For Immediate Release: November 13, 2009
NW: Questions about when to exercise, nutrition influencing genetics, juice
Week of December 28, 2009
Contact: Alice Bender, (202) 328–7744
Karen Collins, MS, RD, CDN
American Institute for Cancer Research
Q: What time of day is exercise most helpful?
A: Time of day is not the most important influence on the benefits of exercise. The best time for activity is when you’ll do it. Overall, whether for weight control or disease prevention benefits, time of day does not seem to make much difference. Many people find that getting in at least some physical activity at the beginning of the day makes it less likely to get pushed aside by other items on the “to do” list. Even if they don’t initially love getting up a little earlier to make sure there’s time, they often end up deciding it starts the day on a great note. However, if your mornings are so hectic that you end up skipping the activity you planned, try to find a time of day that you can more successfully keep open. Some evidence suggests that strength training (e.g., with weights or elastic resistance bands) is most effective through the afternoon and early evening, and greater flexibility then decreases chance of injury. As for other influences, people with diabetes need to talk to their physician or diabetes educator about what timing in relation to meals is best for them. People training for races or other athletic events may most successfully train at the same time of day the event occurs. If your activity is early morning outdoor walks you may want to consider adjustments in time or place during winter months if morning darkness is a safety concern.
Q: I keep hearing stories about nutrition influencing genetics. I thought that genetics refers to inherited traits. Is this stuff true?
A: Scientists used to think that the genes inherited from our parents influenced our health risks in a one–way direction by influencing our absorption and metabolism of various nutrients and affecting our susceptibility to chronic diseases like cancer, diabetes and heart disease. Research now shows that this is a two–way street. Our eating habits affect whether certain genes are turned on or lie dormant in a turned–off state. Nutrients and natural plant compounds in vegetables, fruits, whole grains, beans and nuts seem to act together to turn on genes that can promote self–destruction of cancer cells and turn off genes that promote cancer cell development. Don’t let the stories you hear convince you that we’ve got all the interactions between diet and genes mapped out, however. For now, studies in this area provide one more reason why eating a balanced mostly plant–based diet is linked to good health, and some understanding of why we don’t all get equal protection. But we are a long way from using individual testing to identify recommended amounts of specific nutrients.
Q: Is it true that the healthiest beverage choice when eating out is always juice, especially for breast cancer survivors?
A: Juice is obviously a nutritious drink, and depending on the type, it may provide valuable vitamins and antioxidants. So when you’re eating out somewhere that doesn’t offer many vegetable or fruit selections, juice can be a good option. However, remember that one of the biggest problems with restaurant meals is the excess calories we get from the large portions and hidden fat. Juice is just as concentrated in calories as a regular soft drink, and it does not fill you up in the same way as does eating solid vegetables or fruit. Because excess weight and undesirable weight gain are primary influences raising risk of many types of cancer, including post–menopausal breast cancer and its recurrence, in many cases the best beverage choice is probably water. Or consider another zero–calorie option like club soda or unsweetened ice tea, hot tea or coffee. If you don’t see vegetable or fruit options on the menu, ask what is available. Most restaurants will at least be able to provide a side order of sliced tomatoes or some sort of fruit such as grapes or melon.
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