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Do Over-the-Counter Diet Supplements Really Work as Promised?

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If you have ever wanted to drop a few pounds—or a few dozen—you may have been tempted to get a little help from the pharmacy.

Walk down any diet supplement aisle and you may notice more spring in your step and a new focus in your mental motivation. Then your eye catches the packaging, a beacon that promises you can drop that weight with less effort and discomfort. Your heart races as you reach for the shiny little bottle of pure promise…

Hold on! It’s time to get a grip.

Now that you’re safely back to planet Earth, here’s the real skinny: two separate studies presented this week at the International Congress on Obesity in Stockholm, Sweden have found a broad selection of popular slimming supplements were no more effective than the fake supplements they were compared with.

That’s right. The “real promise,” they hold is nothing more than the placebo effect.

If you have tried diet supplements before, you’re certainly not alone. Americans spend more than $1.6 billion every year on them. In North America losing weight is a mega industry, netting a whopping $50 billion annually. In Western Europe, sales of weight-loss products, excluding prescription medications, topped £900 million ($1.4 billion) in 2009. And yet, Americans still rank as third fattest country on Earth (American Samoa tops the list), according to the 2010 World Health Organization’s obesity analysis. Germany, Bosnia, Croatia and the United Kingdom round out the top 10.

There are legitimate reasons to drop pounds. Body image aside, excess weight can lead to a host of health problems, from insomnia to heart disease; endometrial, breast and colon cancers; type 2 diabetes, breathing problems and stroke.

Slimming down can be difficult, so who would turn down a boost? Especially when there are scores of slimming supplements out there claiming weight-loss effects from all sorts of mechanisms: The so-called fat magnets, mobilizers and dissolvers, as well as appetite tamers, metabolism boosters, carb blockers, full body flushes and so on.

“The market for diet supplements is huge, but unlike for regulated drugs, effectiveness does not have to be proven for these products to be sold," said Dr. Thomas Ellrott, head of the Institute for Nutrition and Psychology at the University of Göttingen Medical School, Germany, who lead one of the studies. “Few of these supplements have been submitted to clinical trials and the landscape of products is always changing, so we need to put them through rigorous scientific evaluation to determine whether they have any benefit.”

So Ellrott's group tested nine popular supplements against placebo pills in a randomized controlled trial. The supplements tested included L-carnitine, polyglucosamine, cabbage powder, guarana seed powder, bean extract, Konjac extract, fibre pills, sodium alginate formulations and selected plant extracts.

The researchers bought the supplements from German pharmacies, changed the packaging and product names to make them look neutral and rewrote the information inserts to eliminate the product name from the text. Then they then gave 189 obese or overweight middle-aged consumers packages of either fake pills or one of the nine supplements for eight weeks in doses recommended by the manufacturers. Some of the products came with dietary advice, while others didn't, so the researchers provided exactly the same advice as that written in the relevant product leaflets.

On average there was no weight loss difference between the group taking the supplement and the placebo group.

This research, funded by a German consumer issues magazine, is significant according to Dr. Ellrot because previous studies have typically examined only one product. This is the first to study nine products with different proposed mechanisms of action and to show that there is no difference in any of the products in producing weight loss over the two months of the study.

Dr. Igho Onakpoya of Peninsula Medical School at the Universities of Exeter and Plymouth, UK, conducted the first systematic review of all existing clinical trials on weight loss supplements involving nine popular slimming supplements, including chromium picolinate, Ephedra, bitter orange, conjugated linoleic acid (CLA), calcium, guar gum, glucomannan, chitosan and green tea. His research, also presented at the conference, mirrors Ellrot’s.

"We found no evidence that any of these supplements studied is an adequate treatment for reducing body weight," Onakpoya said. “People think these supplements are a short cut to weight loss and may spend huge sums of money on them, but they end up disappointed, frustrated and depressed when their long term weight expectations are not met.”

The Centers for Disease Control and Prevention has a lot of great tips on losing weight the healthy way. Check out the CDC's podcast specifically for women and girls.

Lynette Summerill is an award-winning writer who lives in Scottsdale, Arizona.In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.

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We value and respect our HERWriters' experiences, but everyone is different. Many of our writers are speaking from personal experience, and what's worked for them may not work for you. Their articles are not a substitute for medical advice, although we hope you can gain knowledge from their insight.

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