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Study shows broccoli may offer protection against liver cancer

URBANA, Ill. – Consumption of broccoli has increased in the United States over the last few decades as scientists have reported that eating the vegetable three to five times per week can lower the risk of many types of cancer including breast, prostate, and colon cancers.

A new study from the University of Illinois reports that including broccoli in the diet may also protect against liver cancer, as well as aid in countering the development of fatty liver or nonalcoholic fatty liver disease (NAFLD) which can cause malfunction of the liver and lead to hepatocellular carcinoma (HCC), a liver cancer with a high mortality rate.

“The normal story about broccoli and health is that it can protect against a number of different cancers. But nobody had looked at liver cancer,” says Elizabeth Jeffery, a U of I emeritus professor of nutrition. “We decided that liver cancer needed to be studied particularly because of the obesity epidemic in the U.S. It is already in the literature that obesity enhances the risk for liver cancer and this is particularly true for men. They have almost a 5-fold greater risk for liver cancer if they are obese.”

Jeffery says that the majority of the U.S. population eats a diet high in saturated fats and added sugars. However, both of these are stored in the liver and can be converted to body fat. Consuming a high-fat, high-sugar diet and having excess body fat is linked with the development of NAFLD, which can lead to diseases such as cirrhosis and liver cancer.

“We called this a Westernized-style diet in the study because we wanted to model how so many of us are eating today,” Jeffery says.

Previous research suggests that broccoli, a brassica vegetable containing bioactive compounds, may impede the accumulation of fat in the liver and protect against NAFLD in mice. Therefore, Jeffery and her team wanted to find out the impact of feeding broccoli to mice with a known liver cancer-causing carcinogen. The researchers studied four groups of mice; some of which were on a control diet or the Westernized diet, and some were given or not given broccoli.

“We wanted to look at this liver carcinogen in mice that were either obese or not obese,” Jeffery explains. “We did not do it using a genetic strain of obese mice, but mice that became obese the way that people do, by eating a high-fat, high-sugar diet.”

Although the researchers were predominantly interested in broccoli’s impact on the formation and progression of cancerous tumors in the liver, Jeffery explained that they also wanted to observe the health of the liver and how the liver was metabolizing lipids because of the high-fat diet. “There is almost no information about broccoli and high-fat associated diseases,” she says.

The study shows that in mice on the Westernized diet both the number of cancer nodules and the size of the cancer nodules increased in the liver. But when broccoli was added to the diet, the number of nodules decreased. Size was not affected.

“That was what we really set out to show,” Jeffery says. “But on top of that we were looking at the liver health. There are actually two ways of getting fatty liver; one, by eating a high-fat, high-sugar diet and the other by drinking too much alcohol. In this case, it is called non-alcoholic fatty liver, because we didn’t use the alcohol. And it is something that is becoming prevalent among Americans. This disease means you are no longer controlling the amount of fat that is accumulating in your liver.”

With NAFLD, lipid globules form on the liver. During the study, the researchers observed these globules in the livers of the mice on the Westernized diet.

“We found that the Westernized diet did increase fatty liver, but we saw that the broccoli protected against it. Broccoli stopped too much uptake of fat into the liver by decreasing the uptake and increasing the output of lipid from the liver,” she says.

Jeffery notes that adding broccoli to the diet of the mice did not make them “thin,” or affect their body weight, but it did bring the liver under control, ultimately making them healthier. “This is one of the things that makes this very exciting for us,” she says.

“I think it’s very difficult, particularly given the choices in fast food restaurants, for everybody to eat a lower-fat diet. But more and more now you can get broccoli almost everywhere you go. Most restaurants will offer broccoli, and it’s really a good idea to have it with your meal,” Jeffery adds.

Jeffery’s previous research shows that eating broccoli freshly chopped or lightly steamed is the best way to get to the vegetables’ cancer-fighting compound, sulforaphane.

Although the researchers only used broccoli in the study, Jeffery adds that other brassica vegetables, such as cauliflower or Brussel sprouts, may have the same effect.

“Dietary broccoli lessens development of fatty liver and liver cancer in mice given diethylnitrosamine and fed a Western or control diet,” is published in the Journal of Nutrition. Co-authors include Yung-Ju Chen, previously of the U of I, and Matthew Wallig and Elizabeth Jeffery of the U of I.

Funding was provided by the National Cancer Institute (National Institutes of Health).

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New way to detox? “Gold of Pleasure” oilseed boosts liver detoxification enzymes

URBANA, Ill. – University of Illinois scientists have found compounds that boost liver detoxification enzymes nearly fivefold, and they’ve found them in a pretty unlikely place—the crushed seeds left after oil extraction from an oilseed crop used in jet fuel.

“The bioactive compounds in Camelina sativa seed, also known as Gold of Pleasure, are a mixture of phytochemicals that work together synergistically far better than they do alone. This seed meal is a promising nutritional supplement because its bioactive ingredients increase the liver’s ability to clear foreign chemicals and oxidative products. And that gives it potential anti-cancer benefit,” said Elizabeth Jeffery, a U of I professor of nutritional toxicology.

Oilseed crops, including rapeseed, canola, and camelina, contain some of the same bioactive ingredients—namely, glucosinolates and flavonoids—found in broccoli and other cruciferous vegetables and in nearly the same quantities, she noted.

Because the oil from oilseed crops makes an environmentally friendly biofuel, scientists have been hoping to find a green use for the protein-rich seed meal left after oil extraction. Animal feed was the obvious choice, but there were a couple of problems. Some rapeseed glucosinolates are toxic, and producers have balked at paying Canada for canola seed, the low-glucosinolate rapeseed that country had developed.

Jeffery thought Camelina sativa was worth a look so she began to work with USDA scientist Mark Berhow. In the first study of camelina’s bioactive properties, Berhow isolated four major components—three glucosinolates and the flavonoid quercetin—from its defatted seed meal.

Back at Jeffery’s U of I lab, researchers began to test these components on mouse liver cells both individually and together. They found that all four major camelina bioactives induced the detoxifying liver enzyme NQO1 when they were used alone. However, when a particular glucosinolate, GSL9, was paired with the flavonoid quercetin, there was a synergistic effect.

“When these two bioactives were combined, induction of the detoxifying liver enzyme increased nearly fivefold,” said Nilanjan Das, a postdoctoral student in Jeffery’s lab.

In all the experiments, the scientists used sulforaphane, the cancer-protective component of broccoli, as a control because it is known to induce NQO1, the detoxifying enzyme. Like camelina seed meal, broccoli contains the flavonoid quercetin, so they decided to look for synergy between sulforaphane and quercetin.

“As had been the case with camelina’s GSL9 and quercetin, the combined effect of quercetin and sulforaphane—in proportions found naturally in broccoli—was far greater than when either was used alone. This demonstrates to us the importance of eating whole foods. Thanks to synergy among its bioactive components, whole broccoli appears to be more powerful than purified sulforaphane that you might buy at a vitamin store or on the Internet,” Das said.

Nilanjan Das, Mark A. Berhow, Donato Angelina, and Elizabeth H. Jeffery are co-authors of “Camelina sativa Defatted Seed Meal Contains Both Alkyl Sulfinyl Glucosinolates and Quertecin that Synergize Bioactivity.” The article is available pre-publication online in the Journal of Agricultural and Food Chemistry. Funding was provided by USDA.


News Source:  Elizabeth Jeffery, 217-333-3820

Original posting is here.

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Better broccoli, enhanced anti-cancer benefits with longer shelf life

URBANA, Ill. – While researching methods to increase the already well-recognized anti-cancer properties of broccoli, researchers at the University of Illinois also found a way to prolong the vegetable’s shelf life.

And, according to the recently published study, the method is a natural and inexpensive way to produce broccoli that has even more health benefits and won’t spoil so quickly on your refrigerator shelf.

Jack Juvik, a U of I crop sciences researcher, explained that the combined application of two compounds, both are natural products extracted from plants, increased the presence of cancer-fighting agents in broccoli while prolonging the post-harvest storage period.

“We had figured out ways to increase the anti-cancer activity in broccoli, but the way we figured it out created a situation that would cause the product to deteriorate more rapidly after application,” Juvik said. “For fresh-market broccoli that you harvest, it’s not too big a deal, but many of these products have to be shipped, frozen, cut up, and put into other products. Usually the idea is to get it from the farm to at least the distributor (grocery store) within two to three days.

“If we could figure out a way to prolong the appearance, taste, and flavor long after harvest and maintain the improved health-promoting properties, that’s always of great interest to growers,” he added.

The researchers first used methyl jasmonate (MeJA), a non-toxic plant-signal compound (produced naturally in plants) to increase the broccoli’s anti-cancer potential, which they sprayed on the broccoli about four days before harvest. When applied, MeJA initiates a process of gene activity affiliated with the biosynthesis of glucosinolates (GS), which are compounds found in the tissue of broccoli and other brassica vegetables (such as cauliflower, cabbage, and kale).

Glucosinolates have been identified as potent cancer-preventative agents because of their ability to induce detoxification enzymes, such as quinone reductase (QR), that detoxify and eliminate carcinogens from the human body.

However, during this process, MeJA also signals a network of genes that lead to plant decay by inducing the release of ethylene, Juvik explained. “While we can use MeJA to turn on phytochemicals like the glucosinolates and dramatically increase the abundance of those helpful anti-cancer compounds, MeJA also reduces the shelf life after harvest,” he said.

So the researchers tried using the recently developed compound 1-methylcyclopropene (1-MCP), which has been shown to interfere with receptor proteins in the plant that are receptor-sensitive to ethylene. They applied the compound after harvesting the same broccoli that had already been treated with MeJA before harvest.

“Ethylene will move and bind to ethylene receptors and that binding process initiates decay. What this compound does is that it more competitively lands on the protein and binds to or pushes out ethylene,” Juvik explained. “It basically stops or dramatically slows down the decay associated with ethylene.

“The combination is good,” he said.

Like MeJA, 1-MCP is also a non-toxic compound naturally produced in plants, although Juvik said synthetic forms can be produced. He stressed that both the MeJA and 1-MCP treatments required very small amounts of the compounds.

“It’s very cheap, and it’s about as toxic as salt. It takes very little to elevate all the desirable aspects. It’s volatile and disappears from the product after about 10 hours,” he said.

The use of these treatments could make a great impact on important global dilemmas such as food security issues and health-care costs, Juvik said.

“It’s a fairly cheap way to maintain quality, but it provides a preventative approach to all the medical costs associated with degenerative diseases. These are not pills that go in and take away or change damaged tissues, but it’s a way to protect people by reducing the risk they currently have to different diseases. It won’t take it away, but it could prevent further damage,” he said.

As for its impact on impending global food security concerns, Juvik said any mechanisms that will improve people’s health, especially later in life, will benefit food security.

“We need to look at what mechanisms we can use to improve not only food security but the functioning of people later in their life spans. When you look at how much the United States spends on medical costs associated with these diseases, you see it’s a huge burden on the economy, which is the same in all countries. It basically takes away resources that could be used to improve food security,” Juvik said. “Also, promoting and prolonging food stability with quality after harvest means less waste, which is a big issue in terms of food security.”

“Methyl jasmonate and 1-Methylcyclopropene treatment effects on quinone reductase inducing activity and post-harvest quality of broccoli” was published in the October 2013 issue of Plos One and can be accessed online at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0077127. Co-authors of the study were Kang Mo Ku, Jeong Hee Choi, Hyoung Seok Kim, Mosbah M. Kushad, Elizabeth H. Jeffery, and Juvik.

AgroFresh, a division of Rohm & Hass Inc., provided 1-MCP and equipment for the study.


 

Original story posted here.

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Illinois scientists put cancer-fighting power back into frozen broccoli

URBANA, Ill. – There was bad news, then good news from University of Illinois broccoli researchers this month. In the first study, they learned that frozen broccoli lacks the ability to form sulforaphane, the cancer-fighting phytochemical in fresh broccoli. But a second study demonstrated how the food industry can act to restore the frozen vegetable’s health benefits.

“We discovered a technique that companies can use to make frozen broccoli as nutritious as fresh. That matters because many people choose frozen veggies for their convenience and because they’re less expensive,” said Elizabeth Jeffery, a U of I professor of nutrition.

“Whenever I’ve told people that frozen broccoli may not be as nutritious as fresh broccoli, they look so downcast,” she added.

As little as three to five servings of broccoli a week provides a cancer-protective benefit, but that isn’t true for bags of broccoli that you pluck out of your grocery’s freezer, she noted.

The problem begins when soon-to-be-frozen broccoli is blanched, or heated to high temperatures, to inactivate enzymes that can cause off-colors, tastes, and aromas during the product’s 18-month shelf life, she explained.

The extreme heat destroys the enzyme myrosinase, which is necessary to form sulforaphane, the powerful cancer-preventive compound in broccoli, she said.

“We know this important enzyme is gone because in our first study we tested three commercially frozen broccoli samples before and after cooking. There was very little potential to form sulforaphane before the frozen broccoli was cooked and essentially none after it was cooked as recommended,” said Edward B. Dosz, a graduate student in Jeffery’s laboratory.

In the second study, the researchers experimented with blanching broccoli at slightly lower temperatures instead of at 86ºC, the current industry standard. When they used a temperature of 76ºC, 82 percent of the enzyme myrosinase was preserved without compromising food safety and quality.

Sulforaphane is formed when fresh broccoli is chopped or chewed, bringing its precursor glucoraphanin and the enzyme myrosinase into contact with each other. The researchers first thought that thawing frozen broccoli in the refrigerator might rupture the plant’s cells and kick-start the enzyme–substrate interaction. It didn’t work, Dosz said.

But they had previously had success using other food sources of myrosinase to boost broccoli’s health benefits. So the researchers decided to expose frozen broccoli to myrosinase from a related cruciferous vegetable.

When they sprinkled 0.25 percent of daikon radish—an amount that’s invisible to the eye and undetectable to our taste buds—on the frozen broccoli, the two compounds worked together to form sulforaphane, Dosz said.

“That means that companies can blanch and freeze broccoli, sprinkle it with a minute amount of radish, and sell a product that has the cancer-fighting component that it lacked before,” he said.

One question remained: Would sulforaphane survive the heat of microwave cooking? “We were delighted to find that the radish enzyme was heat stable enough to preserve broccoli’s health benefits even when it was cooked for 10 minutes at 120ºF. So you can cook frozen broccoli in the microwave and it will retain its cancer-fighting capabilities,” Dosz said.

Jeffery hopes that food processors will be eager to adopt this process so they can market frozen broccoli that has all of its original nutritional punch.

Until they do, she said that consumers can spice up their frozen, cooked broccoli with another food that contains myrosinase to bring the cancer-fighting super-food up to nutritional speed.

“Try teaming frozen broccoli with raw radishes, cabbage, arugula, watercress, horseradish, spicy mustard, or wasabi to give those bioactive compounds a boost,” she advised.

Jeffery and Dosz of the U of I’s Department of Food Science and Human Nutrition co-authored both studies. Commercially produced frozen broccoli lacks the ability to form sulforaphane was published in the Journal of Functional Foods and is available online at http://www.sciencedirect.com/science/article/pii/S1756464613000510. USDA and the National Institute of Food and Agriculture (NIFA) funded this research.

Modifying the processing and handling of frozen broccoli for increased sulforaphane formation appears in the Journal of Food Science and can be viewed online at http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291750-3841/earlyview. Sakata Vegetables Europe supported this study.


News source: Elizabeth Jeffery, 217-333-3820

Original story posted here.

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Elizabeth H. Jeffery

Dr. Elizabeth H. Jeffery

Biochemical and nutritional toxicology, with an emphasis on cancer prevention, is the focus of our laboratory. Epidemiological studies show that a diet rich in cruciferous vegetables, such as broccoli and Brussels sprouts, can lower the incidence of several cancers, including liver, prostate and colorectal. Our experiments identify how components in crucifers alter the synthesis of detoxification enzymes, resulting in more rapid clearance of deleterious compounds from the body before they can initiate a toxic or carcinogenic response. A major goal is to develop cruciferous vegetables with increased concentrations of chemopreventive agents and we work closely with an interdisciplinary group of 5 faculty to meet this goal. Experiments probing the mechanism of upregulation of detoxification enzymes apply molecular biology and biochemical enzyme assays to human and rodent liver cells in culture. Immunohistochemical and enzyme assay studies using purified chemicals or the whole vegetable fed to rodents confirm the findings from in vitro experiments. We have identified a synergism between two of the more abundant bioactive components in crucifers. The importance of this finding is two-fold: first that smaller doses of the vegetable should provide protection; and second that supplements containing the optimal mixture for protection could be formulated for individuals at high risk for cancer. These studies are being expanded to prostate, since prostate cancer is presently the most common cancer, with the second highest number of mortalities of any cancer, within the U.S. Functional foods; prevention of cancer through diet; role of detoxification enzymes in protection from cancer and toxicity.


Professor Emerita; ejeffery@illinois.edu; more detail here.


 

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