Newsletter: May 22, 2018

Researched and written weekly by the editorial team of Food Technology magazine, the IFTNEXT Newsletter explores what are, arguably, the next big things in the science of food through original reporting of scientific breakthroughs, leading-edge technology, novel food components, and transdisciplinary R&D.

Broccoli Scientists create broccoli extract that kills cancer cells
A team of scientists in the department of biochemistry at National University of Singapore Yong Loo Lin School of Medicine have engineered a concoction made from bacteria and broccoli that finds and destroys colorectal cancer cells. 

Cruciferous vegetables such as broccoli and Brussels sprouts contain plant compounds that have anticancer properties when they are broken down. However, it is unclear how effective those compounds are after they enter the human digestive system. Scientists at National University of Singapore’s school of medicine found a way to improve the bioavailability of the anticancer plant compounds in broccoli by combining them with a type of bacteria normally present in the colon: Escherichia coli Nissle. “We programmed E. coli Nissle to enable colorectal cancer cell-binding so that the reprogrammed E. coli can specifically recognize and localize on the surface of tumors,” says Matthew Wook Chang, an associate professor at National University of Singapore and a co-author of the study explaining the discovery. “Furthermore, we included in the E. coli the ability to produce an enzyme from horseradish to convert a dietary compound from cruciferous plants … to an anticancer compound.” The enzyme converts glucosinolates in broccoli (and other cruciferous vegetables) to sulphoraphane, which is known to have anticancer activity. 

Chang and his research colleagues showed that the engineered cocktail could inhibit the proliferation of colorectal cancer cells in vitro. “The microbial cells are able to recognize cancer biomarkers and localize on the surface of cancer/dysplastic tissue. Following this binding, the produced enzyme facilitates the conversion of the dietary compound around the cancer site to enhance availability of the anticancer compound, thus increasing absorption of the anticancer compound by the cancer tissue. Consequently, the proliferative cancer cells undergo cell-cycle arrest,  … inhibiting the cancer growth. The anticancer compound also increases pro-apoptotic factors and decreases anti-apoptotic factors, hence encouraging the cancer cells to naturally perish,” Chang explains. 

Chang says that the engineered cocktail could be used to help reduce the risk of colorectal development in high-risk populations. “These probiotic cells could be ingested as a supplement or a drink, which could allow the probiotic cells to monitor the state of the gut and target cancer cells in their early stages,” Chang concludes. 


Vegetables and FruitsEating raw fruits and vegetables linked to better mental health
Fruits and vegetables are an important part of a balanced diet and essential to good physical health. But eating them raw, rather than in cooked, canned, or processed form, may also enhance mental health, according to a study published in Frontiers in Psychology by researchers at the University of Otago in New Zealand. Among the top foods to boost mental health are apples, bananas, grapefruit, citrus fruits, berries, dark leafy greens, and kiwifruit.   

In the cross-sectional survey of 422 young adults living in New Zealand and the United States, subjects completed an online survey that assessed the relationship between fruit and vegetable consumption and positive states of psychological well-being. “One of our previous studies had shown that people with the most improved mental health also anecdotally reported eating much of their produce raw,” says study co-author Kate Brookie. “So, we decided that studying the differential effects of raw versus modified fruits and vegetables would be worthwhile.  

“We found that, after controlling for a number of potential confounders, raw fruits and vegetables predicted improvement in mental health across the board,” she reports. “We found positive influences of raw consumption across a range of mental health outcomes—both lower levels of depressive symptomology and higher levels of psychological well-being, such as life satisfaction and flourishing. This relationship did not exist for cooked/canned/processed fruits and vegetables.”  

One of the reasons raw fruit and vegetable intake may positively influence mental health is the effect of micronutrients on the bodily systems involved in mood. “For example,” explains Brookie, “vitamin C—which we get primarily from fruits and leafy greens—is a cofactor in the production of dopamine. And we know that increased dopaminergic synthesis has been associated with increased positive emotion, goal-directed behavior, energy, motivation, and exploration behavior. Unfortunately, cooking and processing of fruits and vegetables has the potential to diminish some of these important nutrients.”  

Raw fruit and vegetable intake also has a positive effect on bodily inflammation, a condition that has been linked to various mental disorders, including depression. Similarly, says Brookie, the diversity and overall health of gut bacteria are affected by raw fruit and vegetable consumption. “There is increasing evidence for bi-directional communication between the gut and the brain,” she explains, “and that the diversity and health of the gut can influence brain functioning, including emotional well-being.” 

Additional research may yield results that can advance new dietary approaches to tackling global mental health difficulties. Says Brookie, “I don’t think diet is the be all and end all to mental health, but dietary approaches are likely to help maintain mental well-being and help protect against mental health problems in the long term.”  

From the perspective of food science, Brookie believes it’s important that the public is educated about the best ways to prepare and consume fruits and vegetables to maintain nutrients. “Ultimately,” she says “the pursuit of health is becoming increasingly multidisciplinary. Psychology and nutrition fields are needing to converge in order to make the most of these findings and improve health in the general population.”  


VirusResveratrol prevents disease-causing virus replication
Resveratrol, a compound perhaps most widely associated with the grapes used to make red wine, can prevent poxviruses (shown in image) from replicating, report researchers at Kansas State University, who worked in collaboration with scientists from the U.S. Centers for Disease Control and Prevention (CDC) on the study. Their research suggests that resveratrol may eventually be a valuable part of the virus-fighting tool kit.  

To yield the virus inhibition effect, resveratrol was chemically synthesized or extracted from fruits and concentrated at a higher level than it occurs naturally in plants. (In addition to grapes, resveratrol can be found in peanuts, cocoa beans, and blueberries.) The researchers then added resveratrol at varying intensities to human cell cultures infected by vaccinia virus, a cousin to the variola virus that causes smallpox. Unlike variola, vaccinia, which was used as the vaccine to eradicate smallpox, is not dangerous, and thus provides a safe model of how viruses operate.  

Cell cultures treated with high levels of resveratrol prevented vaccinia from replicating in the early stages of viral infection, thus stopping the spread of the virus. “In order for a poxvirus to infect a host, it has to first enter a cell and make a lot of copies of its genome inside the host cell,” explains researcher Anil Pant, a doctoral student in biology at Kansas State. “Our research has shown that resveratrol inhibits vaccinia virus from making copies of its DNA and genome.”  

After discovering resveratrol’s effectiveness with vaccinia, the Kansas State team began collaborating with CDC researchers to conduct similar experiments with monkeypox, a dangerous and contagious virus that has caused disease outbreaks in Africa. The encouraging news from that research was that resveratrol had the same inhibitory effect on monkeypox, which means that it may have the potential to inhibit all poxviruses. The researchers note that their work is significant because it may provide a stepping-stone to using resveratrol as a complementary therapy in fighting viral infections.  

Researcher Zhilong Yang, an assistant professor of biology at Kansas State, says that if funding is available, the researchers hope to next conduct animal studies with resveratrol. The compound appears to have significant therapeutic potential in several different areas, although more research is needed to document those benefits. “Resveratrol has shown inhibitory effects on a variety of viruses, for example, influenza virus, HIV, and herpes simplex virus,” says Yang. “It is also being investigated for its effects on aging, diabetes, cancers, [and] blood pressure. But many of these are still not conclusive yet.”  

Results of the research were published in the journal Frontiers in Microbiology.