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This was written in 2009, but it discusses the amazing possibility of infections with high fever treating and curing cancer. This method, originally discovered by William Coley in the 1890s, used a bacterial extract (named Coley's toxins or Coley toxins) to cause an infection in the person with cancer. Try to read the whole fascinating article.From American Scientist:

Healing Heat: Harnessing Infection to Fight Cancer

Conventional wisdom long held that the human immune system was no match for cancer. Born of native cells, the logic went, cancer fooled the immune system into concluding it was harmless. Thus protected from attack, cancer easily thrived until its host died.

A deeper understanding of our biological defenses has changed that. The human immune system does battle cancer. But we could better optimize our defenses to fend off malignant disease. That’s clear from cancer treatments attempted in New York City and Germany as early as the 19th century. Those experiments and other undervalued evidence from the medical literature suggest that acute infection—in contrast to chronic infection, which sometimes causes cancer—can help a body fight tumors.

It’s not the pathogens that do the good work. But the way our bodies respond to the pathogens is key. Infection events, especially those that produce fever, appear to shift the innate human immune system into higher gear. That ultimately improves the performance of crucial biological machinery in the adaptive immune system. This lesson comes, partly, from doctors who risked making patients sicker to try to make them better.

Medicine back then offered little more than amputation and morphine to cancer patients... Shocked by his ineffectiveness, Coley dove into hospital records and the medical literature for clues to how to help more. He found about 90 sarcoma case reports. About half contained follow-up histories....In his literature search,William Coley found more than 40 cases of disappearance of malignancies during an erysipelas attack. 

In April 1891 an Italian immigrant, Mr. Zola, presented at New York Hospital with a large sarcoma tumor in his neck and an egg-sized metastasis in his right tonsil. He had been operated on twice before but was in hopeless condition. He could hardly speak or swallow and was unable to eat solid food. His life expectancy was, at the very most, a few months. He had nothing to lose by undergoing an experimental treatment.

Mr. Zola with large sarcoma in the neck. Credit: Discover magazine.

Since erysipelas was so hazardous, the hospital was reluctant to host Coley’s experiment, so it was performed in a private apartment. Colleagues at the College of Physicians and Surgeons, now part of Columbia University, prepared the bacteria. Three applications were delivered over three weeks, with minor success...Via a friend, Coley obtained fresh and potent bacteria culture from the leading German bacteriologist, Robert Koch. That fall, he again treated Zola, whose temperature that time rose above 104 degrees, with nausea, vomiting and severe pain. The infection almost killed him, but within two weeks, the neck tumor was not observable. The tonsil tumor stopped growing. Zola was in excellent health when Coley saw him four years later.

During the following two years Coley attempted to infect 12 patients who had inoperable cancer. He failed to induce a full-blown infection in four and succeeded in eight. All eight responded. Six had partial tumor remissions. Two showed full remission. But two patients died from infection. So Coley abandoned living cultures and turned toward what today we would call a bacterial extract.

In January 1893 Coley administered for the first time one variant of what today are still called “Coley’s toxins.It was a heat-sterilized, combined culture of S. pyogenes and S. marcescens bacteria administered by injection. The patient was a 16-year-old boy with a large inoperable abdominal tumor, a malignant sarcoma. After receiving increasing doses over 10 weeks, the boy developed symptoms mimicking those of a heavy erysipelas infection: chills, headache, fever, local redness and swelling at injection sites. The tumor shrank by 80 percent. Coley kept in touch with his patient, who remained cancer-free for more than 20 years.

At the beginning of the 20th century radiation treatment came on the cancer therapy scene. This new procedure captured nearly the full attention of the oncology community due to its immediately visible effects. One could now, it seemed, x ray away tumors. Within the medical mainstream, interest in Coley’s methods faded. Still, some physicians did try to test Coley’s treatment.

Coley, throughout his 40-plus-year career, treated hundreds with multiple versions of his toxin. He never achieved a clear-cut, uniform result. Some patients responded...A five-year survival rate of zero after radiation and 38 percent after Coley’s treatments merited deeper scrutiny.

Helen Coley Nauts, Coley’s daughter, meticulously reexamined her father’s clinical cases after his death. This was not easy. Undoubtedly a man of determination, Coley was not a methodical scientist. His patient records were a mess, he treated different patients for different time periods and his bacterial extracts, over time, were inconsistently made. Coley Nauts counted 15 different preparations. Eleven of them, she concluded, were not potent enough to have a strong effect.

Coley Nauts determined that her father had treated several hundred patients by the time he died in 1936, many of whom had received radiation and sometimes surgery as well. To estimate the overall success of extracts, the analysis should be restricted to patients with inoperable cancer and treated by toxin alone. In another review from 1994, immunologist and oncology researcher Charles Starnes identified 170 such patients with adequate medical records (121 with some form of sarcoma, 43 with carcinoma and myeloma, and 6 with melanoma). The remission rate among them was 64 percent; the five-year survival rate was more than 44 percent.

According to the analyses of Coley Nauts and Starnes, treatment success correlated with length of therapy and the fevers induced by the toxins. Higher was better. This correlation was reported among several other observations but without emphasis or any explanation by the authors.

Only a few uncoordinated attempts to apply Coley’s ideas were pursued from mid-century on....Well-controlled studies of bacterial-extract cancer treatment that incorporate all the lessons from the retrospective analysis of Coley’s and other treatments have not been pursued since. But medical case studies, cancer epidemiology and our more precise understanding of immunology make a strong case that they should.

Spontaneous regression or remission is the partial or complete disappearance of an untreated malignant tumor or a tumor treated with a therapy considered inadequate to exert significant influence. It sounds like fantasy, but about 1,000 case studies in the medical literature during the past century detail spontaneous regression from cancer. Surely more have occurred. And there’s a pattern to some of the cases. A prior fever was recorded in 25 to 80 percent of documented cases of spontaneous regression of cancer.

It is not true, as Coley believed of S. pyogenes, that all these pathogens produce some cagey anti-cancerous substance...Much more likely is that the sequence of immune reactions triggered by the infections was the same...Cancer cells can carry hundreds of mutations that distinguish them from healthy cells. But the immune system often remains in an “observer” state in their presence rather than engaging in battle as it does against bacterial or viral infections. The reason for this incomplete immune response is a long-standing puzzle in cancer immunology. William Coley’s experiments may help today’s scientists solve it.

There may be prophylactic potential here as well. Epidemiological studies suggest that a personal history that includes several infections with fever sometimes significantly reduces the likelihood a person will develop cancer later (see What the Literature Says). One potential explanation is that feverish infections reduce would-be malignant cells. If that’s true, the implications are profound.

The following medical article (actually an interview with Prof. Cedric F Garland, Department of Family & Preventive Medicine, University of California San Diego School of Medicine) is strongly in favor of Americans getting their Vitamin D levels tested, and taking vitamin D3 (if needed) to raise serum levels of vitamin D's metabolite 25(OH)D to at least 30 ng/mL and preferably more.

It is suggested that taking 1000 IU of vitamin D3 daily would achieve these levels in most people. From Medscape:

Vitamin D and Mortality Risk: Should Clinical Practice Change?

Traditionally associated with skeletal disease including osteoporosis and fractures, low levels of serum 25-hydroxyvitamin D (25[OH]D), the metabolite usually measured as a mark of vitamin D status, more recently have been linked to a wide range of nonskeletal diseases, including some cancers and autoimmune, cardiometabolic, and neurologic diseases. A number of studies also have reported an inverse association between 25(OH)D concentration and all-cause mortality.

To explore this association more, Medscape reached out to Dr. Cedric Garland, a well-known expert on vitamin D. Dr. Garland is a professor in the Division of Epidemiology, Department of Family and Preventive Medicine, and a Fellow of the American College of Epidemiology. He has a Doctor of Public Health degree from University of California San Diego and studied epidemiology at Johns Hopkins. His research has focused on vitamin D status in health and the association between vitamin D deficiency and increased risk for disease, including some common cancers (breast cancer, colon cancer, leukemia, and melanoma) and diabetes. He is active in seeking to reduce the risk for cancer and diabetes by improving vitamin D status among the US population.

To examine the relation between serum 25(OH)D and mortality, Dr. Garland and colleagues at the University of California San Diego and others in the United States pooled data from 32 studies published between 1966 and 2013.[6] They found an overall relative risk of 1.8 (95% confidence interval [CI]: 1.7-1.8; P <.001) comparing the lowest (0-9 ng/mL) with the highest (>30 ng/mL) category of 25(OH)D for all-cause mortality. Serum 25(OH)D concentrations ≤30 ng/mL were associated with higher all-cause mortality than concentrations >30 ng/mL (P <.01).

The investigators noted that these findings confirmed observations from the Institute of Medicine (IOM) that 25(OH)D levels of <20 ng/mL are too low for safety,[8] but they suggested a cut-off point of >30 ng/mL rather than >20 ng/mL for all-cause mortality reduction. This level "could be achieved in most individuals by intake of 1000 IU per day of vitamin D3," the investigators said, noting that this is described as a safe dose in almost all adults by both the IOM[8] and Endocrine Society[9] clinical guidelines on dietary intake of vitamin D.

In particular, a randomized clinical trial by Lappe et al[12] had demonstrated a reduced risk for all cancers with vitamin D supplementation in postmenopausal women.... Only one third of the US population is below 20 ng/mL,[15] but two thirds of the population is below 30 ng/mL.[16]

We decided to look at what would happen if we put together all the existing studies that have looked at the survival of "ordinary" people; that is, mostly people in general practices who did not, for the most part, have illnesses. Studies that only included people who were already ill were not eligible for inclusion in our analysis. We found 88 relevant studies, of which 32 presented their data by quartiles of intake, allowing us to see a dose response

The incidence of colon cancer is very high in countries like Iceland and Sweden, and other countries nearer the North Pole, and in countries like New Zealand, which is closer to the South Pole, and intermediate in countries at intermediate latitudes such as the United States, which is, on average, 38º north of the Equator. By the time you get down within the tropics, which is 23º from the Equator, it begins to decrease, and within 5º of the Equator there are vanishingly low incidence rates of colon cancer. In the past, some scientists theorized that the low incidence rates near the equator were due to intake of a high-fiber diet, but now my group believes -- and many others are leaning more in this direction -- that it is the high UVB irradiance and high circulating 25(OH)D year-around nearer the equator rather than a high-fiber diet that best explains the inverse association with solar UVB irradiance

Raising the serum 25(OH)D from 30 to 40 ng/mL reduces the incidence of breast, bowel, and lung cancer by 80%, as reported by Lappe and colleagues in their clinical trial.[12]On the other hand, if you lump all cancers together, in both sexes, and include countries where there is a whole lot of cigarette smoking, then you may obscure the effect of the vitamin D. Vitamin D is not able to overcome the effect of heavy smoking, and the CHANCES analysis[7] included data from people in countries like the Czech Republic, Poland, and Lithuania, where there is a huge amount of smoking. Although the effects are still there, they are weakened.

Studies such as our meta-analysis have provided us an opportunity to not just be locked into the present but to predict mortality on the basis of vitamin D levels in the present. I had expected our results to be convincing, but we were shocked at the persistence of the belief that very low levels of vitamin D, such as approximately 20 ng/mL, are safe. They are not safe with regard to breast and colon cancer, several other cancers, diabetes in youth and adulthood, fractures, and other complications of 25(OH)D <30 ng/mL. Even higher levels, such as 40-60 ng/mL, would be even safer, according to a letter of consensus of expert vitamin D scientists and physicians.

In addition, 2 ongoing trials, the CAPS study[23] (aiming to replicate the findings of Lappe et al[12]) and the VITAL study,[22] are both using a vitamin D3 dose of 2000 international units (IU)/day. I think that if I were to design a trial, knowing what we know today, I would use 4000-5000 IU/day. It seems as though each time we do a clinical trial, by the time the trial is completed, we know that the doses were too small to elicit an effect.

I am also concerned that there may be not enough calcium to see an effect. In CAPS, the women are being given 1500 mg of calcium, which was done in the original randomized controlled trial in which 80% of the cancers in postmenopausal women were prevented. I would have stayed with this design and dose for the VITAL trial. We know that it helps because in their original trial, Lappe and colleagues[12]examined the effects of vitamin D alone vs vitamin D plus calcium, and the effects were stronger when the calcium was included.

Testing should be universal. And ideally it should be done in March when the vitamin D is at its lowest levels. This will prevent hundreds of thousands of cases of serious diseases worldwide annually, beginning with postmenopausal breast cancer and including colon cancer and types 1 and 2 diabetes. Skipping this test would be equivalent to not measuring blood pressure, serum lipids, or weight at an annual exam.

No one should run a serum 25(OH)D less than 30 ng/mL. This means that two thirds of the US population needs supplementation. You may have noticed that President Obama was recently tested for his vitamin D, and it was 22.9 ng/mL.[35] His physicians wisely decided to treat him, and he is now taking vitamin D.

Another study finding health benefits from eating dairy foods (vs not eating any dairy foods).

From Science Daily: A heart-felt need for dairy food: Small serving beneficial, large not necessary

A daily small serve of dairy food may reduce the risk of heart disease or stroke, even in communities where such foods have not traditionally formed part of the diet according to new research.

A study of nearly 4000 Taiwanese, led by Emeritus Professor Mark Wahlqvist from Monash University's Department of Epidemiology and Preventive Medicine and the Monash Asia Institute, considered the role increased consumption of dairy foods had played in the country's gains in health and longevity.

"We observed that increased dairy consumption meant lower risks of mortality from cardiovascular disease, especially stroke, but found no significant association with the risk of cancer," Professor Wahlqvist said.

Milk and other dairy foods are recognised as providing a broad spectrum of nutrients essential for human health. According to the study findings, people only need to eat small amounts to gain the benefits.

"Those who ate no dairy had higher blood pressure, higher body mass index and greater body fatness generally than other groups. But Taiwanese who included dairy food in their diet only three to seven times a week were more likely to survive than those who ate none."

For optimal results, the key is daily consumption of dairy foods -- but at the rate of about five servings over a week. One serving is the equivalent to eight grams of protein: a cup of milk, or 45 grams of cheese. Such quantities rarely cause trouble even for people considered to be lactose intolerant, Professor Wahlqvist said.

Eating more tomatoes is doable, tastes delicious, and reduces prostate cancer risk! From Science Daily:

Fighting prostate cancer with tomato-rich diet

Men who eat over 10 portions a week of tomatoes have an 18 percent lower risk of developing prostate cancer, new research suggests. With 35,000 new cases every year in the UK, and around 10,000 deaths, prostate cancer is the second most common cancer in men worldwide. Rates are higher in developed countries, which some experts believe is linked to a Westernised diet and lifestyle.

To assess if following dietary and lifestyle recommendations reduces risk of prostate cancer, researchers at the Universities of Bristol, Cambridge and Oxford looked at the diets and lifestyle of 1,806 men aged between 50 and 69 with prostate cancer and compared with 12,005 cancer-free men.

The NIHR-funded study, published in the medical journal Cancer Epidemiology, Biomarkers and Prevention, is the first study of its kind to develop a prostate cancer 'dietary index' which consists of dietary components -- selenium, calcium and foods rich in lycopene -- that have been linked to prostate cancer. Men who had optimal intake of these three dietary components had a lower risk of prostate cancer.

Tomatoes and its products -- such as tomato juice and baked beans -- were shown to be most beneficial, with an 18 per cent reduction in risk found in men eating over 10 portions a week. This is thought to be due to lycopene, an antioxidant which fights off toxins that can cause DNA and cell damage. 

The researchers also looked at the recommendations on physical activity, diet and body weight for cancer prevention published by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR). Only the recommendation on plant foods -- high intake of fruits, vegetables and dietary fibre -- was found to be associated with a reduced risk of prostate cancer. 

Here it is, a list of 17 cancers linked to being overweight or obese. From Science Daily:

Overweight and obesity linked to 10 common cancers, over 12,000 cases every year in UK

A higher body mass index (BMI) increases the risk of developing 10 of the most common cancers, the largest study of its kind on BMI and cancer, involving more than 5 million adults in the UK, shows. Each 5 kg/m² increase in BMI was clearly linked with higher risk of cancers of the uterus (62% increase), gallbladder (31%), kidney (25%), cervix (10%), thyroid (9%), and leukemia (9%). Higher BMI also increased the overall risk of liver, colon, ovarian, and breast cancers.

Using data from general practitioner records in the UK's Clinical Practice Research Datalink (CPRD), the researchers identified 5·24 million individuals aged 16 and older who were cancer-free and had been followed for an average of 7·5 years. The risk of developing 22 of the most common cancers, which represent 90% of the cancers diagnosed in the UK, was measured according to BMI after adjusting for individual factors such as age, sex, smoking status, and socioeconomic status. A total of 166 955 people developed one of the 22 cancers studied over the follow-up period. BMI was associated with 17 out of the 22 specific types of cancer examined.

Each 5 kg/m² increase in BMI was clearly linked with higher risk of cancers of the uterus (62% increase), gallbladder (31%), kidney (25%), cervix (10%), thyroid (9%), and leukemia (9%). Higher BMI also increased the overall risk of liver (19% increase), colon (10%), ovarian (9%), and breast cancers (5%), but the effects on these cancers varied by underlying BMI and by individual-level factors such as sex and menopausal status. Even within normal BMI ranges, higher BMI was associated with increased risk of some cancers.

There was some evidence that those with high BMI were at a slightly reduced risk of prostate cancer and premenopausal breast cancer. Based on the results, the researchers estimate that excess weight could account for 41% of uterine and 10% or more of gallbladder, kidney, liver, and colon cancers in the UK.

Treating tumors with bacteria is very exciting and new.From Medical Express:

Injected bacteria shrink tumors in rats, dogs and humans

A modified version of the Clostridium novyi (C. noyvi-NT) bacterium can produce a strong and precisely targeted anti-tumor response in rats, dogs and now humans, according to a new report from Johns Hopkins Kimmel Cancer Center researchers.

In its natural form, C. novyi is found in the soil and, in certain cases, can cause tissue-damaging infection in cattle, sheep and humans. The microbe thrives only in oxygen-poor environments, which makes it a targeted means of destroying oxygen-starved cells in tumors that are difficult to treat with chemotherapy and radiation. The Johns Hopkins team removed one of the bacteria's toxin-producing genes to make it safer for therapeutic use.

For the study, the researchers tested direct-tumor injection of the C. noyvi-NT spores in 16 pet dogs that were being treated for naturally occurring tumors. Six of the dogs had an anti-tumor response 21 days after their first treatment. Three of the six showed complete eradication of their tumors, and the length of the longest diameter of the tumor shrunk by at least 30 percent in the three other dogs.

In a Phase I clinical trial of C. noyvi-NT spores conducted at MD Anderson Cancer Center, a patient with an advanced soft tissue tumor in the abdomen received the spore injection directly into a metastatic tumor in her arm. The treatment significantly reduced the tumor in and around the bone. "She had a very vigorous inflammatory response and abscess formation," according to Nicholas Roberts, Vet.M.B., Ph.D. "But at the moment, we haven't treated enough people to be sure if the spectrum of responses that we see in dogs will truly recapitulate what we see in people."

"One advantage of using bacteria to treat cancer is that you can modify these bacteria relatively easily, to equip them with other therapeutic agents, or make them less toxic as we have done here, " said Shibin Zhou, M.D., Ph.D., associate professor of oncology at the Cancer Center.  He and colleagues at Johns Hopkins began exploring C. novyi's cancer-fighting potential more than a decade ago after studying hundred-year old accounts of an early immunotherapy called Coley toxins, which grew out of the observation that some cancer patients who contracted serious bacterial infections showed cancer remission.

The researchers focused on soft tissue tumors because "these tumors are often locally advanced, and they have spread into normal tissue," said Roberts, a Ludwig Center and Department of Pathology researcher. The bacteria cannot germinate in normal tissues and will only attack the oxygen-starved or hypoxic cells in the tumor and spare healthy tissue around the cancer.

Verena Staedtke, M.D., Ph.D., a Johns Hopkins neuro-oncology fellow, first tested the spore injection in rats with implanted brain tumors called gliomas. Microscopic evaluation of the tumors showed that the treatment killed tumor cells but spared healthy cells just a few micrometers away. The treatment also prolonged the rats' survival, with treated rats surviving an average of 33 days after the tumor was implanted, compared with an average of 18 days in rats that did not receive the C. noyvi-NT spore injection.

Zhou said that study of the C. noyvi-NT spore injection in humans is ongoing, but the final results of their treatment are not yet available. "We expect that some patients will have a stronger response than others, but that's true of other therapies as well. Now, we want to know how well the patients can tolerate this kind of therapy."

It may be possible to combine traditional treatments like chemotherapy with the C. noyvi-NT therapy, said Zhou, who added that the researchers have already studied these combinations in mice. "Another good thing about using bacteria as a therapeutic agent is that once they're infecting the tumor, they can induce a strong immune response against tumor cells themselves," Zhou said.

Excellent way to lower breast cancer risk. From Science Daily:

Postmenopausal breast cancer risk decreases rapidly after starting regular physical activity

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 new data.

"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

"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.

I have seen a lot of excitement about this research, especially whether several day fasting would be beneficial for other diseases (e.g., Crohn's disease) or even for middle-aged or older people who just want to boost their immune system. From Science Daily:

Fasting triggers stem cell regeneration of damaged, old immune system

In the first evidence of a natural intervention triggering stem cell-based regeneration of an organ or system, a study shows that cycles of prolonged fasting not only protect against immune system damage -- a major side effect of chemotherapy -- but also induce immune system regeneration, shifting stem cells from a dormant state to a state of self-renewal.

In both mice and a Phase 1 human clinical trial, long periods of not eating significantly lowered white blood cell counts. In mice, fasting cycles then "flipped a regenerative switch": changing the signaling pathways for hematopoietic stem cells, which are responsible for the generation of blood and immune systems, the research showed.

The study has major implications for healthier aging, in which immune system decline contributes to increased susceptibility to disease as we age. By outlining how prolonged fasting cycles -- periods of no food for two to four days at a time over the course of six months -- kill older and damaged immune cells and generate new ones, the research also has implications for chemotherapy tolerance and for those with a wide range of immune system deficiencies, including autoimmunity disorders.

"When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged," Longo said. "What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from?"

Prolonged fasting forces the body to use stores of glucose, fat and ketones, but also breaks down a significant portion of white blood cells. Longo likens the effect to lightening a plane of excess cargo.

During each cycle of fasting, this depletion of white blood cells induces changes that trigger stem cell-based regeneration of new immune system cells. In particular, prolonged fasting reduced the enzyme PKA, an effect previously discovered by the Longo team to extend longevity in simple organisms and which has been linked in other research to the regulation of stem cell self-renewal and pluripotency -- that is, the potential for one cell to develop into many different cell types. Prolonged fasting also lowered levels of IGF-1, a growth-factor hormone that Longo and others have linked to aging, tumor progression and cancer risk.

"PKA is the key gene that needs to shut down in order for these stem cells to switch into regenerative mode. It gives the 'okay' for stem cells to go ahead and begin proliferating and rebuild the entire system," explained Longo, noting the potential of clinical applications that mimic the effects of prolonged fasting to rejuvenate the immune system. "And the good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting. Now, if you start with a system heavily damaged by chemotherapy or aging, fasting cycles can generate, literally, a new immune system."

Prolonged fasting also protected against toxicity in a pilot clinical trial in which a small group of patients fasted for a 72-hour period prior to chemotherapy, extending Longo's influential past research: "While chemotherapy saves lives, it causes significant collateral damage to the immune system. The results of this study suggest that fasting may mitigate some of the harmful effects of chemotherapy," said co-author Tanya Dorff, assistant professor of clinical medicine at the USC Norris Comprehensive Cancer Center and Hospital. 

"We are investigating the possibility that these effects are applicable to many different systems and organs, not just the immune system," said Longo, whose lab is in the process of conducting further research on controlled dietary interventions and stem cell regeneration in both animal and clinical studies.

Very interesting. Gives people a way to eat red meat, but not increase their colorectal cancer risk (by also eating resistant starch, e.g., potato salad or beans). From Science Daily:

Eating resistant starch may help reduce red meat-related colorectal cancer risk

Consumption of a type of starch that acts like fiber may help reduce colorectal cancer risk associated with a high red meat diet, according to a study. "Red meat and resistant starch have opposite effects on the colorectal cancer-promoting miRNAs, the miR-17-92 cluster," said one researcher. "This finding supports consumption of resistant starch as a means of reducing the risk associated with a high red meat diet.

Unlike most starches, resistant starch escapes digestion in the stomach and small intestine, and passes through to the colon (large bowel) where it has similar properties to fiber, Humphreys explained. Resistant starch is readily fermented by gut microbes to produce beneficial molecules called short-chain fatty acids, such as butyrate, she added.

"Good examples of natural sources of resistant starch include bananas that are still slightly green, cooked and cooled potatoes [such as potato salad], whole grains, beans, chickpeas, and lentils. Scientists have also been working to modify grains such as maize so they contain higher levels of resistant starch," said Humphreys.

After eating 300 g of lean red meat per day for four weeks, study participants had a 30 percent increase in the levels of certain genetic molecules called miR-17-92 in their rectal tissue, and an associated increase in cell proliferation. Consuming 40 g of butyrated resistant starch per day along with red meat for four weeks brought miR-17-92 levels down to baseline levels.

The study involved 23 healthy volunteers, 17 male and six female, ages 50 to 75. Participants either ate the red meat diet or the red meat plus butyrated resistant starch diet for four weeks, and after a four-week washout period switched to the other diet for another four weeks.

Great reason to enjoy spicy food. From Science Daily:

Chili peppers for a healthy gut: Spicy chemical may inhibit gut tumors

Researchers report that dietary capsaicin – the active ingredient in chili peppers – produces chronic activation of a receptor on cells lining the intestines of mice, triggering a reaction that ultimately reduces the risk of colorectal tumors.

...the current study suggests one potential remedy might be spicy capsaicin, which acts as an irritant in mammals, generating a burning sensation in contact with tissue. Capsaicin is already broadly used as an analgesic in topical ointments, where its properties as an irritant overwhelm nerves, rendering them unable to report pain for extended periods of time. It's also the active ingredient in pepper spray.

The researchers fed capsaicin to mice genetically prone to developing multiple tumors in the gastrointestinal tract. The treatment resulted in a reduced tumor burden and extended the lifespans of the mice by more than 30 percent. The treatment was even more effective when combined with celecoxib, a COX-2 non-steroidal anti-inflammatory drug already approved for treating some forms of arthritis and pain.