers, Richard Doll and Richard Peto, estimated that in the US perhaps one-third of all cancer deaths might be caused by diet.

This was fighting talk, and most governments found it difficult to act on. Research dollars were beginning to push genetic explanations to the top of the pile, leaving the full, complex tale of cancer and environmental factors (nutrition, lifestyle, work) to be unravelled. Contradictory-sounding and constantly changing public messages from often quite small-scale research served to compound the problem, leaving the public thoroughly confused and cynical about the role of diet in cancer.

But a decade later, the tide started to turn. In 1992 the world's largest study into cancer and diet, the European Prospective Investigation into Cancer and Nutrition (EPIC), started recruiting over 520,000 people from 10 European countries for an extraordinarily ambitious research programme designed to tease apart once and for all the complicated links between cancer, diet and genes.

And in 1997, the World Cancer Research Fund published Food, Nutrition and the Prevention of Cancer: A global perspective. It had a bold message: "Policy-makers should now recognise that the incidence of cancer throughout the world can be reduced by 30 to 40 per cent by feasible changes in diets and related lifestyles."

The report was tough on diet, with instructions, among other things, to eat five or more portions of vegetables and fruit a day (7 per cent of total energy); starchy or protein-rich foods of plant origin (45 to 60 per cent) via seven portions of cereals, pulses, roots, tubers and plantains; no or minimal alcohol (less than 5 per cent for men, less than 2.5 per cent for women); and little or no red meat (80 grams). An updated, still tougher report is due in 18 months.

EPIC now holds an enormous amount of data gained from detailed questionnaires and blood samples from its subjects. In fact, EPIC's chief, Elio Riboli, believes that we are getting close to comprehensive answers on certain cancers. With colorectal cancer, for example, it looks certain that 70 per cent or more can be attributed to known factors: diet, level of activity and low intake of folates. The remaining 30 per cent or so is due to genetic susceptibility.
The cancer prevention diet

YOUR DIET SHOULD BE...

high in starchy, unprocessed cereal foods, such as maize, wheat and unpolished, unrefined rice; roots and tubers, such as potatoes and sweet potatoes; and pulses such as beans and lentils

high in fruit and vegetables, at least five portions a day. A portion can be: 1 large banana, 1 medium apple, 3 plums, 2 satsumas, 2 kiwis, half a fresh pepper, 2 spears of broccoli, 3 heaped tablespoons of sliced carrots. The Greek government and the US National Institutes of Health recommend nine portions a day

high in foods that are as fresh as possible. Mouldy food produces aflatoxins, which are known carcinogens

low in saturated fat (down to 30 per cent from 40 per cent), particularly reducing saturated fat in meat or dairy products

low in red meat - a maximum of 80 grams per day - lots of fish or white meat (no limits but keep to average daily female/male calorie intakes: 2000/ 2400)

low in salt - no more than 6 grams per day

little or no alcohol. Despite evidence that wine is good for the heart, it is linked to breast cancer. Maximum 1 or 2 units per day

low in meat and fish cooked at very high temperatures - barbecue-style food, in other words - as this produces carcinogenic chemicals called heterocyclic amines

YOU SHOULD ALSO:

avoid being overweight. Aim to have a body-mass index of 20 to 25

take exercise. If your life is sedentary, walk briskly for an hour daily and take vigorous exercise for an hour very week
Mushroom and hazelnut streusel

Richly flavoured with balsamic vinegar and garlic, this delicious mushroom stew is topped with a crumbly hazelnut, oat and sage topping, then baked until golden. Serve with steamed carrots and stir-fried cabbage for a completely balanced meal.

INGREDIENTS

Streusel topping:
50g wholemeal flour
50g oats
50g soya margarine
50g hazelnuts, chopped
3 tablespoons fresh sage, chopped extra sage leaves to garnish

Base:

2 tablespoons olive oil
1 onion, chopped
3 flat mushrooms, sliced
375g mixed closed-cup and shitake mushrooms, halved
2 garlic cloves, crushed
2 tablespoons wholemeal flour
300ml vegetable stock
2 tablespoons balsamic vinegar
1 tablespoon tomato purée
1 teaspoon Dijon mustard salt and pepper

METHOD

1. To make the topping, put the flour, oats and margarine in a bowl and rub the fat into the flour with your fingertips until the mixture resembles fine breadcrumbs. Stir in the hazelnuts and sage and set aside

2. Heat 1 tablespoon of oil in a large frying pan, add the onion and cook for 5 minutes, stirring occasionally until softened

3. Add the remaining oil, then mix in the mushrooms and garlic. Cook for 3 to 4 minutes until lightly browned

4. Sprinkle the flour over the mushrooms then mix in. Pour the stock into the pan, add the vinegar, tomato purée, mustard, salt and pepper and bring to the boil, continuing to stir gently

5. Transfer the mushroom mixture to a shallow 1.8-litre ovenproof dish. Sprinkle the streusel mixture over the top and bake in a preheated oven at 190 °C (375 °F, gas mark 5) for 20 to 25 minutes until the topping is browned. Garnish with extra sage leaves and serve

Recipe by Sara Lewis from Cancer: The power of food