News Briefs – September 2008

MEDITERRANEAN DIET — WHAT FOODS CUT CANCER

You’ve heard previously that the so-called Mediterranean diet seems to lower the risk of cancer. But a new study is one of the largest yet to look at the potential impact on cancer of the various individual foods within this diet. It confirms specific cancer risk reductions for different foods and proves that there is no one “super food” in the Mediterranean diet.

Generally, the Mediterranean diet is summarized as eating more vegetables, grains and fish; less red meat; cooking in olive oil; and consuming moderate amounts of alcohol.

Researchers from Harvard University persuaded thousands of Greek people of various ages to record their food intake over an eight-year-period. Their adherence to the Mediterranean diet was ranked using a scoring system, and the group with the worst score compared with those who followed a couple of aspects of the diet, and those who followed it the most closely. The results were published in the July 2008 issue of the British Journal of Cancer.

The biggest effect they found (a 9% reduction in risk) was achieved simply by eating more unsaturated fats, such as olive oil. But just two changes – eating less red meat, and more peas, beans and lentils – cut the risk of cancer by 12%.

Another study suggesting that food has the power to prevent cancer came from the Institute of Food Research in Norwich and was published in the July 2008 issue of the journal, the Public Library of Science. In this study, scientists compared the effects of adding 400 grams of broccoli or peas a week to the diet of men at high risk of prostate cancer. In the case of broccoli, they found differences in the activity of genes in the prostate, genes which other studies have linked to cancer.

Their findings raised the possibility that broccoli (or other “cruciferous” vegetables, such as cauliflower, spinach or Brussels sprouts) might help prevent or slow down the disease, particularly if the man had a particular gene variant (GSTM1). Speaking to News Briefs last month, professor Richard Mithen, who led the research, said: “Eating two or three portions of cruciferous vegetables per week, and maybe a few more if you lack the GSTM1 gene, should be encouraged (for men).”

Vague links between cruciferous vegetables and cancer prevention have been suggested before. But the significance of this latter study is that it’s the first time that a properly controlled clinical trial has shown that broccoli – and likely other cruciferous produce – changes the actual expression of specific genes in the prostate gland.

 

TORONTO CELL PHONE WARNING

Toronto’s department of public health is advising teenagers and young children to limit their use of cellphones to avoid potential health risks. Loren Vanderlinden, a health department supervisor who issued the July 11 warning, says a pattern is emerging that suggests people who have used their cellphones for a long period are at greater risk of certain kinds of brain tumours.

The advisory – believed to be the first of its kind in Canada – warns that because of “possible” side effects from radio frequencies, children under eight should only use a cellphone in emergencies and teenagers should limit calls to less than ten minutes. Health Canada disagrees.

“Health Canada currently sees no scientific reason to consider the use of cellphones as unsafe,” commented the agency. “Health Canada is basing this conclusion upon the bulk of scientific evidence from . . . studies that have been carried out worldwide, including at our laboratory.”

Meanwhile, the head of a US cancer research institute issued an unprecedented warning to his 3,000 faculty and staff in mid-August: Limit cellphone use because of the possible risk of cancer.

The warnings from Ronald B. Herberman, PhD, director of the University of Pittsburgh Cancer Institute, and from Toronto’s Vanderlinden, is contrary to numerous studies that found no link between cancer and cell phone use. Herberman admitted in an interview with News Briefs that no studies had confirmed his fears: “Really at the heart of my concern is that we shouldn’t wait for a definitive study to come out, but err on the side of being safe rather than sorry later,” he said.

 

YOU ARE WHAT…YOUR MOTHER EATS?

Is breastfeeding always better? Inconclusive research suggests that may depend on your diet. Eating a poor diet when pregnant or breastfeeding may cause long-lasting health damage to your child, new animal studies suggest.

The offspring of rats fed fatty, processed foods had high levels of fat in their bloodstream and around major organs, even after adolescence – and even if they had always eaten healthily. The animals also had a raised diabetes risk.

Studies by the same team – the Royal Veterinary College, working with London’s Wellcome Trust – have already shown that rats whose mothers were fed junk food during pregnancy and breastfeeding were more likely to crave similar snacks themselves. However, the importance of this new study is that it shows – in animals at least and just possibly in humans – that even when offspring are weaned off this diet, the damage may already have been done.

The study appeared in the July 2008 issue of the Journal of Physiology.

 

TOFU LINKED TO DEMENTIA

High tofu consumption – at least once a day – has been associated with a diminished memory, particularly among those over age 68. The study focused on 719 elderly Indonesians living in urban and rural regions of Java. (Soy products are a major alternative protein source to meat for many people in the developing world.)

Soy products are rich in micronutrients called phytoestrogens, which mimic the impact of the female sex hormone estrogen. There is some evidence that they may protect the brains of younger and middle-aged people from damage. But their estrogenic effect on the aging brain is less clear. The latest study suggests phytoestrogens – at least in high quantity – may actually heighten the risk of dementia.

In a July 4-5 e-mail interview with News Briefs, lead researcher Professor Eef Hogervorst said that previous research had linked estrogen therapy to a doubling of dementia risk in the over-65s. She said, “Estrogens, and probably phytoestrogens, tended to promote growth among cells, not necessarily a good thing in the aging brain.” Alternatively, high doses of estrogens might promote the damage caused to brain cells by the particles known as free radicals.

There is a third possibility. Damage might be caused – not by the tofu – but by formaldehyde, which is sometimes used in Indonesia as a tofu preservative. However, previous research has linked high tofu consumption to an increased risk of dementia in older Japanese American men.

There seems to be something happening in the brain as we age that makes it react to estrogens in the opposite way to what one would expect. The latest study also found that eating tempeh, a fermented soy product made from the whole soy bean, was associated with better memory. Hogervorst explained that the beneficial effect of tempeh might be related to the fact that it contains high levels of the vitamin folate, which is known to reduce dementia risk: “It may be that the interaction between high levels of both folate and phytoestrogens protects against cognitive impairment.”

While the research may be alarming to heavy soy-users, readers should note that this study is preliminary and more research is needed to draw hard conclusions. Also, the consumption of soy among study participants was substantial.

The Loughborough University-led study appears in the July 2008 issue of the journal, Dementias and Geriatric Cognitive Disorders.

 

VIAGRA – OR WATERMELON?

Watermelons contain an ingredient called citrulline that can trigger production of a compound that helps relax the body’s blood vessels – very similar to what happens when a man takes Viagra, says a new unpublished study from Texas, one of North America’s top producers of the seedless variety.

Found in the flesh and rind of watermelons (60% more in the rind), citrulline reacts with the body’s enzymes when consumed in large quantities and is changed into arginine, an amino acid that benefits the heart and the circulatory and immune systems. That may help those with high blood pressure and circulatory problems. (The relationship between citrulline and arginine might also prove helpful to those who are obese or suffer from type-2 diabetes.)

However, it is not as “organ-specific” as the drug Viagra. So, as researchers cautioned, it may not be a perfect substitute. Those who would rather avoid drugs altogether would need to eat about six cups of watermelon to get enough citrulline to sufficiently boost the body’s arginine level.

That might be an alternative to Viagra – but at a cost. When you eat a lot of watermelon, you tend to run to the bathroom more. Watermelon is a diuretic and was a homeopathic treatment for kidney patients before dialysis became widespread. Another issue is the amount of sugar that much watermelon would spill into the bloodstream – a jolt that could cause cramping. (And to answer your next question, yes, the researchers are investigating the possibility of a sugar-free watermelon in the future.)

Citrulline is present in other curcubits, like cucumbers and cantaloupe, at very low levels, and in the milk protein casein. The highest concentrations of citrulline are found in walnut seedlings, but they’re bitter and most people don’t want to eat them.

 

OREGANO FIGHTS INFLAMMATION

Scientists have discovered that oregano (and other spices) contain a substance that, amongst other qualities, appears to help cure inflammation. The researchers administered oregano’s active ingredient – known as beta-caryophyllin or E-BCP – to mice with inflamed paws. In seven out of ten cases, there was a more rapid improvement in inflammatory symptoms.

E-BCP also might be of use against disorders such as osteoporosis and arteriosclerosis, suggests the study, which appears in the June 23, 2008 issue of the Proceedings of the National Academy of Sciences (PNAS). E-BCP might also help us to control such chronic disorders as Crohn’s disease – an inflammation of the intestinal tract. E-BCP is a typical ingredient of many spices and food plants, such as basil, rosemary, cinnamon, and black pepper.

However, oregano works by affecting specific receptor structures on the surfaces of certain cells. This means that it will not work to prevent any inflammation or osteoporosis. It will only work to correct the problem once it has occurred. It is similar to antidepressants, which may work on those who are depressed but which have no beneficial effect on those who are merely at risk for depression. Scientists speculated that E-BCP one day might be extracted and sold as a medicine for those already afflicted.

 

NEWS NOTES

• Vitamin D deficiency: Linked to heart disease? New research published in the July 2008 edition of the Archives of Internal Medicine found that people with the lowest blood levels of vitamin D are roughly twice more likely to die from “any cause” during the next eight years than those with the highest levels of the vitamin. Specifically mentioned was a potential link between deficiency and heart problems.
• Green tea—again: More evidence for the beneficial effect of green tea on risk factors for heart disease has emerged in a new study reported in the July 2008 issue of European Journal of Cardiovascular Prevention and Rehabilitation. The Greek study found that the consumption of green tea rapidly improves the function of endothelial cells which line the circulatory system. Endothelial dysfunction is a key event in the progression of atherosclerosis, or hardening of the arteries.
• Cancer survivors cautioned: Older cancer survivors should consult with a doctor before taking vitamin supplements, according to recommendations of a study at Duke University Medical Center. The team found that many older cancer patients who’ve survived five years or more take vitamins, minerals and other dietary supplements in an effort to remain disease-free. However, the study concluded that those most likely to take supplements were those who needed them least – and some supplement use can increase the risk of a cancer recurrence. The research, posted July 11, 2008 ahead of publication, appears in the journal Cancer Survivorship.
• Red Bull a serious risk: Just one can of the very popular stimulant energy drink Red Bull can increase the risk of heart attack or stroke, even in young people, Australian medical researchers announced August 15. Only one hour after drinking the beverage, subjects’ systems showed all the symptoms of serious cardiovascular disease. The lead researcher said Red Bull could be deadly when combined with stress or high blood pressure, impairing proper blood vessel function and possibly lifting the risk of blood clotting.
• Pork super-bugs found in Ontario: Scientists are beginning to detect antibiotic-resistant bacteria in pork, pigs and some veterinarians, raising the issue of whether these so-called “super-bugs” might find a new route to infect farm workers or even people who eat pork. University of Minnesota researchers reported they found the antibiotic-resistant bugs in seven per cent of swine veterinarians tested. Public-health doctors at the University of Iowa found the same bacterial strains among 147 of 299 pigs tested with nasal swabs. Perhaps of greater concern, Ontario Veterinary College researcher Scott Weese also detected these bacteria in ten per cent of 212 samples of ground pork and pork chops collected in four Canadian provinces. No one in Canada has been sickened yet, although people have become ill in Europe.
• Animal ‘pain’ studies of limited use: Using animals to research pain has “limited value” and should be replaced by newer technologies, argues a panel of medical experts from across England. Animal tests can only simulate some aspects of chronic pain and are too simplistic, the report says. With newer brain-imaging techniques, more studies could be done in humans, they wrote in the August 2008 edition of the journal Neuroimage
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• Omegas prevent artery hardening: A diet rich in omega-3 fats may explain why middle-aged men in Japan have fewer problems with clogged arteries than similar men in the United States. The new research found that Japanese men living in Japan had twice the blood levels of omega-3 fats – and also lower levels of atherosclerosis, compared to middle-aged white men or Japanese-American men living in the US. (Atherosclerosis is the buildup of plaque inside your arteries. Over time, it can lead to serious problems such as heart attacks and stroke.) Nutritional studies show that intake of omega-3 fats averages 1.3 grams per day in Japan, compared to 0.2 grams per day in the United States and Canada.
• Asian medicine over-exploiting environment: Two reports from TRAFFIC (the world’s largest wildlife trade monitoring network) focusing on traditional medicine systems in Cambodia and Vietnam have suggested that illegal wildlife trade – including entire tiger skeletons, and unsustainable harvesting – is depleting the region’s rich and varied biodiversity and putting the primary healthcare resource of millions at risk. In Cambodia, over 800 types of plants – approximately 35 percent of the country’s native species – are used in Traditional Khmer Medicine; eight of those plants species are considered high priority for national conservation. In north and south Vietnam where more than 3,900 species of flora and 400 species of fauna are used in traditional remedies, seventy-one of the animals traded and used for medicinal purposes in are listed on the IUCN Red List of globally threatened species.