Health Bytes-q3-09

Tea may inhibit the absorption of iron into the body, potentially leading to iron deficiency issues, according to recent research.

The tannins found in tea, while offering drinkers the advantage of their proven anti-oxidant properties, can act as chelators, binding to minerals and making it harder for them to be taken in by the body. However, scientists do not believe the problem is serious enough to cause significant deficiency problems for most tea drinkers in the western world as most people ake in more iron than they actually need.

One team measured the iron levels of subjects after they ate a meal of hamburger, mashed potato ad string bean and drank a variety of different beverages. Including a cup of tea with the meal caused a 62% decrease I the amount of iron absorbed. Coffee drinkers experienced a 35% reduction. But orange juice helped boost absorption by 85%. A further complicating factor is that the iron absorption from meat, fish and poultry (heme-iron) is unaffected by tea or coffee. Only the absorption of iron found in vegetables and grains (non-heme iron) is inhibited.

A study conducted in China by a team led by Dr. Andy H. Lee of Curtin University of Technology in Perth, Australia published in the journal Stroke found that respondents who drank at least one cup of tea every week for 30 years or more had a 60% lower risk of suffering ischemic stroke, which is caused by partially or completely blocked oxygen-delivering arteries in the brain. Drinking more than 2 cups of tea daily lent a 40% lower risk of such strokes but the odds increased in one’s favor depending on the typs\e of tea commonly consumed. Green tea drinkers have a 72% lower risk for ischemic stroke, oolong drinkers 79%.

While the team could come up with no obvious explanation for the findings, they pointed out that tea, or some of its components, help to reduce high blood pressure and other risk factors.

Lee recommended more research in other countries be conducted to "ascertain whether tea consumption can enhance survival of stroke patients."

Green tea appears to be a weapon against leukemia, according to Tait Shanafelt, a hematologist at the Mayo Clinic in Roch-ester, Minnesota and lead author of a study published in the online issue of the Journal of Clinical Oncology.

The positive results were discovered during early leukemia clinical trials using the chemical epigallocatechin gallate, a substance found in green tea.

"The majority of individuals who entered the study with enlarged lymph nodes saw a 50% or greater decline in their lymph node size," said Shanafelt. "Patients tolerated the green tea extract at very high doses."

Patients suffering from incurable chronic lymphocytic leukemia, the most common type of leukemia in the US, were used in the trials. According top te researchers, about half of all early stage patients have an aggressive form of the cancer that that results in an early death. The green tea extract can stabilize early-stage patients, possibly working in tandem with other treatments.

According to the report, the 33 patients in the trial received variations of eight different oral doses of Polyphenon E, a pro-prietary compound whose primary active ingredient is epigallocatechin gallate, of from 400 to 2,000 mg twice daily. Researchers believe that the maximum tolerated dose would exceed 4,000 mg daily.

In the second phase of clinical testing a similar number of patients will receive the highest dose administered from the previous trial.

If you are one of those people that enjoys their tea hot from the pot, perhaps you might want to consider slowing down a bit. Research published on the British Medical Journal website claims that drinking tea at temperatures of 70ºC or more can increase the risk of throat cancer, affecting the oesophagus.

"Compared with drinking warm or lukewarm tea (65°C or less), drinking hot tea (65-69°C) was associated with twice the risk of oesophageal cancer, and drinking very hot tea (70°C or more) was associated with an eight-fold increased risk," according to researchers from New Zealand’s University of Auckland. "Likewise, compared with drinking tea four or more minutes after being poured, drinking tea less than two minutes after pouring was associated with a five-fold higher risk," the study found.

The study was conducted in northern Iran, where the locals drink a lot of tea and suffer from one of the world’s highest rates of oesophageal cancer

However, researchers concluded that "there was no association between the amount of tea consumed and risk of cancer."

White tea may inhibit fat cell formation and may also help break down existing fat cells according to a recent German study published in Nutrition and Metabolism.

Previous research has indicated the high anti-oxidant content of white tea may help inhibit some cancer cells, help lower blood pressure and increase bone strength.

Since white tea is uncured and unoxidized like other teas, it may contain more ingredients that are active on human cells.

Researchers conducted in vitro studies to explore the cellular and molecular mechanisms underlying fat metabolism, more specifically the effect of white tea extract on cultured human subcutaneous preadipocytes and adiopocytes (fat cells). They found that white tea extract effectively inhibits adipogenesis (the production of fat) and stimulates lipolysis activity (the destruction of fats).

White tea extract "can be utilized to modulate different levels of the adipocyte life cycle," the study concluded.

The American Journal of Obstetrics and Gynecology reports that pregnant women who consume 200 milligrams or more of caffeine a day the amount in 10 ounces of coffee or 25 ounces of tea may double their risk of miscarriage. The lead author of the study, Dr. De-Kun Li, a reproductive and perinatal epidemiologist at the Kaiser Permanente Division of Research in Oakland, California, suggests that pregnant women may want to reduce their intake or cut it out entirely. "Stopping caffeine really doesn’t have any downside," Li said.

It is well known that caffeine crosses the placenta and reaches the developing baby, which cannot metabolize caffeine like an adult. For this reason, there has been much controversy on how much caffeine is safe for the developing baby if any at all. But this is the first study which links caffeine and miscarriage.

Recently the American Pregnancy Association weighed in on the benefits of drinking herbal tea during pregnancy and concluded along with several recent studies that not only do most herbal teas pose no risk to the developing child and mother, but herbal teas can also play a central role in strengthening the uterus muscles, decreasing the length of labor and decreasing the number of interventions used such as artificial rupture of membranes (AROM), assisted delivery, and cesarean delivery, as well as provide important vitamins and minerals like calcium, iron, vitamin D, K and C. They do, however, caution that expecting mothers should consult with their midwife or Doctor before starting a strict regimen of herbal tea.

Professor Mel Rosenberg, a breath specialist at Tel Aviv University’s Sackler Faculty of Medicine has discovered that a component in coffee can actually prevent bad-smelling bacteria from creating bad breath.

"Everybody thinks that coffee causes bad breath," "and it’s often true, because coffee, which has a dehydrating effect in the mouth, becomes potent when mixed with milk, and can ferment into smelly substances," Rosenberg said.

Certainly, Rosenberg and his colleagues were expecting to find evidence that coffee breath is connected to bacterial interaction with saliva in the mouth. But what they discovered surprised them.

"Contrary to our expectations, we found some components in coffee that actually inhibit bad breath," Rosenberg said. "The lesson we learned here is one of humility: we expected coffee would cause bad breath, but there is something inside this magic brew that has the opposite effect."

The task now is to isolate the bacterial-inhibiting component and find a way to incorporate it into a new category of breath fresheners such as gum, mouthwash and breath mints.

"It’s not the raw extract we will use but an active material within it," Rosenberg clarified.

Once again, it has been proven that coffee has great positive effects on the health of mice. According to a report in Cancer magazine, the University of South Florida conducted a study using 55 mice that had been bred to develop symptoms of Alzheimer’s disease.

Half the mice were given plain water, the other half water infused with caffeine. After two months, the mice that had been given the caffeinated water performed memory and cognitive tests as well as unimpaired mice of the same age that were not suffering from dementia. The researchers also discovered that levels of the beta amyloid protein, which is responsible for creating harmful masses in the brains of Alzheimer and dementia victims, were reduced by almost half.

Germany’s Green Cross has produced a brochure extolling the benefits of coffee drinking. Among the benefits listed, it says coffee improves digestion and protects against age-related diabetes, Alzheimer’s Disease and cirrhosis of the liver.

The brochure cites several studies on coffee consumption and notes that caffeine is an important element of coffee that offers important benefits including improving concentration and decreasing the risk of cirrhosis of the liver by up to 80% for those drinking at least four cups of coffee a day.

It also notes that coffee contains the anti oxidant chlorogene acid, which it claims can almost halve the risk of contracting Alzheimer’s Disease.