Recent graduate of the UC Davis Graduate Group in Nutritional Biology Ph.D. Program, Dr. Seth Adu-Afarwuah (front row, second from right in photo at right) and Nutrition Department faculty member Dr. Kathryn Dewey (front row, third from right) have completed a study in Ghana that showed that infants who consumed Nutributter, a fat-based nutrient supplement, showed no deficit in either growth rate or gross motor development compared to international standards. Drs. Dewey and Adu-Afarwuah are shown at right with the study’s research staff in Ghana.

A nine month old child is weighed at her home.

In Ghana, UC Davis researchers conducted a randomized controlled trial of ~400 infants in 4 groups . One group received 20 g/day (108 kcal/day) of a fat-based nutrient supplement called “Nutributter”, added daily to complementary foods given to children between 6 and 12 months of age.  Results for this group were compared with those for groups who received daily a multiple micronutrient powder, a crushable multiple micronutrient tablet, or no intervention during the same period.  Iron status and prevalence of anemia were improved in all three of the intervention groups, but only in the Nutributter group was there an impact on growth.  In that group, there was no faltering in length gain between 6 and 12 months, whereas in the other groups there was the typical decline in relative length-for-age compared to WHO growth standards that one sees in most developing country populations. 

Dr. Adu-Afarwuah explains details of the study to a mother.

The statistical analysis suggested that the effect on growth was largely due to the essential fatty acids provided by the Nutributter, not to increased calories.  Motor development of the infants was assessed at 12 months.  In the non-intervention control group, only 25% of the infants were able to walk independently at that age, which is half of what would be expected in a healthy population (50% should be walking at 12 months) and indicative of developmental delay in the general population.  In all three intervention groups, there was a significant improvement in this outcome, but the percentage able to walk at 12 months was higher in the Nutributter group (49%) than in the two groups that received the micronutrient powder (39%) or tablet (36%).  Thus, the Nutributter group showed no deficit in either growth or gross motor development compared to international standards, which is a remarkable outcome. 

Results from the study were recently published in an article in the American Journal of Clinical Nutrition titled “Randomized comparison of 3 types of micronutrient supplements for home fortification of complementary foods in Ghana: effects on growth and motor development.”  Dr. Adu-Afarwuah  now works as a Nutrition Specialist with UNICEF-Ghana, supporting the UNICEF Nutrition Officers in the planning  and implementation of nutrition intervention activities in Ghana. His research interests include the development and evaluation of low cost interventions to improve nutrition and health of infants and children in low income populations.

Haj Welcome Reception 2007

Dr. Haj is currently conducting research to understand the molecular signals responsible for metabolic diseases such as obesity and diabetes.  He is particularly interested in protein-tyrosine phosphatases, or PTPs, enzymes which up- or down-regulate intracellular signals via dephosphorylation.

Dr. Fawaz Haj

“For a long time, these enzymes were ignored,” Dr. Haj says.  “People had the misconception that phosphatases were boring.” 

Each phosphatase has numerous substrates.  Studying such promiscuous enzymes, the thinking went, couldn’t possibly yield useful insight into metabolic regulation.  But then, two independent labs generated knockout mice deficient in protein-tyrosine phosphatase 1B.  Surprisingly, given that PTP1B has so many substrates, the two independently derived knockout strains shared the same phenotype of increased insulin sensitivity and resistance to diet-induced obesity.  PTP1B thus appeared to have very specific intracellular targets.  Additional work using knockout and RNAi approaches revealed the specificity of other phosphatases as well. 

“This raised the hope that you could inhibit PTP1B in humans to increase insulin response and energy expenditure,” says Dr. Haj.  In 1999, he began exploring the workings of PTP1B as a postdoctoral scholar in the laboratory of Harvard’s Dr. Benjamin Neel.  Now, as a recently appointed Assistant Professor of Nutrition, he’s bringing his research to UC Davis.  

To understand how phosphatases can be inhibited, Dr. Haj needs to understand their actions both at the whole-body level and within each cell.  “We’re using tissue-specific knockouts of PTPs to see what these enzymes do in a physiological setting,” he says.  His team will test the PTPs’ regulatory roles in peripheral insulin-responsive tissues.  They’ve already demonstrated that the liver is a site of PTP1B action.  Future work will let them see the level of communication and redundancy between tissues with respect to these enzymes.

In close collaboration with the laboratory of Dr. Philippe Bastiaens in Germany, Dr. Haj is using fluorescence resonance energy transfer (FRET) to examine PTP regulation inside each cell.  This technique will help determine how enzymes with many substrates target their actions.  “We know that localizing PTPs within the cell controls which substrates they can access,” Dr. Haj says.  PTP1B is tethered to the endoplasmic reticulum, where it must wait for substrates to come to it.  This system of enzymatic regulation is rather like having sit-down service in a restaurant instead of a buffet.  FRET will show what “meals” arrive at the enzyme and which “waiters” bring them.

Although Dr. Haj is very busy setting up his lab and building collaborative relationships with scientists from Europe to China, he is keen to explore sit-down and buffet service in Davis at the macroscopic level.  He grew up in Lebanon and has lived in the UK and Boston, so he eats “everything” – but sushi is his favorite. 

By Erin Digitale

Nancy Hudson and Dr. Francene Steinberg

"Dietetics is at the center of many overlapping domains of knowledge,” says Dr. Francene Steinberg, Associate Professor of Nutrition.  With assistance from Nancy Hudson, Dr. Steinberg directs the Didactic Program in Dietetics, which forms the core of the Clinical Nutrition course work.  The program, developmentally accredited by the Commission on Accreditation for Dietetics Education, is the first step toward becoming a Registered Dietitian, and covers nutrition science, food science, medical nutrition therapy, human physiology, public health and wellness, business and food service management, the social sciences and general education courses.

Future dietitians at Davis are taught by the country’s best nutrition scientists.  “We place great emphasis on rigorous science courses,” Dr. Steinberg says.  “It’s a definite benefit of studying here.” 

Students especially enjoy their upper-division medical nutrition therapy classes.  Using case histories based on real patients, they conduct nutrition assessments, plan diet modifications and nutrition education, and practice writing chart notes to communicate with other health professionals.  “It’s a chance to integrate their knowledge from basic nutrition, physiology, and adult learning theory in the setting of disease pathology,” Dr. Steinberg says.  Outside the classroom, students are encouraged to find paid or volunteer positions in clinical nutrition, community nutrition, and food service management.  Many students also gain hands-on exposure to nutrition science by working part-time in campus research labs.

The program attracts people from a wide variety of backgrounds.  A few enter the major as freshmen, but the majority of Clinical Nutrition students are juniors and seniors, including many who transfer from other institutions.  “We’re working hard to increase our program’s ethnic and cultural diversity as well,” Dr. Steinberg says.  “The population we serve as professionals is very diverse.  It’s important to connect culturally with our clientele.”

After leaving UC Davis, many graduates complete accredited internships in dietetics to qualify for the exam that certifies them as Registered Dietitians.  Dr. Steinberg says that at this stage of their education, Davis students stand out.  “Internship directors value the type of training we provide,” she says.  “We also hear from program graduates that they really come to appreciate the hard work we put them through.”  Graduates who chose not to become Registered Dietitians pursue educational and professional paths that include other health professions, graduate study, and work in the business world.  Click here for a list of jobs held by alumni of the Clinical Nutrition major.

By Erin Digitale

The garden based research program that Dr. Sheri Zidenberg-Cherr planted more than seven years ago has grown. A nutrition specialist in Cooperative Extension at UC Davis, Zidenberg-Cherr (shown at right) has done several studies centering on the use of school gardens in academic instruction to teach nutrition and promote better eating habits. Moving beyond school gardens, Zidenberg-Cherr has begun research on comprehensive nutrition services in schools. Her group is measuring the impact of a multi-faceted approach to nutrition education on changes in eating behavior.

The program offers science-based classroom curricula, reinforced with hands-on experiences in instructional gardens, kitchen classrooms, and composting programs. Whenever possible, fresh fruits and vegetables from local growers are used to improve food selection in school cafeterias. Comprehensive school nutrition programs seek to help students make connections between food, health, agriculture, their community, and the environment. “They say it takes a whole village to raise a child—that’s really what is required to improve children’s nutrition,” says Zidenberg-Cherr. “We want children to realize that it feels better to eat healthier foods and to exercise. We want to give them the tools to make changes for life. Simply changing the food selection at schools and forcing kids to eat it is not enough.”

The need for nutrition education is pressing. In California, more than 25 percent of K–12 students are overweight or obese, and nearly 40 percent are considered physically unfit.
Schools are excellent settings for nutrition education because large numbers of children can be reached in a systematic fashion. Children eat at least one or two meals daily on school grounds, and the food on campus can strongly influence their eating habits.

One of the main obstacles to teaching nutrition to schoolchildren is a shortage of instructional time. Nutrition is not a mandatory subject. California teachers are required to address the mathematics and language arts curricula for each grade level, so Zidenberg-Cherr and others have developed lesson plans that link nutrition to the state standards for core subjects.

Another challenge for nutrition educators is that many children today, across all income levels, lack food preparation skills. Families eat out frequently or buy packaged food. Some have kitchens that aren’t even equipped with the basic tools to prepare food. “Maybe you could get them to buy a stalk of broccoli, but they really have no idea what to do with it,” says Marilyn Briggs, the former deputy California State Superintendent of Public Instruction shown at right, now a graduate student working with Zidenberg-Cherr. Briggs has begun work with Zidenberg-Cherr on a nutrition intervention in a rural school district near Redding, Calif. Over the course of three years, Zidenberg-Cherr’s group will measure the activity levels, food preferences, and food selection of the 300 middle school and high school students in the study to evaluate the effectiveness of a multi-component approach to nutrition education.

Zidenberg-Cherr and others recently established the UC Davis Center for Integrative Nutrition Environments in School Communities (CNS) to serve as a resource for schools and nutrition educators. To better inform students, CNS works with the California Department of Education to give teachers accurate nutrition information that incorporates the latest scientific findings from universities. The teacher training programs are sponsored in part by a UC Davis endowment established in the name of former dietitian Barbara Van Zandt by her daughter Karen (Van Zandt) Medford.

“We’re moving nutrition education beyond school gardens to the entire school community,” says Briggs. “We want to define the determinants that really make positive improvements in children’s eating behaviors.”

by Robin DeRieux, originally published in CA&ES Outlook Fall 2007

Dr. Liz Applegate, a nationally renowned expert on nutrition and fitness, is a faculty member of the Nutrition Department at the University of California, Davis. Her enthusiasm and informal style make her undergraduate nutrition classes the nation’s largest, with enrollments exceeding 2,000 annually.

“The thrill of interacting with students” is Dr. Applegate’s favorite part of her job. “It’s exciting to get e-mails that say, ‘I lost 20 pounds after I took your course.’ I think, wow, delivering this material made a difference.”

UC Davis’s Nutrition 10 course, Discoveries and Concepts in Nutrition, is one of the country’s most popular undergraduate courses. The course covers the foundations of nutrition science, including nutrient digestion and metabolism, with special focus on areas relevant to college students, such as diet supplements, food labels and diet guidelines, the nutritional effects of alcohol, nutrition for athletes, and the links between nutrition and chronic disease risk.

“My emphasis is to cover basic nutrition in a way that interests students in science and brings in their own personal issues related to nutrition and health,” says instructor Dr. Liz Applegate.

“If I pick up on what students really want to hear about nutrition, they learn the material much better than if they’re just memorizing facts. So I make the course as personable and applicable as possible.”

Students give rave reviews to Dr. Applegate’s enthusiastic style and her extensive use of innovative classroom technologies.

“Using PowerPoint slides during lectures allows me to communicate complicated scientific concepts because students can see the concepts sequentially,” Dr. Applegate says. She uses cartoons and animations to draw analogies between the body’s machinery and everyday life: antioxidants are firefighters, DNA encodes protein on a factory assembly line, and the body’s cholesterol transport system runs like a bus service.

Lecture podcasts are a popular recent addition to the course. Podcasting, a method of distributing digital media files over the Internet, has been used since 2005 to provide students with audio recordings of Nutrition 10 classes. Lecture recordings are posted on the course Web site after each class. Students can download and listen to lectures on their computers or MP3 players.

Lecture podcasts are extremely popular with students. Students recently gave the podcasts a rating of 4.8 of a possible 5 points on course evaluations. “Podcasts are one way that we can accommodate different learning styles,” says Dr. Liz Applegate, the instructor of Nutrition 10. “Podcasts let students review the parts of lecture that they didn’t understand. Students feel better in class knowing the podcast will be there.”

Students whose schedules conflict with out-of-class activities such as the pre-exam review sessions also appreciate the podcasts. “Most of the class material is summarized in the review sessions,” Dr. Applegate says. “Listening to a review via podcast is almost as good as being there live.” She emphasizes, however, that although some students listen to the podcasts instead of coming to lectures, she doesn’t see them as a substitute for attending class. “There’s a lot to be gained in terms of engaging in the material through face-to-face instruction,” she says.

In her classes, Dr. Applegate emphasizes that she doesn’t view individual foods as good or bad. “For example, I eat potato chips and In ‘N Out – in perspective with other foods,” she says. “Eating well isn’t about being perfect, but about finding out what food has to offer, and striking a balance between your needs, personal preferences, culture, and family experiences.”

Her own balance includes lots of veggies – tomatoes are her favorite – and twice-a-day swimming, cycling or running workouts.

Dr. Applegate earned a B.S. in biochemistry and a Ph.D. in nutrition at UC Davis. During her student days, she could often be found prepping vegetables at her part-time Coffee House job.

As a faculty member, she has received the University of California’s prestigious Excellence in Education and Excellence in Teaching Awards. She is the author of several books and has written over 300 articles for national magazines. She speaks frequently at industry, athletic and scientific meetings and on international, national and local radio and television shows such as Good Morning America and the health segments on CNN and ESPN. She serves as a nutrition consultant to NBA and NFL individuals and teams and is currently the team nutritionist for the Oakland Raiders. She is also the director of sport nutrition for Intercollegiate Athletics at UC Davis.

By Erin Digitale

Patrice Armstrong, Denise L. Chapel, Rene Urquidez Romeroy

Graduate student Patrice Armstrong and Dr. Charles Stephensen are studying the effects of genes and diet on inflammation-mediated heart disease risk among African-Americans.  The body’s inflammatory response relies upon signal molecules such as leukotrienes, prostaglandins, and cytokines.  Increased inflammation from these signals raises heart disease risk. 

The project, funded by the National Center for Complementary and Alternative Medicine, is a collaboration between UC Davis, the USDA’s Western Human Nutrition Research Center, and researchers in Sacramento and Oakland.

The team is studying 5-lipoxygenase, a gene in the leukotriene biosynthesis pathway.  Several variant forms of the 5-lipoxygenase gene are found in human populations.  Some variants confer increased heart disease risk relative to the most common form of the gene, whereas others are associated with decreased risk.  In addition, the 5-lipoxygenase gene is nutritionally responsive: its activity can be changed by changes in dietary fatty acid composition.

Patrice Armstrong, Jessical Luo

The research team is screening healthy African-American adults, aged 20 to 59, to see which variants of the 5-lipoxygenase gene are found in this population.  The team hypothesizes that high-risk gene variants are common among African-Americans, and may contribute to their high rates of heart disease. 

After screening, subjects with six variants of the 5-lipoxygenase gene that confer different levels of heart disease risk are being recruited for the study’s nutrition intervention.  During the intervention, subjects consume an omega 3 fatty acid supplement (fish oil) or a placebo for 6 weeks.  Omega 3 fatty acids have known anti-inflammatory effects, including reducing activity of the 5-lipoxygenase gene.  The researchers are measuring a variety of inflammatory markers and heart disease risk factors both before and after the treatment.  They anticipate that people with the gene variants that confer higher risk of heart disease may experience the greatest reductions in inflammation and thus benefit most from consuming fish oil supplements.  If this hypothesis is correct, the study’s results could eventually be used to design individually-tailored diet plans aimed at preventing heart disease.

Recruitment for the study is ongoing.  For more information about this study, please see http://www.ars.usda.gov/Main/docs.htm?docid=11240 under “Heart & Health Study.”    

By Erin Digitale

DVM/PhD student Bethany Cummings (show at right) and Associate Research Endocrinologist Dr. Peter Havel are testing whether certain nutritional supplements prevent or delay type 2 diabetes.  Type 2 diabetes arises from inadequate action of the sugar transport hormone insulin.  The disease, which presently has no cure, significantly elevates individuals’ risk for heart disease, kidney failure, blindness, and limb amputations.  Cost-effective ways to prevent or delay type 2 diabetes are urgently needed.

The Havel lab is testing the preventive efficacy of three diet supplements: eicosapentanoic acid (EPA), a polyunsaturated fatty acid; fish oil, which contains EPA; and the antioxidant lipoic acid.  These supplements were chosen for their plausible mechanisms of action, low cost, and apparent lack of side effects.  The supplements are being fed to a strain of diabetic rats developed by the Havel lab.  The animals, known as UC Davis Type 2 Diabetes Mellitus Rats, exhibit a disease syndrome very similar to human type 2 diabetes.  Animals are eating one of three supplemented diets or a control diet and are being monitored for the elevated blood sugar levels characteristic of type 2 diabetes. 

Dr. Havel’s team hypothesizes that EPA and fish oil stave off diabetes by activating the peroxisome proliferator-activated class of nuclear receptors (PPARs) to increase circulating adiponectin, a hormone made by fat cells, and to reduce circulating free fatty acid and triglyceride levels.  These metabolic changes are linked to lower diabetes risk in humans and animals.  Lipoic acid’s antioxidant activities are hypothesized to protect against oxidative changes that promote diabetes.  For example, pancreatic beta cells, which produce insulin, are very susceptible to oxidative damage and thus might be protected by lipoic acid.

The lab’s preliminary findings suggest that lipoic acid may delay diabetes onset.  Additionally, EPA and fish oil appear to have positive effects on lipid metabolism in rats both before and after diabetes onset.  The next phase of the project will test the mechanisms of lipoic acid action in an environment of diet-induced oxidative stress.  The study is being funded by a grant from the National Center for Complementary and Alternative Medicine.

By Erin Digitale

Recent Ph.D. graduate Angela Zivkovic (shown at right in adjacent photo) was awarded the Max Kleiber Prize for innovative research in nutrition and metabolism.  The prize honors the late Max Kleiber, Professor of Animal Science, who had a long and distinguished career as a teacher and scientist at UC Davis. 

Dr. Zivkovic was recognized for her work to build metabolic assessment tools that could be used to evaluate potential disease trajectories of currently healthy individuals.  She assessed complete lipid profiles in obese individuals with fatty liver and in healthy subjects.  Complete lipid profiling measures all lipid metabolites found in the blood, providing a much more detailed metabolic assessment than single measures such as blood cholesterol level.  Individuals were compared in both fasted and postprandial (after a meal) conditions.  The metabolic changes found as a result of meal consumption and as a result of fat accumulation in the liver will be used in future work to predict individuals’ progression to fatty liver disease.  Dr. Bruce German, a Food Science professor and member of the Graduate Group in Nutritional Biology, mentored the project.

Dr. Zivkovic is currently conducting postdoctoral research with Dr. Bruce Hammock, UC Davis Professor of Entomology, and at Lipomics, a UC Davis spin-off company started by Dr. Steve Watkins, a former student of Dr. German.  She is also working to establish a private practice as a nutrition consultant, with a focus on preventive health care.

By Erin Digitale

Women in rural areas of Vietnam often suffer from poor nutrition, underweight and anemia.  When they become pregnant, these women are at high risk for inadequate weight gain, complications of pregnancy, and unfavorable birth outcomes. 

UC Davis Nutritional Biology Ph.D. student Andrew Hall (in adjacent photo seated at right) and Research Professor Dr. Janet King are developing a low-cost nutrition intervention designed to improve maternal health and pregnancy outcomes among rural Vietnamese women.  Their study, currently in the pilot stage, will recruit approximately 500 women of childbearing age from 21 communes in rural Vietnam.

During the two-year study, women in control communes will receive nutrition education, while those in treatment communes will receive nutrition education and a daily food supplement.  The supplement will consist of locally available animal-source foods such as chicken eggs, small shrimp, field crabs, and small fish.  Animal-source foods are rich in nutrients needed for fetal development, including iron, zinc, vitamin A, and vitamin B12.  However, in rural Vietnam, social and economic obstacles and dietary taboos observed during pregnancy often limit women’s consumption of these foods. 

The foods will be prepared by study cooks according to local tastes, and will be eaten by subjects at the study center.  Some women will receive food supplements throughout the study, beginning before they become pregnant.  Others will start receiving the supplements in the second trimester of pregnancy, the time when local customs dictate dietary changes for expectant mothers. 

The research team anticipates that maternal health and infant birth weight and health will be improved more by the daily food supplement than by nutrition education alone.  Because prior studies have shown strong effects of maternal nutrient status at conception on the offspring’s future health, they also expect that improving women’s diets before pregnancy will have greater benefits than waiting until pregnancy to initiate dietary changes.  The researchers hope their findings will be used to develop sustainable, locally sourced, low-cost nutrition interventions that will improve maternal and child health in Vietnam and other developing countries.

By Erin Digitale

The Department of Nutrition recently honored Dr. Louis Grivetti with a celebration of over 30 years of service as a faculty member, colleague, mentor, and friend. Before the retirement celebration a special symposium in Nutritional Geography was held with three distinguished speakers, Britta Antonsson-Ogle speaking on edible wild plants in nutrition and food security, Jan L. Corlett speaking on perspectives on nutritional geography, and Betram M. Gordon speaking on California, France, and the medium of chocolate.

Dr. Louis Grivetti’s professional niche is the study of food-related behaviors and their nutritional consequences.  His work spans 35 countries, chronological periods from antiquity to the present, and research topics from famine survival to the history of chocolate. 

Dr. Grivetti began his nutrition career as a research assistant studying zinc deficiency in Egypt.  He didn’t know much about nutrition when he started – his bachelor’s and master’s degrees are in paleontology – but he took the job because he liked the idea of living in an Egyptian village and learning Arabic.  “My parents said I was throwing my life away,” he says with a grin. 

The researcher who hired Grivetti, Dr. William J. Darby of Vanderbilt University, later asked him to co-write a book on food history.  Food: The Gift of Osiris, by Darby, Ghalioungui and Grivetti, was recognized by the Nutrition Foundations of Europe and North America as the best nutrition book published globally in 1977.  Grivetti developed further expertise in nutrition while earning a Ph.D. in geography at UC Davis and writing an interdisciplinary dissertation on drought survival among the peoples of Botswana.  His finding that the Tswana peoples of the Kalahari Desert avoid famine by eating drought-resistant wild plants mushroomed into years of study in developing countries. 

Dr. Grivetti and his graduate students called their work “salvage ethnobotany.”  They interviewed village elders to collect fast-vanishing knowledge of plants, knowledge that younger individuals often disdained.  The work was paired with direct nutrient assessment of traditionally consumed plant foods.  They found that many “weeds” of modern agriculture have food value, especially in times of drought. 

“This raises an ethical dilemma,” Dr. Grivetti says.  “If people are encouraged to use herbicides on their crops, they increase yield but reduce dietary diversity.  If they don’t spray their crops, they increase the diversity of the diet, but only if young people can identify the useful plants.”  One of his students, Noelle Johnson, coined the phrase “nutritional extinction” to describe the cultural loss that arises as knowledge of wild food plants disappears.  This can lead to, in Dr. Grivetti’s words, “starvation in the midst of food plenty.”

Dr. Grivetti’s work has also encompassed many other areas of food ethics and food history.  He is a frequent commentator on the ethics of international food relief programs.  And his historical research has a wide span, with a focus on the history of chocolate.  He’s currently working on a book, expected out in mid-2008, tracing chocolate’s history “as a social glue that holds people’s cultures together.”

Slowing down for retirement isn’t on Dr. Grivetti’s agenda.  “Professors have the best job in the world,” he says, noting how greatly he has enjoyed the variety of his work and his continual interaction with students.  Perhaps his most satisfying teaching has been his highly successful course to help graduate students prepare for their qualifying exams.  He always asks students to think broadly about the purpose of their education.  “As scientists, we have special responsibilities,” he says.  “We have gifts of intellect that require us to help our fellow people.”

By Erin Digitale

UC Davis Nutrition Department Professor Dr. Barbara Schneeman Retires

Every phase of Dr. Barbara Schneeman’s varied career has had one constant.  Her work transcends boundaries – between scientific disciplines, between researchers and university administrators, and between academia and the wider world. 

Dr. Schneeman, shown at right, was drawn to UC Davis in 1976 by a joint faculty appointment between the Food Science and Nutrition departments.  “At the time, it was unique to have an opportunity to build bridges between these two fields,” she says.

Her research topic, the human gastrointestinal tract, was well-positioned at the intersection of the two disciplines.  “Food makes the transition to nutrients in the GI tract,” Dr. Schneeman explains.  She began by studying the seemingly contradictory behavior of dietary fiber.  “Fiber isn’t digested in the small intestine, yet it acts there to modify blood glucose and cholesterol levels,” she says.  She found that fiber works by interacting with digestive enzymes and changing the physical properties of the intestinal contents. 

This work led to a sustained interest in the impact of food components on cardiovascular disease and obesity.  For example, Dr. Schneeman’s team studied how fiber changes blood levels of triglyceride-rich lipoproteins, the protein-lipid packages that transport fat through the bloodstream.  Elevated TG-rich lipoprotein levels increase heart disease risk.  Dr. Schneeman developed a method for distinguishing between TG-rich lipoproteins from different sources, allowing her research team to monitor TG-rich lipoproteins assembled in the gut after meals and thus track fiber’s effect on heart disease risk.  Another line of research examined the effect of food components on women’s ability to feel full at the end of a meal.  Secretion of the hormone cholecystokinin, an important satiety signal, was enhanced when fiber was added to women’s diets. 

As a researcher, Dr. Schneeman especially enjoyed mentoring the graduate students and postdocs who worked in her lab.  “The one-on-one interactions and mutual discovery with my students and colleagues were great benefits of being at the university,” she says. In addition, the expertise developed through her teaching and research program gave Dr. Schneeman the opportunity to become involved in national and international policy issues such as the development of food-based dietary guidelines.

In the 1990s, Dr. Schneeman worked extensively as a university administrator, serving as Chair of the Department of Nutrition, Dean of the College of Agricultural and Environmental Sciences, and Associate Vice-Provost for University Outreach at UC Davis.  “As an administrator, it was very satisfying to facilitate the success of others and build innovative programs,” she says.  For example, at the College of A&ES, she oversaw the development of new undergraduate majors in biotechnology and animal biology and the implementation of the Science and Society program, and helped the college significantly increase its endowment.  “Organizations must remain responsive and relevant in new situations, and I enjoy facilitating that process,” Dr. Schneeman says.

In 2004 Dr. Schneeman moved from UC Davis to work more directly on the challenges of developing food and nutrition policy.  She is now directing the Office of Nutrition, Labeling, and Dietary Supplements within the Center for Food Safety and Applied Nutrition at the US Food and Drug Administration, where she works at federal and international levels to plan and implement public health policy.  “I often refer to my current position as ‘reality nutrition’ and sometimes ‘reality food science’,” Dr. Schneeman says.  “In this position I must consider not only what new research is needed in food and nutrition but also how we use our knowledge to improve public health.”

By Erin Digitale

Whether he’s in the lab studying enzymatic cofactors or playing in the brass section of the UC Davis symphony, Dr. Robert Rucker has long been passionate about scientific and humanistic discovery.

Dr. Rucker began his career at Purdue University, earning a Ph.D. in Biochemistry under the guidance of Dr. Herbert Parker. “Graduate support was plentiful and the research questions one addressed were considerably less focused. I was merely told to go into the lab and study some aspect of copper-related metabolism.” He examined the mineral’s roles in growth, development, and extracellular matrix formation. His work had ties to nutrition, so an offer, in 1969, of a faculty position in the growing Department of Nutrition at UC Davis was a good fit. “The department was looking for someone with a biochemistry background who could link himself to things going on in Medicine,” Dr. Rucker says.

His early research at UC Davis examined the biomechanical consequences of copper deficiency. Copper is a cofactor for lysyl oxidase, the enzyme responsible for cross-linking fibers of collagen and elastin to give these proteins structural integrity. Faulty cross-linking of collagen leads to structural defects such as weakened bones, while poor elastin cross-linking increases risk of aneurysms. Dr. Rucker’s work to isolate and sequence tropoelastin, a precursor to mature elastin fibers, allowed other researchers to understand the etiology of emphysema. Rucker’s lab also showed that, surprisingly, elastin does not turn over. “Elastic fibers are designed to last a lifetime,” Dr. Rucker says. Most of the body’s other proteins are completely replaced when they wear out, whereas elastin can only be repaired. “Loss of elastic fiber integrity underpins diseases such as emphysema and the wrinkling associated with aging,” he adds.

Investigating copper eventually piqued Dr. Rucker’s curiosity in other cofactors, particularly those in the quinone family. Recently, he has focused on pyrroloquinoline quinone (PQQ), a dietary component which exerts widespread physiologic effects as a cofactor for a family of redox enzymes. PQQ also appears to have signaling activity, perhaps helping trigger the development of new mitochondria. The Rucker lab has shown that dietary PQQ deprivation leads to defective mitochondrial development in neonatal rodents. This sort of cytokine-like cell signaling by food components is poorly understood. “If PQQ is indeed a key player in mitochondriogenesis,” Dr. Rucker says, “this research could serve as a model for the study of other dietary components, such as flavanols and flavonols, that have cytokine-like activity.”

In addition to his lab work, Dr. Rucker has impressive teaching and academic service records. As both Vice Chair and Chair of the Department of Nutrition, he helped the department develop strong links with the UC Davis Medical School. He is a past president of the American Society for Nutrition, has served on the editorial boards of several scientific journals, and has contributed significantly to the development and teaching of several courses in biochemistry and micronutrient metabolism at UC Davis.

Away from his professorial duties, Dr. Rucker is a loyal fan of UC Davis sports teams and an accomplished tubaist with several local musical groups. He has been married for 40 years to his wife, Margaret, a professor of textiles and clothing at UC Davis. The Ruckers aren’t planning to slow down for retirement; more PQQ research, travel, and perhaps a book are on the horizon.

“The keys to success are to surround your self with those who have more insight and smarts and then pay attention,” says Dr. Rucker. “At UC Davis, I’ve been blessed for 40 years with students and colleagues who have had incredible insight and smarts. Fortunately for me, on occasion, I have paid attention.”

By Erin Digitale

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