A review article published within the journal Foods provides an in depth overview of the therapeutic effectiveness of phytonutrients in obesity.

Background

Obesity is a metabolic disease brought on by complex interactions between genetic, environmental, and lifestyle aspects. A person with a body mass index (BMI) above 30 is taken into account obese. The prevalence of obesity is exponentially increasing worldwide, making it a big public health concern.

Obesity increases the chance of diabetes, heart problems, neurological disease, and certain malignancies, including breast, liver, pancreatic, kidney, gallbladder, and colorectal cancers.

Phytonutrients present in traditional diets, including the Mediterranean food regimen, Nordic food regimen, African Heritage food regimen, Asian food regimen, and DASH, are known to have useful effects in treating obesity. Nevertheless, the bioavailability of those phytonutrients depends upon various aspects, including intestinal digestion and absorption processes, interactions with other substances, cooking processes, and individual differences. 

Review: A Comprehensive Review of Phytonutrients as a Dietary Therapy for Obesity. Image Credit: marilyn barbone / Shutterstock

Impact of phytonutrients on obesity

Dietary interventions containing plant-based bioactive compounds have change into a promising therapeutic approach for treating obesity mainly due to avoiding opposed negative effects brought on by anti-obesity drugs. Many studies have been conducted to research the anti-obesity effects of those phytonutrients.

Polyphenols

Polyphenols are essentially the most abundant bioactive phytonutrients present in plants. Mechanistically, polyphenols prevent obesity by inhibiting adipocyte differentiation, regulating lipid metabolism, inhibiting appetite, stimulating energy expenditure, and modulating gut microbiota.

Evidence indicates that (-)-Epigallocatechin gallate (EGCG) derived from green tea extracts reduces lipid accumulation by inhibiting adipocyte differentiation and stimulating the conversion of white adipocytes into brown adipocytes. Curcumin has been found to forestall lipid accumulation by increasing lipolysis, stopping fatty acid synthesis, and increasing mitochondrial fatty acid oxidation.

Muscadine grape and muscadine grape wine contain numerous polyphenols and polysaccharides, which might effectively reduce body weight and stop lipid accumulation by increasing antioxidant levels, reducing leptin levels, stopping fatty acid absorption, and inhibiting pro-inflammatory mediators.

In clinical trials, consumption of green tea extract-enriched bread has been found to cut back waist circumference and maintain normal blood pressure.

Phlorizin

Phlorizin is a phytonutrient present in apples. The mix of phlorizin and other strategies has been used to forestall body weight gain and reduce fat accumulation. Mechanistically, phlorizin has been found to suppress enzymes related to fat production and storage and cholesterol synthesis.

Overconsumption of fatty foods alters gut microbiota composition by reducing useful bacterial populations. Evidence indicates that phlorizin helps prevent obesity by maintaining gut microbiota composition and intestinal barrier integrity.

Gallic acid

Gallic acid is a phenolic acid derived from vegetables and fruits. Evidence indicates that gallic acid reduces lipogenesis and fat accumulation by activating adenosine 5′-monophosphate-activated protein kinase/sirtuin 1/peroxisome proliferator-activated receptor γ coactivator-1 (AMPK/SIRT1/PGC-1) pathway. Furthermore, gallic acid has been found to cut back the scale of adipocytes in obese mice.

Nevertheless, studies involving obese human participants have shown that gallic acid cannot reduce body weight and food intake mainly due to its low bioavailability in blood.

Resveratrol and Quercetin

A mixture of resveratrol and quercetin has been found to be effective in reducing body weight gain, adipocyte size, and adipose tissue weight and improving dyslipidemia. These phytonutrients can significantly reduce high-fat diet-induced obesity and inflammation by activating the AMP-activated protein kinase/sirtuin 1 (AMPKα1/SIRT1) signaling pathway.

The mix of resveratrol and quercetin has also been found to inhibit adipogenesis by reducing gene expression of key adipogenic aspects and reducing levels of adipokines, adipsin, and glycolysis-related enzymes.   

Alkaloids

Alkaloids are nitrogen-containing compounds that could be divided into many sub-classes depending on their precursors. Alkaloids exert anti-obesity effects by increasing lipolysis and thermogenesis and reducing appetite. Evidence indicates that alkaloids inhibit adipocyte differentiation by downregulating PPAR, SREPB-1c, and CEBP proteins.  

Cinchonine, an alkaloid, has been found to cut back adipogenesis by downregulating the WNT and galanin-mediated signaling pathways. Other alkaloids, reminiscent of lansiumamide B and mahanimbine, have shown anti-obesity effects by inhibiting adipogenesis, stopping hyperlipidemia and fat accumulation, and reducing inflammation and oxidative stress.

Terpenoids

Terpenoids are the biggest secondary metabolites mostly present in essential oils. Carotenoids are tetraterpene pigments with anti-obesity properties. These metabolites are known to interfere with nuclear receptors to suppress adipocyte development. Lycopene can also be known to forestall obesity by increasing the browning of white adipose tissue, upregulating the expression of thermogenic genes, and reducing the expression of fibroblast growth aspects.

Saponins are triterpene glycosides with emulsifying properties. Panax ginseng, Panax japonicas, and Platycodi radix are essentially the most widely known saponins with proven efficacy in reducing obesity.

Anthocyanins

Anthocyanins are plant-derived color pigments with anti-inflammatory and anti-obesity properties. These compounds exert anti-inflammatory effects by stopping nuclear factor kappa B (NF-κB) activation. Evidence indicates that anthocyanins improve gut dysbiosis, prevent lipid accumulation, reduce weight gain, and control obesity.    

Cyanidin 3-glucoside derivatives have been found to cut back obesity-induced inflammation by inhibiting adipocytokine secretion. These derivatives have been found to forestall obesity by stimulating energy expenditure and regulating lipid metabolism.

Phytonutrient-based anti-obesity food supplements

The utility of phytonutrients could be maximized through the use of their byproducts and waste products. Many phytonutrient-rich parts of plants, reminiscent of peels, stems, and leaves, are discarded as waste products. Bioactive compounds present in these waste products could be used to develop healthy food supplements.

Revolutionary food processing technologies could be implemented to extract these bioactive compounds and incorporate them into regional diets to enhance dietary value.