It’s in the general area of food chemistry, looking at naturally occurring toxicants and naturally occurring health protectants, namely isoflavone content in commercial soybean foods. When I started my work here at Iowa State many years ago, these isoflavones—which are now being cited in a lot of articles—were considered toxicants because of their estrogen activity. It was at the same time that DES (diethystilbesterol) was removed from use in beef cattle as a growth stimulant because of the concerns about DES residues in beef. In the late 1970s and early 1980s these phytoestrogens in soy were considered toxic constituents. By 1990, everything had turned around and now they were considered good guys or health-protective agents through probably the same estrogen mechanism and others.

Interest in natural toxicants and health protectants has been a fluid field. With compounds that were once considered toxic, now cross out "toxic" and put in "health-protective agent." The attention this area now receives has been great because it’s opened up a whole new approach where these compounds are now considered very important health protective agents.

We’ve looked at other components in soy that also may have health-protective effects. That includes soy proteins and a new compound called soy saponins. They’re another phytochemical associated with soy proteins. Saponins are ethanol extractable like isoflavones, so they’re in many nutraceutical products that are marketed as phytoestrogens.

We’re interested in looking at the less famous compounds in soy foods because we think that they also have health-protective effects. There are many components in soy that may be health-beneficial and working together gives the overall good health picture for soy. That’s why we see people who eat whole soy protein having a better health status than people who maybe just select to eat an isoflavone extract. You don’t see the lowering of plasma cholesterol when people take isoflavone extract as tablets, but if they eat soy protein with its associated natural non-protein components we do see cholesterol lower.

For about 20 years. In the old days when you came to a department your chairman said, "You’re going to work in this area." I was interested in looking for some compounds with which I could learn to use HPLC technology, which was new when I was a beginning professor, and working with the non-protein components associated with soy fit the bill. Isoflavones were a way to learn that technology and it’s just expanded since then.

I’ve seen the field go back and forth. Now there’s a concern that there may be some toxic effects for certain population groups versus health-protective effects for probably most individuals. Some groups want to label soy phytoestrogens as endocrine disrupters; however, the evidence is not persuasive. Data on individuals who consumed soy-based infant formula and who are now in their 30s and 40s show no differences from the norm. There is considerable data that the phytoestrogens may protect against certain cancers if individuals are exposed to them during early life. The Chinese have been consuming these compounds as part of their diet for more than 2000 years and we do not see problems.

I think I’ve been fortunate to be working in a field that went pretty much unnoticed for a decade and then suddenly—and you’re still working there—everyone notices by chance or serendipity what you’ve been doing.

  What have been some of the greatest challenges in performing your work?

I always think the biggest challenge for people at universities is getting funding to support their work and graduate students. In the last 20 years it’s really changed in my field. In about 1990, the National Institutes of Health really got interested in diet for promoting good health. Prior to that there was not that much of a concern for this particular approach. There was more of a focus on what to do after the disease has occurred. Post-1990, NIH embraced a philosophy that included looking at what we can do to prevent diseases before they occur, and this is where food and nutrition have found more room for getting grants from NIH, which is certainly the major government agency to do health-related research. Because of that interest, it has spurred this whole area of soy in particular, but also all kinds of different work with food and food components and how they affect health.

  How rapidly has the state of knowledge in your field evolved in the last decade and what were some of the key discoveries that furthered that advancement?

Food scientists are typically generalists. We know a lot about many sciences, but less depth in particular areas. However, we interface with people in chemical engineering, nutrition, chemistry, and biochemistry. It’s that ability to form interfaces that’s critical for this knowledge to go forward. One of the positive aspects that’s evolved in the soy health field over the years is an understanding by the clinician community that soy is not just a black box. There are a variety of components in it, and the soy products that the food industry produces are not all the same.

Another area that we’re learning more about is the differences in individuals in their ability to adjust and absorb phytochemicals from foods due to differing microbial populations among individuals. We have observed different bioavailability groups for the soy isoflavones. Some individuals are fast isoflavone degraders in their gut and hence are low isoflavone absorbers into their plasma. Other individuals are slow isoflavone degraders in the gut, so have higher bioavailability of the isoflavones and therefore absorb more into their plasma. These data are probably the result of several factors, including differences in the microorganisms in the gut and genetics and diet that govern gut transit time. The longer the food stays in the gut, the better chance it has to be absorbed, if it is not first degraded by the gut microbes. What this all means is that we may be able to change how people absorb phytochemicals by learning the combination of diet, genetics, and physiology that works best.

  What is the implication of your work for the future of your field and allied fields?

We’re headed in the direction of just understanding these components and how we can design processes to make foods that either enhance components, make higher concentrations in products where we want them, or lower concentrations where we want them. And we want to also design specialty products to help us understand the health effects of soy components. Our ability to make soy products with specific amounts of soy protein and/or isoflavones and/or saponins and/or other phytochemicals can be used for research, and if shown to be efficacious can be developed for consumers.

  Where do you predict the state of knowledge in your field will be in 10 years?

I think we’re going to learn ways to enhance people’s ability to absorb these compounds so that they’ll have the health effects that we think they do. We’re going to understand the variations among individuals in their ability to absorb probiotic products to change microbial flora in the gut so you’ll absorb what you want or not absorb what you don’t want.

I think we’ll also see a larger use of soy and other vegetable products in the US and in the world as people try to make healthier choices in what they eat. And I think the technology in our ability to identify what's in products is going to improve. Microrarray technologies are going to come about to supplant some of the conventional wet chemistry we use. That will allow us to do many more analyses per unit time. Right now it takes one hour to do an analytical analysis of one isoflavone sample, and we can only run one at a time on our HPLC. If we can design technologies to give us multiple tests at once, our efficiency will be improved. I think the bioinformatics revolution is going to speed up our understanding of what’s going on.

  What advice would you give to those entering a research career in general?

I recommend if they haven’t tried doing any research as an undergrad they should find a professor that they can work for and try doing research. That’s a great way to find out if you’re suited for this type of career. I also suggest that students try not to close any doors. Take as many of those tough courses that you may want to avoid, but take them because that could allow you many options.

  What would you like the general public to understand about your work?

I hope that they will begin to understand how to make judgments about what’s in their food and to make good judgments based on knowledge, not on irrationality. And to understand that to have a good food supply there are a variety of different foods as well as nutraceuticals out there with health protective compounds. We know a lot about foods and can make good recommendations. We know very little about the long-term effects of nutraceutical products and want the public to use caution. There’s no substitute for grandma’s advice of eating lots of different things in moderation and nothing to excess. That statement still applies today in how we make choices about what we eat.