Few cancers linked to specific genes

By: KAREN COLLINS - For the North County Times | Saturday, February 23, 2008 7:44 PM PST ∞

Q: Is my cancer risk inherited?

A: According to the latest international report on diet, weight, physical activity and cancer prevention, only about 5 to 10 percent of cancers are linked to a specific inherited gene. More commonly, people may inherit small genetic abnormalities that can trigger cancer if a person is exposed to potential carcinogens in the environment or makes certain lifestyle choices (tobacco use, for example).

People with a family history of cancer do face a higher risk of developing cancer themselves, however. It is important to know your family medical history so your health care provider can help advise you on a timeline for appropriate screening tests. Yet those individuals with no family cancer history are not cleared of risk. About 85 percent of cancer patients don't have a family history of the disease.

For almost all of us, daily habits like eating healthfully, being physically active, preventing weight gain and avoiding tobacco have a greater effect on our chances of developing cancer than our family history.

Q: Are avocados really as high-calorie as some people say?

A: Because avocados naturally contain a significant amount of fat, they are indeed much more concentrated in calories than most fruits or vegetables. Avocados provide heart-healthy fat, however, so they are still a highly nutritious choice when eaten in moderation. But eat a whole avocado by yourself and you may get more than you bargained for. One avocado contains roughly 320 calories ---- more than half the number of calories recommended for an average adult meal. But you can enjoy a half-cup of the creamy fruit for 120 calories and still benefit from 5 grams of dietary fiber and more than 10 percent of the Recommended Daily Values for potassium and folate.

Q: Is it true that vinegar helps control blood sugar?

A: Reducing large spikes in blood sugar is an important step in preventing organ damage from diabetes and likely reducing the development of insulin resistance. Evidence from at least six small studies in the last decade suggests that vinegar may improve blood sugar control in certain situations. On average, the studies showed that people who consumed about two or three teaspoons of white or cider vinegar with a high-carbohydrate meal had lower blood sugar levels (from 20 to 55 percent lower) than when they ate a similar meal without vinegar.

Researchers suggest that the acetic acid in vinegar may decrease the activity of one of the enzymes central to carbohydrate digestion, thus slowing the release of glucose into the blood stream. Some earlier research suggested that acetic acid might also delay stomach emptying. Either way, these findings could provide an extra incentive to include a salad with a vinegar-based dressing (or other foods containing vinegar) alongside a meal that is particularly carb-heavy. Medicinal use of vinegar is not recommended.

Because it appears to work only when consumed with a high-carbohydrate meal, vinegar should not be taken to reduce blood sugars that are already elevated. Many blood sugar problems are due to overweight and lack of physical activity. Don't try to make up for overeating with a simple dose of vinegar. In the end, your greatest ally in blood sugar control is a healthy lifestyle.

Karen Collins is a registered dietitian who writes for the American Institute for Cancer Research. Visit www.aicr.org.

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