Phytochemicals In Plant-based Foods Could Help Battle Obesity, Disease

The cheeseburger and French fries might look tempting, but eating a serving of broccoli or leafy greens first could help people battle metabolic processes that lead to obesity and heart disease, a new University of Florida study shows.Eating more plant-based foods, which are rich in substances called phytochemicals, seems to prevent oxidative stress in the body, a process associated with obesity and the onset of disease, according to findings published online in advance of the print edition of the Journal of Human Nutrition and Dietetics.

To get enough of these protective phytochemicals, researchers suggest eating plant-based foods such as leafy greens, fruits, vegetables, nuts and legumes at the start of a meal. Using what is known as a phytochemical index, which compares the number of calories consumed from plant-based foods compared with the overall number of daily calories, could also help people make sure they remember to get enough phytochemicals during their regular meals and snacks, said Heather K. Vincent, Ph.D., the lead author of the paper.

"We need to find a way to encourage people to pull back on fat and eat more foods rich in micronutrients and trace minerals from fruits, vegetables, whole grains and soy," said Vincent, an assistant professor in the UF Orthopaedics and Sports Medicine Institute. "Fill your plate with colorful, low-calorie, varied-texture foods derived from plants first. By slowly eating phytochemical-rich foods such as salads with olive oil or fresh-cut fruits before the actual meal, you will likely reduce the overall portion size, fat content and energy intake. In this way, you're ensuring that you get the variety of protective, disease-fighting phytochemicals you need and controlling caloric intake."

The researchers studied a group of 54 young adults, analyzing their dietary patterns over a three-day period, repeating the same measurement eight weeks later. The participants were broken into two groups: normal weight and overweight-obese.

Although the adults in the two groups consumed about the same amount of calories, overweight-obese adults consumed fewer plant-based foods and subsequently fewer protective trace minerals and phytochemicals and more saturated fats. They also had higher levels of oxidative stress and inflammation than their normal-weight peers, Vincent said. These processes are related to the onset of obesity, heart disease, diabetes and joint disease, she added.

"Diets low in plant-based foods affect health over the course of a long period of time," Vincent said. "This is related to annual weight gain, low levels of inflammation and oxidative stress. Those are the onset processes of disease that debilitate people later in life."

Oxidative stress occurs when the body produces too many damaging free radicals and lacks enough antioxidants or phytochemicals to counteract them. Because of excess fat tissue and certain enzymes that are more active in overweight people, being obese can actually trigger the production of more free radicals, too.

Because many phytochemicals have antioxidant properties, they can help combat free radicals, Vincent said. Phytochemicals include substances such as allin from garlic, lycopene from tomatoes, isoflavones from soy, beta carotene from orange squashes and anythocyanins from red wine, among others.

"People who are obese need more fruits, vegetables, legumes and wholesome unrefined grains," she said. "In comparison to a normal-weight person, an obese person is always going to be behind the eight ball because there are so many adverse metabolic processes going on."

Instead of making drastic changes, people could substitute one or two choices a day with phytochemical-rich foods to make a difference in their diets, Vincent said. For example, substituting a cup of steeped plain tea instead of coffee or reaching for an orange instead of a granola bar could increase a person's phytochemical intake for the day without even changing the feeling of fullness. Over time, replacing more pre-packaged snacks with fresh produce or low-sugar grains could become a habit that fights obesity and disease, Vincent said.

"We always want to encourage people to go back to the whole sources of food, the nonprocessed foods if we can help it," Vincent said. "That would be the bottom line for anyone, regardless of age and body size, keep going back to the purer plant-based foods. Remember to eat the good quality food first."

Currently, there are no recommendations for how much of these plant compounds people should be getting each day, says Susanne Talcott, Ph.D., an assistant professor of food science and nutrition at Texas A&M University. Using the phytochemical index could be a good way to come up with these recommendations, she said.

Like Vincent, Talcott also cautions people to try and stick to the whole sources of foods and be wary of processed foods that promise benefits from added plant compounds.

"Consumers should stick with what we have known for decades and eat fresh or frozen fruits and vegetables," she said. "Stick with those kinds of foods rather than reaching out for a tropical wonder pill or juice."

Smart Rat 'Hobbie-J' Produced By Over-expressing A Gene That Helps Brain Cells Communicate

Over-expressing a gene that lets brain cells communicate just a fraction of a second longer makes a smarter rat, report researchers from the Medical College of Georgia and East China Normal University.Dubbed Hobbie-J after a smart rat that stars in a Chinese cartoon book, the transgenic rat was able to remember novel objects, such as a toy she played with, three times longer than the average Long Evans female rat, which is considered the smartest rat strain. Hobbie-J was much better at more complex tasks as well, such as remembering which path she last traveled to find a chocolate treat.

The report comes about a decade after the scientists first reported in the journal Nature that they had developed "Doogie," a smart mouse that over-expresses the NR2B gene in the hippocampus, a learning and memory center affected in diseases such as Alzheimer's. Memory improvements they found in the new genetically modified Long Evans rat were very similar to Doogie's. Subsequent testing has shown that Doogie maintained superior memory as he aged.

"This adds to the notion that NR2B is a universal switch for memory formation," says Dr. Joe Z. Tsien, co-director of the MCG Brain & Behavior Discovery Institute and co-corresponding author on the paper published Oct. 19 in PLoS One. Dr. Xiaohua Cao at East China Normal University also is a co-corresponding author.

The finding also further validates NR2B as a drug target for improving memory in healthy individuals as well as those struggling with Alzheimer's or mild dementia, the scientists says.

NR2B is a subunit of NMBA receptors, which are like small pores on brain cells that let in electrically-charged ions that increase the activity and communication of neurons. Dr. Tsien refers to NR2B as the "juvenile" form of the receptor because its levels decline after puberty and the adult counterpart, NR2A, becomes more prevalent.

While the juvenile form keeps communication between brain cells open maybe just a hundred milliseconds longer, that's enough to significantly enhance learning and memory and why young people tend to do both better, says Dr. Tsien, the Georgia Research Alliance Eminent Scholar in Cognitive and Systems Neurobiology. This trap door configuration that determines not just how much but how fast information flows is unique to NMBA receptors.

Scientists found that Hobbie-J consistently outperformed the normal Long Evans rat even in more complex situations that require association, such as working their way through a water maze after most of the designated directional cues and the landing point were removed. "It's like taking Michael Jordan and making him a super Michael Jordan," Deheng Wang, MCG graduate student and the paper's first author, says of the large black and white rats already recognized for their superior intellect.

But even a super rat has its limits. For example with one test, the rats had to learn to alternate between right and left paths to get a chocolate reward. Both did well when they only had to wait a minute to repeat the task, after three minutes only Hobbie-J could remember and after five minutes, they both forgot. "We can never turn it into a mathematician. They are rats, after all," Dr. Tsien says, noting that when it comes to truly complex thinking and memory, the size of the brain really does matter.

That's one of the reasons scientists pursue this type of research: to see if increased production of NR2B in more complex creatures, such as dogs and perhaps eventually humans, gets the same results. He also is beginning studies to explore whether magnesium – a mineral found in nuts, legumes and green vegetables such as spinach – can more naturally replicate the results researchers have obtained through genetic manipulation. Magnesium ion blocks entry to the NMDA receptor so more magnesium forces the brain cell to increase expression levels of the more efficient NR2B to compensate. This is similar to how statin drugs help reduce cholesterol levels in the blood by inhibiting its synthesis in the liver.

Scientists created Hobbie-J and Doogie by making them over-express CaMKII, an abundant protein that works as a promoter and signaling molecule for the NMDA receptor, something that likely could not be replicated in humans. In October 2008, they reported in Neuron that they could also safely and selectively erase old and new memories alike in mice by over-expressing CaMKII while the memory was being recalled

"We want to make sure this is a real phenomenon," Dr. Tsien says of the apparent connection between higher levels of NR2B and better memory. "You should never assume that discovery you made in a cell line or a mouse can be translated to other species or systems unless you do the experiments." He adds that the failure of new drugs and other disappointments result from the lack of sufficient scientific evidence.

The transgenic rat has other practical value as well. There is substantial scientific and behavior data already available on rats and because rats are larger, it's easier to do memory tests and record signals from their brain. For example they are strong enough to press levers to get a food reward and their size and comfort level with water means they won't just float aimlessly in a water maze as "fluffy" mice tend to do.

Smoking Bans Reduce Risk Of Heart Attacks Associated With Secondhand Smoke

Smoking bans are effective at reducing the risk of heart attacks and heart disease associated with exposure to secondhand smoke, says a new report from the Institute of Medicine. The report also confirms there is sufficient evidence that breathing secondhand smoke boosts nonsmokers' risk for heart problems, adding that indirect evidence indicating that even relatively brief exposures could lead to a heart attack is compelling."It's clear that smoking bans work," said Lynn Goldman, professor of environmental health sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, and chair of the committee of experts that wrote the report. "Bans reduce the risks of heart attack in nonsmokers as well as smokers. Further research could explain in greater detail how great the effect is for each of these groups and how secondhand smoke produces its toxic effects. However, there is no question that smoking bans have a positive health effect."

About 43 percent of nonsmoking children and 37 percent of nonsmoking adults are exposed to secondhand smoke in the United States, according to public health data. Despite significant reductions in the percentages of Americans breathing environmental tobacco smoke over the past several years, roughly 126 million nonsmokers were still being exposed in 2000.

A 2006 report from the U.S. Surgeon General's office, The Health Consequences of Involuntary Exposure to Tobacco Smoke, concluded that exposure to secondhand smoke causes heart disease and indicated that smoke-free policies are the most economical and effective way to reduce exposure. However, the effectiveness of smoking bans in reducing heart problems has continued to be a source of debate.

The IOM committee conducted a comprehensive review of published and unpublished data and testimony on the relationship between secondhand smoke and short-term and long-term heart problems. Eleven key studies that evaluated the effects of smoking bans on heart attack rates informed the committee's conclusions about the positive effects of smoke-free policies. The studies calculated that reductions in the incidence of heart attacks range from 6 percent to 47 percent. Given the variations in how the studies were conducted and what they measured, the committee could not determine more precisely how great the effect is. Only two of the studies distinguished between reductions in heart attacks suffered by smokers versus nonsmokers. However, the repeated finding of decreased heart attack rates overall after bans were implemented conclusively demonstrates that smoke-free policies help protect people from the cardiovascular effects of tobacco smoke, the committee said.

The report also provides a detailed discussion of the evidence from animal research and epidemiological studies showing a cause-and-effect relationship between secondhand smoke exposure and heart problems. The committee was not able to determine the exact magnitude of the increased risk presented by breathing environmental tobacco smoke, but noted that studies consistently indicate it increases the risks by 25 percent to 30 percent. Although there is no direct evidence that a relatively brief exposure to secondhand smoke could precipitate a heart attack, the committee found the indirect evidence compelling. Data on particulate matter in smoke from other pollution sources suggest that a relatively brief exposure to such substances can initiate a heart attack, and particulate matter is a major component of secondhand smoke.

The report was sponsored by the U.S. Centers for Disease Control and Prevention. Established in 1970 under the charter of the National Academy of Sciences, the Institute of Medicine provides independent, objective, evidence-based advice to policymakers, health professionals, the private sector, and the public. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies.