Nutritional Pearls: Weight Loss Supplements

Sarah is a 30-year-old overweight woman struggling to improve her cholesterol levels.

Recently, several family members have recommended various daily weight loss supplements to her. She asks you which of the supplements you think would be best.

How do you advise your patient?
(Answer and discussion on next page)

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Answer: The best way to improve your cholesterol score is to follow a Mediterranean-style diet

There are really 2 problems with most weight loss supplements. The first, and most concerning from a drug interaction standpoint, is that because the supplement industry is not regulated by the Food and Drug Administration (FDA), you cannot be certain what any supplement actually contains. Aftermarket tests of common supplements, especially those marketed for weight loss, have been found to contain a wide variety of active ingredients that don't appear on the label. These ingredients have included everything from trace amounts of prescription weight loss medications that have been removed from the market for being dangerous to ingredients that can interact negatively with other medications.
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The second problem with weight loss supplements is that there's no solid evidence that they work. Research you might see cited on the product's website often has not actually been published in a peer-reviewed publication, meaning it's not been subject to critical scrutiny. Other times, the study might have been published but it's too small to be applicable to the overall population, or (and worse) there might be no control group. (As my wife likes to say, "The plural of ‘anecdote’ is not ‘data’.") There is also the question of dosage: the appropriate dosage for prescription drugs is determined by careful research so that any side effects are minimized. Once again, often this very important safety research hasn't been done for supplements, even when the active ingredient has been identified.

The Research

Today we have good news, however. A team in Taiwan designed a placebo-controlled study to assess the effects of a decaffeinated green tea extract on weight loss in obese women.¹ Seventy-seven women between the ages of 20 and 60 with a body mass index of at least 27 and a waist circumference of at least 80 centimeters participated in the 12-week study. The women were all otherwise healthy, with no liver or kidney problems, heart trouble, thyroid problems, or diabetes.

Half the women were assigned to take a standard dose of green tea extract 3 times per day (after meals). The other half of the women took a placebo. The women were instructed to follow their usual diet and engage in their usual amount of exercise throughout the study, and to verify this they kept dietary and exercise records. At the start and end of the study the women's height, weight, and waist circumference were measured, and blood was drawn for cholesterol scores, blood sugar levels, and circulating levels of appetite-related hormones.

The Results

Those women taking the green tea extract lost about 1.1 kilograms, on average—about 2.4 pounds. Those taking the placebo actually lost more weight: an average of 2 kilograms, or 4.4 pounds. Similar results applied for waist circumference: the green tea group lost an average of 2.3 centimeters from their waist while the placebo group lost 4.2 centimeters.

The weight loss results might have been disappointing, but other results are much more interesting. The women in the green tea group improved their total cholesterol significantly more than the placebo group, decreasing their score by 7% while the women in the placebo group actually increased their score slightly. Similarly, they reduced their LDL cholesterol by as much as 10% while the placebo groups' score also increased slightly.

What’s the “Take-Home”?

The green tea extract used in this study was highly purified product that is not available commercially. While this study is encouraging, you should not take it as a license to start taking green tea extract from the corner drugstore in order to treat your cholesterol. The best way to improve your cholesterol score is to follow a Mediterranean-style diet that is high in whole grains and low in saturated fats, and to take any prescription cholesterol medication as your doctor recommends.

Reference:

1. Chen J, Liu C, Chui J, Hsu C. Therapeutic effect of high-dose green tea extract on weight reduction: A randomized, double-blind, placebo-controlled clinical trial. Clin Nutr. 2016(35):592-599.