Posts Tagged "Cancer"

Lung cancer can lie dormant for more than 20 years before turning deadly, helping explain why a disease that kills more than 1.5 million a year worldwide is so persistent and difficult to treat, scientists said on Thursday.

Two papers detailing the evolution of lung cancer reveal how after an initial disease-causing genetic fault — often due to smoking — tumor cells quietly develop numerous new mutations, making different parts of the same tumor genetically unique.

By the time patients are sick enough to be diagnosed with cancer, their tumors will have developed down multiple evolutionary pathways, making it extremely hard for any one targeted medicine to have an effect.

The findings show the pressing need to detect lung cancer before it has shape-shifted into multiple malignant clones.

“What we’ve not been able to understand before is why this is really the emperor of all cancers and one of the hardest diseases to treat,” said Charles Swanton, an author on one of the papers from Cancer Research UK’s London Research Institute.

“Previously, we didn’t know how heterogeneous these early-stage lung cancers were.”

Lung cancer is the world’s deadliest cancer, killing an estimated 4,300 people a day, according to the World Health Organization. Around 85 percent of patients have non-small cell lung cancer (NSCLC), the type analyzed in the two studies.

To get a clearer understanding of the disease, the two groups of British and American scientists looked at genetic variability in different regions of lung tumors removed during surgery and worked out how genetic faults had developed over time.

What they found was an extremely long latency period between early mutations and clinical symptoms, which finally appeared after new, additional faults triggered rapid disease growth.

In the case of some ex-smokers, the initial genetic faults that started their cancer dated back to the time they were smoking cigarettes two decades earlier. But these faults became less important over time and more recent mutations were caused by a new process controlled by a protein called APOBEC.

The research was published in the journal Science.

Ramaswamy Govindan of Washington University School of Medicine, who was not involved in the studies, said better understanding of such genetic alterations was key to developing more effective treatments.

There are also hopes for a new generation of immunotherapy drugs that boost the immune system’s ability to detect and fight tumors, which could be particularly applicable to lung cancer.

“The large number of mutations may be the tumor’s Achilles heel because every time a new mutation forms there is a chance for the immune system to recognize it,” Swanton told Reuters.

Immunotherapy drugs from companies such as Bristol-Myers Squibb, Merck & Co, Roche and AstraZeneca are already undergoing tests in lung cancer, with data on Bristol’s medicine Opdivo due later this year.

Apart from better drugs, a critical challenge is to find improved ways to detect lung cancer before it develops the multiple genetic faults that eventually trigger rapid tumor growth and spread.

Currently, doctors use computerized tomography (CT) to detect lung cancer — but by the time a nodule is big enough to be spotted it on a scan it may contain a billion genetically diverse cancer cells.

For the future, oncologists are pinning hopes on a new approach, known as liquid biopsy, that may be able to detect signs of cancer much earlier from DNA circulating in the blood.

The current prognosis for NSCLC is grim, with most patients diagnosed when the disease has already spread and only around 15 percent surviving for at least five years after that.

Source: Reuters

A new study suggests that drops of fuel spilled at gas stations — which occur frequently with fill-ups — could cumulatively be causing long-term environmental damage to soil and groundwater in residential areas in close proximity to the stations.

Few studies have considered the potential environmental impact of routine gasoline spills and instead have focused on problems associated with large-scale leaks. Researchers with the Johns Hopkins Bloomberg School of Public Health, publishing online Sept. 19 in the Journal of Contaminant Hydrology, developed a mathematical model and conducted experiments suggesting these small spills may be a larger issue than previously thought.

“Gas station owners have worked very hard to prevent gasoline from leaking out of underground storage tanks,” says study leader Markus Hilpert, PhD, a senior scientist in the Department of Environmental Health Sciences in the Johns Hopkins Bloomberg School of Public Health. “But our research shows we should also be paying attention to the small spills that routinely occur when you refill your vehicle’s tank.”

Over the lifespan of a gas station, Hilpert says, concrete pads underneath the pumps can accumulate significant amounts of gasoline, which can eventually penetrate the concrete and escape into underlying soil and groundwater, potentially impacting the health of those who use wells as a water source. Conservatively, the researchers estimate, roughly 1,500 liters of gasoline are spilled at a typical gas station each decade.

“Even if only a small percentage reaches the ground, this could be problematic because gasoline contains harmful chemicals including benzene, a known human carcinogen,” Hilpert says.

Hilpert and Patrick N. Breysse, PhD, a professor in the Department of Environmental Health Sciences, developed a mathematical model to measure the amount of gasoline that permeates through the concrete of the gas-dispensing stations and the amount of gasoline that vaporizes into the air.

The model demonstrates that spilled gasoline droplets remain on concrete surfaces for minutes or longer, and a significant fraction of spilled gasoline droplets infiltrate into the pavement, as concrete is not impervious.

“When gasoline spills onto concrete, the droplet will eventually disappear from the surface. If no stain is left behind, there has been a belief that no gasoline infiltrated the pavement, and all of it evaporated,” Hilpert says. “According to our laboratory-based research and supported by our mathematical model, this assumption is incorrect. Our experiments suggest that even the smallest gasoline spills can have a lasting impact.”

Since the health effects of living near gasoline stations have not been well studied, Breysse says there is an urgency to look more closely, especially since the new trend is to build larger filling stations with many more pumps. These stations continue to be located near residential areas where soil and groundwater could be affected.

“The environmental and public health impacts of chronic gasoline spills are poorly understood,” says Breysse. “Chronic gasoline spills could well become significant public health issues since the gas station industry is currently trending away from small-scale service stations that typically dispense around 100,000 gallons per month to high-volume retailers that dispense more than 10 times this amount.”

“In a perfect world, it would be ideal to avoid chronic spills,” Hilpert says. “However, if these spills do occur, it is also important to prevent rainwater from flowing over the concrete pads underneath the pumps. Otherwise, storm runoff gets contaminated with benzene and other harmful chemicals and can infiltrate into adjacent soil patches or form storm water that may end up in natural bodies of water.”

 

Source: Johns Hopkins Bloomberg School of Public Health

Men with a certain pattern of baldness at age 45 had a 39% increased risk of developing aggressive prostate cancer versus men with no baldness, a new U.S. study found.

Men with frontal baldness and moderate baldness on the crown of the head had a higher risk of developing an aggressive form of prostate cancer.

Researchers said the finding adds to evidence of a hormone-based, biological link between baldness and prostate cancer, but added that more studies would be needed to support whether baldness patterns should be part of a screening system. Until more research is available, men shouldn’t be overly concerned about baldness patterns, the study’s researchers said.

The hair-loss pattern associated with a higher risk was frontal baldness plus moderate baldness on the vertex, or crown of the head, which about 10% of the men in the study recalled having at age 45. Other patterns—frontal only, and frontal plus mild or severe vertex baldness—weren’t associated with an increased risk of aggressive prostate cancer. The results of the study were published online Monday in the Journal of Clinical Oncology.

The finding arose from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, a large study started in the early 1990s by the National Cancer Institute to determine whether certain screening methods reduce cancer death rates.

In one segment of the trial, from 2006 to 2008, researchers provided questionnaires to men asking them to choose one of five illustrations that most closely resembled their hair-loss patterns at the age of 45, based on memory. The median age of the approximately 39,000 men who responded to the survey was about 70.

After a median follow-up period of 2.8 years after they responded to the survey, about 1,140 cases of prostate cancer were diagnosed. About half of them were classified as aggressive.

About 53% of the total group recalled some form of male-pattern baldness at age 45. Overall, men who had any of the baldness patterns at the age of 45 didn’t have a statistically significant increased risk of any form of prostate cancer later in life, versus men with no baldness.

However, men with frontal plus moderate vertex balding—about 10% of the men in the study—had a 39% increased risk of aggressive prostate cancer versus men with no baldness. Researchers called this a statistically significant finding, meaning it wasn’t likely due to chance.

Still, a large majority of men in this group, and in the study’s other groups, weren’t diagnosed with any prostate cancer during the follow-up period.

If future studies confirm the link, “it may help the doctor-patient discussion about whether men should opt for prostate cancer screening,” said Michael Cook, an epidemiologist with the NCI and one of the study’s authors.

Until then, he cautioned, men shouldn’t be “overly concerned” about their baldness patterns, and shouldn’t alter their current practices and beliefs about prostate cancer screening.

The study had certain limitations, including relying on men’s recollection of their baldness patterns years earlier, and an under-representation of black men.

Prostate-cancer screening has become controversial in recent years amid evidence that it has led to overtreatment of the disease. The American Cancer Society estimates a man’s lifetime risk of developing prostate cancer is 15.3%, while the risk of dying from it is 2.7%.

Source: Wall Street Journal

Pilots and flight attendants may be at an increased risk of developing the most deadly form of skin cancer, suggests a new analysis.

While the study cannot pinpoint why flight crews are at higher risk, the researchers suggest it could be the result of greater exposure to ultraviolet (UV) radiation, which causes damage to the DNA in skin cells, at high altitudes.

“This is very worrisome and awareness needs to increase and protective measurements must be undertaken,” said the study’s lead author, Dr. Martina Sanlorenzo from the University of California, San Francisco.

Pilots and other members of the cabin crew should be aware of the increased risk, she told Reuters Health in an email. Additionally, they should get skin checks and protect themselves from UV radiation.

Skin cancer is the most common form of cancer in the U.S., Sanlorenzo and her colleagues write in JAMA Dermatology.

Over 3.5 million Americans will be diagnosed with skin cancers in 2014, according to the American Cancer Society. About 76,000 people will be diagnosed with melanoma, which is the type of skin cancer that is most likely to lead to death.

Past studies have suggested that airline pilots and other flight crew members are prone to getting more skin cancers, but the association was poorly understood, the researchers write.

For the new analysis, they combined data from 19 previous studies published between 1990 and 2013. In total, they had data on over a quarter million people.

The researchers used a measure known as standardized incidence ratio, which helps gauge whether the cancer cases observed among specific groups of people are more or less than what would be expected in the general population.

According to the National Cancer Institute, the average American has about a 2 percent risk of developing melanoma during his or her lifetime.

Among participants in the 19 studies, the researchers found that melanoma was about twice as common among pilots and flight crew members than would be expected in the general population.

The researchers caution that they can’t say why cabin crews may be more likely to develop melanoma. It could be due to greater exposure to solar radiation as altitude increases and the protective barrier of the atmosphere thins.

There may, however, be other unknown factors among cabin crews, apart from UV exposure, that affect their melanoma risk, the study team writes.

The researchers don’t have any data on airplane passengers, but Sanlorenzo notes that “frequent flyers that fly as often as cabin crew should get regular skin checks and protect themselves from UV radiation.”

She suggested that the U.S. Federal Aviation Administration should take more measurements of how much UV radiation pilots and cabin crews are exposed to inside commercial planes, versus, for example, aircraft with special radiation-blocking windows.

“A prospective study could be done studying melanoma incidence in pilots/cabin crew flying airplanes where windows block UVA and UVB (radiation) entirely,” she said.

UVA and UVB radiation from the sun damage skin-cell DNA and are partly responsible for skin aging and for promoting skin cancer.

Source: Reuters

Postmenopausal women who in the past four years had undertaken regular physical activity equivalent to at least four hours of walking per week had a lower risk for invasive breast cancer compared with women who exercised less during those four years, according to data published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

But those benefits quickly disappear if regular physical activity stops.

“Twelve MET-h [metabolic equivalent task-hours] per week corresponds to walking four hours per week or cycling or engaging in other sports two hours per week and it is consistent with the World Cancer Research Fund recommendations of walking at least 30 minutes daily,” said Agnès Fournier, PhD, a researcher in the Centre for Research in Epidemiology and Population Health at the Institut Gustave Roussy in Villejuif, France. “So, our study shows that it is not necessary to engage in vigorous or very frequent activities; even walking 30 minutes per day is beneficial.”

Postmenopausal women who in the previous four years had undertaken 12 or more MET-h of physical activity each week had a 10 percent decreased risk of invasive breast cancer compared with women who were less active. Women who undertook this level of physical activity between five and nine years earlier but were less active in the four years prior to the final data collection did not have a decreased risk for invasive breast cancer.

“Physical activity is thought to decrease a woman’s risk for breast cancer after menopause,” said Fournier. “However, it was not clear how rapidly this association is observed after regular physical activity is begun or for how long it lasts after regular exercise stops.

“Our study answers these questions,” Fournier continued. “We found that recreational physical activity, even of modest intensity, seemed to have a rapid impact on breast cancer risk. However, the decreased breast cancer risk we found associated with physical activity was attenuated when activity stopped. As a result, postmenopausal women who exercise should be encouraged to continue and those who do not exercise should consider starting because their risk of breast cancer may decrease rapidly.”

Fournier and colleagues analyzed data obtained from biennial questionnaires completed by 59,308 postmenopausal women who were enrolled in E3N, the French component of the European Prospective Investigation Into Cancer and Nutrition (EPIC) study. The mean duration of follow-up was 8.5 years, during which time, 2,155 of the women were diagnosed with a first primary invasive breast cancer.

The total amount of self-reported recreational physical activity was calculated in MET-h per week. The breast cancer risk-reducing effects of 12 or more MET-h per week of recreational physical activity were independent of body mass index, weight gain, waist circumference, and the level of activity from five to nine years earlier.

Source: American Association for Cancer Research

You may want to stand up to read this.

A new study suggests that people who spend the bulk of their day sitting — whether behind the wheel, in front of the TV or working at a computer — appear to have an increased risk for certain kinds of cancers.

Previous studies have tied too much time spent sedentary to a variety of health problems, including heart disease, blood clots, a large waistline, higher blood sugar and insulin, generally poor physical functioning, and even early death.

For the new study, researchers zeroed in on 43 studies that specifically looked at the link between sitting and nearly 70,000 cases of cancer.

After combining the results from individual studies — a statistical tool that helps to reveal trends in research — there was good news and bad news.

The good news? Being sedentary did not appear to be linked to every kind of cancer. Scientists found no relationship between sitting and breast, ovarian, testicular or prostate cancers, or cancers of the stomach, esophagus and kidneys, or non-Hodgkin lymphoma.

The bad news was that there did seem to be a consistent relationship between hours spent sitting and an increased risk for colon and endometrial cancers.

People who spent the most time sitting during the day had a 24 percent increased risk of getting colon cancer compared to those who logged the least number of hours in a chair, according to the study.

When the researchers looked just at time spent watching TV, the risk jumped even more. Those who clocked the most hours glued to the tube had a 54 percent increased risk of colon cancer compared to those who watched the least.

That may be because viewers tend to consume unhealthy snacks and drinks while watching TV, said study author Daniela Schmid, an epidemiologist at the University of Regensburg in Germany.

For endometrial — or uterine — cancer, the risks were even higher. There was a 32 percent increased risk for women who spent the most time seated compared to those who sat the least, and a 66 percent increased risk for those who watched the most TV, the study authors said.

Moreover, every two-hour increase in sitting time was linked to an 8 percent increased risk of colon cancer and a 10 percent increased risk of endometrial cancer.

The risks remained even for “active couch potatoes” — folks who squeeze in some time at the gym but still spend most of their day off their feet. This suggests that regular exercise can’t offset the risks of too much sitting, the study authors said.

The findings, published June 16 in the Journal of the National Cancer Institute, make sense to Dr. Graham Colditz. He’s the associate director for prevention and control at Washington University’s Siteman Cancer Center in St. Louis.

“High blood sugar and high insulin is a clear sort of pathway to colon cancer, and we know from intervention studies that walking lowers insulin and getting up after meals lowers blood sugar compared to sitting,” said Colditz, who was not involved in the research.

As for endometrial cancer, “Obesity is a phenomenally strong cause. In fact, it is the main modifiable risk factor for endometrial cancer,” he said.

“So for me, the likely scenario there is that the sitting, the weight gain and obesity really go together and exacerbate the risk of endometrial cancer,” he added.

Because the studies included in the review only looked at broad relationships, they can’t prove that sitting, by itself, causes cancer. But the findings appeared to be remarkably consistent across studies, so Colditz thinks they should be taken seriously.

The study authors agree.

Continue reading below…

“Cutting down on TV viewing and sedentary time is just as important as becoming more active,” said Schmid. “For those whose jobs require them to sit at a desk most of the day, we recommend breaking up the time spent sitting by incorporating short bouts of light activity into the daily routine,” she added.

Source: Web MD

Prostate cancer (PC) is the most common male-related malignancy in the United States, the second most common cause of cancer-related death among US men, and the fourth most prevalent male malignancy worldwide.

Clinical aspects of PC vary widely, and two men with similar PC stage and PSA values may develop sharply different outcomes. The fact that most men are asymptomatic at diagnosis is a reflection of the tendency of PC to arise in the peripheral aspect of the prostate, distant from the urethra.

Obstructive and irritative urinary symptoms are consistent with larger-volume tumors involving the central tissue zone. Such symptoms are by no means restricted to PC and may be mimicked by such conditions as benign prostatic hyperplasia (BPH), urinary tract infection, and prostatitis. Progressive bone pain involving the spine, pelvis, or hips may herald the presence of metastases.

Currently, the most typical initial scenario is an older asymptomatic man with an elevated PSA who is found at subsequent biopsy to have an unanticipated histologic surprise in the form of PC. Fortunately, 90% of PC cases detected today are at a clinically localized stage.

PC screening tools include the PSA blood test and the digital rectal examination (DRE). Since the introduction of PSA testing in 1987, PC incidence has increased sharply, and mortality rates have trended downward.

Yet the cumulative risk/benefit comparisons for screening are not consistently persuasive due to the disturbing lack of randomized controlled trials (RCTs) demonstrating reduced mortality in screened populations. In fact, the US Preventive Services Task Force currently recommends against PSA-based screening.

In 1995, the Office of Technology Assessment concluded that available evidence indicated that PSA testing was of no proven mortality benefit. The CDC, American Cancer Society, and American Urological Association endorse testing with PSA and DRE annually in men reaching age 50 years, with earlier screening at age 40 years for black men or those with a family history of PC.

Since 90% of men with elevated PSA and normal DRE will be proven at biopsy to have disease confined to the prostate, most men can anticipate a favorable prognosis and a wide array of treatment options.

PSA is a serine protease that functions to liquefy the ejaculate. The prostate gland is the predominant source of PSA in serum. Elevations of PSA occur with architectural disruption of the gland as in PC, BPH, prostatitis, prostate biopsy or massage, transurethral resection of prostate, and (transiently) ejaculation.

PC detection and treatment strategies are influenced by current scientific data, recommended therapies with narrow risk/benefit profiles, quality-of-life concerns, and personal perceptions and values prior to initiating treatment. Patient involvement in treatment choice is especially important in early-stage, low-risk PC, where WW is a viable option, especially in older men with limited life expectancy

Although evidence is conflicting, RP appears more appropriate for younger men with organ-confined malignancy and higher Gleason scores, in which case curative resection is clinically attractive for preventing disease progression, distant metastasis, and tumor recurrence in anticipation of >10 years of life expectancy. Large-scale RCTs are underway to further clarify treatment decisions for men with PC.

The Prostate, Lung, Colorectal, and Ovary study, involving 76,693 US men over the span of 13 years, and the European Randomized Screening for Prostate Cancer study, involving 182,160 men in Europe over the span of nine years, are promising and intended to further define relative mortality benefits of PC screening.

Criteria are being evaluated for selective identification of tumors destined to become more aggressive and metastatic, thereby warranting closer surveillance or more intensive oncologic intervention at earlier dates. New candidate biomarkers in prostate tissue may become useful in creating a genetic fingerprint of tumors likely to become aggressive and invasive.

Current genes are still research-based and include such sequenced peptides as GSTP-1, RASSFIA, AMACR, PBOV1, hepsin, DD3, and NMP48.18 Future laboratory developments may allow complementary determination of histologic features and molecular biology panels to predict transformation of PC from indolent to important clinical status. It is worth noting that the researcher who discovered PSA, Richard Ablin, PhD, has decreed overdiagnosis of PC by PSA “a hugely expensive public health disaster.”

Emerging data and applied technologies are being developed to predict which PCs will awaken to progression and which will remain dormant. Such techniques should allow the PSA screening debate to settle considerably. Clinical insights are emerging toward consensus for patients and providers searching for answers to the dilemma of whether to screen for PC or not.

Criteria are being evaluated for selective identification of tumors destined to become more aggressive and metastatic, thereby warranting closer surveillance or more intensive oncologic intervention at earlier dates. New candidate biomarkers in prostate tissue may become useful in creating a genetic fingerprint of tumors likely to become aggressive and invasive.

Current genes are still research-based and include such sequenced peptides as GSTP-1, RASSFIA, AMACR, PBOV1, hepsin, DD3, and NMP48.⁸ Future laboratory developments may allow complementary determination of histologic features and molecular biology panels to predict transformation of PC from indolent to important clinical status.

It is worth noting that the researcher who discovered PSA, Richard Ablin, PhD, has decreed overdiagnosis of PC by PSA “a hugely expensive public health disaster.”

Emerging data and applied technologies are being developed to predict which PCs will awaken to progression and which will remain dormant. Such techniques should allow the PSA screening debate to settle considerably. Clinical insights are emerging toward consensus for patients and providers searching for answers to the dilemma of whether to screen for PC or not.

Source: MPR

Cancer Control Month celebrates advances in the fight against cancer. These include all aspects of prevention, early detection, and treatment of this devastating disease.

The best way to fight cancer is to find cancer cells early and get rid of them. The earlier cancer is found, the better the prognosis.

Cancer is the second leading cause of death in America, after heart disease. Today, about half of all men and about 1 in every 3 women will develop cancer at some point in their lives.

However, cancer rates and deaths have been on the decline since the 1990s. We now know ways to prevent cancer from developing. One third of all cancers detected will be related to obesity or being overweight, physical inactivity, and nutrition choices.

While everyone is at risk for cancer, some factors cause certain people to be at greater risk. Age is the greatest risk factor for cancer, with 77% of cancers being detected at age 55 or older. Smokers, heavy drinkers, the physically inactive, those with a poor diet, and those who have had prolonged and unprotected exposure to sunlight are also all at an increased risk for different types of cancers.

At PHC, we provide the most intensive and thorough cancer screening available. Our preventive executive physicals include tests designed to catch cancer in its earliest stages. Each patient receives a personalized program of studies tailored specifically for individual risk factors, including family history. This April, celebrate Cancer Control Month by scheduling your executive physical as soon as possible!

Read more information here.

Men with early-stage prostate cancer who had their prostates surgically removed were significantly more likely to be alive nearly two decades later than men who went without surgery and were monitored through so-called “watchful waiting,” the latest findings from a long-running Swedish study show.

The 700-patient study, which found similar results at earlier stages, is likely to heighten debate about the value of surgery versus observation or watchful waiting, which generally involves no immediate treatment. In recent years, doctors increasingly have embraced watchful waiting, in part because other large studies have shown that surgery provides no benefit yet has potentially undesirable side effects.

The Swedish study, published Wednesday in the New England Journal of Medicine, showed that after 18 years, there were 13% fewer deaths from any cause, and 11% fewer deaths from prostate cancer specifically, in the group that had surgery versus the watchful-waiting group. By the 18-year mark, 200 of 347 men in the surgery group had died from any cause, versus 247 of 348 monitored men.

The benefits of surgery were most pronounced in men who were under 65 when diagnosed. In these patients, there were 25.5% fewer deaths from any cause and 15.8% fewer deaths from prostate cancer in the surgery group. Among men 65 and older at diagnosis, there was no significant reduction in death in the surgery group, according to the study, which was led by Swedish physicians and funded by the Swedish Cancer Society.

Moreover, men whose cancers had an intermediate risk of growing or spreading were more likely to benefit from surgery than men whose cancer had a low or high risk of spreading. Among intermediate-risk patients, there were 24.2% fewer deaths from prostate cancer in the surgery group than in the watchful-waiting group. Among low-risk patients, there were 3.8% fewer deaths from prostate cancer in the surgery group, a slim enough difference that the researchers said it could have been due to chance. In high-risk patients, there was no significant difference in prostate-cancer death between the groups.

James McKiernan, director of urologic oncology at New York-Presbyterian Hospital and Columbia University Medical Center, said the results should help doctors better target patients for surgery. “On first pass, this looks like a green light to go operating on everyone, but what it really does is shed a lot of light on the subset of patients who will benefit from surgery,” he said. “The younger patient with relatively aggressive cancer is the patient who will benefit most from treatment.”

Source: Wall Street Journal

Middle-aged people who eat protein-rich food are four times more likely to die of cancer than someone who only eats a little, according to a new study. The researchers said eating a lot of protein increased the risk of cancer almost as much as smoking 20 cigarettes a day.

They reached their findings, published in the journal Cell: Metabolism, after tracking thousands of people over 20 years. “We provide convincing evidence that a high-protein diet – particularly if the proteins are derived from animals – is nearly as bad as smoking for your health,” one of the academics behind the work, Dr Valter Longo, of the University of Southern California, told The Daily Telegraph.

A high-protein diet was defined as one in which 20 per cent of the calories came from protein. They recommended eating 0.8g of protein per kilogram of body weight a day during middle age.

However, the researchers said protein had benefits during later life. Dr Eileen Crimmins, a co-author of the study, said: “We also propose that at older ages, it may be important to avoid a low-protein diet to allow the maintenance of healthy weight and protection from frailty.”

However Dr Gunter Kuhnle, a food nutrition scientist at the University of Reading, criticised the study for making a link to smoking. “While this study raises some interesting perspectives on links between protein intake and mortality… It is wrong, and potentially even dangerous, to compare the effects of smoking with the effect of meat and cheese,” he said. “The smoker thinks: ‘Why bother quitting smoking if my cheese and ham sandwich is just as bad for me?’”

And Professor Tim Key, of Cancer Research UK, said: “Further research is needed to establish whether there is any link between eating a high protein diet and an increased risk of middle aged people dying from cancer.”

Source: The Independent