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Ruth MacDonald

Professor and Chair, Food Science and Human Nutrition, Assistant Dean of Graduate Programs, College of Agriculture and Life Sciences, Iowa State University

Expert Bio

Ruth MacDonald is currently the Chair and Professor of the Department of Food Science and Human Nutrition at Iowa State University since 2004. She received her Ph.D. in Nutrition and Food Science from University of Minnesota, and since then, she has written multiple publications about the relationship between soy components and botanicals and breast, prostate, and colon cancer progression.

For the 17 years before her position at Iowa State, she served on the faculty at University of Missouri in the Departments of Food Science and Nutritional Sciences. She was a member of the Food for the 21st Century Nutrition Cluster, and she serves on the editorial board of the Journal of Nutrition, The Korean Journal of Nutrition, been on grant review panels for the US Army Breast Cancer Program, US Department of Agriculture, National Institutes of Health and other funding groups. Additionally, she is a member of the American Association for Nutritional Sciences, American Association for Cancer Research, Sigma Xi, and the Institute for Food Technologists.

Studies, Articles and Answers

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Q: Hasn’t the rise in obesity been linked directly to when GMOs were introduced into our diet?

Answered By Ruth MacDonald - Jul 30, 2013

A: First, let’s start with the definition of obesity. “Obesity occurs when, over time, the body takes in more calories than it burns,” according to the Endocrine Society.  When a person’s body mass index (BMI) is over 30, that person is considered obese.  Because obesity is related to the number of calories a person consumes, a GM crop would have to contain considerably more calories than non-GM varieties of that crop to be linked to obesity. But the fact is that GM crops are carefully reviewed to make sure they are substantially equivalent to non-GM crops in their composition and [...]

GMO Basics Health & Safety How GMOs Are Made


Q: How can you say that there are very few products in our grocery stores that have GMO's, when every packaged food is filled with them. My estimate is 75% and I read labels all of the time and I know what foods have genetically modified corn, soy, etc. Just

Answered By Ruth MacDonald - Aug 27, 2013

A: There is a great deal of confusion about what foods are GMOs in the grocery store. Many people believe that the produce aisle is full of GM foods, which is not accurate. Nothing in the produce aisle in the United States is GM―with the exception of papayas from Hawaii and some squash and sweet corn. The majority of corn and soybeans grown in the United States are GM. These commodities are processed to generate food ingredients that enter the food supply. From corn we obtain corn oil and corn starch. The starch can be converted into corn syrup, and sweeteners as well. From soybeans we obtain soy [...]

GMO Basics How GMOs Are Made


Q: How come food items that contain GMOs are unlabeled in America?

Answered By Ruth MacDonald - Sep 05, 2013

A: The U.S. Food and Drug Administration, which regulates food labels, has determined that the process of using biotechnology to produce foods does not need to be identified on a food label unless the process has modified the food or ingredient in a manner that changes how it is used in the food, its nutritional composition or whether it includes a potential allergen. Based on scientific evidence, the FDA scientists have concluded that the GM foods and food ingredients being used in the United States today are no different from their non-GM counterparts in any way that would requi [...]

GMOs in Groceries How GMOs Are Made


Q: Does Xanthin gum come from a genetically modified source

Answered By Ruth MacDonald - Oct 02, 2014

A: Xanthan gum is made by allowing a very specific bacteria (Xanthomonas campestris) to grow in a liquid solution that contains carbohydrates and other nutrients. While growing, the bacteria uses the carbohydrate to produce the xanthan gum which is released into the liquid. The xanthan gum is then separated completely from the bacteria and the liquid and dried into a powder. Xanthan gum has a chemical structure that is in the same family as carbohydrates but has unique properties for adding texture and volume to foods. Depending on what company is making the xanthan gum, the source of carbohydra [...]

Environment GMO Basics Health & Safety