Lancet Oncology Sept 1 reviews

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Hi All,

Lancet Oncology September 1 issue came in.

There is an I thought good PDFs available review of:

Overweight, obesity and cancer risk.

Franca Bianchini, Rudolf Kaaks, and Harri Vainio

Lancet Oncol 2002; 3: 565–74

I included only the abstract and conclusions, the latter from which I

enjoyed:

“The best way to achieve a healthy body weight is to

balance energy intake with energy expenditure. Excess

body fat can be reduced by restricting calorific intake and

increasing physical activity. Calorific intake can be reduced

by decreasing the size of food portions and limiting the

intake of calorie-dense foods that are high in fat and

refined sugars. Such foods should be replaced with foods

like vegetables, fruits, whole grains, and beans.”

Abstract

“Over the past few decades the proportion of people with

excess body weight has been increasing in both

developed and less developed countries. About 50% of

men and 35% of women in Europe are currently

estimated to be overweight or obese. In addition to an

increase in the risk of cardiovascular disease and type II

diabetes, the evidence summarised here shows that

excess body weight is directly associated with risk of

cancer at several organ sites, including colon, breast (in

postmenopausal women), endometrium, oesophagus,

and kidney. In part, these associations with cancer risk

may be explained by alterations in the metabolism of

endogenous hormones—including sex steroids, insulin,

and insulin-like growth factors—which can lead to

distortion of the normal balance between cell

proliferation, differentiation, and apoptosis. Avoidance of

weight gain thus seems to be an important factor for

cancer prevention.

……….

Conclusions

There is sufficient evidence that adiposity can cause cancers

of the colon, breast (in postmenopausal women),

endometrium, kidney, oesophagus, and gastric cardia.

Furthermore, plausible mechanistic explanations exist for

most of these associations. Nevertheless, uncertainties

remain about the extent of excess weight that constitutes an

increase in cancer risk. For prevention of diabetes and

cardiovascular disease, a BMI in the range 18.5–25 kg/m2

has been recommended. The breadth of this range has been

justified by the fact that the ratio of adipose tissue to lean

body mass can vary substantially between individuals with

the same BMI. However, there is increasing evidence that,

even within the range of 20–25 kg/m2, BMI is directly

associated with the risk of cardiovascular disease,81 and

some epidemiological studies suggest an increased cancer

risk with BMI below 25 kg/m2 , eg, for colon cancer16,17 and

postmenopausal breast cancer.31 Therefore, for many individuals

it would be advisable to maintain weight within

the lower part of this range to reduce their risk of cancer.

For people who are already overweight, avoiding further

weight gain should be recommended, and, if possible, they

should aim to reduce weight by 5–10% 38

The best way to achieve a healthy body weight is to

balance energy intake with energy expenditure. Excess

body fat can be reduced by restricting calorific intake and

increasing physical activity. Calorific intake can be reduced

by decreasing the size of food portions and limiting the

intake of calorie-dense foods that are high in fat and

refined sugars. Such foods should be replaced with foods

like vegetables, fruits, whole grains, and beans.

We also emphasise that, at the population level, obesity

cannot be prevented solely by issuing health recommend-ations

to individuals. Governmental and non-governmental

organisations, the food industry, media,

worksites, schools, health professionals, and educators all

have a responsibility to work together to produce an

environment less conducive to weight gain. Individual

efforts to make improvements in nutrition and physical

activity are difficult and often ineffective without a

supportive community environment. Safe and attractive

places to walk, bicycle, and engage in other activities are

essential to help everyone live a healthy life. Furthermore,

because excess weight in youth tends to continue

throughout life, the prevention of obesity should begin

early in life. It is essential that teachers emphasise the

importance of healthy food, nutrition, and an active

lifestyle to children, inform them of the risks of developing

chronic diseases, and provide healthy meals and sports

facilities at schools. Educators, health professionals, and

families must all set a positive example for young people to

help them achieve this objective.

Conflict of interest

None declared.

This next also PDF available review was nice:

You are what you eat – PDF available from The Lancet Oncology

“The threat of ‘globesity’—a term recently coined by

WHO to describe the global epidemic of obesity—has

caused panic in the media and among policy makers,

especially in the US (see Reviews page 565). The publication

of US obesity prevalence statistics for 2000

brought the issue to the fore by declaring that 61% of

Americans are overweight. Since then, the high profile of

fat-related news stories has ensured that the problem is

never far from people’s minds. One recent report claims

that Hispanic women are losing their racial advantage of

a low breastcancer risk because they are increasingly

becoming obese. Trends such as these, where traditionally

low-risk populations lose their genetic advantages,

will soon add to the increasing burden of obesity-related

diseases—including type 2 diabetes, cardiovascular

diseases, and certain types of cancer—which kill

300 000 people in the US, and 30 000 people in the UK,

each year.

However, rather than stimulating the necessary rational

debate, recent statistical revelations have started a

manic rush to apportion blame. Fast-food producers are

the prime target and are rapidly becoming a focus for

classaction lawsuits on the back of legal successes

against tobacco companies. But although many useful

parallels can be drawn between the tobacco and fast-food

industries, there are several obvious distinctions

that mean court battles are the wrong approach.

Food, no matter how unhealthy, cannot be compared

to tobacco—with its abundance of addictive and

carcinogenic components. Similarly, fast-food companies

should not be accused of covering up evidence.

The link between high-calorie foods and obesity is

common knowledge; specific nutritional information is

easy to find and often on display in fast-food outlets.

Furthermore, unlike tobacco manufacturers, there is no

single party which can shoulder all responsibility. If we

are to blame the fast-food industry for obesity, shouldn’t

we also blame slimming organisations for eating

disorders? Or modelling agencies for promoting unhealthily

thin ideals? This debate hinges on the fact that

there is no moral standpoint whereby individuals are

relinquished of their personal responsibility. And if

these legal tussles show anything, it will be that obesity

cannot be resolved by continuously shifting blame.

However, mere recognition of the problem is cold

comfort when urgent action is needed. Obesity prevention

has been half-heartedly attempted by most developed

countries through health policies that aim to raise

public awareness. But the fact that obesity prevalence

continues to rocket is testament to the ineffectiveness of

these policies. Governments are still ignoring issues that

would make a real difference. Long working hours and

high-pressure environments—factors which are exacerbated

in large cities where most workers spend hours in

transit commuting long distances—contribute to the

general decrease in leisure time and prohibit regular

exercising or healthy cooking. Most prevention policies,

however, are reliant on stimulating the desire to be

healthy; this approach is not only redundant for

individuals who are limited by work commitments, but

it is also ineffective for people that associate healthiness

with compulsory and undesirable activities. To achieve

results, a change in personal aspirations is required and

prevention initiatives must emphasise that healthy living

is a necessity, not a choice.

The paradox is, of course, that good health is already

a necessity. Overweight people are discriminated against

in every aspect of their lives. They are jeered at, have

difficulty buying clothes, are deemed undesirable, and

often have trouble accessing public services. Furthermore,

employers are sometimes prejudiced against over-weight

interviewees and often favour active employees

by offering health-related benefits rather than financial

bonuses. But the immediate fallout from the perpetuation

of anti-fat attitudes is that overweight people

are made to feel excluded and stigmatised. Forcing this

belief simply adds to the problem because these people

frequently seek solace in excessive eating. On the flip

side of the coin, urging people to conform to a slim

social ‘norm’ may also lead to an aggressive backlash

against those extolling the virtues of being thin. ‘Fat is

beautiful’ groups who champion ‘freedom of lifestyle

choice’ adamantly refuse to decrease their weight and

protest against healthy-eating campaigns, which they

perceive as an infringement of personal liberty.

There is the potential for a public health crisis if the

continued lack of practical solutions means that governmental

policies run at odds to people’s personal goals.

But despite this necessity, adequate solutions may still be

a long way off as efforts are focused on development of

anti-obesity drugs and quick-fix economic strategies.

However, making even small changes to diet and lifestyle

patterns will require a monumental shift in personal

aspirations, and a corresponding shift in government

policy, that can only be achieved with uniform

commitment. So, the real question becomes, are people

really prepared to make the effort?”

This week’s main Lancet has a good review about food allergies, with much on

what causes them, how to assess them and what to do.

Cheers, Al.

Alan Pater, Ph.D.; Faculty of Medicine; Memorial University; St. 's, NF

A1B 3V6 Canada; Tel. No.: (709) 777-6488; Fax No.: (709) 777-7010; email:

apater@...