Monday, October 27, 2008

St. John's Wort Relieves Symptoms of Depression

New research provides support for the use of St. John's wort extracts in treating major depression. A Cochrane Systematic Review backs up previous research that showed the plant extract is effective in treating mild to moderate depressive disorders.

"Overall, we found that the St. John's wort extracts tested in the trials were superior to placebos and as effective as standard antidepressants, with fewer side effects," says lead researcher, Klaus Linde of the Centre for Complementary Medicine in Munich, Germany.

Extracts of the plant Hypericum perforatum, commonly known as St. John's wort, have long been used in folk medicine to treat depression and sleep disorders. The plant produces a number of different substances that may have anti-depressive properties, but the whole extract is considered to be more effective.

Cochrane Researchers reviewed 29 trials which together included 5,489 patients with symptoms of major depression. All trials employed the commonly used Hamilton Rating Scale for Depression to assess the severity of depression. In trials comparing St. John's wort to other remedies, not only were the plant extracts considered to be equally effective, but fewer patients dropped out of trials due to adverse effects. The overall picture is complicated, however, by the fact that the results were more favourable in trials conducted in German speaking countries, where St. John's extracts have a long tradition and are often
prescribed by doctors.

Despite the favourable findings for St. John's wort, generalizations about the plant's use as an anti-depressant are not warranted. I recommend consulting a doctor, rather than self-medicating with St. John's wort, especially since the extracts can sometimes affect the actions of other drugs. Also, the products available on the market vary considerably.

Tuesday, October 7, 2008

The Soy Supplement Genistein Can Interfere with Breast Cancer Treatment

The dietary supplement genistein can undermine breast cancer treatment

Many supplements sold without a prescription and marketed to post-menopausal women include plant compounds, such as genistein, that can block the effectiveness of Letrozole, a breast cancer drug. Women taking aromatase inhibitors to treat breast cancer or prevent its recurrence should think twice before also taking a soy-based dietary supplement, researchers report.

Genistein, a soy isoflavone that mimics the effects of estrogen in the body, can negate the effectiveness of aromatase inhibitors, which are designed to reduce the levels of estrogens that can promote tumor growth in some types of breast cancer.

The new study, which included researchers from the University of Illinois, Virginia Polytechnic and State University and the National Center for Toxicological Research, appears in the journal Carcinogenesis.

Aromatase inhibitors are a mainstay of breast cancer treatment in post-menopausal women. These drugs work by interfering with the enzyme aromatase, which catalyzes a crucial step in converting precursor molecules to estradiol, the main estrogen in the body.

About two-thirds of all cases of breast cancer diagnosed in the U.S. are estrogen dependent or estrogen sensitive, which means that the tumors grow more rapidly in the presence of estrogen.

Most women diagnosed with breast cancer are post-menopausal, so their ovaries are no longer producing normal levels of estrogen. Other tissues, however, produce a steroid hormone, androstenedione (AD), which, with the help of aromatases, is converted to testosterone and estrogens. The estrogens produced from AD can stimulate the growth of some types of breast cancer tumors.

"To think that a dietary supplement could actually reverse the effects of a very effective drug is contrary to much of the perceived benefits of soy isoflavones, and unsettling," said William Helferich a professor of food science and human nutrition at Illinois and principal investigator on the study. "You have women who are taking these supplements to ameliorate post-menopausal symptoms and assuming that they are as safe as consuming a calcium pill or a B vitamin."

Many women take genistein supplements to control hot flashes and other symptoms of menopause. The researchers found that the doses commonly available in dietary supplements were potent enough to negate the effectiveness of aromatase inhibitors.

"These compounds have complex biological activities that are not fully understood," Helferich said. "Dietary supplements containing soy-based phytoestrogens provide high enough dosages that it could be a significant issue to breast cancer patients and survivors."

Plant estrogens from soy are not the only ones of concern, Helferich said. In a recent study, he and his colleagues found that certain mixtures of estrogenic botanical components and extracts marketed as supplements to assist "female libido enhancement" and sold without a prescription appeared to spur breast cancer tumor growth at low doses, while having no effect on tumors at high doses.

That study appeared last year in Food and Chemical Toxicology.

"We are just starting to understand the complex effects of the dietary supplements that contain phytoestrogens," Helferich said. "There is an ongoing human experiment in which the outcome is unknown. These findings raise serious concerns about the potential interaction of the estrogenic dietary supplements with current breast cancer therapies."

Thursday, October 2, 2008

Chocolate for your Heart

Italian researchers have calculated how much chocolate we need to protect against heart disease. It isn't much - 6.7 grams, about the amount you would get from eating two or three small squares of dark chocolate per week. The investigators looked at chocolate consumption among 4,849 Italians enrolled in one of the largest health studies ever conducted in Europe. The researchers checked participants' levels of C-reactive protein (CRP), a marker for chronic inflammation in the body that indicates increased risk of heart disease. They related CRP levels to chocolate intake and found that participants who ate moderate amounts of dark chocolate regularly had significantly lower levels of CRP. The benefits of chocolate remained even after the researchers adjusted for other dietary factors including consumption of wine, fruits and vegetables. Unfortunately, the bad news is that if you eat more than the equivalent of 6.7 grams of chocolate per day, the beneficial effects on CRP levels seem to disappear. The study was published in the October, 2008 issue of the Journal of Nutrition.