Stimulating Our Appetites

Food magazines and advertisers know it: looking at mouthwatering images of foods often triggers the urge to eat. Blame that craving on a hormone, suggests a new study featured in yesterday’s issue of Cancer Research Update.

The study looked at a hormone that has received a lot of attention lately in obesity science circles: ghrelin. The hormone is recognized for stimulating our appetite. Ghrelin levels increase before meals and decrease afterwards. Circulating ghrelin then travels to receptors in the hypothalamus that are involved in appetite regulation.

This study collected ghrelin blood levels from 8 men every 10- or 15-minutes from before breakfast until after lunch during two sessions. Between meals, the well-fed participants looked at images of tantalizing foods during one session. A week later at the next session, the men looked at images of everyday, non-food objects, like a pair of shoes or a bike.

In the 30-minutes after the men looked at both sets of images, their ghrelin levels were higher after seeing the food images then the non-food ones.

You can see the study abstract here. The study adds to what we know about how environmental factors influence eating behaviors, an important area of research for preventing cancer and other diseases.

To see how ghrelin stimulates appetite in the brain, here’s a video related to a 2008 study related to ghrelin stimulating our appetite.


Can Our Height Influence Cancer Risk?

The research AICR supports and highlights focuses on lifestyle choices people can make to prevent cancer, recurrence, and help survivors. So it may seem odd that one of those factors relates to height, a factor seemingly uncontrollable. The topic grabbed headlines the other week after a new study was published.

The study was big: drawing data on height and cancer from 1.3 million U.K. women. The women were tracked for almost 10 years, during which almost 100,000 of the women were diagnosed with cancer.

It was published in the Lancet Oncology. Here is the abstract.

And you can read more about the study in today’s issue of Cancer Research Update.

For every 10 centimeters (4 inches) increase in height above 5 foot 1 inch, the risk of cancer increased by 16 percent overall. When analyzed by cancer type, ten sites were significantly linked to increased height.

The women were all middle aged and the authors also looked at if the height-cancer link was modified by personal characteristics, including body weight, activity level, socioeconomics. Out of 12 factors, 11 of them did not alter the height-cancer link (only smoking slightly did.)

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The Fiber-Cancer Link

Fiber: You know it’s good for us but why? Studies consistently find a link between diets high in fiber and lower risk of chronic diseases, including cancer.

This whole wheat veggie wrap has about 4 g fiber

In May, WCRF/AICR’s report on colorectal cancer upgraded its conclusions on fiber. In reviewing all the relevant studies, the report found the evidence was now strong enough to say that foods containing fiber convincingly protect against colorectal cancer. (The 2007 report concluded the evidence was ‘probable.’)

One indirect reason for fiber’s many health benefits comes from the fiber-carrying foods. Foods containing fiber include fruits, vegetables, and whole grains – all foods packed with plenty of vitamins, minerals and phytonutrients linked with lower risk of chronic diseases. Not surprisingly, studies also show that people who eat more fruits, vegetables, and whole grains are also less likely to be overweight or obese, which is linked to increased risk of seven different cancers.

But as fiber wends its way through our body, it leaves by-products. One of them, for example, butyrate,  may link to cancer prevention.

You can read about the research in latest issue of Cancer Research Update.

If you’re wondering if you get enough fiber, the basic rule is: eat 14 grams of fiber for every 1,000 calories. If you’re not counting calories, in general women should try to eat 21 to 25 grams of fiber a day; men should aim for 30 to 38 grams a day.

Here are a few examples of high fiber foods: 1/2 cup cooked kidney beans – 7 g fiber; whole wheat wrap – 2 g fiber and 1 apple with skin – 3 g fiber.

And to find out how much fiber is in other foods, the USDA has a long list (a pdf) in Dietary Fiber Content of Selected Foods.