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LIFESTYLE
MEDICINE

Dietary Weight Loss Supplements:

What does the evidence say?

By Edwin Davila, DO, MS, CISSN
CDC population data from 2022 showed 22 variable disclosed, or sometimes undisclosed, dosages. The following

states have an adult obesity prevalence at
are several of these ingredients and what the data tells us.
or above 35 percent, compared to 19 states

in 2021. This starkly contrasts with 10 years prior, when no state had Berberine
an adult obesity prevalence at or above 35 percent. Furthermore, obe- Berberine is a bioactive alkaloid isolated from a variety of plants. Re-
sity in the United States is estimated to affect 100.1 million (41.9 per- search models of varying designs have identified several possible effects,
cent) adults and 14.7 million (19.7 percent) children, accounting for ranging from impacting the gut microbiota, improving insulin resist-
1
approximately $147 billion in annual healthcare costs. Significant ance, and decreasing adipocyte proliferation. Its popularity has in-
strides have been made in developing pharmacologic agents assisting creased substantially due to its being dubbed "nature's Ozempic®" by
in weight management. Data from the STEP and SURMOUNT trials social media influencers. While the initial data is promising, trials in-
have shown that Incretin agonists generate substantial weight reduc- dicating benefits have few participants and are short in duration. Cur-
tion. Unfortunately, barriers such as significant costs, difficulty with rently, no evidence supports claims of reductions in weight to a degree
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prior authorization and medication shortages limit their use. As a re- anywhere near those of injectable GLP-1 and associated Incretins.
sult, many patients turn to dietary supplements advertised as weight-
loss-promoting agents in the hope of helping them reach their goals. Garcinia Cambogia
It is estimated that approximately 15 percent of U.S. adults have used The claimed ergogenic effect of this agent is due to the hydroxycitric
a "weight-loss" supplement at some point in their lives, leading to an an- acid (HCA) extracted from the fruit in which it is produced. HCA has
nual spending of over $2.1 billion. The products' forms vary considerably been reported to inhibit ATP citrate lyase, an extramitochondrial en-
from pills, liquids, powders, gummies, bars, etc. A quick Google search zyme that provides the two carbon units required in the initial steps of
of weight loss supplements displays a plethora of strategic marketing fatty acid and cholesterol biosynthesis. This inhibition would, in theory,
campaigns with robust verbiage with examples like "increased thermo- decrease de novo lipogenesis and reduce body fat. In vitro rat studies
genesis," "advanced fat-burning potential" and "body recomposition showed suppression of food intake and reduction in weight. However,
agent," just to name a few. While the FDA regulates dietary supplements, a review of numerous randomized placebo-controlled trials showed no
the focus is on the ingredients they are composed of, confirming the significant weight loss compared to placebo, with several case reports
4,5
component's safety and whether it is in line with the Dietary Supple- identifying hepatotoxicity and the need for liver transplantation.
2
ment Health and Education Act (DSHEA). The FDA does not require
a premarket review of the finished product, and leaves considerable lee- Raspberry Ketones
way for manufacturers in combining and dosing ingredients. Many The associated fat-burning potential of raspberry ketones is based on
products utilize a "Proprietary Blend" format on their nutrition label, a speculated sympathomimetic effect on adipocytes, which may in-
which further complicates transparency. This method combines several crease fatty acid oxidation and suppress lipid accumulation similar to
ingredients and provides the total combined dose as one number with- epinephrine. This has been based on rat models showing reduced adi-
out indicating how much of a particular ingredient is being used. posity when utilized. However, issues associating these findings with
The question remains: what are these products' efficacy, and what tri- human application are observed when comparing the dose-to-weight
als can be referenced to back their claims? This question was addressed ratio used in rats and the recommended dose advertised in supplements.
by the U.S. Government Accountability Office, which concluded that While many brands recommend a daily dose of 100 – 200mg, animal
"little is known about whether weight loss supplements are effective, models would indicate that human consumption would need at least
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but some supplements have been associated with the potential for phys- five times that amount to possibly create a benefit.
3
ical harm." A review of the top-selling weight loss supplements through Beyond just the lack of peer-reviewed evidence to substantiate claims,
several online retailers shows a standard collection of ingredients in concerns of safety need to be addressed. Some ingredients in weight-

14 SAN ANTONIO MEDICINE • January 2024