Nutritional and Environmental Factors & Cancer

Eating at least five portions a day of certain fruit and vegetables could cut the risk of developing pancreatic cancer by 50%, US researchers believe.

Onions, garlic, beans, carrots, corn, dark leafy vegetables, broccoli and citrus fruits were among the most protective foods, according to the study.

A University of California team compared the diets of 2,200 people.

Cancer experts said previous studies had revealed similar findings, but more research was still needed.

More than 10,000 people die each year in the UK from pancreatic cancer. It remains largely untreatable, with the five-year survival rate at under 3%.

HIGHLY PROTECTIVE FOODS: Onions, Garlic, Beans, Carrots, Dark leafy vegetables, Broccoli, Corn, Sweet potatoes, Citrus fruits

The report, published in the Cancer, Epidemiology, Biomarkers and Prevention journal, said eating five portions daily of the most protective vegetables cuts the risk in half.

Or it said eating any nine fruit or vegetables could have the same effect.

Raw vegetables were found to be more protective than cooked ones, the study said after conducting interviews with 532 people with the cancer, and 1,700 people who did not have the disease.

But researchers acknowledged the results may have been influenced by food which may often be eaten with the vegetables.

Report co-author Elizabeth Holly said: "Pancreatic cancer is not nearly as common as breast or lung cancer, but its diagnosis and treatment are particularly difficult.

"Finding strong confirmation that simple life choices can provide significant protection from pancreatic cancer may be one of the most practical ways to reduce the incidence of this dreadful disease."

Dr Julie Sharp, cancer information officer at Cancer Research UK, said: "Previous research has implied that a diet rich in fruit and vegetables may help to prevent pancreatic cancer.

"This research adds to these findings, but large-scale studies are vital to confirm whether fruit and vegetables really have an effect on pancreatic cancer risk."

And she added other lifestyle factors, such as smoking, also played a key role.

(Leaflady's note: Pancreatic enzymes are usually one of the main factors missing in the mainstream medical treatment of pancreatic cancer.)  

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Yummmm, a favorite food: a bowl of steamed broccoli or brussel sprouts!

The Cancer-Fighting Power of Broccoli Sprouts from Science Daily, October 2005

A group of studies presented at the annual meeting of the American Association for Cancer Research have added to the evidence that diet can be crucial to health. In particular, two studies focused on the cancer-preventive powers of broccoli sprouts.

Prevents Stomach Cancer 

A team from Japan found that a diet rich in broccoli sprouts reduced Helicobacteri pylori infection. H. pylori is a cause of gastritis, and it is believed to be an important factor in stomach cancer. Sulforaphane The scientists were investigating the anti-cancer properties of sulforaphane, a chemical derived from broccoli sprouts. It acts as an antioxidant, and may destroy the H. pylori bacteria. In another study on sulforaphane, performed by a researcher from Johns Hopkins University, broccoli sprout extract was applied to the skin of hairless mice, where it was found counteract the carcinogenic response caused by exposure to ultraviolet light.

Half the Tumors 

By the end of the study, 100 percent of the mice who had not been treated with the extract developed cancerous skin tumors. Only half that amount developed tumors among the treated mice, however, and those that did developed only half as many tumors. 

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One third of cancer deaths due to avoidable factors
By Patricia Reaney

LONDON - If people avoided major risk factors for cancer, more than a third of the 7 million annual deaths from the disease could be prevented, scientists said on Friday.

In a report in The Lancet medical journal, the researchers estimated how many deaths from 12 types of cancer were caused by exposure to nine risk factors.

They calculated that smoking, alcohol, obesity, poor diet, unsafe sex, lack of exercise and other factors contributed to 2.43 million cancer deaths worldwide in 2001.

"A third of cancer deaths could have been avoided had those risks been reduced," said Dr Majid Ezzati of the Harvard School of Public Health in the United States.

"Prevention is probably still our best bet for reducing cancer deaths. It is by far larger than what we may be able to achieve using medical technology."

Smoking, which is linked to lung, mouth, stomach, pancreatic and bladder cancers, is the biggest avoidable risk factor, followed by alcohol and not eating enough fruits and vegetables.

"Of the 2.43 million deaths, 37 percent of them are from lung cancer," said Ezzati. "The total lung cancer deaths in the world are 1.23 million and of those 900,000 of them are caused by these risk factors."

Smoking has increased in developing countries in the past few decades so the number of avoidable deaths could grow, he added.

Obesity also plays a role in colorectal and breast cancer in high income countries, according to the research.

Infection with the human papillomavirus (HPV) through unsafe sex is a contributing cause of cervical cancer in women in sub-Saharan Africa and parts of Asia, mainly because of a lack of screening and clinical services.

Urban air pollution is a risk factor for cancer in eastern and southern Asia, while indoor smoke from burning coal is a particular problem in China.

Ezzati said hepatitis infection, which is linked to liver cancer, is sometimes spread by the use of contaminated syringes in health centers in poor countries.

More than 100 scientists around the world contributed data for the study and reviewed medical evidence.11/17/05 © Copyright Reuters Ltd. All rights reserved. 

Cancer and Vitamin Therapy  -  In a recent presentation at the American Cancer Society meeting, Dr. David Golde of Memorial Sloan-Kettering Cancer Center speculated that supplemental vitamin C may be harmful to cancer patients. Dr. Golde had previously shown how vitamin C gets into and accumulates in cancer cells. Golde and others are concerned that the extra vitamin C in cancer cells may enhance their growth or protect them from the cell-killing free radicals produced by radiation and some chemotherapeutic drugs.

While different cancer cells may respond differently to vitamin C, it is important to view these concerns in the context of the experimental cell culture, small animal, and human clinical studies. In some cell culture and small animal studies, vitamin C has enhanced cancer cell growth. Dr. Chan Park has found that the growth of leukemic cells from some leukemia patients put into culture was enhanced by vitamin C. The growth of cells taken from other leukemia patients was either inhibited or unaffected by vitamin C. It is unknown whether similar effects would have been observed in the same patients taking supplemental vitamin C. Dr. Joel Schwartz of the National Institutes of Health has published studies in which supplemental vitamin C enhanced the growth of tumors induced in hamsters by a chemical carcinogen. Interestingly, the growth of tumors was significantly inhibited by supplemental vitamin E and by a mixture of antioxidants, including beta-carotene, vitamin E, and vitamin C.

Studies published by LPI scientists since the 1970s have demonstrated that supplemental vitamin C delayed the onset of tumors in mice that developed spontaneous mammary tumors, in mice exposed to ultraviolet radiation, and in guinea pigs implanted with liver cancer cells. In these experiments, vitamin C did not appreciably affect the growth rate of tumors once they formed. Other studies published by Dr. Constance Tsao and her colleagues at LPI showed that supplemental vitamin C (sometimes combined with oxidation products of vitamin C) inhibited the growth of human colon, lung, and mammary tumors implanted into mice. LPI investigations also demonstrated that vitamin C and its derivatives have anticancer effects against a number of cancer cell lines in culture.

What about clinical studies on vitamin C in cancer patients? Dr. Pauling and his medical collaborator, Dr. Ewan Cameron, former Chief of Surgery at Vale of Leven Hospital in Scotland, published numerous papers on the response of cancer patients given large doses of supplemental vitamin C as an adjunct to the appropriate conventional treatment for cancer. In their book Cancer and Vitamin C, they concluded that supplemental vitamin C is of benefit to most cancer patients. The benefit ranged from an increased sense of well-being to a prolongation of survival time in terminal patients to rare complete regressions. However, two clinical studies carried out by Drs. Edward Creagan and Charles Moertel of the Mayo Clinic and published in 1979 and 1985 showed no benefit from supplemental vitamin C on survival time. As Drs. Cameron and Pauling pointed out, however, the patients in the first Mayo Clinic study had undergone extensive chemotherapy that damaged their immune systems prior to the use of vitamin C. In the second study supplemental vitamin C was abruptly stopped after only about two months. There was also evidence that some of the patients in the placebo group were taking extra vitamin C, thus muddying the differences between groups.

When Cancer and Vitamin C was first published in 1979, Drs. Cameron and Pauling noted that little information was available on the interaction between vitamin C and chemotherapeutic drugs. They cautioned that patients undergoing aggressive chemotherapy expected to be curative should refrain from taking large doses of vitamin C at the same time in case the vitamin interfered with the drug action. There is some evidence that vitamin C increases the activity of liver enzymes that detoxify xenobiotics, including drugs. When the chemotherapy was merely palliative, they did not believe that the use of concurrent vitamin C was contraindicated. They believed that vitamin C potentiates radiation, and even many clinicians who disagree on this point nevertheless agree that supplemental vitamin C given after radiation ameliorates radiation sickness.

In the early 1990s, Dr. Pauling published two papers with Dr. Abram Hoffer, who developed a regimen for use in cancer patients that includes B vitamins, vitamin E, large doses of vitamin C, beta-carotene, selenium, zinc, and other substances. The statistical analysis of their data revealed that about 40% of the cancer patients survived five years or more after the initiation of the regimen. (A new book by Dr. Hoffer, Vitamin C & Cancer, features major contributions by Linus Pauling and further discussion of these results.) Only about 10% of the patients treated by Dr. Cameron in Scotland with vitamin C alone survived as long, although all of the Scottish study patients had terminal cancer. These studies, as well as Dr. Cameron's studies in Scotland, were not designed as placebo- controlled, randomized, double-blind trials because of ethical concerns and practical problems concerning appropriate placebos.

Interestingly, Dr. Hoffer's regimen is remarkably similar to that recommended by Dr. Kedar Prasad of the University of Colorado and his colleagues, who advocate the use of a combination of B vitamins, large doses of calcium ascorbate (vitamin C), vitamin E, and beta-carotene for cancer patients undergoing either chemotherapy or radiation. Dr. Prasad acknowledges the accumulation of antioxidant vitamins in cancer cells, but argues that this has favorable biochemical effects, including the inhibition of oncogenes and the induction of factors that inhibit cell growth, favor differentation, or induce apoptosis (programmed cell death). In an extensive and well-referenced recent review published in the Journal of the American College of Nutrition, Dr. Prasad presented results from cell culture experiments demonstrating that the killing effect of many cancer drugs or radiation on mouse and human cancer cells is enhanced in the presence of vitamins C or E. Of course, cell culture studies (or animal studies) cannot always predict what will happen in humans. In another extensive review published in Alternative Medicine Review in 1999, Drs. Lamson and Brignall reached conclusions similar to those of Dr. Prasad. These authors noted that "considerable data exists showing increased effectiveness of many cancer therapeutic agents, as well as a decrease in adverse effects, when given concurrently with antioxidants."

A Finnish non-randomized clinical study published in Anticancer Research in 1992 by Dr. Jaakkola and colleagues showed that the provision of B vitamins, large doses of vitamins C and E, beta-carotene, fatty acids, and minerals in combination with chemotherapy and radiation to patients with small-cell lung cancer resulted in significantly prolonged survival, especially when started early. These patients were compared to patients in other studies who were treated only with chemotherapy and radiation. Another clinical study by Dr. Emmanuel Cheraskin published in 1968 showed that the response to radiation among women with cervical carcinoma was enhanced by daily supplements of 750 mg of vitamin C given during radiation.

What can we conclude about vitamin C and cancer? While the theoretical speculation by Dr. Golde seems plausible, there is no clinical evidence that supplemental antioxidant vitamins, including vitamin C, harm cancer patients. Indeed, much of the recent cell culture and clinical research suggests that a combination of antioxidant vitamins and minerals as an adjunct to conventional therapy may have benefit. This is a complex issue, however, and there is clearly more to learn from controlled clinical trials about the use of these modalities in treating cancer before definitive conclusions can be drawn.  from Linus Pauling Institute Is Vitamin C Harmful to Cancer Patients 

Vitamin C The Master Nutrient by Sandra Goodman, Ph.D.