Nutrition Notes

Nutritional Supplementation in the Fight Against Obesity

A paper published late last year in the New England Journal of Medicine presented some alarming predictions about the prevalence of obesity in the US in the next decade. According to a data analysis conducted by researchers at Harvard University’s T.H. Chan School of Public

Health, nearly half of all adults in the US will have obesity by 2030. Rates of obesity are predicted to exceed 50 percent in 29 states, and no state is predicted to have an obesity prevalence of less than 35 percent. Researchers predicted that severe obesity—defined as a body mass index (BMI) ≥35—will afflict close to 1 in 4 adults, with a prevalence exceeding 25 percent in 25 states. Obesity affects individuals, families, communities, and has even been called “a national security issue” by senior US military leaders. Changing diet and exercise habits is fundamental to getting to and maintaining a healthy weight. But anyone who’s fought valiantly against unwanted pounds knows how difficult it is to be victorious. Let’s take a look at some compounds that may be able to offer some needed support in this challenging struggle.      


It’s nearly impossible to lose body fat in the absence of altering the patterns that led to obesity in the first place. Very low-carbohydrate ketogenic style diets have been shown to be effective for improving obesity and several comorbid conditions. Moreover, this way of eating appears to facilitate weight loss without impairing capacity for physical activity, potentially making it an especially effective intervention. Beyond this, though—and keeping in mind that a very low-carb way of eating may not appeal to everyone—a host of nutrients and other compounds have been shown to aid in weight loss and supporting a healthy metabolism. 


7-oxo DHEA

One such compound is 3-acetyl-7-oxo DHEA, a stabilized form of 7-oxo DHEA. Once ingested,

acetyl-7-oxo DHEA is cleaved to 7-oxo DHEA, a DHEA metabolite naturally found in the body, and usually referred to by the name “7-keto-DHEA” or sometimes just “7-keto.” (The name refers to the structure of the molecule and is unrelated to ketogenic diets.) With regard to supporting fat loss, animal and in vitro studies show that 7-oxo-DHEA induces an increased proton leak through the mitochondrial inner membrane, which may contribute to an enhanced thermogenic effect. 7-oxo-DHEA may induce uncoupling proteins, thereby reducing mitochondrial membrane potential and increasing substrate oxidation rates—meaning, it may take more “calories” to produce the same amount of ATP. This would increase energy expenditure at the cellular level even in the absence of an increase in deliberate physical activity.


Incorporating exercise with 7-oxo DHEA supplementation may be even more effective, though. A study of overweight adults showed that including 7-oxo-DHEA in a protocol calling for an 1800 calorie per day diet plus three 60-minute supervised exercise sessions weekly for eight weeks resulted in significantly larger reductions in body weight and body fat compared to the same regimen with placebo. The study also found that in those taking 7-oxo-DHEA, levels of triiodothyronine (T3) increased significantly compared to those on placebo, but with no significant changes to T4 or TSH, suggesting no adverse changes to thyroid function, at least in the short term. Higher levels of T3 could have a beneficial impact on overall metabolic rate, which may be responsible, in part, for the observed effects of 7-oxo-DHEA.


Garcinia cambogia

The dried fruit rind of Garcinia cambogia (GC), also called Malabar tamarind, is a source of hydroxycitric acid (HCA). This compound has been demonstrated to inhibit ATP-citrate lyase, a key enzyme in fatty acid and triglyceride synthesis. It also favors the storage of glucose as glycogen in the muscles and liver rather than being converted to triglycerides for storage in adipose tissue. Data from human trials show GC has a small but significant impact on fat oxidation and body weight—and small is better than nothing. Considering how difficult it is for many people to get rid of stubborn body fat, any possible edge may be welcome. In 60 human subjects given a 2,000 kcal/day diet, who also participated in a walking program and were given a placebo or supplement providing 2,800 mg HCA/day in divided doses before meals, body weight and BMI had decreased by 5.4% and 5.2%, respectively, by the end of the 8-week study. “Food intake, total cholesterol, LDL, triglycerides and serum leptin levels were significantly reduced, while HDL and serotonin levels, and excretion of urinary fat metabolites (a biomarker of fat oxidation) significantly increased.” 


Garcinia cambogia may be helpful for preferentially targeting abdominal obesity—the visceral fat that is believed to be more harmful than subcutaneous fat elsewhere in the body. In a study of overweight adults with visceral fat area > 90cm2, 12 weeks of supplementation with GC extract taken before meals resulted in significant decreases in visceral and total body fat. Body weight and BMI were numerically but not significantly lower compared to placebo. With a significant decrease in visceral fat but not in body weight or BMI, this highlights the importance of distinguishing between fat loss and weight loss. The numbers here were small overall, so this study doesn’t cement GC as a primary go-to intervention for fat loss, but some individuals must fight tooth and nail for every ounce lost. These dieters—disciplined and dedicated, yet unsuccessful—may benefit from any possible edge.   


Green tea extract (EGCg)

Green tea extract has been shown to enhance thermogenesis and increase fat oxidation. Green tea extract contains caffeine, but research indicates that the effects of the extract go beyond the influence of caffeine, alone. Administration of a green tea extract containing 90 mg EGCg with 50 mg of caffeine three times per day to healthy, sedentary young men increased 24-hour energy expenditure (EE) by 3.5% compared to placebo and 2.8% compared to 50 mg of caffeine alone. The increase in EE was due to more than the presence of the caffeine, as the combination of caffeine and EGCg led to a greater increase in EE than the caffeine alone. 


In the study mentioned above, the percentage of calories derived from fat for the 24-hour EE was 41% in the green tea extract group versus 31% in the placebo group and 34% for caffeine alone, while following the same diet and sedentary activity pattern. The decreased respiratory quotient (RQ) in the green tea extract group compared to the placebo and caffeine groups (0.852 versus 0.881 and 0.873, respectively) demonstrated a metabolic shift to oxidizing more fat and less glucose. (A lower RQ indicates more energy being derived from fat; a higher RQ indicates greater energy derived from carbohydrate.) The percentage of energy derived from carbohydrates was 45% in the green tea group versus 55% in the placebo group and 53% in the caffeine group. The percentage of energy derived from fat was 41.5% in the green tea group compared to 31.6% in the placebo group and 33.8% in the caffeine group. This shows again that EGCg with caffeine exerts effects greater than those induced by caffeine alone: 


“Of particular interest in this study was that the effects of the green tea extract in enhancing thermogenesis and fat oxidation could not be explained solely on the basis of its caffeine content because treatment with an amount of caffeine equivalent to that in the extract failed to alter EE, RQ, or substrate oxidation. The implication of this finding is that these metabolic effects resulted from ingredients other than caffeine in the green tea extract.” (Source)


One biological action of green tea polyphenols is believed to be the inhibition of the COMT enzyme, which degrades norepinephrine, thus prolonging its lipolytic effect. Other research corroborates an increase in EE of about 2 percent from supplementation with green tea extract and caffeine. A small difference, yes, but it’s possible this could translate into a clinically relevant increase over the long term, particularly if combined with other interventions. 


With predictions for half the adults in the US to be living with obesity in the next ten years, compounds that can offer even a slight advantage may be considered as part of a multifaceted strategy for battling excess weight. Several slight advantages combined can add up to bigger effects.