Nutrition News by Charlyn Fargo

For postmenopausal breast cancer, there's a strong body of evidence that shows exercising reduces the risk. But cancer can take years to develop. So how can exercise help? A new study suggests that when young women jog and are aerobically active it causes changes in estrogen metabolism, which then plays a role in reducing later breast cancer risk. And the study shows that just a half hour a day of exercise can make a difference.

The study, published in Cancer Epidemiology, Biomarkers and Prevention, is one of only a few clinical trials to focus on exercise and estrogen metabolism among younger women.

Study researchers wanted to focus on estrogen metabolism because the majority of breast cancers are related to the hormone estrogen. Research suggests that a higher lifetime exposure to estrogen increases a woman's risk for breast cancer. Yet there are many forms of estrogen and they appear to play a different role in risk.

Lab studies have suggested that two of the forms, estradiol and estrone, play a role in cancer development. These forms of estrogen break down or metabolize into compounds and it's the ratio of these metabolites that studies have suggested may influence breast cancer risk.

For this study, researchers randomly divided almost 400 sedentary young women into two groups: about half of the women were asked to exercise regularly and the others continued with their inactive lifestyle. All the women were premenopausal and the groups included women who were roughly the same age and weight.

For 16 weeks, the exercising women took to the step, the treadmill or the elliptical machine for half an hour five days a week so that they were getting a moderate to vigorous workout.

Both right before and after the 16-week exercise period, researchers collected three-days of urine samples. They then analyzed the samples for estradiol, estrone and another parent compound, and nine of their metabolites.

By the end of the study, the forms of estrogen and their metabolites were significantly different between the exercisers and the inactive women. The exercisers had far less estrone, for example, and an increase in the amount of the metabolites linked to decreased risk. The women who exercised also led to improved fitness and less body fat.

Information courtesy of the Cancer Epidemiology, Biomarkers & Prevention and the American Institute for Cancer Research.

App to Check

A new Apple App caught my eye recently — Ask the Nutritionist: Recipes for Fighting Cancer.

It was created by the Dana-Farber Cancer Institute and delivers a forum for asking nutrition questions, recipes, nutrient analyses and shopping lists to help people stay healthy through cancer treatment and beyond. Included in the app are recipes searchable to common symptoms like mouth sores or nausea. The cancer and nutrition information provided by registered dietitians is high-quality. We wish the Q & A archive was searchable, but maybe that will come.

Q and A

Q: Why are some egg yolks and eggshells different colors?

A: While shell and yolk color may differ between chicken eggs, the difference in color bears no relation to the flavor, nutritional value or the quality of the egg. The egg's size and shell color is determined by the breed of the hen. For example, the Leghorn lays large, pearl-white-eggs while Rhode Island Reds lay eggs that are medium to dark brown and are larger than the average-size-egg on the market. When it comes to yolks, the color is determined by a hen's diet, not its breed or the freshness of the egg. Hen diets heavy in green plants, yellow corn, alfalfa and other plant material with xanthophylls pigment (a yellow-orange hue) will produce a darker yellow-orange yolk. Diets of wheat or barley produce pale yellow yolks; hens fed white cornmeal produce almost colorless yolks. Free-range hens may have access to more heavily pigmented food so they may produce eggs with darker yolks. According to the American Egg Board, consumer preference in the U.S. is typically for light gold-or lemon-colored yolks.

Information courtesy of the Food & Nutrition magazine, May/June 2013.

Recipe

Lately, I'm into smoothies for a quick, grab-and-go breakfast. I typically use frozen berries and bananas with Greek yogurt (for more protein), but I came across this recipe for Peanut Butter, Banana and Flax Smoothies from Cooking Light magazine. It's packed with potassium, protein and fiber, and it's worth a whirl in the blender.

Peanut Butter, Banana and Flax Smoothies

—1/2 cup 1 percent low-fat milk

—1/2 cup vanilla fat-free yogurt

—2 tablespoons ground golden flaxseed

—1 tablespoon creamy peanut butter

—1 teaspoon honey

—1/4 teaspoon vanilla extract

—1 ripe banana, sliced

Place all ingredients in a blender; process until smooth. Makes two servings.

Per serving: 229 calories, 9.2 g protein, 32 g carbohydrate, 8.4 g fat, 3 mg cholesterol, 4 g fiber, 113 mg sodium.

Charlyn Fargo is a registered dietitian from Springfield, Ill. For comments or questions, contact her at charfarg@aol.com or follow her on Twitter @NutritionRD. To find out more about Charlyn Fargo and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

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