Beverages

Cranberries and Urinary Tract Infections

Chemical Institute of Canada — Mon, 12 Sep 2011 15:48:32 GMT

Mention cranberry juice and “urinary tract infection” springs to mind. Most women and many men are familiar with the frequent urination and accompanying burning sensation that signals a bacterial invasion of the urinary tract. Today antibiotics solve the problem, but what did people do before? “Flushing the system” seemed a logical approach. All sorts of beverages were tried, but by the mid-1800s books on folkloric medicine were suggesting the use of cranberry juice. Based on anecdotal evidence, the juice developed a solid reputation for treating and preventing urinary tract infections.

Once bacteria had been identified as the cause of UTIs, scientists began to explore possible mechanisms by which cranberry juice could offer relief. Acidifying the urine to make it more inhospitable to bacteria was a possibility, as was the antibacterial action of hippuric acid, a component of cranberries. But trying to explain how cranberry juice worked before clearly demonstrating that it did was putting the cart before the horse. Finally, in 1994, Harvard researchers decided to mount a proper clinical study of the claims. They enrolled 153 older women, half of whom were given 10 ounces (285 millilitres) of cranberry juice every day, while the other half were given a look-alike drink containing no cranberry. The women who drank cranberry juice were 58 percent less likely to have levels of bacteria in their urine that would be expected to cause infections. As we would eventually learn, the effect was not due to acidity of the urine, nor to the antibacterial effect of hippuric acid. It had to do with compounds that prevented bacteria from adhering to the lining of the urinary tract.

Bacteria produce adhesives that enable them to stick to tissues so they can pick up nutrients more readily. These molecules fit into specific receptor sites on the epithelial cells that line the urinary tract. As was cleverly shown by Yale University researchers in 1994, compounds in cranberries block these receptors. Urine samples were collected from volunteers who were then given four ounces (115 millilitres) of cranberry juice to drink. Four to six hours later urine was again collected and incubated with E. coli bacteria, the kind that normally are responsible for urinary tract infections. The experiment was then repeated with eight ounces (230 millilitres) of juice. Separately, the scientists cultured cells taken from the lining of the human bladder and then mixed them with the urine samples. Lo and behold, the bacteria did not stick as effectively to the cells when the urine samples came from women who had consumed cranberry juice! Furthermore, the more juice consumed, the less the bacteria adhered to the cells.

Although the specific ingredients in the juice responsible for this effect have not been conclusively identified, speculation is that substances known as trimeric procyanidins may be responsible. Unfortunately, however, not every study has shown that cranberry juice acts favourably on UTIs. In some it worked no better than placebo. And there’s no question that in women with a history of UTIs, antibiotics (trimethoprim-sulfamethoxazole) prevent recurrence far better than cranberry juice. But of course with antibiotics there is the problem of resistance.

These procyanidins may do more than prevent urinary tract problems. Most ulcers are caused by infection with the Helicobacter pylori bacterium. Well, it seems that the procyanidins may also prevent these bacteria from infecting the stomach. Researchers in China chose a population with a high rate of Helicobacter infection, and in a placebo-controlled double-blind study, gave 97 people 500 millilitres (just over two cups) of cranberry juice for 90 days, while 92 others got a placebo. They found that H. pylori was eradicated in 14 people in the cranberry group but in only five in the placebo group. Not an earth-shaking difference, but significant nevertheless, especially given the resistance issues we are now encountering with antibiotics.

Paradoxe blanc - Mon dieu!

Chemical Institute of Canada — Thu, 21 Jul 2011 18:45:11 GMT

If you take a look at all the literature put out by the French wine industry, you'll start to wonder whether you should replace wine drinking by intravenous infusions of red wine. They make a case for wine being virtually a drug to prevent heart disease. They offer reams of scientific evidence about neutralizing free radicals and preventing cholesterol from damaging the walls of arteries. Of course, that doesn't prove that wine is responsible for the French Paradox. That paradox is the low rate of heart disease compared to North America in spite of a high fat diet.

Red wine may indeed be part of the answer because the skin of red grapes contains compounds called polyphenols which do have antioxidant properties and which may prevent cholesterol from being converted into a damaging form. But what about people who favor white wine? This has a far smaller antioxidant capacity than red wine. Leave it to French ingenuity though. A team of wine researchers at Montpelier University have come up with a Chardonnay that has almost the same antioxidant potential as red wine. They found that if the grapes were macerated with the skins and seeds and the fermentation temperature increased, the polyphenol content of the wine increased dramatically.

Furthermore, these scientists managed to show that the wine really has an effect on the antioxidant potential of the blood. They destroyed some of the insulin producing cells in the pancreas of rats to make the animals diabetic. This is because diabetes is known to reduce the antioxidant capacity of the blood. Then they administered the new Chardonnay to the critters for six weeks and found that the antioxidant capacity was restored. And they say laboratory rats don't lead good lives. The special polyphenol enriched Chardonnay is supposedly available in France but I’ve been unable to track down a sample in Canada. Of course the real paradox is why people just don't eat more fruits and vegetables which have more antioxidants than red or white wine!

Yikes! There Are Hormones in My Bottled Water!

Chemical Institute of Canada — Mon, 14 Mar 2011 03:28:16 GMT

For scientists and physicians, the Internet has been both a blessing and a curse. Journal articles are at our fingertips and information about virtually any subject is just a few keystrokes away. But not all of the available information is reliable. A frightening amount of pseudo-scientific drivel permeates the web and spreads like wildfire when attached to emails. Either we are warned about some nasty chemical that is unraveling the very fabric of society, or we are alerted to the discovery of some miraculous natural healing agent that can cure virtually any disease.

The warnings often begin with the phrase “this is no joke,” and then continue with some ghastly revelation about the dangers of some substance in our daily life. Like plastic water bottles that leach a dangerous hormone called diethylhydroxylamine (DEHA) into their contents to make people feel younger and stimulate them to buy more bottled water. Where does the idea that bottled water is laced with hormones come from? The essence of the message is as follows: “the plastic used to make these bottles contains a potentially carcinogenic element (something called diethylhydroxylamine or DEHA)” which leaches out of the plastic on repeated washing and rinsing.” Consumers are then warned that such water bottles should not be refilled but be discarded after a single use.

The seed from which this story germinated can be traced to a scare circulating on the Internet about the migration of a chemical commonly referred to as DEHA into water from plastic water bottles. Of course, DEHA is not an “element,” it is a compound. And in any case, the author of this epic epistle has the wrong compound. Diethylhydroxylamine is indeed sometimes abbreviated as DEHA, but it has nothing to do with plastic water bottles. The chemical in question is diethylhexyladipate, commonly and perhaps confusingly, also abbreviated as DEHA. This is an approved plasticizer, a substance added to certain plastics to make them soft and pliable. Furthermore, neither of the “DEHAs” is classified as a carcinogen. But there is yet a further problem with the scare. While diethylhexyladipate is commonly used as an additive in certain plastics, it is not an ingredient in the polyester used to make water bottles! Polyester is innately flexible and does not require plasticizers.

So how did a compound that isn’t even present in plastic bottles trigger an alarm? The scare seems to have been spawned by an abstract of a talk given by a Master’s student from the University of Idaho at a scientific conference. Such abstracts are not subjected to peer review and are not considered to be a form of scientific publication. The intent is that the information presented will eventually be submitted as a paper to a journal where it will undergo appropriate peer review by experts in that field of research. This never happened in this case, probably because the study performed did not have the scientific rigor required for publication. The student investigated contaminants in bottled water and found a number of organic compounds, including diethylhexyladipate. Apparently unaware that this is not used in polyester bottles, the author assumed it was leaching out of the plastic. Stimulated by this, the Idaho student examined a variety of other plastic bottles and found DEHA in the water they contained leading to the conclusion that “migration of DEHA was not limited to polyester bottles alone and other bottles may also pose a health hazard.”

But a critical control experiment was never performed. Was there any DEHA in water stored in glass bottles or in water that came from the tap water? The answer is yes. Because DEHA is a ubiquitous plasticizer used in the manufacture of items ranging from toys to shower curtains, it shows up in trace amounts everywhere. You can find it in food, clothing and water. We know this because the Swiss Federal Laboratories for Materials Testing and Research studied this issue extensively. All sorts of water samples that had never been in contact with any plastic bottle showed traces of DEHA! Whether the samples came from plastic bottles or glass bottles they contained the inconsequential amount of about 0.01 to 0.05 parts per billion. The World Health Organization has set a maximum of 80 ppb for DEHA in drinking water so there is simply no issue here with plastic bottles. At least not as far as DEHA goes. There may be reasons not to refill water bottles, but that has to do with possible bacterial contamination, not with the leaching of diethylhexyladipate.

So far, so good. But what about the business of DEHA making people feel younger? That’s a puzzler. But it can probably be traced to someone’s fingers dancing on the keyboard while they were “researching” the DEHA-water bottle connection. A little slip and they typed DHEA instead of DEHA. All of a sudden, claims of the potential rejuvenating properties of dehydroepiandrosterone began to frolic on the screen. A “fountain of youth,” many websites claim, a “superhormone!” And what is this miracle? DHEA is a naturally occurring compound synthesized from cholesterol in the adrenal glands. Production peaks in the 20s and then declines so that by the eight decade the amount of circulating DHEA is only 20% of that found during the vigor of youth.

Reasonably, researchers began to explore the possibility that maintaining the DHEA in the blood at levels found in young people may help avert some of the problems of aging. Animal studies showed some intriguing results in terms of delaying cancer and the hardening of arteries. A widely reported study in humans showed that taking 50 mgs of DHEA for three months resulted in an improved feeling of well-being. And then there is the other side of the coin. Researchers worry that DHEA being a relative of testosterone may increase the risk of prostate cancer in men and cause facial hair growth in women. DHEA is illegal in Canada but can be freely sold as a “dietary supplement” in the US. Curiously, people who would not consider taking prescription hormone replacement therapy, uncritically jump on the DHEA bandwagon.

Obviously, DHEA is not the same as DEHA, but neither substance is present in the polyester used to make water bottles. Manufacturers are certainly not sneaking DHEA into the plastic in order to increase sales by making people feel young. But it is interesting to explore how a collection of scientific smidgens can be blended together into meaningless hodge-podge.