BlogDay 2006

31 08 2006

Today it’s BlogDay, and it seems that all bloggers should celebrate this day recommending 5 new blogs.

Recently, the scientific journal Nature published a list of 50 popular science blogs. In the next link you’ll find the top 5 science blogs written by scientists. Enjoy them:

Top five science blogs

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Calorie restriction may fight aging

22 08 2006

Big Burger Some time ago I watched a program on TV where some people believed that calorie restriction could lead to a longer life. They followed a special diet, low in calories and high in micronutrients. Now it seems those advocates for a low-calorie diet may be right.

After a few preliminary studies, results suggests that eating a low-calorie yet nutritionally balanced diet extends human life. It seems that six months of calorie restriction reduces two key markers of aging: fasting insulin levels and body temperature. Also, after an average of six years on calorie restriction, people’s hearts functions like the hearts of much younger people.

The studies show that the hearts of people on calorie restriction appear more elastic than those of age- and gender-matched control subjects. All subjects who dieted or increased their exercise lost weight and body fat. But those on a calorie restriction diet ended the study with lower fasting insulin levels and lower core body temperatures. They also had less oxidative damage to their DNA, thought to be a marker of aging at the biochemical and cellular level.

Researchers are getting ready to launch a second phase of an important study called CALERIE, to look at the effects of calorie restriction over the course of two years. In this study is involved the Calorie Restriction Society, whose members served as subjects in a previous study.

Check these two studies for more information:

Long-Term Caloric Restriction Ameliorates the Decline in Diastolic Function in Humans

Effect of 6-Month Calorie Restriction on Biomarkers of Longevity, Metabolic Adaptation, and Oxidative Stress in Overweight Individuals

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Policosanol: another scam in cholesterol treatment

20 08 2006

Policosanol is a natural extract of plant waxes usually produced from sugar cane. It is sold as a dietary supplement in more than 40 countries mainly because of its supposed lipid-lowering effects, increasing (good) HDL-cholesterol and lowering (bad) LDL-cholesterol.

Many of the studies that have found positive effects of policosanol and published in the scientific literature, have come from a single research group from Cuba. This research group is founded by a company that markets policosanol. And we have to remind that Cuba is a big producer of sugar cane, one of the sources of policosanol.

A new study carried out by a research group in Germany, suggests that use of the dietary supplement policosanol does not lower LDL-cholesterol levels any more than placebo. There weren’t any other effects either in total cholesterol, HDL-cholesterol nor VLDL.

We see again how alternative therapies use a scientific approach to sell us a product with no beneficial effect on the health of its consumers.

The study, titled “Effect of policosanol on lipid levels among patients with hypercholesterolemia or combined hyperlipidemia: a randomized controlled trial“, has published in the may issue of the Journal of the American Medical Association.

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Alternative therapies and menopause symptoms

2 08 2006

During menopause many women complain of a variety of symptoms such as night sweats, sleep problems or hot flashes. About 40 percent of women seek medical help for these problems.

There was some alarm after a large clinical trial of hormone therapy was halted because of an increased risk of breast cancer. Since then, many patients began to seek alternative treatments for menopausal symptoms.

A recent review titled “Complementary and Alternative Therapies for the Management of Menopause-Related Symptoms” and published in the Archives of Internal Medicine, shows that insufficient evidence exists to support the use of complementary and alternative therapies to relieve menopause-related symptoms.

Alternative/complementary therapies reviewed were biologically based treatments, mind-body therapies, a body-based therapy, energy-based treatments; and whole medical systems, such as traditional Chinese medicine or ayurvedic medicine.

The main problems found in alternative therapy research is that the quality of the studies is low. In this review the overall quality and quantity of data was not sufficient to recommend any of the treatments. Even though, some of the individual studies suggested benefits for certain therapies, chiefly biologically based therapies.

These biologically based therapies consisted mainly in dietary supplements based in soy-derived phytoestrogens that in many of the studies had a large placebo effect, meaning that even women who were not assigned to receive active therapy still reported improvement in their symptoms. Authors say that “the placebo effect likely plays an important role in the expanding number of dietary supplements marketed to menopausal women.”

The authors explain that “millions of dollars are spent on over-the-counter products for menopausal symptoms by women who have little knowledge of their quality, safety, or effectiveness”. So, it’s important to note that this study shows the low effect of these dietary supplements, which is opposed to a well-planned diet where soy and soy-derived products, such as tofu, have shown efficacy in treating those symptoms.

With this in mind, it is important to differentiate between a simple phytoestrogen dietary supplement and a soy rich diet. Also we shouldn’t be confused by the cure-all dietary supplements promoted by alternative therapies and the evidence based sciences of nutrition and dietetics.

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