Obesity and and Cancer

Report stresses link between obesity and cancer

Keeping slim is one of the best ways of preventing cancer, as is avoiding excessive amounts of red meat and wine, a landmark study has revealed.

The World Cancer Research Fund (WCRF) said the link between body fat and cancer is closer than generally realized.

It found convincing evidence of a link to six types of cancer, five more than in its last report, 10 years ago.

Among the new types are colorectal (bowel) and post-menopausal breast cancer.

Professor Michael Marmot, chair of the panel of 21 eminent scientists who compiled the report, said: "We are recommending that people aim to be as lean as possible within the healthy range, and that they avoid weight gain throughout adulthood."

The report, which selected 7,000 studies from a worldwide pool of 500,000 written since records began in the 1960s, includes five key findings.

They are that processed meats, such as ham and bacon, increase the risk of colorectal cancer, and should be eaten sparingly.

Another is the link between red meat and colorectal cancer, for which the evidence is stronger than ever. People should not eat more than 500g of cooked red meat a week -- or between 700g and 750g for "blue" or uncooked meat.

A further finding was the strongest evidence yet that alcohol is a cause of cancer. If people must drink, the report said, they should limit their intake to two units a day for a man or one for a woman. A unit is a half pint of beer or a small glass of wine.

The report recommended mothers breastfeed exclusively for the first six months after birth followed by complementary breastfeeding, after evidence showed breastfeeding protects the mother against breast cancer.

It did not recommend dietary supplements as prevention.

"This report is a real milestone in the fight against cancer, because its recommendations represent the most definitive advice on preventing cancer that has ever been available anywhere in the world," said Professor Martin Wiseman, project director of the report.

Scientists believe there are several reasons for the link between body fat and cancer.

One is the relationship between excess fat and the hormonal balance in the body.

Research has shown that fat cells release hormones such as estrogen, which increases the risk of breast cancer, while fat around the waist encourages the body to produce growth hormones, which can increase levels of risk.

Evidence of a link is most convincing for cancer of the esophagus, pancreas, colorectum, endometrium (womb), kidney and post-menopausal breast cancer.

The report makes 10 recommendations including 30 minutes of moderate activity a day, rising to 60 minutes; drinking water rather than sugary drinks; eating fruit, vegetables and fiber and limiting salt consumption.

The WCRF report can be found at: http://www.dietandcancerreport.org/

Body Mass and Headaches

This study confirms something I have believed for a number of years, that
migraines headaches are more prevalent in persons who are overweight.
Though this study doesn't answer the why, I believeit has to do with the
hormonal influences from adipose tissue.




Marcelo E. Bigal, MD, PhD; Amy Tsang; Elizabeth Loder, MD; Daniel Serrano, PhD; Michael L. Reed, PhD;Richard B. Lipton, MD; for the American Migraine Prevalence and Prevention Advisory Group

Arch Intern Med. 2007;167:1964-1970.

Background We investigated the influence of the body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) on the frequency, severity, and patterns of treatment of migraine, probable migraine (PM), and severe episodic tension-type headache (S-ETTH).

Methods A validated questionnaire was mailed to 120 000 households selected to be representative of the US population. The participants were divided into 5 categories based on BMI: underweight (<18.5),> (25.0-29.9), obese (30.0-34.9), and morbidly obese (>35.0). Analyses were adjusted by covariates that included demographic variables (age, sex, race, and income), duration of illness, comorbidities, use of preventive medication, and use of opioids.

Results The response rate was 65%. We identified 18 968 individuals with migraine, 7564 with PM, and 2051 with S-ETTH. The distribution of very frequent headaches (10-14 d/mo) was assessed by BMI. Among individuals with migraine, very frequent headaches (10-14 d/mo) occurred in 7.4% of the overweight (P = .10), 8.2% of the obese (P < .001), and 10.4% of the morbidly obese (P < .0001) subjects, compared with 6.5% of those with normal weight, in adjusted analyses. Among individuals with PM and S-ETTH, the differences were not significant (P = .20). The disability of migraineurs, but not of those with PM or S-ETTH, also varied as a function of BMI. Among migraineurs, 32.0% of those with normal weight had some disability compared with 37.2% of the overweight (P < .01), 38.4% of the obese (P < .001), and 40.9% of the morbidly obese (P < .001) subjects.

Conclusion These findings support the concept that obesity is an exacerbating factor for migraine but not for other types of episodic headaches.

Author Affiliations: Departments of Neurology (Drs Bigal and Lipton) and Epidemiology and Population Health (Dr Lipton), Albert Einstein College of Medicine and The Montefiore Headache Center (Drs Bigal and Lipton and Ms Tsang), Bronx, New York; The New England Center for Headache, Stamford, Connecticut (Dr Bigal); Spaulding Rehabilitation Hospital, Boston, Massacusetts (Dr Loder); and Vedanta Research, Chapel Hill, North Carolina (Drs Serrano and Reed).