Friday Favorites: Are Weight-Loss Supplements Safe and Effective?

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

In this video, I look into weight loss supplements. If you’re interested in more on weight loss, look no further than my book How Not to Diet, and of course lots of videos on NutritionFacts.org. Just type weight loss into the search bar and watch to your heart’s content.

According to a national survey, a third of adults who’ve made serious attempts at weight loss have tried using dietary supplements, for which Americans spend literally billions of dollars every year. Most mistakenly thought that over-the-counter appetite suppressants, herbal products, and weight-loss supplements had to be approved for safety by some governmental agency, like the FDA, before being sold to the public—or at least include some kind of warning on the label about potential side effects. Nearly half even thought they had to demonstrate some sort of effectiveness. None of that is true.

The Food and Drug Administration estimates that dietary supplements in general cause 50,000 adverse events annually––most commonly liver and kidney damage. Of course, prescription drugs don’t just adversely effect, but kill more than 100,000 Americans every year. But, at least you notionally have the opportunity to parse out the risks versus benefits, thanks to testing and monitoring requirements typically involving thousands of individuals.

When the manufacturer of the ephedrine-containing supplement Metabolife 356 had it tested—on 35 people—only minor side effects were found, such as dry mouth, insomnia, and headaches. However, once unleashed on the populace, nearly 15,000 adverse effects were reported before it was pulled from the market, including heart attacks, strokes, seizures, and deaths.

Given the lack of government oversight, there’s no guarantee that what’s on the label is even in the bottle. FDA inspectors have found that 70 percent of supplement manufacturers violated so-called Good Manufacturing Practices, which are considered the minimum quality standards. This includes things like basic sanitation and ingredient identification. Not 7 percent in violation; 70 percent.

DNA testing of herbal supplements across North America found that most could not be authenticated. In a significant percentage of the supplements tested, the main labeled ingredient was missing completely, and substituted for something else. For example: a “St. John’s wort” supplement containing nothing but senna, a laxative that can cause anal blistering. Only 2 out of 12 supplement companies had products that were accurately labeled.

This problem isn’t limited to just fly-by-night phonies in some dark corner of the internet. The New York State Attorney General commissioned DNA testing of 78 bottles of commercial herbal supplements sold by Walgreens, Walmart, Target, and GNC. “Four out of five [bottles] did not contain any of the herbs on their labels.” Instead, capsules were often little more than cheap fillers like powdered rice “and houseplants.”

In my last video, I noted that one investigation found four of out five bottles of commercial herbal supplements bought at major retailers didn’t contain any of the herbs on their labels, instead often containing little more than cheap fillers like powdered rice “and houseplants.”

At least you hope it just contains houseplants. Weight-loss supplements are infamous for being adulterated with drugs. In a sampling of 160 weight-loss supplements sampled that claimed to be “100 percent natural,” more than half were tainted with drugs: active pharmacological ingredients, ranging from antidepressants like Prozac to erectile dysfunction meds like Viagra. Diuretic drugs are frequent contaminants, which makes sense. In my keto videos, I talk about rapid water loss as the billion-dollar gimmick that has sold low-carb diets for more than a century. But why the Viagra?

At least the spiked Viagra and Prozac are drugs that are legal. Researchers in Denver tested every weight-loss supplement they could find within a 10-mile radius, and alarmingly found a third were adulterated with banned ingredients. The most common illegal adulterant of weight loss supplements is sibutramine, which was sold as Meridia before it was yanked off the market back in 2010 for heart attack and stroke risk; now also blamed for cases of slimming supplement-induced psychosis.

An analysis of weight-loss supplements bought off the internet advertised with claims such as “purely natural,” ‘‘harmless,’’ or ‘‘traditional herbal” found that a third contained high-dose banned sibutramine, and the rest contained caffeine. Wouldn’t you be able to tell if caffeine was added to a supplement? Perhaps not if it also had Temazepam added—a controlled substance (benzodiazepine) “downer” sedative found in half of the caffeine-tainted supplements.

Doesn’t the FDA demand recalls of adulterated supplements? Yes, but they just pop back up on store shelves. Twenty-seven supplements purchased at least six months after the recalls were released, and two-thirds still contained banned substances—17 out of 27—with the same pharmaceutical adulterant found originally, and six containing one or more additional banned ingredients. Aren’t the manufacturers penalized for noncompliance? Yes, but “fines for violations are small compared to the profits.”

One of the ways supplement makers can skirt the law is by labeling them as “not intended for human consumption;” for example, labelling the fatal fat-burner DNP as an industrial or research chemical. That’s like how designer street drugs can be sold openly at gas stations and convenience stores as “bath salts.” Another way is to claim synthetic stimulants added to slimming supplements are actually natural food constituents, like listing the designer drug dimethylamylamine (DMAA) as “geranium oil extract.” The FDA banned it in 2012 after it was determined DMAA was “not found in geraniums.” (And who eats geraniums anyway?) Despite being tentatively tied to cases of sudden death and hemorrhagic stroke, DMAA has continued to be found in weight-loss supplements with innocuous names like Simply Skinny Pollen, made by Bee Fit with Trish.

There is little doubt that certain banned supplements, like ephedra, could help people lose weight. “There’s only one problem,” wrote a founding member of the American Board of Integrative Medicine: “This supplement may kill you.”

Are there any safe and effective dietary supplements for weight loss? When popular slimming supplements were put to the test in a randomized placebo-controlled trial, not a single one could beat out sugar pills. A systematic review of systematic reviews of diet pills came to a similar conclusion; that none appear to generate appreciable impacts “on body weight without undue risks.” That was the conclusion reached in a similar review out of the Weight Management Center at Johns Hopkins recently, which ended with this: “It is fitting to highlight that perhaps the most general and safest alternative/herbal approach to weight control is to substitute low-[calorie] density foods for high-[calorie] density and processed foods, thereby reducing total [calorie] intake.” (In other words, more whole plant foods and fewer animal foods and junk.) “By taking advantage of the low-[calorie] density and health-promoting effects of plant-based foods, one may be able to achieve weight loss, or at least assist weight maintenance without cutting down on the volume of food consumed or compromising its nutrient value.”

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Motion graphics by Avocado Video