By some estimates, 30 to 35 percent of all cancers are related to environmental factors. Of those factors, diet is considered one of the most significant.
And although studies are frequently reported that suggest one type of food may increase or decrease your risk of cancer or other diseases, the truth, said Dr. John Milner, chief of the DCP Nutritional Sciences Research Group, is that those risks are going to vary from person to person.
"Not all people respond identically to anything, whether it's food or drugs or exercise," Dr. Milner said.
For a long time, researchers have been attempting to help unravel how and why these different responses occur. Some of the research supported by Dr. Milner's group at NCI is focused on better understanding the impact of dietary components - both essential nutrients like calcium or selenium, and nonessential nutrients like flavonoids and n-3 fatty acids - on things like gene expression, often called nutrigenomics. But nutrition, he stressed, also has an impact on proteomics and metabolomics.
Using advanced technologies like microarrays and RNA interference, researchers are identifying the molecular sites of action of certain bioactive food components and teasing out how these nutrients influence processes such as carcinogen metabolism, inflammatory response, and DNA repair.
Dr. Milner pointed to the example of studies demonstrating that omega fatty acids, such as those found in abundance in certain types of fish, may inhibit the HER2 receptor, the same protein targeted by trastuzumab (Herceptin) that is linked to a particularly aggressive form of breast cancer.
But underlying this line of research, he continued, is the need to account for the differences between individuals that influence their response to the more than 25,000 bioactive food components in the diet.
"We have consistently seen a lot of variability in the response to different dietary components, and that's linked to a number of things," said Dr. Milner. "It's the number of interactions with those components and their interactions with the genes of the individual. There's also the influence of the duration and the timing of exposure. What we're trying to do is define the circumstances when dietary interventions can minimize cancer risk and change tumor behaviors."
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