Is curcumin effective for weight loss?

The prevalence of obesity has continued to increase over the past century. According to the latest estimates, approximately 40% of the US population, 26% of the UK population, and 15% of French people are obese. Obesity is the main risk factor for developing diabetes, and it is estimated that nearly as many people suffer from diabetes 5% in France.

Losing weight is one of the best strategies to reduce your risk of diabetes and other chronic diseases, such as cardiovascular disease. Even if this is modest, it translates into a significant benefit in terms of risk reduction. For example, losing one kilogram of fat from starting weight can reduce the relative risk of developing diabetes by 16%.⁽¹⁾.

Changing your habits, especially by improving your diet and exercising regularly, is one of the best strategies to reduce your weight and your risk of developing obesity-related diseases such as diabetes.⁽²⁾. In addition to these aspects, many natural substances found in some foods (also called “nutrients”) have been shown to be beneficial for weight loss. Curcumin, one of the bioactive compounds found in the spice turmeric, has been shown to increase fatty acid oxidation.⁽³⁾reduces the biosynthesis of fats⁽⁴⁾ It increases basal metabolism⁽⁵⁾ In particular, thanks to its effect on the AMPK protein, as shown in Chart 1. Furthermore, several clinical trials have shown that curcumin supplements can promote weight loss.⁽⁶⁾Loss of body fat⁽⁷⁾ Low body mass index. However, other clinical trials have found no effect on weight loss⁽⁸⁾⁽⁹⁾.

Many of these trials have been conducted with different doses, formulations, and durations, so it is difficult to determine whether curcumin actually has a beneficial effect. The current study⁽¹¹⁾ What we are going to decode is a systematic review and meta-analysis aimed at evaluating currently available data on the effect of curcumin supplements on weight, BMI, and waist circumference.

Decode the study

Participants

The trials analyzed (which included adults over 18 years of age) aimed to evaluate the effect of curcumin on weight and waist circumference as well as BMI.

A total of 876 subjects (53% women) were examined in these 11 clinical trials. All studies included obese or overweight participants, many of whom had comorbidities such as type 2 diabetes (n = 3), diabetes Non-alcoholic fatty liver (n = 3), and metabolic syndrome (n = 3).

The trials consisted of daily intake of 70 to 1900 mg of different formulations of curcumin and lasted between 4 weeks and 10 months (average 8 weeks). In these 11 trials, 8 measured body weight, 10 BMI, and 6 waist circumference. Sensitivity analyzes were performed to examine the influence of specific studies on the results. Subgroup analyzes were also performed to examine the effect of dose, study duration, and average age of participants.

The quality of studies was assessed using New points, which evaluates randomization and blinding and describes dropouts. 3 out of 11 studies were rated as low quality, while the remainder were rated as high quality. There was also significant heterogeneity in body weight (I² = 86.7%), body mass index (I² = 60.2%), and waist circumference (84.0%).

Results

Curcumin resulted in a weight loss of 1.14 kg and a decrease in BMI of 0.48 compared to placebo. Subgroup analysis showed that study duration is important for weight loss, with studies lasting less than eight weeks showing no significant effect of curcumin on this parameter. In contrast, dosage does not appear to have an effect on pooled weight loss outcomes. Overall, the results were highly reliable compared to sensitivity analyzes and individual studies did not influence the results.

In the combined analysis, curcumin had no effect on waist circumference. However, as you can see in Figure 1, individual subgroup analyzes showed that curcumin led to a greater reduction in waist circumference with:

• Doses of at least 1,000 milligrams (2.55 mg) per day.
• Studies lasting eight weeks (3.71 cm).
• Studies conducted on participants who were overweight, but not obese (3.71 cm).

Sensitivity analysis showed that no study had a significant effect on the overall results.

This large systematic review, meta-analysis, and meta-regression showed that curcumin supplements may have modest, but not insignificant, beneficial effects on weight, BMI, and waist circumference. Meta-regression showed that dose, duration, and initial weight had no effect on weight and BMI results, but initial weight had an effect on BMI values ​​and waist size. Sensitivity analysis revealed that no single study had a significant impact on the results. Egger regression did not reveal significant bias.

This study thus allows us to answer an important clinical question: Can curcumin help reduce body weight, BMI, and waist circumference? Based on the available information, it seems that the answer is: yes. Curcumin can cause a moderate but noticeable decrease in weight (about 1 kg) and BMI (about 0.5). Since weight loss is one of the best ways to reduce the risk of many chronic diseases, curcumin may provide some benefits.

A major limitation of this study is that most trials used unprepared curcumin, which has low bioavailability. Other forms of curcumin, such as those containing a hydrophilic carrier (phytosome), have approximately 50 times greater bioavailability. Therefore, the results of the present analysis may underestimate the potential of curcumin formulations with much higher bioavailability.

Furthermore, the results of these meta-analyses cannot be reliably applied to specific groups of people, such as athletes, thin people (because none of the trial participants had a BMI less than 25), or people with high Very obese, because the highest values ​​mentioned were those related to moderate obesity, not morbid obesity.

The current analysis supports a previous systematic study⁽¹²⁾ on curcumin which reported similar benefits on body weight. It also supports randomized controlled trials proving that curcumin can increase weight loss by approximately 2-5%.⁽¹³⁾ In people with obesity and metabolic syndrome. Additionally, consistent with several other studies, the current study found no effect of curcumin on waist circumference.

However, these results contradict a study that found plant-based curcumin⁽¹⁴⁾which has greater bioavailability than unprepared curcumin, resulted in a reduction in waist circumference.

There are several mechanisms by which curcumin may cause weight loss. Curcumin may increase fatty acid oxidation by regulation Peroxisome proliferator-activated receptor γ (PPAR-γ)⁽¹⁵⁾. Curcumin has also been shown to reduce fatty acid biosynthesis⁽¹⁶⁾. In mice, curcumin has been shown to have a pleiotropic effect on body fat regulation mechanisms as well as fat metabolism. For example, curcumin regulates carnitine palmitoyl transferase 1 (CPT-1).⁽¹⁷⁾ In proportion to the dose. CPT-1 is a key enzyme involved in transferring fatty acids to mitochondria for oxidation. Curcumin also inhibits the differentiation of pre-adipocytes into mature adipocytes⁽¹⁸⁾.

Although obese people were not directly evaluated in the current analysis, curcumin may also benefit them, mainly due to its anti-inflammatory properties.⁽¹⁹⁾. In fact, inflammation is one of the typical manifestations of excess adipose tissue and plays a role in insulin resistance, immune system modulation, and overall metabolic disturbance in people with obesity. In obese mice, curcumin has been shown to reduce the activity of the transcription factors that regulate inflammation, NF-kB.⁽²⁰⁾With increased expression of the anti-inflammatory hormone adiponectin⁽²¹⁾.

What to remember

The current analysis supports previous systematic studies showing that curcumin has a beneficial effect on body weight. There are several hypothesized mechanisms by which curcumin exhibits its weight loss properties: reducing fatty acid biosynthesis, increasing fatty acid oxidation, and inhibiting the differentiation of pre-adipocytes into mature adipocytes. Additionally, curcumin has anti-inflammatory properties that may have beneficial effects beyond weight loss.

Your frequently asked questions

Does curcumin have an effect on blood sugar?

Yes. Curcumin has been shown to have hypoglycemic effects in both humans and animals with insulin resistance. In particular, it lowers blood sugar, improves insulin resistance and regulates key enzymes of glucose metabolism (glucokinase) in diabetic mice.⁽²²⁾. In humans, curcumin has also been shown to reduce insulin resistance and blood triglyceride levels.⁽²³⁾.

What is the most bioavailable form of curcumin?

Although unprocessed curcumin has a very low bioavailability, there are many different formulations that increase its bioavailability. According to a recent analysis⁽²⁴⁾There are 11 different formulations on the market that have been shown to improve bioavailability. Most formulations rely on several different methods: conjugation with black pepper (piperine), nanoparticles and nanoemulsions, plant particles, or conjugation with lipids. Nanoemulsions⁽²⁵⁾ They consist of lipids, emulsifying agents (substances soluble in fat and water) and aqueous phases and are systems used in pharmaceuticals for sub-micron size particles. Phytosomes⁽²⁶⁾ They are complexes of an active ingredient (eg curcumin) and a phospholipid (eg lecithin).

As you can see in Chart 2, different formulations have been shown to increase relative bioavailability by approximately 10 to 100 times, depending on the formulation.