Archive | Manabu T. Nakamura

RSS feed for this section

Graphical display of nutrition information helps keep health-conscious eaters on target

URBANA, Ill. – Diseases such as obesity, diabetes, and heart disease can often be prevented or treated by managing the intake of certain nutrients. However, in a time-constrained situation, such as standing in line at a cafeteria or restaurant, it can be difficult for consumers to quickly calculate and use numerical nutrition information—beyond the amount of calories—provided for menu items.

A new study from the University of Illinois found that when consumers are shown a graphical display of select nutrients on a 2-dimensional plot when ordering in a café setting, they purchase healthier, not just lower-calorie, menu items as a meal.

Manabu T. Nakamura, an associate professor of nutrition at U of I, said understanding how to best present nutrition information is an important, new area of research for him and his lab. “We have researched how fats or carbs metabolize and are regulated, for example. Based on this kind of research, the message of what nutrients we should eat is pretty set. The important thing is learning how you select the right foods. We need to provide a way to communicate what foods to select for certain health problems.

“Current nutrition labels provide comprehensive nutrient information, but unfortunately they’re not working for consumers to help them make decisions in restaurants and grocery stores,” he said.

As part of the Affordable Care Act, chain restaurants and retail food establishments with 20 or more locations are required to provide nutrition information for menu items. But Nakamura said most people, except those who have specific health concerns or food allergies, don’t ask to see this information or don’t know how to use the information provided.

Previous research has been done showing that a “traffic light” labeling system in which menu items are designated as green, yellow, or red based on calories had some effect on diners’ choice of foods. But Nakamura explained that even that system had no effect on consumers’ purchases when multiple nutrients are color coded.

In order to see if presenting the nutrition information graphically would change diners’ purchasing behavior, Nakamura, along with doctoral student, Nathan Pratt, and a team of other researchers set up two experiments using a visual, 2-dimensional plot showing the values of fiber and protein per calorie for each menu item. The graph also includes a target box that represents the recommended dietary amounts of those nutrients per calorie of food.

The researchers chose to plot fiber and protein per calorie values because these two nutrients are closely tied to weight management. Fiber has been linked to greater satiety and lean protein has been linked to improving body fat loss. “Promoting fiber intake is important. It could help in preventing overeating. Only 10 percent of the U.S. population meets the fiber recommendation. So there’s a long way to go.”

“Most people would agree that these are two nutrients most relevant for managing weight,” Nakamura said. “Of course sodium, saturated fat, and all vitamins and minerals are also important for overall health. But we had to limit the number of nutrients in order to have an impact on decision making in a time-constrained condition.”

He added that other combinations of nutrients, depending on specific dietary needs, could also be plotted using the graph.

The team began with an experiment to see how well participants could recall nutrition information when shown the information for foods either using the 2-dimensional graph or numerical information. The participants were then asked to recall the information. Recall accuracy improved by up to 43 percent when they were shown the information graphically versus numerically.

The second experiment was a 12-week study of purchasing behavior in U of I’s Bevier Café. In this setting customers stand in line to order and pay for their food at registers near the entrance of the café.

During some weeks of the study, menu items were plotted either on the 2-dimensional graph according to their fiber, protein, saturated fat, and sodium per calorie values with the information signposted where customers could see before ordering, or other weeks, nutrition information was displayed numerically. Facts about managing a healthy weight, such as keeping calories in a healthy range, limiting saturated fat and sodium, and increasing fiber and protein was also signposted near where food was ordered.

How did having a visual target to shoot for when ordering a meal work for consumers?

Ultimately, when nutrition information was provided on the 2-dimensional graph, consumers purchased fewer calories, but purchased more protein per calorie and more items that were rated high as healthy on the plot. Nakamura calls this a “clear success.”

“This may be the first study that shows unambiguous purchasing changes from displaying the nutrition information,” he said.

During the weeks in which nutrition information was displayed graphically, calories purchased from entrees decreased by 10 percent compared to when no information was displayed, and decreased by 13 percent compared to when numerical information was provided. During the graphical stage, calories from side items purchased decreased from 43 percent compared to when no label was displayed, and 47 percent from the numerical stage.

Protein per calorie increased by nearly 24 percent when the graph was present compared to when no nutrition label was provided, and 20 percent from the numerical stage.

“If you are looking at just calories when choosing food, that’s not enough. If you stop eating something, you can certainly reduce calorie intake. But the important thing is that you when you make your meal healthy, it’s not just about calories, you have to think about other nutrients, too,” Nakamura said. “In terms of weight maintenance, you can reduce calories but increase the protein per calorie and the same with fiber, a fiber per calorie increase. These two things have to be maintained or it’s a bad diet that you can’t maintain.”

In the future, the researchers hope the graph can be used to present nutrition information in restaurants, grocery stores, and dining halls, as well as in households for recipe analysis. Nakamura said future studies on this graphical method may look at more diverse populations, menus that offer a greater variety in fiber offerings, and more nutrient combinations.

Another possibility Nakamura is excited about is the possibility of creating mobile apps with the graph that consumers can use to plot nutrients in menu items as they order during time-constrained situations.

“We are hoping this system can be quickly understood and can provide the information needed to make a decision,” Nakamura said.

“Improvements in recall and food choices using a graphical method to deliver information of select nutrients” was published in Nutrition Research. Co-authors include Nathan S. Pratt, Brenna D. Ellison, Aaron S. Benjamin, and Manabu T. Nakamura, all of the University of Illinois.

The authors acknowledge the Bevier Café for hosting the study.

Comments are closed

Illinois scientists link dietary DHA to male fertility

Original story published here on January 9, 2012.

URBANA — Who knew that male fertility depends on sperm-cell architecture? A University of Illinois study reports that a certain omega-3 fatty acid is necessary to construct the arch that turns a round, immature sperm cell into a pointy-headed super swimmer with an extra long tail.

“Normal sperm cells contain an arc-like structure called the acrosome that is critical in fertilization because it houses, organizes, and concentrates a variety of enzymes that sperm use to penetrate an egg,” said Manabu Nakamura, a U of I associate professor of biochemical and molecular nutrition.

The study shows for the first time that docosahexaenoic acid (DHA) is essential in fusing the building blocks of the acrosome together. “Without DHA, this vital structure doesn’t form and sperm cells don’t work,” said Timothy Abbott, a doctoral student who co-authored the study.

Men concerned about their fertility may wonder what foods contain DHA. Marine fish, such as salmon or tuna, are excellent sources of this omega-3 fatty acid.

The scientists became intrigued with DHA’s role in creating healthy sperm when they experimented with “knockout” mice that lack a gene essential to its synthesis. “We looked at sperm count, shape, and motility, and tested the breeding success rate. The male mice that lacked DHA were basically infertile,” Nakamura said.

But when DHA was introduced into the mice’s diet, fertility was completely restored. “It was very striking. When we fed the mice DHA, all these abnormalities were prevented,” he said.

The scientists then used confocal laser scanning (3D) microscopy to look at thin slices of tissue in progressive stages of a sperm cell’s development. By labeling enzymes with fluorescence, they could track their location in a cell.

“We could see that the acrosome is constructed when small vesicles containing enzymes fuse together in an arc. But that fusion doesn’t happen without DHA,” he said.

In the absence of DHA, the vesicles are formed but they don’t come together to make the arch that is so important in sperm cell structure, he noted.

Nakamura finds the role this omega-3 fatty acid plays in membrane fusion particularly exciting. Because DHA is abundant in specific tissues, including the brain and the retina as well as the testes, the scientists believe their research findings could also impact research relating to brain function and vision.

“It’s logical to hypothesize that DHA is involved in vesicle fusion elsewhere in the body, and because the brain contains so much of it, we wonder if deficiencies could play a role, for example, in the development of dementia. Any communication between neurons in the brain involves vesicle fusion,” he noted.

The Illinois scientists will continue to study sperm; meanwhile, Nakamura has sent some of his DHA-deficient knockout mice to other laboratories where scientists are studying DHA function in the brain and the retina.

The study was published in a recent issue of Biology of Reproduction. Co-authors are Manuel Roqueta-Rivera, Timothy L. Abbott, Mayandi Sivaguru, and Rex A. Hess, all of the U of I. The work was supported in part by a CONACyT Mexico fellowship award.

Comments are closed

Manabu T. Nakamura

Dr. Manabu T. Nakamura

Most people are familiar with the message that reducing intake of saturated and trans fat can improve health. However, there are some types of fats, called essential fatty acids that must be consumed in the diet. Essential fatty acids and their metabolic products exert a variety of physiologic functions in our body, including inflammation, reproduction and regulation of lipid metabolism. Dr. Nakamura’s laboratory created a gene knockout mouse to investigate functions of the essential fatty acids, which is a current focus of research activity in his laboratory.The increasing incidence of obesity worldwide is a significant public health concern, which brings an opportunity and responsibility to the nutrition research community. To address this challenge, his laboratory has been investigating how our body can adapt to diets with varying composition of carbohydrates, fats and proteins. Understanding biochemical and molecular mechanism of metabolic adaptation will provide a basis for dietary prevention of obesity. In addition to this basic research, his laboratory has been developing a new nutrition information delivery system for prevention and treatment of obesity.


Associate Professor; mtnakamu@illinois.edu; more detail here.


 

Comments are closed

Some Fats Are Good Fats

Original story published here on May 27, 2004.

Although most people believe that fat in the diet is a bad thing, leading to clogged arteries and other health problems, certain types of fat are necessary for our bodies to function properly, said Manabu Nakamura, a specialist in biochemical and molecular nutrition at the University of Illinois.

In fact, omega-3s and omega-6s are so important to body function that they are called essential fatty acids, and they are critical to fetal development and to skin, nerve, and brain function. Omega-3s can reduce the clotting factors that precipitate stroke and heart disease, and they can lower blood triglycerides, another risk factor of heart disease.

Furthermore, our bodies can’t make these essential fatty acids, so we have to consume them in our diets. “Fatty fish, such as salmon, is a good source of omega-3s, and I recommend cooking with canola or soybean oil. Consumers can already purchase eggs that are rich in omega-3s, and other enhanced products should be available soon,” he said.

Omega-6s can be consumed in pistachios and sunflower seeds or consumed in borage oil or evening primrose oil, available as dietary supplements. Nakamura said it’s important to keep omega-3s and 6s in balance, and he added that genetic modifications to soybeans and other oil seeds are under way that will help us do that.

Saturated fats, on the other hand, found in animal fats and fried and processed foods, are the “bad” fats, implicated in everything from heart disease to breast cancer.

Nakamura has been investigating the way in which essential fatty acids regulate the production of certain enzymes in the liver. “We know that the essential fatty acids help regulate body fat deposition, increasing the body’s use of fat by causing fat-burning enzymes to kick in,” said Nakamura.

“Although it looked promising at first, we are finding that this phenomenon is mostly restricted to the liver, not to fat storage tissue in the body. The liver seems to regulate fat synthesis in such a way that it makes just enough unsaturated fat to promote flexibility in human cell membranes,” he said.

Nakamura is also investigating the way two types of carbohydrate–glucose and fructose– are metabolized in the body. Table sugar, he said, contains about half glucose and half fructose. Most soft drinks contain a lot of high-fructose corn sugar because fructose is sweeter than glucose and makes a better sweetening ingredient in beverages.

“Although it’s still early to talk about the results, one of our animal studies seems to show that fructose may not be as good as glucose for the body. Fructose may actually have a strong effect on whether food is used as energy or stored as body fat,” he said.

Although the metabolism of fat is still not fully understood, scientists know enough to be able to say that some types of fat are beneficial while others cause health problems.

While research continues in Nakamura’s lab and others, he suggests eating one to three servings of fish weekly for the essential fatty acids that our bodies need and avoiding the saturated fats, found in fried and processed foods, that have unhealthy effects on our bodies.

Comments are closed