For thousands of years, the people of China, Japan, India, and Thailand have consumed green tea and used it medicinally to treat everything from headaches to heart diseases. Over the past few decades, however, research in both Asia and the West have taken place providing scientific evidence of green tea’s numerous health benefits. As a whole, studies indicate that regular consumption of green tea may slow or prevent conditions including high cholesterol, heart disease, arthritis, impaired immune disease and liver disease. In yet another recent study on the beverage’s healthful properties, published in the academic journal Phytomedicine, researchers have found evidence that enzymes in the drink may help in fighting Alzheimer’s and other forms of dementia.
Researchers at the Newcastle University have also found that the Chinese brew may also play a vital role in guarding against cancer. The Newcastle team focused on whether or not once the tea was in the digestive system if the protective properties were still as effective. “What was really exciting was that we found when green tea is digested, the resulting chemicals are actually more effective against key triggers of Alzheimer’s,” said Ed Okello, from the university’s School of Agriculture, Food and Rural Development. “The digested compounds also had anti-cancer properties, significantly slowing down the growth of tumour cells which we were using in our experiments,” Okello said.
Previous studies have shown that polyphenols, present in black and green tea, bind with the toxic compounds and protect brain cells. When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the team tested in their research. According to Okello, there are many factors that together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important. “But I think it’s fair to say that at least one cup of green tea a day may be good for you and I would certainly recommend it,” he added.
Regularly drinking green tea could protect the brain against developing Alzheimer’s and other forms of dementia. The study, published in the academic journal Phytomedicine, also suggests this ancient Chinese remedy could play a vital role in protecting the body against cancer. Led by Dr Ed Okello, the Newcastle team wanted to know if the protective properties of green tea – which have previously been shown to be present in the undigested, freshly brewed form of the drink – were still active once the tea had been digested. Digestion is a vital process which provides our bodies with the nutrients we need to survive. But, says Dr Okello, it also means that just because the food we put into our mouths is generally accepted to contain health-boosting properties, we can’t assume these compounds will ever be absorbed by the body.
“What was really exciting about this study was that we found when green tea is digested by enzymes in the gut, the resulting chemicals are actually more effective against key triggers of Alzheimer’s development than the undigested form of the tea,” explains Dr Okello, based in the School of Agriculture, Food and Rural Development at Newcastle University and executive director of the university’s Medicinal Plant Research Group. “In addition to this, we also found the digested compounds had anti-cancer properties, significantly slowing down the growth of the tumour cells which we were using in our experiments.”
As part of the research, the Newcastle team worked in collaboration with Dr Gordon McDougall of the Plant Products and Food Quality Group at the Scottish Crop Research Institute in Dundee, who developed technology which simulates the human digestive system. It is this which made it possible for the team to analyse the protective properties of the products of digestion. Two compounds are known to play a significant role in the development of Alzheimer’s disease – hydrogen peroxide and a protein known as beta-amyloid. Previous studies have shown that compounds known as polyphenols, present in black and green tea, possess neuroprotective properties, binding with the toxic compounds and protecting the brain cells.
When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the Newcastle team tested in their latest research. “It’s one of the reasons why we have to be so careful when we make claims about the health benefits of various foods and supplements,” explains Dr Okello. “There are certain chemicals we know to be beneficial and we can identify foods which are rich in them but what happens during the digestion process is crucial to whether these foods are actually doing us any good.” Carrying out the experiments in the lab using a tumour cell model, they exposed the cells to varying concentrations of the different toxins and the digested green tea compounds.
Dr Okello explained: “The digested chemicals protected the cells, preventing the toxins from destroying the cells. “We also saw them affecting the cancer cells, significantly slowing down their growth. Green tea has been used in Traditional Chinese medicine for centuries and what we have here provides the scientific evidence why it may be effective against some of the key diseases we face today.”
The next step is to discover whether the beneficial compounds are produced during digestion after healthy human volunteers consume tea polyphenols. The team has already received funding from the Biotechnology and Biological Sciences Research Council (BBSRC) to take this forward. Dr Okello adds: “There are obviously many factors which together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important. “But I think it’s fair to say that at least one cup of green tea every day may be good for you and I would certainly recommend it.”
(Source: Newcastle University: Phytomedicine)
Prostate cancer is the second most common cause of cancer related deaths in men. Previous cell and animal research suggests that genistein, a potent soy isoflavone, may prevent the spread of prostate cancer. Now research reports that a genistein-derived drug may help prevent the spread of prostate cancer in men with prostate cancer.
The study, presented at the Ninth Annual American Association for Cancer Research Frontiers in Cancer Prevention Research Conference, investigated the effect of the genistein-drug in men with localized prostate cancer. Researchers at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University administered the genistein-drug once daily to 38 men with localized prostate cancer one month before prostate surgery.
The participant’s prostate cancer cells were analyzed after surgery. The researchers found an increased expression of genes that stop cancer cell spread (metastasis). Furthermore, there was a decreased expression of genes that enhance metastasis.
“The first step is to see if the drug has the effect that you want on the cells and the prostate, and the answer is ‘yes, it does,'” says lead researcher Raymond Bergan, MD, professor of hematology and oncology at Northwestern University Feinberg School of Medicine, in a news release. “All therapies designed to stop cancer cell movement that have been tested to date in humans have basically failed have because they have been ineffective or toxic. If this drug can effectively stop prostate cancer from moving in the body, theoretically, a similar therapy could have the same effect on the cells of other cancers.”
Extracts of broccoli and banana may help in fighting stomach problems, research suggests. Laboratory studies show fibres from the vegetables may boost the body's natural defences against stomach infections. Trials are under way to see if they could be used as a medical food for patients with Crohn's disease. Crohn's disease is an inflammatory bowel disease that causes symptoms such as diarrhoea and abdominal pain. It affects about 1 in 1,000 people, and is thought to be caused by a mixture of environmental and genetic factors. The condition is common in developed countries, where diets are often low in fibre and high in processed food.
Scientists at the University of Liverpool looked at how roughage from vegetables influenced the passage of harmful bacteria through cells inside the gut. They found that fibres from the plantain, a type of large banana, and broccoli, were particularly beneficial. But a common stabiliser added to processed foods during the manufacturing process had the opposite effect.
Dr Barry Campbell, from the University of Liverpool, said: “This research shows that different dietary components can have powerful effects on the movement of bacteria through the bowel. “We have known for some time the general health benefits of eating plantain and broccoli, which are both high in vitamins and minerals, but until now we have not understood how they can boost the body's natural defences against infection common in Crohn's patients. “Our work suggests that it might be important for patients with this condition to eat healthily and limit their intake of processed foods.”
The research, published in the journal Gut, and carried out in collaboration with experts in Sweden and Scotland, investigated special cells, called M-cells, which line the gut and ward off invading bacteria. Work was carried out in laboratory-grown cells and tissue samples from patients undergoing surgery for stomach problems. Clinical trials are now underway in 76 Crohn's patients to find out whether a medical food containing plantain fibres could help keep the disease at bay. “It may be that it makes sense for sufferers of Crohn's to take supplements of these fibres to help prevent relapse,” said Professor Jon Rhodes of the University of Liverpool.
Curcumin, a natural phytochemical from turmeric that is used as a spice in curry, holds promise in treating or preventing liver damage from an advanced form of a condition known as fatty liver disease, new Saint Louis University research suggests. Curcumin is contained in turmeric, a plant used by the Chinese to make traditional medicines for thousands of years. SLU's recent study highlights its potential in countering an increasingly common kind of fatty liver disease called non-alcoholic steatohepatitis (NASH). Linked to obesity and weight gain, NASH affects 3 to 4 percent of U.S. adults and can lead to a type of liver damage called liver fibrosis and possibly cirrhosis, liver cancer and death.
“My laboratory studies the molecular mechanism of liver fibrosis and is searching for natural ways to prevent and treat this liver damage,” said Anping Chen, Ph.D., corresponding author and director of research in the pathology department of Saint Louis University. The findings were published in the September 2010 issue of Endocrinology. “While research in an animal model and human clinical trials are needed, our study suggests that curcumin may be an effective therapy to treat and prevent liver fibrosis, which is associated with non-alcoholic steatohepatitis (NASH).”
High levels of blood leptin, glucose and insulin are commonly found in human patients with obesity and type 2 diabetes, which might contribute to NASH-associated liver fibrosis. Chen's most recent work tested the effect of curcumin on the role of high levels of leptin in causing liver fibrosis in vitro, or in a controlled lab setting. “Leptin plays a critical role in the development of liver fibrosis,” he said.
High levels of leptin activate hepatic stellate cells, which are the cells that cause overproduction of the collagen protein, a major feature of liver fibrosis. The researchers found that among other activities, curcumin eliminated the effects of leptin on activating hepatic stellate cells, which short-circuited the development of liver damage (Courtesy of EurekAlert!, a service of AAAS).
Reference: Youcai Tang, Anping Chen. Curcumin Protects Hepatic Stellate Cells against Leptin-Induced Activation in Vitro by Accumulating Intracellular Lipids. Endocrinology Vol. 151, No. 9 4168-4177 begin_of_the_skype_highlighting 9 4168-4177 end_of_the_skype_highlighting. doi:10.1210/en.2010-0191
More than half of women with breast cancer have low vitamin D levels, British researchers report.”Women with breast cancer should be tested for vitamin D levels and offered supplements, if necessary,” says researcher Sonia Li, MD, of the Mount Vernon Cancer Centre in Middlesex, England. The findings were presented at the San Antonio Breast Cancer Symposium.
Some studies have suggested a link between low vitamin levels and breast cancer risk and progression, but others have not, she says. No studies have proven cause and effect. Previous research suggests a biologic rationale for vitamin D putting the brakes on breast cancer development and spread, Li says. Breast cancer cells have vitamin D receptors, and when these receptors are activated by vitamin D, it triggers a series of molecular changes that can slow cell growth and cause cells to die, she says. Even if it does not have a direct effect on the tumor, vitamin D is needed to maintain the bone health of women with breast cancer, Li says. That's especially important given the increasing use of aromatase inhibitors, which carry an increased risk of bone fractures, she says.
Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health.
For the study, Li and colleagues collected blood samples from 166 women with breast cancer and measured their levels of vitamin D. Of the total, 46% had vitamin D insufficiency, defined as levels between 12.5 and 50 nanomoles per liter (nmol/L) of blood. Another 6% had vitamin D deficiency, with levels lower than 12.5 nmol/L. When ethnicity was considered, vitamin D levels were lower in Asian women than in white or other women: an average of about 36 nmol/L vs. 61 nmol/L and 39 nmol/L, respectively.
The researchers theorized that vitamin D levels would be higher in the summer, when there are more daylight hours, but the study showed no association between vitamin D levels and seasons. Last month, the U.S. Institute of Medicine issued updated guidelines stating that a blood level of 50 nmol/L (or 20 nanograms/milliliter) is sufficient for 97% of people.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.
Diabetic kidney disease (nephropathy), a common complication of diabetes, may respond to a dietary supplement. Researchers at the Medical College of Georgia found that chromium reduced inflammation associated with diabetic kidney disease in mice.
It has long been known that chromium has a role in glucose (sugar) metabolism by boosting the effects of insulin. Insulin is secreted by cells in the pancreas in response to increased levels of glucose in the blood, and it provides cells with glucose for energy.
The results of this new study suggest that chromium may play another part in diabetes. Researchers used three groups of mice: one lean, healthy group and two groups that were genetically engineered to be obese and have diabetes. The healthy mice and one group of diabetic mice were fed regular rodent food while the remaining group received a diet enriched with chromium picolinate, a form that is more easily absorbed by the body.
During the six months of the study, the researchers found that the untreated diabetic mice excreted nearly ten times more albumin than the healthy mice, which was expected. However, the treated diabetic mice excreted about 50 percent less albumin than their untreated diabetic counterparts. Albuminuria (protein in the urine) is a sign of kidney disease.
After six months, the mice were euthanized and tissue samples from the kidneys were examined. The untreated mice had cytokines (interleukin 6 and interleukin 17) associated with inflammation and an enzyme (IDO) that regulates the production of the cytokines. The treated mice had reduced levels of the cytokines compared with the untreated group.
Much research has been done on the relationship between chromium, insulin, and blood sugar levels, as well as use of the mineral in weight loss. Some experts claim that chromium deficiency is a cause of type 2 diabetes and obesity and that supplementation can help prevent and treat both conditions.
The investigators in the current study, which was discussed at the 2010 American Physiological Society conference, concluded that chromium picolinate reduced inflammation in the treated diabetic mice by affecting the activity of the cytokines and IDO. Further research is needed to more clearly define chromium’s role in diabetes and in diabetic kidney disease.
American Physiological Society
The pilot study used four women, all of whom were breast cancer survivors, and monitored changes in their blood of key molecules involved in the growth of cancer cells. The participants were asked to fast on the day of the tests and had blood samples taken before and after eating a portion of watercress. The scientists found that six hours after they had eaten the leaves, the women experienced a drop in the activity of a molecule called 4E binding protein, which is thought to be involved in helping cancer cells survive.
Laboratory studies also showed that extracts taken from watercress leaves inhibited the growth of breast cancer cells. The findings build on epidemiological studies that have shown people who eat watercress and other vegetables rich in isothiocyanates, such as broccoli and cabbage, are at lower risk of developing cancer.
Hazel Nunn, Cancer Research UK's health information manager, said the current study was too small to draw any firm conclusions.
She added: “Watercress may well have benefits but there's no reason to believe that it should be superior to a generally healthy, balanced diet that is high in fibre, vegetables and fruit and low in red and processed meat, salt, saturated fat and alcohol.”
Pancreatic tumor cells use fructose to divide and proliferate, U.S. researchers said on Monday in a study that challenges the common wisdom that all sugars are the same.Tumor cells fed both glucose and fructose used the two sugars in two different ways, the team at the University of California Los Angeles found.
They said their finding, published in the journal Cancer Research, may help explain other studies that have linked fructose intake with pancreatic cancer, one of the deadliest cancer types. “These findings show that cancer cells can readily metabolize fructose to increase proliferation,” Dr. Anthony Heaney of UCLA's Jonsson Cancer Center and colleagues wrote. “They have major significance for cancer patients given dietary refined fructose consumption, and indicate that efforts to reduce refined fructose intake or inhibit fructose-mediated actions may disrupt cancer growth.”
Americans take in large amounts of fructose, mainly in high fructose corn syrup, a mix of fructose and glucose that is used in soft drinks, bread and a range of other foods. Politicians, regulators, health experts and the industry have debated whether high fructose corn syrup and other ingredients have been helping make Americans fatter and less healthy.
Too much sugar of any kind not only adds pounds, but is also a key culprit in diabetes, heart disease and stroke, according to the American Heart Association. Several states, including New York and California, have weighed a tax on sweetened soft drinks to defray the cost of treating obesity-related diseases such as heart disease, diabetes and cancer. The American Beverage Association, whose members include Coca-Cola (KO.N) and Kraft Foods (KFT.N) have strongly, and successfully, opposed efforts to tax soda. The industry has also argued that sugar is sugar.
Heaney said his team found otherwise. They grew pancreatic cancer cells in lab dishes and fed them both glucose and fructose. Tumor cells thrive on sugar but they used the fructose to proliferate. “Importantly, fructose and glucose metabolism are quite different,” Heaney's team wrote. “I think this paper has a lot of public health implications. Hopefully, at the federal level there will be some effort to step back on the amount of high fructose corn syrup in our diets,” Heaney said in a statement.
Now the team hopes to develop a drug that might stop tumor cells from making use of fructose.
U.S. consumption of high fructose corn syrup went up 1,000 percent between 1970 and 1990, researchers reported in 2004 in the American Journal of Clinical Nutrition.
The research is being presented at the conference of the British Society for Research on Ageing (BSRA) in Newcastle. It was conducted by scientists at the BBSRC Centre for Integrated Systems Biology of Ageing and Nutrition (CISBAN) at Newcastle University.
Working with the theory that cell senescence – the point at which a cell can no longer replicate – is a major cause of ageing the researchers set out to investigate what effect a restricted diet had on this process. By looking at mice fed a restricted diet the team found that they had a reduced accumulation of senescent cells in their livers and intestines. Both organs are known to accumulate large numbers of these cells as animals age.
Alongside this the CISBAN scientists also found that the telomeres of the chromosomes of the mice on restricted diets were better maintained despite their ageing. Telomeres are the protective 'ends' of chromosomes that prevent errors, and therefore diseases, occurring as DNA replicates throughout an organisms lifetime but they are known to become 'eroded' over time.
The adult mice were fed a restricted diet for a short period of time demonstrating that it may not be necessary to follow a very low calorie diet for a lifetime to gain the benefits the scientists found.
Chunfang Wang, the lead researcher on this project at CISBAN, said: “Many people will have heard of the theory that eating a very low calorie diet can help to extend lifespan and there is a lot of evidence that this is true. However, we need a better understanding of what is actually happening in an organism on a restricted diet. Our research, which looked at parts of the body that easily show biological signs of ageing, suggests that a restricted diet can help to reduce the amount of cell senescence occurring and can reduce damage to protective telomeres. In turn this prevents the accumulation of damaging tissue oxidation which would normally lead to age-related disease.”
Professor Thomas von Zglinicki, who oversaw the research, said: “It's particularly exciting that our experiments found this effect on age-related senescent cells and loss of telomeres, even when food restriction was applied to animals in later life. We don't yet know if food restriction delays ageing in humans, and maybe we wouldn't want it. But at least we now know that interventions can work if started later. This proof of principle encourages us at CISBAN in our search for interventions that might in the foreseeable future be used to combat frailty in old patients.”
CISBAN is one of the six BBSRC Centres for Integrative Systems Biology. The centres represent a more than £40M investment by the Biotechnology and Biological Sciences Research Council (BBSRC) to support the development of systems biology in the UK. The centres are also supported by the Engineering and Physical Sciences Research Council.
Systems biology uses the study of a whole, interconnected system – a cell, an organism or even an ecosystem – with computer modelling to better make the outputs of biology more useful to scientists, policymakers and industry.
Prof Douglas Kell, BBSRC Chief Executive and keynote speaker at the BSRA Conference, said: “As lifespan continues to extend in the developed world we face the challenge of increasing our 'healthspan', that is the years of our lives when we can expect to be healthy and free from serious or chronic illness. By using a systems biology approach to investigate the fundamental mechanisms that underpin the ageing process the CISBAN scientists are helping to find ways to keep more people living healthy, independent lives for longer.”