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Researchers at MIT and their colleagues said they have devised a way to produce liver-like cells from stem cells, a key step in studying why people respond differently to Hepatitis C.
An infectious disease that can cause inflammation and organ failure, Hepatitis C has different effects on different people, but no one is sure why, the researchers said in a press release from MIT. Some people are very susceptible to the infection, while others are resistant.
The researchers said that by studying liver cells from different people in the lab, they may determine how genetic differences produce these varying responses. However, liver cells are hard to get and very difficult to grow in a lab dish because they tend to lose their normal structure and function when removed from the body.
The researchers, from MIT, Rockefeller University and the Medical College of Wisconsin, have come up with a way to produce liver-like cells from induced pluripotent stem cells (iPSCs), which are made from body tissues rather than embryos. Those liver-like cells can then be infected with Hepatitis C and help scientists study the varying responses to the infection.
The scientists claim this is the first time an infection has been made in cells derived from iPSCs. Their new technique is described in the Jan. 30 issue of the Proceedings of the National Academy of Sciences. The development, they said, may also eventually enable personalized medicine, in which doctors could test the effect of different drugs on tissues derived from the patient being treated and then customize therapy for that patient.
The new study is a collaboration between Sangeeta Bhatia, professor of health sciences and technology and electrical engineering and computer science at MIT; Charles Rice, professor of virology at Rockefeller; and Stephen Duncan, professor of human and molecular genetics at the Medical College of Wisconsin.
The iPSCs are derived from normal body cells, often skin cells. By turning on certain genes in those cells, the scientists can revert them to an immature state that is identical to embryonic stem cells, which can turn into any cell type. Once the cells become pluripotent, they can be directed to become liver-like cells by turning on genes that control liver development.
The researchers’ goal is to take cells from patients who have unusual reactions to hepatitis C infection, transform them into liver cells and study their genetics to see why people respond as they do. “Hepatitis C virus causes an unusually robust infection in some people, while others are very good at clearing it. It’s not yet known why those differences exist,” Bhatia said in a statement.
Blood Test Instead of Biopsy Identifies Liver Damage Siemens is marketing the first rapid, automated biomarker test for diagnosing and assessing liver fibrosis. The ELF test (Enhanced Liver Fibrosis test) takes approximately one hour to complete and requires only a blood sample
The ELF test (Enhanced Liver Fibrosis test) takes approximately one hour to complete and requires only a blood sample. The process is therefore less invasive but just as reliable as the previously required biopsy, and it usually takes about a week to deliver a biopsy result.
The new test was developed by Siemens Healthcare in collaboration with University College London and can be used as a routine test on the Siemens ADVIA Centaur Immunoassay System.
Liver fibrosis is the result of chronic liver damage caused by vi-ral hepatitis, alcoholic cirrhosis, or fatty liver disease. It is characterized by scarring of the liver tissue, which can lead to cirrhosis or cancer of the liver over the long term — a frequent cause of death worldwide.
At present, the “gold standard” for assessing the severity of a liver fibrosis is a liver biopsy, which involves the removal of a small amount of liver tissue. This biopsy has drawbacks, however: It is painful; it entails some risk for the patient; and it tests only a small sample of the liver.
With the automated ADVIA Centaur ELF Test, a fast and mini-mally invasive technique is now available for determining both the severity of a liver fibrosis and the risk that it will worsen. The test examines three direct blood serum biomarkers: hyaluronic acid (HA), procollagen III N-terminal propeptide (PIIINP), and the tissue inhibitor of metalloproteinase 1 (TIMP-1). These direct biomarkers are molecules that are involved in the formation of fibrosis. In the test, special reagents react with the biomarkers and generate light in the process. The greater the intensity of this chemiluminescence, the greater the presence of the biomarker.
A special algorithm is used to convert the results of the three biomarkers into the ELF score, which indicates the degree of fibrosis. The combination of three biomarkers increases the accuracy of the test. As an international clinical trial has shown, the ELF test can precisely differentiate between slight, moderate, and serious cases of fibrosis. In the event of slight or moderate fibrosis, patients normally have no symptoms. Doctors can thus intervene before significant damage to the liver and monitor the progress of therapy.
To complement the ELF test, Siemens is also offering imaging and laboratory diagnostic technologies like hepatitis blood tests and ultrasound systems that help physicians identify liver fibrosis at an early stage and monitor its development.
Dr. Norbert Aschenbrenner | Source: Siemens Innovation News
Further information:
www.siemens.com/innovationnews
A molecule in liver cell membranes that plays a role in cholesterol uptake also enables hepatitis C virus (HCV) to enter cells, according to research reported in the
January 8, 2012, advance online edition of Nature Medicine.
Big Pharma
Vertex Falls as Analyst Cuts Sales Estimates on Hepatitis C Pill
Vertex Pharmaceuticals Inc. (VRTX) fell the most in two months after an analyst with Leerink Swann & Co. cut sales predictions for the company’s hepatitis C pill that was approved by U.S. regulators last year.
Vertex’s Incivek, among the first new hepatitis C drugs to reach the market in nearly a decade, could be eclipsed by new pill-only treatments with fewer side effects and shorter courses of treatment. Incivek is given with interferon, an injected medicine.
Merck & Co.’s similar pill, Victrelis, was also approved last year.
Shares of Cambridge, Massachusetts-based Vertex
fell 4.2 percent to $34.48 at 10:18 a.m., after declining 5.2 percent in the biggest intraday drop since Nov. 14.
Howard Liang, an analyst with Leerink Swann in
Boston, cut his sales forecast for Incivek by 35 percent from $2.3 billion this year to $1.5 billion. Liang also cut his target price for Vertex shares from $66 to $48.
“In light of recent development of interferon-free regimens and likely more aggressive development as a result of recent transactions in the space, we are further curtailing the Incivek tail,” Liang said in a
note to clients today.
Vertex had $420 million in revenue from Incivek in the third quarter of 2011. Revenue from the drug accounts for 64 percent of the company’s sales.
To contact the reporter on this story: Drew Armstrong in Washington at
darmstrong17@bloomberg.net;
Liver Cancer
by George Ochoa
Two Mayo Clinic studies have clarified the importance of chronic hepatitis C virus (HCV) in the rising trend of liver cancer, or hepatocellular carcinoma (HCC).
One study (Yang et al. Mayo Clin Proc. 2012;87:9-16) analyzed longitudinal trends in the incidence, etiology, treatment of HCC and survival in community residents in Olmsted County, Minn. The researchers found that in earlier periods (1976-1990, 1991-2000), alcohol use was the most common risk factor, but, in 2001 to 2008, HCV filled that role. At the same time, HCC incidence rose dramatically, from 3.5 per 100,000 person-years for the 1976 to 1990 time period, to 3.8 for the period from 1991 to 2000, to 6.9 for the 2001 to 2008 period.
Study author W. Ray Kim, MD, associate professor of medicine, Mayo Clinic College of Medicine, Rochester, Minn., wrote in an email: “The biggest and unique risk factor of HCC is underlying liver disease. Our data showed that previously alcohol, more recently HCV has become the underlying cause.”
The second study (Shire et al. Mayo Clin Proc. 2012;87:17-24) investigated a sample of Somali immigrants seen at Mayo Clinic from July 1, 1996, to Oct. 31, 2009. Non-Somali Olmsted County residents served as controls. The frequencies of chronic hepatitis B virus (HBV) and HCV, and their associations with HCC, were studied. Both HBV and HCV occurred frequently in the sample of Somalis, but HCV was the major risk factor for HCC. There were significant differences in the HCV genotype distributions between Somalis and non-Somalis.
The high prevalence of HCV in the Somali sample came as a surprise to the researchers. “We didn’t expect it,” Abdirashid M. Shire, PhD, assistant professor of medicine, Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, said in an interview. The study, Dr. Shire added, “supports the value of early detection” of HCV. “It’s very important to screen for HCV.” Dr. Kim reported that his study also “indirectly” supports the value of early detection and treatment to improve outcomes.
—Drs. Kim and Shire had no relevant financial disclosures
28 January 2012
Researchers at CIC Biogune, the Cooperative Centre for Research into Biosciences and led by Dr. Maria Luz Martinez Chantar, have found a strong relationship between high levels of Hu antigen R (HuR) protein and the...
By Denise Mann
HealthDay Reporter
THURSDAY, Jan. 26 (HealthDay News) -- Popular cholesterol-lowering statins may also lower risk for liver cancer among people with hepatitis B, a new study shows. Hepatitis B, an inflammation of the liver due to the hepatitis B virus, is one of the main causes of liver cancer.
This is not the first time that statins have shown promise in reducing risk for cancer. Other studies have hinted that these drugs may play a role in preventing certain types of cancer, including breast cancer.
In the new study of more than 33,000 individuals with hepatitis B followed from 1997 to 2008, those who took a statin were less likely to develop liver cancer, when compared to participants who were not prescribed statins. What's more, the longer a person took statins, the greater the liver-cancer risk reduction. Study participants were prescribed the statins to treat high cholesterol levels. Overall, 1,021 people developed liver cancer during the study period.
More research is needed to see how statins may lower liver cancer risk among people with hepatitis B, the researchers said.
"Statins have potential protective effects against cancers [and] carriers of hepatitis B virus infection have a substantial risk of [liver] carcinoma," said Dr. Pau-Chung Chen, a professor of environmental medicine and epidemiology at National Taiwan University, in Taipei. "Statin use is not only a benefit to preventing cardiovascular diseases, but also an additional, convenient and acceptable strategy for preventing hepatocellular carcinoma," or liver cancer, Chen said.
However, statins can cause a potentially dangerous rise in liver enzymes and liver damage. Regular liver function tests are required for all people who take statins.
The study appeared online Jan. 23 in the Journal of Clinical Oncology.
"This is exciting and unequivocally solid research," said Dr. Eugene Schiff, a professor of medicine and director of the Center for Liver Diseases at the University of Miami Miller School of Medicine.
"One of the issues is that statins are relatively contraindicated in people with liver disease," Schiff said. But "the take-home message for people with hepatitis B or anybody with liver disease is that statins are safe. This re-emphasizes the point that if someone has chronic hepatitis B and there is an indication for statins, they should get them and they may be beneficial far beyond lowering cholesterol: They may also reduce their risk for liver cancer."
Dr. David Bernstein, chief of hepatology at North Shore University Hospital and Long Island Jewish Medical Center in Manhasset, N.Y., is more cautious. "In almost all other liver conditions, cirrhosis must be present before [liver cancer] develops," he said. During cirrhosis, scar tissue replaces healthy liver tissue. "Statins must be used with caution in patients with cirrhosis, which can limit their use in patients with liver disease at risk of developing liver cancer," he said. "Further studies are needed in this patient population to confirm these findings."
More information
For information on
hepatitis B, visit the U.S. National Digestive Diseases Information Clearinghouse.
Copyright © 2012
HealthDay. All rights reserved.
Transplant
27 January 2012
According to Johns Hopkins researchers, individuals who donate a portion of their liver for live transplantation usually recover safely from the procedure and can expect to live long, healthy lives...
A study in February's issue of Gastroenterology estimates early death, acute liver failure, and long-term mortality among live liver donors.
Dr Abimereki Muzaale and colleagues from Maryland, USA estimated the risk of perioperative mortality or acute liver failure for live liver donors in the United States, and avoid selection or ascertainment biases and sample size limitations.
The research team followed up 4111 live liver donors in the United States between 1994 and 2011 for a mean of 8 years.
Deaths were determined from the Social Security Death Master File. Survival data were compared with those from live kidney donors and healthy participants of the National Health and Nutrition Examination Survey (NHANES) III.
The team observed that 7 donors had early deaths.
Risk of early death among live liver donors is almost 2 per 1000 donors
Gastroenterology
The research team found that risk of death did not vary with age of the liver recipient or portion of liver donated.
There were 11 catastrophic events.
The team found that risk did not vary with recipient age, or portion of liver donated.
The researchers noted that long-term mortality of live liver donors was comparable to that of live kidney donors and NHANES participants.
Dr Muzaale's team concluded, "The risk of early death among live liver donors in the United States is almost 2 per 1000 donors."
"Mortality of live liver donors does not differ from that of healthy, matched individuals over a mean of 8 years."
30 January 2012
How common is transmission of hepatitis C through organ donation, and what types of preventive practices can be put into place to prevent this from happening?
Even after a liver transplant, patients can often experience a recurrence of hepatitis C. How should it be treated in this setting?
HCV Brain Function
Chronic HCV infection causes progressive liver disease and can also be associated with various CNS abnormalities. To date, however, few studies have investigated the mechanisms by which these abnormalities arise, that is, whether they are a result of impaired hepatic function or virus replication in the CNS. Thus, the researchers quantified HCV RNA levels in the brain and liver of 10 individuals infected with HCV. They also investigated the expression of HCV entry receptors in the brain, and conducted in vitro studies to ascertain whether two brain-derived endothelial cell lines could support HCV infection.
The issue of whether the hepatitis C virus (HCV) affects brain function continues to arouse interest, investigation, and debate. Symptoms such as fatigue, poor memory, and concentration ("brain fog") are commonplace and an effect of this infection on mental health related quality of life, which is independent of liver fibrosis, is well established this study provides a substantial link between HCV and cerebral dysfunction by demonstrating a reduction in spectroscopic markers of cerebral inflammation and an improvement in cognition, following HCV eradication
Research
This article takes an in-depth look at hepatitis C treatment options in a specialized community of people on methadone maintenance.
FDA
The FDA recently granted a waiver under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) to OraSure Technologies for its OraQuick HCV Rapid Antibody Test for use with fingerstick whole blood and venous whole blood specimens. With this waiver, the OraQuick HCV test now can be used by more than 180,000 sites in the United States to test individuals who are at risk for hepatitis C virus (HCV) infection.
The CLIA, passed by Congress in 1988, establishes quality standards for all laboratory testing to ensure the accuracy, reliability and timeliness of patient test results, regardless of where a test is performed. As defined by the CLIA, waived tests are categorized as “simple laboratory examinations and procedures that have an insignificant risk of an erroneous result.” The FDA determines the criteria for tests being simple with a low risk for error, and approves manufacturers’ applications for waivers.
The CLIA waiver granted for OraSure’s OraQuick HCV Rapid Antibody Test, extends the use of the assay to more than 180,000 facilities, such as outreach clinics, community-based organizations and physician offices, according to a press release from OraSure.
“A CLIA waiver for our OraQuick HCV test represents a critical milestone in our quest to make the test available to the widest possible range of at-risk individuals in the United States,” said Douglas A. Michels, president and CEO of OraSure Technologies. “The CLIA waiver will enable health care providers, those on the front lines of fighting this devastating disease, to use this simple and accurate test in physician offices and outreach settings so more individuals infected with hepatitis C can be diagnosed and treated.”
The OraQuick HCV Rapid Antibody Test is the first and only FDA-approved rapid test for the detection of antibodies to HCV. The test is approved for fingerstick whole blood specimens and venipuncture whole blood specimens in individuals aged 15 years or older, and provides results in 20 minutes. The assay has not been approved for use in patient populations without signs or symptoms of HCV, and its use has not been established for testing patients younger than 15 years of age or for pregnant women.
—Based on a press release from OraSure Technologies
Healthy You
A study recently published in the
Journal of Pain Research shows that practicing yoga boosts levels of the stress hormone
cortisol and could help ease some symptoms of
fibromyalgia such as pain, fatigue, muscle stiffness and depression.
Under stressful conditions yeast genomes become unstable, readily acquiring or losing whole chromosomes to enable rapid adaption. The musical spectrum was derived from the copy number data of the aneuploid yeast genomes selected under different stress conditions, where the gain and loss of chromosomes are represented as red and green bars, respectively.
Newswise — KANSAS CITY, MO— Cells trying to keep pace with constantly changing environmental conditions need to strike a fine balance between maintaining their genomic integrity and allowing enough genetic flexibility to adapt to inhospitable conditions. In their latest study, researchers at the Stowers Institute for Medical Research were able to show that under stressful conditions yeast genomes become unstable, readily acquiring or losing whole chromosomes to enable rapid adaption.
The research, published in the January 29, 2012, advance online issue of Nature, demonstrates that stress itself can increase the pace of evolution by increasing the rate of chromosomal instability or aneuploidy. The observation of stress-induced chromosome instability casts the molecular mechanisms driving cellular evolution into a new perspective and may help explain how cancer cells elude the body’s natural defense mechanisms or the toxic effects of chemotherapy drugs.
“Cells employ intricate control mechanisms to maintain genomic stability and prevent abnormal chromosome numbers,” says the study’s leader, Stowers investigator Rong Li, Ph.D. “We found that under stress cellular mechanisms ensuring chromosome transmission fidelity are relaxed to allow the emergence of progeny cells with diverse aneuploid chromosome numbers, producing a population with large genetic variation.”
Known as adaptive genetic change, the concept of stress-induced genetic variation first emerged in bacteria and departs from a long-held basic tenet of evolutionary theory, which holds that genetic diversity—evolution’s raw material from which natural selection picks the best choice under any given circumstance—arises independently of hostile environmental conditions.
“From an evolutionary standpoint it is a very interesting finding,” says graduate student and first author Guangbo Chen. “It shows how stress itself can help cells adapt to stress by inducing chromosomal instability.”
Aneuploidy is most often associated with cancer and developmental defects and has recently been shown to reduce cellular fitness. Yet, an abnormal number of chromosomes is not necessarily a bad thing. Many wild yeast strains and their commercial cousins used to make bread or brew beer have adapted to their living environs by rejiggering the number of chromosomes they carry. “Euploid cells are optimized to thrive under ‘normal’ conditions,” says Li. “In stressful environments aneuploid cells can quickly gain the upper hand when it comes to finding creative solutions to roadblocks they encounter in their environment.”
After Li and her team had shown in an earlier Nature study that aneuploidy can confer a growth advantage on cells when they are exposed to many different types of stress conditions, the Stowers researchers wondered whether stress itself could increase the chromosome segregation error rate.
To find out, Chen exposed yeast cells to different chemicals that induce various types of general stress and assessed the loss of an artificial chromosome. This initial screen revealed that many stress conditions, including oxidative stress, increased the rate of chromosome loss ten to 20-fold, a rate typically observed when cells are treated with benomyl, a microtubule inhibitor that directly affects chromosome segregation.
The real surprise was radicicol, a drug that induces proteotoxic stress by inhibiting a chaperone protein, recalls Chen. “Even at a concentration that barely slows down growth, radicicol induced extremely high levels of chromosome instability within a very short period of time,” he says.
Continued growth of yeast cells in the presence of radicicol led to the emergence of drug-resistant colonies that had acquired an additional copy of chromosome XV. Yeast cells pretreated briefly with radicicol to induce genomic instability also adapted more efficiently to the presence of other drugs including fluconazole, tunicamycin, or benomyl, when compared to euploid cells.
Interestingly, certain chromosome combinations dominated in colonies that were resistant to a specific drug. Fluconazole-resistant colonies typically gained an extra copy of chromosome VIII, tunicamycin-resistant colonies tended to lose chromosome XVI, while a majority of benomyl-resistant colonies got rid of chromosome XII. “This suggested to us that specific karyotypes are associated with resistance to certain drugs,” says Chen.
Digging deeper, Chen grew tunicamycin-resistant yeast cells, which had adapted to the presence of the antibiotic by losing one copy of chromosome XVI, under drug-free conditions. Before long, colonies of two distinct sizes emerged. He quickly discovered that the faster growing colonies had regained the missing chromosome. By returning to a normal chromosome XVI number, these newly arisen euploid cells had acquired a distinctive growth advantage over their aneuploid neighbors. But most importantly, the fast growing yeast cells were no longer resistant to tunicamycin and thus clearly linking tunicamycin resistance to the loss of chromosome XVI.
Researchers who also contributed to the work include William D. Bradford and Chris W. Seidel both at the Stowers Institute for Medical Research.
The study was funded in part by the National Institute of General Medical Sciences.
About the Stowers Institute for Medical Research
The Stowers Institute for Medical Research is a non-profit, basic biomedical research organization dedicated to improving human health by studying the fundamental processes of life. Jim Stowers, founder of American Century Investments, and his wife Virginia opened the Institute in 2000. Since then, the Institute has spent over 800 million dollars in pursuit of its mission.
Currently the Institute is home to over 500 researchers and support personnel; over 20 independent research programs; and more than a dozen technology development and core facilities. Learn more about the Institute at
www.stowers.org.
New research finds milk drinkers scored better on memory and brain function tests
Pouring at least one glass of milk each day could not only boost your intake of much-needed key nutrients, but it could also positively impact your brain and mental performance, according to a recent study in the International Dairy Journal.1 Researchers found that adults with higher intakes of milk and milk products scored significantly higher on memory and other brain function tests than those who drank little to no milk. Milk drinkers were five times less likely to "fail" the test, compared to non milk drinkers.
Researchers at the University of Maine put more than 900 men and women ages 23 to 98 through a series of brain tests – including visual-spatial, verbal and working memory tests – and tracked the milk consumption habits of the participants. In the series of eight different measures of mental performance, regardless of age and through all tests, those who drank at least one glass of milk each day had an advantage. The highest scores for all eight outcomes were observed for those with the highest intakes of milk and milk products compared to those with low and infrequent milk intakes. The benefits persisted even after controlling for other factors that can affect brain health, including cardiovascular health and other lifestyle and diet factors. In fact, milk drinkers tended to have healthier diets overall, but there was something about milk intake specifically that offered the brain health advantage, according to the researchers.
In addition to the many established health benefits of milk from bone health to cardiovascular health, the potential to stave off mental decline may represent a novel benefit with great potential to impact the aging population. While more research is needed, the scientists suggest some of milk's nutrients may have a direct effect on brain function and that "easily implemented lifestyle changes that individuals can make present an opportunity to slow or prevent neuropsychological dysfunction."
New and emerging brain health benefits are just one more reason to start each day with lowfat or fat free milk. Whether in a latte, in a smoothie, on your favorite cereal, or straight from the glass, milk at breakfast can be a key part of a healthy breakfast that help sets you up for a successful day. The 2010 Dietary Guidelines for Americans recommend three glasses of lowfat or fat free milk daily for adults and each 8-ounce glass contains nine essential nutrients Americans need, including calcium and vitamin D.
About the National Milk Mustache "got milk?"® Campaign
The Milk Processor Education Program (MilkPEP), Washington, D.C., is funded by the nation's milk processors, who are committed to increasing fluid milk consumption. The National Fluid Milk Processor Promotion Board, through MilkPEP, runs the National Milk Mustache "got milk?"® Campaign, a multi-faceted campaign designed to educate consumers about the health benefits of milk. For more information, go to
www.whymilk.com. Deutsch, A Lowe and Partners Company, is the creative agency for the National Milk Mustache "got milk?"® Campaign.
1Crichton GE, Elias MF, Dore GA, Robbins MA. Relation between dairy food intake and cognitive function: The Maine-Syracuse Longitudinal Study.
International Dairy Journal. 2012; 22:15-23.
For Your Reading Pleasure
Chuck Garcia is launching the January 2012 collection of daily blog entries for the “31 Days of Wellness”, our annual celebration of the New Year, and the opportunity to start anew as we ring in the New Year. Enjoy, visit us daily, and send us your feedback.
Dr. Joe Galati
OH My Aches And Pains
As I am getting ready to start Hepatitis C (HCV) treatment, I've been running across some pretty interesting pieces of information that I think will make my treatment experience more successful.
Behind The Headlines
Behind the Headlines provides an unbiased and evidence-based analysis of health stories that make the news.
How our system works
- Each day the NHS Choices team selects health stories that are making headlines.
- These, along with the scientific articles behind the stories, are sent to Bazian, a leading provider of evidence-based healthcare information.
- Bazian's clinicians and scientists analyse the research and produce impartial evidence-based assessments, which are edited and published by NHS Choices.
The idea that regularly eating fried foods causes heart attacks is a ‘myth’, The Daily Telegraph has today reported.
The newspaper has panned conventional wisdom based on a large Spanish study investigating how people’s fried food consumption was linked to their risk of events such as heart attacks and episodes of heart pain. To study the relationship researchers surveyed over 40,000 people on how much fried food they ate during the previous year, looking at any episodes related to coronary heart disease over an average period of 11 years.
In this particular setting the researchers found no link between consuming food fried in olive or sunflower oils and the risk of
heart disease (the UK’s biggest killer) or death from any cause. However, while such a phenomenon could exist in the context of this specific group of people eating a specific type of diet, the research does not support the idea that fried food is generally harmless, or that it represents diets among the UK population. For example, most participants reported eating a relatively small amount of fried food each day, much less than might be typically found in a fry-up or a fast food meal. In short, it is not clear whether the same study conducted in the UK would have the same results.
Many news sources have reported the results in an accurate, measured way. However, The Daily Telegraph’s account has been somewhat overcooked, as the study did not look at the impact of factors such as frying with other types of fats, reusing oils several times (as is the case in most fast food outlets), or consuming fried snacks high in salt, sugar or calories.
Where did the story come from?
The study was carried out by a collaboration of researchers from Spanish universities and other health organisations based in Spain. It was funded by Spain’s FIS Fund for Health Research and published in the
peer-reviewed British Medical Journal.
Media reports were generally balanced, with many making the point that the study was primarily concerned with a Mediterranean diet containing olive oil, which is typically very different from the dietary patterns in the UK. This limits how relevant this study is to the UK population. Many news sources also rightly warn against assuming that the study results suggested that consuming large amounts of fried foods is not harmful. The Telegraph included a picture of a full English breakfast, which is not a recognised part of a Mediterranean dietary pattern.
What kind of research was this?
This prospective
cohort study investigated the association between people’s consumption of fried foods and their risk of experiencing coronary heart disease events such as heart attacks and heart pain (angina) which require surgery. It was conducted in a Spanish population.
Previous research has shown fried foods have been associated with high blood pressure, obesity and low levels of ‘good’ cholesterol (high-density lipoproteins or HDL cholesterol). However, existing studies into the association of fried food and coronary heart disease provided mixed results, the authors report.
When food is fried the nutritional content changes; water is lost and fat is absorbed, increasing the calorie content of the food. During frying, the oils also deteriorate and change into other forms, especially when reused, as is often the case in fried fast food outlets. This process leads to a loss of unsaturated fats and an increase in harmful trans fats.
A prospective cohort study is a good way of investigating whether fried foods are linked to heart disease because you can be sure the consumption of the food occurred before the development of the disease. However, the limitation is that you cannot be certain that fried foods caused a disease because its development may be influenced by numerous other factors, some measured in the research and some not.
The best type of study to definitively assess this link would be a large
randomised controlled trial, providing it could be performed ethically. However, given the cost and complexity of such a task, this approach may ultimately be impractical.
What did the research involve?
The participants were Spaniards enrolled in a research project called the European Prospective Investigation into Cancer and Nutrition (the EPIC-Spain cohort). The analysed cohort consisted of 40,757 adults aged between 29 and 69 who were recruited between 1992 and 1996. They were followed up for an average of 11 years to see what diseases they developed and what they died of.
When enrolled, participants were asked by trained interviewers to complete a questionnaire about the food they consumed over a typical week during the previous 12 months. Only foods consumed at least twice a month were recorded.
The study’s authors report that this method had previously been shown to be accurate (validated) at assessing the diet of Spanish people. The type of oil used for frying (olive oil versus sunflower oil or other vegetable oils) was recorded and then checked again after two years. No further information on diet was collected at a later date.
At enrolment, the researchers also recorded non-dietary variables. These included demographic variables such as age and sex as well as educational level, body mass index (BMI), smoking and physical activity levels. Participants were also asked if they had coronary heart disease, diabetes, high blood pressure, cancer or angina or had experienced a heart attack or stroke in the past.
For the analysis, people were divided into four groups depending on their level of fried food consumption. The researchers specifically analysed how consuming fried food was linked to the chance of having a coronary heart disease event and dying from any cause (known as all-cause mortality) and how these varied for the four groups.
The analysis was adjusted for a large number of factors, including energy intake, educational level, smoking and physical activity. This statistical technique aims to minimise the effect these external factors have on the association of interest, in this case between fried food and heart disease.
What were the basic results?
An average of 138g of fried food was consumed daily, including 14g of oil used for frying. About 7% of the total amount of food consumed was fried. Of the total amount of fried food consumed, 24% (34g/day) was fish, 22% (31g/day) meat, 21% (30g/day) potatoes, and 11% (15g/day) eggs. Almost two thirds (62%) of participants used olive oil for frying, the rest used sunflower oil or other vegetable oils.
During the 11-year follow up, 606 definite cases of heart disease were recorded (466 heart attacks and 140 episodes of angina requiring surgery) and 1,135 deaths from all causes.
Fried food consumption was not associated with the risk of coronary heart disease after adjusting for possible confounders. There was also no association between fried fat consumption and death from all causes. These findings were no different in those who fried using olive oil compared to sunflower oil or other vegetable oils.
In the study, coronary heart disease events were defined as definite, probable and possible depending how they were assessed. The researchers first analysed their data using only the definite cases of coronary heart disease and found no association between fried food and these cases. The same result was found when they combined the definite coronary heart disease cases with those that were less certain (probable and possible groups).
How did the researchers interpret the results?
The researchers concluded that within the EPIC-Spanish cohort they found ‘no association between consumption of fried food and risk of coronary heart disease or all-cause mortality’.
They point out that their results are ‘directly applicable only to Mediterranean countries with frying methods similar to those in Spain’ and state that oil (mainly olive and sunflower) rather than solid fat is used for frying in Spain. They also point out that the majority of fried food eaten in Spain is not necessarily fast food.
They also make the important point that ‘frying with other types of fats, reusing oils several times, or consuming fried snacks high in salt may still be harmful’.
Conclusion
This study found no association between how often people ate fried food and their risk of coronary heart disease or death from any cause in a large Spanish cohort.
This study has strengths, including using a valid method of assessing diet, a large sample size and long follow-up time, but also has significant limitations. The following limitations should be considered when interpreting the findings of this study:
- The study looked at frying using olive oil or sunflower oil in the context of a Mediterranean diet. The authors make the important point that frying with other types of fats or reusing oils several times may still be harmful. Reusing oils is common in fast food preparation in the UK, and so this study does not show that consuming this type of food is not linked to heart disease.
- Diet was measured only when the participants were first enrolled. Any changes in diet after this will be missed and could lead to an association being masked because of error in the classification of fried food consumption.
- Fried food consumption was self-reported using a computerised questionnaire and so there may have been under-reporting given that many people perceive it to be unhealthy and may want to partially conceal the amount they eat. This could potentially hide an association.
- The study did not assess the extent to which the oils were reused, assuming that this was not common in foods consumed in the home. Hence, the effects of foods fried in reused oils are still unknown and may warrant further research as reusing oils is known to make them more harmful, the authors report.
- This study cannot separate the effect of the food from the cooking method. For example, the beneficial effect of omega 3 fatty acids from fish compared with the effect of frying this fish in oil that may be harmful. Therefore, the food itself blurs the link between the cooking method and disease. It is not clear whether the same results would be found if the study was conducted on the UK diet, which is generally considered less healthy than the Mediterranean diet.
- This study cannot say that consuming fried foods at a higher level than their highest consumption group (249.6g/day) does not increase risk of heart disease.
Bearing in mind the limitations, this study showed that there may not be a link between consuming foods fried in olive oil or vegetable oil and coronary heart disease in Spanish adults consuming a typical Mediterranean diet. The relevance of this to the UK is limited due to differences in diet and the type of fried foods consumed in the two countries.
It is important to note that frying foods with other types of fats, particularly saturated fats such as lard or butter, reusing oils several times, or consuming fried snacks high in salt may still be harmful.
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