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Category: cancer

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Citrus paradisi (Grapefruit, pink) white bg.jpgWill these research results hold up over time? It is known that certain fruits (citrus fruits and juices) and vegetables contain photosensitizing chemicals called psoralens, and the researchers suspected that a high intake of citrus products over time could make individuals more susceptible to melanoma than people who rarely ate citrus fruits. During more than 2 decades of following more than 100,000 persons they found 1840 melanomas , And yes, even though there were relatively few melanomas, they did find a dose-dependent relationship between citrus product consumption and melanoma risk, specifically that ingesting citrus fruit 1.6 or more times per day had a 36% higher risk for melanoma than people who ate it less than twice per week. But this association was only with whole grapefruit and orange juice, and weirdly, not with consumption of grapefruit juice or whole oranges. Before people panic, remember that citrus fruits have all sorts of great health benefits and should be eaten. From Science Daily:

Can orange juice, grapefruit raise your melanoma risk?

People who enjoy a glass of orange juice or some fresh grapefruit in the morning may face a slightly increased risk of melanoma—the least common but most deadly form of skin cancer. That's the finding from a study of more than 100,000 U.S. adults followed for about 25 years. Researchers discovered that those who regularly consumed orange juice or whole grapefruit had a higher risk of developing melanoma, compared to people who avoided those foods.

Experts were quick to stress that the findings, reported online June 29 in the Journal of Clinical Oncology, do not prove that citrus foods help cause skin cancer. It is plausible, however, that certain compounds in citrus explain the association, said senior researcher Dr. Abrar Qureshi, chair of dermatology at Brown University and a dermatologist at Rhode Island Hospital, in Providence.

Citrus foods contain particular "photoactive" chemicals—namely, psoralens and furocoumarins—that are known to make the skin more sensitive to the sun when they're applied topically, Qureshi said."You'll see children get a sunburn in spots where a citrus popsicle dripped down the chin, for example," Qureshi explained.

But even if citrus foods potentially make some people susceptible to sunburn, it's not orange juice that should be avoided, Qureshi said. "The citrus can't hurt you without the excessive sun exposure," he pointed out. So the message remains the same, Qureshi said: Protect your skin from soaking up too many rays by staying in the shade, using sunblock and wearing a hat. "I don't think the general public should make any changes based on this study," said Berwick, a professor of dermatology at the University of New Mexico in Albuquerque. 

For the study, the researchers analyzed data from two long-running studies of U.S. health professionals. Every couple of years, the participants answered detailed surveys on their health and lifestyle. Over about 25 years, more than 1,800 people developed melanoma and the risk was higher among those who regularly drank orange juice or ate whole grapefruit. That was true, the researchers found, even when several other factors were taken into account—including people's reports of their overall sun exposure and history of bad sunburns.

People who had orange juice at least once a day were about 25 percent more likely to develop melanoma than those who drank the juice less than weekly. Similarly, people who ate whole grapefruit at least three times a week had a 41 percent higher melanoma risk, versus those who never ate it. On the other hand, there was no connection between melanoma risk and either whole oranges or grapefruit juice, the researchers found.

Qureshi did offer a potential explanation for why only orange juice and whole grapefruit may be tied to melanoma risk."There are different types of these photoactive compounds in different parts of the fruit," he said. So, it's possible that not all citrus fruits are alike when it comes to melanoma risk. Plus, Qureshi said, heat—like that used in pasteurizing juice—neutralizes the photoactive compounds. That might help explain why grapefruit juice was not connected to melanoma risk.

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The study results of 218 overweight, postmenopausal women who had insufficient levels of vitamin D (like most people) at the beginning of the study found that weight loss (including exercise), in combination with vitamin D supplementation, had a greater effect on reducing chronic inflammation than weight loss alone.

Current thinking is that chronic inflammation is linked to various chronic diseases as well as cancers. So reducing chronic inflammation is good. From Medical Xpress:

Weight loss plus vitamin D reduces inflammation linked to cancer, chronic disease

For the first time, researchers at Fred Hutchinson Cancer Research Center have found that weight loss, in combination with vitamin D supplementation, has a greater effect on reducing chronic inflammation than weight loss alone. Chronic inflammation is known to contribute to the development and progression of several diseases, including some cancers.

"We know from our previous studies that by losing weight, people can reduce their overall levels of inflammation, and there is some evidence suggesting that taking vitamin D supplements can have a similar effect if one has insufficient levels of the nutrient," said lead and corresponding author Catherine Duggan, Ph.D., a principal staff scientist in the Public Health Sciences Division at Fred Hutch. 

To explore this question, Duggan and colleagues recruited 218 healthy, overweight older women who had lower-than-recommended levels of vitamin D (less than 32 ng/mL). The women then took part in a 12-month diet and exercise program (including 45 minutes of moderate-to-vigorous exercise five days a week). Half of the study participants were randomly selected to receive 2,000 IU of vitamin D daily for the duration of the year-long trial, and the other half received an identical-appearing placebo, or dummy vitamin. 

At the end of the study, all of the participants had reduced levels of inflammation, regardless of whether they took vitamin D, "which highlights the importance of weight loss in reducing inflammation," Duggan said. However, those who saw the most significant decline in markers of inflammation were those who took vitamin D and lost 5 to 10 percent of their baseline weight. These study participants had a 37 percent reduction in a pro-inflammatory cytokine called interleukin-6, or IL-6, as compared to those in the placebo group, who saw a 17.2 percent reduction in IL-6. The researchers found similar results among women in the vitamin D group who lost more than 10 percent of their starting weight. While IL-6 has normal functions in the body, elevated levels are associated with an increased risk of developing certain cancers and diabetes and may be implicated as a cause of depression, Duggan said.

Inflammation occurs when the body is exposed to pathogens, such as bacteria or viruses, which puts the immune system in overdrive until the "attack" ceases and the inflammatory response abates. Overweight or obese people, however, exist in a state of chronic inflammation. This sustained upregulation of the inflammatory response occurs because fat tissue continually produces cytokines, molecules that are usually only present for a short time, while the body is fighting infection, for example.

"It is thought that this state of chronic inflammation is pro-tumorigenic, that is, it encourages the growth of cancer cells," she said. There is also some evidence that increased body mass "dilutes" vitamin D, possibly by sequestering it in fat tissue."Weight loss reduces inflammation, and thus represents another mechanism for reducing cancer risk," Duggan said. "If ensuring that vitamin D levels are replete, or at an optimum level, can decrease inflammation over and above that of weight loss alone, that can be an important addition to the tools people can use to reduce their cancer risk."

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New research finding health benefits to humans from a four day low calorie diet - the Fasting Mimic Diet (FMD). Cutting calories to 34 to 54% of normal for a few days is obviously much easier to do than actual fastiing, so these results look very promising. In summary: the researchers found that in a small human trial, three cycles of this diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer (and with no major adverse side effects). Three earlier posts on various types of minifasting health benefits: Minifasting May Benefit Health, Health Benefits of Feast and Famine Diet, Fasting and the Immune System. From Science Daily:

Diet that mimics fasting appears to slow aging

Want to lose abdominal fat, get smarter and live longer? New research led by USC's Valter Longo shows that periodically adopting a diet that mimics the effects of fasting may yield a wide range of health benefits. In a new study, Longo and his colleagues show that cycles of a four-day low-calorie diet that mimics fasting (FMD cut visceral belly fat and elevated the number of progenitor and stem cells in several organs of old mice -- including the brain, where it boosted neural regeneration and improved learning and memory.

The mouse tests were part of a three-tiered study on periodic fasting's effects -- testing yeast, mice and humans...Mice, which have relatively short life spans, provided details about fasting's lifelong effects. Yeast, which are simpler organisms, allowed Longo to uncover the biological mechanisms that fasting triggers at a cellular level. And a pilot study in humans found evidence that the mouse and yeast studies were applicable to humans.

In a pilot human trial, three cycles of a similar diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer with no major adverse side effects, according to Longo.

The diet slashed the individual's caloric intake down to 34 to 54 percent of normal, with a specific composition of proteins, carbohydrates, fats and micronutrients. It decreased amounts of the hormone IGF-I, which is required during development to grow, but it is a promoter of aging and has been linked to cancer susceptibility. It also increased the amount of the hormone IGFBP-, and reduced biomarkers/risk factors linked to diabetes and cardiovascular disease, including glucose, trunk fat and C-reactive protein without negatively affecting muscle and bone mass.

Longo has previously shown how fasting can help starve out cancer cells while protecting immune and other cells from chemotherapy toxicity. 'It's about reprogramming the body so it enters a slower aging mode, but also rejuvenating it through stem cell-based regeneration,' Longo said. 'It's not a typical diet because it isn't something you need to stay on.'

For 25 days a month, study participants went back to their regular eating habits -- good or bad -- once they finished the treatment. They were not asked to change their diet and still saw positive changes. Longo believes that for most normal people, the FMD can be done every three to six months, depending on the abdominal circumference and health status. For obese subjects or those with elevated disease risk factors, the FMD could be recommended by the physician as often as once every two weeks. His group is testing its effect in a randomized clinical trial, which will be completed soon, with more than 70 subjects.

Despite its positive effects, Longo cautioned against water-only fasting and warned even about attempting the fasting mimicking diet without first consulting a doctor and seeking their supervision throughout the process....Longo also cautioned that diabetic subjects should not undergo either fasting or fasting mimicking diets while receiving insulin, metformin or similar drugs. He also said that subjects with body mass index less than 18 should not undergo the FMD diet.

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This latest study finding health benefits of eating nuts was a review of 36 observational studies, involving a total of 30,000 people. Nut consumption was associated with a lower risk of cancer in general, and a decreased risk of some types of cancer (colorectal, endometrial, pancreatic), but not with type 2 diabetes. So go ahead - eat a small handful of nuts for your health at least several times a week.From Medpage Today:

A Nutty Way to Prevent Cancer?

Nut consumption was associated with a decreased risk of some types of cancer but not with type 2 diabetes in a large review.When patients eating the most nuts were compared with those eating the least, those in the first group had a lower risk of colorectal cancer in three studies (RR 0.76, 95% CI 0.61-0.96; I2=51.3%), of endometrial cancer in two studies (RR 0.58, 95% CI 0.43-0.79; I2=0%), and pancreatic cancer in one study (RR 0.68, 95% CI 0.48-0.96; I2 not available). Those results were reported in the meta-analysis of 36 observational studies, with a total population of more than 30,000 patients.

Nut consumption was also associated with a lower risk of cancer in general (RR 0.85, 95% CI 0.76-0.95;I2=66.5%), according to the authors. But it was not associated with other types of cancer or with type 2 diabetes (RR 0.98, 95% CI 0.84-1.14; I2=74.2%), found the researchers, who were led by Lang Wu, a PhD candidate at the Mayo Clinic. They published their results on June 16 in Nutrition Reviews.

"Overall, nut intake was associated with a decreased risk of cancer," wrote Wu and colleagues. "Given the scarcity of currently available data, however, evidence from additional studies is required to more precisely determine the relationship between nut consumption and risk of individual cancer types." Evidence for the association between nuts and cancer has been mixed, according to the authors. Follow-up time in the studies ranged from 4.6 years to 30 years, found the review.

The amount of nuts eaten ranged from none for some of the patients to eating nuts more than seven times a week....No associations were found between nut consumption and acute myeloid leukemia, breast cancer, gastric cancer, glioma, hepatocellular carcinoma, leukemia, lymphoma, ovarian cancer, prostate cancer, or stomach cancer.

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A wonderful commentary by Dr. Mandrola about recent research of almost 500,000 UK citizens. Researchers found that just asking the patient several basic questions was a better predictor of 5 year mortality than all sorts of blood tests, measurements, and analyses. The best basic questions were: Is your health excellent, good, average, or poor? Is your walking pace slow, average, or brisk? Along with smoking, those two basic questions were the best predictors of staying alive in the next 5 years. These excerpts are from Medscape:

Health Is Not Complicated—Just Ask the Patient

It turns out predicting health is not so complicated. Nor is it digital at all. For persons of middle age (40 to 70 years), self-reported overall health and walking speed were the best predictors of death in the next 5 years, according to a study published this week in the Lancet.[1]

In an analysis of nearly 500,000 UK citizens followed for 5 years, these two simple questions outperformed 655 measurements of demographics, health, and lifestyle. Is your health excellent, good, average, or poor? Is your walking pace slow, average, or brisk? Along with smoking, those two basic questions, inquiries that hardly require a digital device, were the best predictors of staying alive in the next 5 years.

Pause for a moment here and ponder the beauty of that top-line result. Half a million people followed for 5 years; 655 measures of health, including heart rate, blood pressure, and lab tests, and the best predictors were that simple.

In the 5 years of follow-up, 8532 (1.7%) subjects died. Overall, cancer was the most common cause of death (53% in men; 69% in women). The most common cancer-related cause of death was lung cancer in men (n=546) and breast cancer in women (n=489). Cardiovascular disease was the second leading cause of death (26% in men; 33% in women).

 

There were gender differences in predictors of death. Self-reported health was the strongest predictor of death in men (C index 0.74). In women, a previous cancer diagnosis was the strongest predictor (C index 0.73).Self-reported walking pace was a strong predictor of death in both men and women (C index 0.72 and 0.69, respectively.) For example, a man aged 40 to 52 years who reported a slow walking pace was 3.7 times more likely to die than a similarly aged man who reported a steady walking pace. In a large subset of subjects with no reported health conditions, smoking was the best predictor of mortality.

 

The final, and perhaps niftiest, aspect of this study was that researchers developed an 11 to 13 question risk prediction score, which they then put on an interactive website. Anyone can answer these simple questions and get their health-related age relative to the UK population. The researchers call this age the UK Longevity Explorer (UbbLE) age.

I am drawn to these findings because they emphasize something that is increasingly lost on both doctors and patients. True health is not complicated. And the big picture is still useful.Any experienced clinician will testify that patients know when they are well and when they are not. The finding that self-reported health predicts death urges clinicians, generalists and specialists alike, to ask our patients how they feel about their health.

Then there is the matter of self-reported walking pace. How easy it is to be distracted by digital data. We walk into the exam room to see our patient. He is still. We look at him. We poke and listen to his body. We assess his ECG and other measures. Soon we will review his smartphone metrics and DNA data. Yet we tend to forget the obvious: to move is to be healthy. Drs Ganna and Ingelsson teach us that to move briskly may be healthier.

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Prostate cancer diagnosis is scary enough, but knowing that dietary changes can increase favorable odds is good. Once again a Mediterranean style diet  or "healthy diet"(whole grains, fruits, vegetables, seeds, nuts, legumes, olive oil, and fish) is beneficial, while a Western diet (highly processed foods, red meat, processed meat, and dairy) is linked to higher rates of death. This study was from the Harvard School of Public Health and followed male physicians for an average of 14 years after prostate cancer diagnosis. From Science Daily:

Western diet may increase risk of death after prostate cancer diagnosis

After a prostate cancer diagnosis, eating a diet higher in red and processed meat, high-fat dairy foods, and refined grains--known as a Western diet--may lead to a significantly higher risk of both prostate cancer-related mortality and overall mortality compared with eating a diet rich in vegetables, fruits, fish, whole grains, legumes, and healthy oils, according to a new study from Harvard T.H. Chan School of Public Health.

The study, which appears online June 1, 2015 in the journal Cancer Prevention Research, offers insight on how diet may help improve survivorship for the nearly three million men living with prostate cancer in the U.S."There is currently very little evidence to counsel men living with prostate cancer on how they can modify their lifestyle to improve survival. Our results suggest that a heart-healthy diet may benefit these men by specifically reducing their chances of dying of prostate cancer," said Jorge Chavarro, assistant professor of nutrition and epidemiology at the Harvard Chan School and senior author of the study.

Researchers examined health and diet data from 926 men participating in the Physicians' Health Study I and II who were diagnosed with prostate cancer. They followed the men for an average of 14 years after their diagnosis, grouping them into quartiles according to whether they followed a Western dietary pattern or a "prudent" (higher consumption of vegetables, fruits, fish, legumes, and whole grains) dietary pattern.

They found that men who ate mostly a Western diet (those in the highest quartile of the Western dietary pattern) had two-and-a-half times higher risk of prostate cancer-related death--and a 67% increased risk of death from any cause--than those in the lowest quartile. Men who ate mostly a "prudent" diet had a 36% lower risk of death from all causes.

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New research finds much lower rates of endometrial cancer in women eating a Mediterranean diet. This means: fruits, vegetables, legumes, whole grains, seeds, nuts, fish, olive oil, little meat or dairy products, and moderate alcohol.

They use the term "womb cancer" in the article, but the medical term is endometrial cancer (or can be called uterine cancer). Other risk factors for endometrial cancer are being older (post-menopausal), being overweight, and taking estrogen-alone hormone replacement therapy.

From Science Daily: Eating a Mediterranean diet could cut womb cancer risk

Women who eat a Mediterranean diet could cut their risk of womb cancer (endometrial cancer) by more than half (57 per cent), according to a study published today (Wednesday) in the British Journal of Cancer. The Italian researchers looked at the diets of over 5,000 Italian women to see how closely they stuck to a Mediterranean diet and whether they went on to develop womb cancer.

The team broke the Mediterranean diet down into nine different components and measured how closely women stuck to them. The diet includes eating lots of vegetables, fruits and nuts, pulses (legumes), cereals and potatoes, fish, monounsaturated fats but little meat, milk and other dairy products and moderate alcohol intake.

Researchers found that women who adhered to the Mediterranean diet most closely by eating between seven and nine of the beneficial food groups lowered their risk of womb cancer by more than half (57 per cent).Those who stuck to six elements of the diet's components reduced their risk of womb cancer by 46 per cent and those who stuck to five reduced their risk by a third (34 per cent). But those women whose diet included fewer than five of the components did not lower their risk of womb cancer significantly.

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More studies need to be done, but the possibility of simply taking 500 mg twice a day of nicotinamide (a vitamin B3 derivative) to reduce the incidence of basal and squamous cell carcinoma is exciting.

Nonmelanoma skin cancer is the most common cancer in the world.

From Medical Xpress: Study: Vitamin B3 may help prevent certain skin cancers

For the first time, a large study suggests that a vitamin might modestly lower the risk of the most common types of skin cancer in people with a history of these relatively harmless yet troublesome growths.

In a study in Australia, people who took a specific type of vitamin B3 for a year had a 23 percent lower rate of new skin cancers compared to others who took dummy pills. In absolute terms, it meant that vitamin takers developed fewer than two of these cancers on average versus roughly 2.5 cancers for the others.The study did not involve melanoma, the most deadly form of skin cancer. Instead, it aimed at more common forms—basal and squamous cell cancers. He and other doctors with the oncology group said the vitamin, called nicotinamide, could offer a cheap, easy way to lower risk.

The study involved 386 people who had at least two skin cancers in the previous five years. They took either 500 milligrams of the vitamin or dummy pills twice a day for a year. Neither they nor their doctors knew who got what until the study ended.

Besides reducing the rate of skin cancers, vitamin use also seemed to cut the rate of precancers—scaly patches of skin called actinic keratoses—by 11 percent after three months of use and 20 percent after nine months. Participants were tracked for six months after they stopped taking their pills, and the rate of new skin cancers was similar in both groups. "The benefit wears off fairly quickly," Damian said. "You need to continue taking the tablets for them to continue to be effective."

Nicotinamide is thought to help repair DNA in cells damaged by sun exposure. It is not the same as nicotine, the addictive stuff in tobacco. It's also not the same as niacin and some other forms of B3, which can cause flushing, headaches and blood pressure problems. Those problems were not seen with nicotinamide in the study. Nicotinamide is sold over the counter, is easy to take, and "there are essentially no side effects," Schilsky said.

 Credit: WebMD, Healthwise, Inc.

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This research was done in a laboratory using cells, but the results support some other research finding that eating cruciferous vegetables frequently may help prevent cancer. They found that compound levels that were anti-cancer (killed off cancer cells) in this study could be achieved through diet alone. Cruciferous vegetables are vegetables of the family Brassicaceae (also called Cruciferae) such as cauliflower, cabbage, garden cress, bok choy, broccoli, brussels sprouts, kale, and similar green leaf vegetables. From Science Daily:

Plant-derived compound targets cancer stem cells

A compound and an enzyme that occur naturally in cruciferous vegetables--cauliflower, cabbage, broccoli and Brussels sprouts--may help prevent recurrence and spread of some cancers, according to researchers. When they treated human cervical cancer stem cells with phenethyl isothiocyanate (PEITC) in a Petri dish, about 75 percent died within 24 hours using a 20-micromolar concentration of the compound.

The precursor compound and enzyme in cruciferous vegetables combine during the chewing process to produce PEITC within the body, Dey explained. Though PEITC is a good candidate to develop as a dietary supplement, studies have also shown that sufficient cancer-preventing levels of PEITC can be achieved through diet alone.

When cancer is treated with chemotherapy or radiation, the tumor disappears but the cancer stem cells live on. "These cells are frequently resistant to conventional therapies," Dey said. Though cancer stem cells make up less than 5 percent of a tumor, they can regenerate the original tumor and migrate through the blood vessels spreading cancer to secondary locations."These tiny cells are very difficult to detect in a tumor," Dey pointed, adding that for a long time scientists did not even know they existed. 

Based on information from scientific literature, the concentrations of PEITC that Dey and her team typically use in their research -- 5 to 15 micromolars -- may be achieved through diets rich in certain types of cruciferous vegetables, particularly land cress and watercress.

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A recent study confirms all my recent posts on the importance of fiber, fruits, vegetables, whole grains, seeds, nuts, and legumes for beneficial gut bacteria health (have to feed the them!). This study found dramatic changes in the colon (specifically in the colonic mucosa) from dietary changes in as little as 2 weeks.

In the study, for 2 weeks the Americans ate the typical low-fat, high fiber diet of South Africa which included foods such as hi-maize corn fritters, beans, salmon croquettes, spinach, red pepper and onions, homemade tater tots, mango slices,okra, tomatoes, corn muffins, black-eyed peas, catfish nuggets, navy bean soup, banana, lentils, rice, fish taco (tilapia), and pineapple. Meanwhile, people in South Africa ate an “American” high-fat, low-fiber diet. Foods included beef sausage links and pancakes for breakfast; hamburger and French fries for lunch; and meatloaf and rice for dinner. Plus all sorts of American favorites such as macaroni and cheese, steak, beef hot dog and beans.

The African style low fat and high fiber diet contained about 55 grams of fiber per day, and the American diet (low fiber and high fat ) had about 14 grams of fiber per day (which is typical of a Western diet). Bottom line: fiber feeds beneficial microbes in the gut, which results in beneficial changes in the gut (in the mucosa of the colon). From Science Daily:

Diet swap has dramatic effects on colon cancer risk for Americans and Africans

Scientists have found dramatic effects on risk factors for colon cancer when American and African volunteers swapped diets for just two weeks. Western diets, high in protein and fat but low in fibre, are thought to raise colon cancer risk compared with African diets high in fibre and low in fat and protein.The new study, published in Nature Communications today, confirms that a high fibre diet can substantially reduce risk, and shows that bacteria living in the gut play an important role in this effect.

Colon cancer is the fourth commonest cause of death from cancer worldwide, accounting for over 600,000 deaths per year. Colon cancer rates are much higher in the western world than in Africa or the Far East, yet in the United States, African Americans shoulder the greatest burden of the disease.

To investigate the possible roles of diet and gut bacteria, an international team including scientists from the University of Pittsburgh and Imperial College London carried out a study with a group of 20 African American volunteers and another group of 20 participants from rural South Africa. The two groups swapped diets under tightly controlled conditions for two weeks.... At the start, when the groups had been eating their normal diets, almost half of the American subjects had polyps -- abnormal growths in the bowel lining that may be harmless but can progress to cancer. None of the Africans had these abnormalities.

After two weeks on the African diet, the American group had significantly less inflammation in the colon and reduced biomarkers of cancer risk. In the African group, measurements indicating cancer risk dramatically increased after two weeks on the western diet.

"The findings suggest that people can substantially lower their risk of colon cancer by eating more fibre. This is not new in itself but what is really surprising is how quickly and dramatically the risk markers can switch in both groups following diet change. These findings also raise serious concerns that the progressive westernization of African communities may lead to the emergence of colon cancer as a major health issue."

Professor Stephen O'Keefe at the University of Pittsburgh, who directed the study, said: "Studies on Japanese migrants to Hawaii have shown that it takes one generation of westernization to change their low incidence of colon cancer to the high rates observed in native Hawaiians. Our study suggests that westernization of the diet induces changes in biomarkers of colon cancer risk in the colonic mucosa within two weeks. Perhaps even more importantly, a change in diet from a westernized composition to a 'traditional African' high fiber low fat diet reduced these biomarkers of cancer risk within two weeks, indicating that it is likely never too late to change your diet to change your risk of colon cancer."

The study found that a major reason for the changes in cancer risk was the way in which the bacteria in the gut -- known as the microbiome -- altered their metabolism to adapt to the new diet. In the American group, the researchers found that the African diet led to an increase in the production of butyrate, a byproduct of fibre metabolism that has important anti-cancer effects.