As the world's largest temperate fruit crop, fruit extracts (especially apple polyphenols, pectin, and flavonoids) occupy an important position in the field of functional foods and dietary supplements. However, is there any basis for the claim that "apples can eliminate toxins from the body" in scientific literature and official health guidelines?
Theoretical mechanism: Potential correlation between apple active ingredients and the liver detoxification enzyme system
1.1 Scientific Definition of Liver Detoxification Enzyme System (Phase I & Phase II)
The detoxification function of the human body mainly relies on the cytochrome P450 enzyme system (CYP450, belonging to Phase I reaction) and the binding enzyme system (Phase II reaction) of the liver, including glutathione S-transferase (GST) and UDP glucuronosyltransferase (UGT). These enzymes convert endogenous and exogenous toxins into easily excreted water-soluble metabolites through oxidation, hydrolysis, and binding reactions.
1.2 Induction of detoxification enzymes by apple polyphenols: animal experimental evidence
According to the search results, the regulatory effect of Apple Polyphenols on the detoxification enzyme system mainly remains at the stage of in vitro cell experiments and animal models. A study published in Food&Function in 2015 showed that apple polyphenol extract has a protective effect on acute carbon tetrachloride (CCl ₄) - induced liver injury in mice, which may involve the activation of the Nrf2/ARE signaling pathway, thereby increasing the mRNA expression levels of phase II detoxifying enzymes (GST and UGT). Another 2010 study also indicated that apple polyphenols can induce GST and UGT activity in colon cancer cells, but did not provide quantitative data on liver tissue.
Quercetin, the main flavonoid compound in apples, has been shown to induce UGT1A1 expression in Caco-2 intestinal epithelial cells. However, such studies have two major limitations: firstly, the concentration of quercetin used in cell experiments (usually 50-200 μ M) is much higher than the peak plasma concentration after daily consumption of apples (about 0.5-1 μ M); Secondly, no intervention studies in the Chinese population between 2020 and 2024 have confirmed that continuous intake of apples leads to a dose-dependent increase in UGT enzyme activity in the liver or intestine.
Industry Practice: Compliance Application Direction of Apple Extract
2.1 Functional Food Development: Evidence-based Health Claims
Although the claim of "detoxification" lacks evidence, apple extract has solid scientific support in the following directions:
- Antioxidant: The ORAC value (oxygen free radical absorption capacity) of apple polyphenols is 2670 μ mol TE/100g, and its effect in reducing oxidative stress markers (MDA) has been confirmed in multiple human trials.
- Intestinal health: Pectin, as a prebiotic, can promote the proliferation of bifidobacteria and improve constipation. A Chinese study in 2022 confirmed that daily intake of 10 grams of apple pectin shortened the intestinal transit time of participants by 18% (p<0.05) after 4 weeks.
- Blood glucose regulation: Phloridzin in apples can slow down glucose absorption by inhibiting the SGLT1/2 transporter. A randomized controlled trial in 2023 showed that consuming apples before meals can reduce the area under the 2-hour postprandial blood glucose curve by 23%.
Plant extract companies should focus on the quantifiable and verifiable efficacy points mentioned above, and use compliant expressions such as "helps with antioxidant" and "maintains normal intestinal function" in product labels, avoiding vague terms such as "detoxification" and "purification".
For more details about apple polyphenols, connect with Serrisha from APPCHEM. (Email: cwj@appchem.cn; +86-138-0919-0407)
Reference
[1]Pectin in Metabolic Liver Disease. Wanchao Hu et al.[2023]
[2]Jingyu Yang, Yan Li et al. "Hepatoprotective effects of apple polyphenols on CCl4-induced acute liver damage in mice.." Journal of agricultural and food chemistry (2010).[2010-04-23]
[3]Risk assessment and monitoring of dinotefuran and its metabolites for Chinese consumption of apples. Yu. [2017-09-26]
[4]Yue Zhang, M. Zeng et al. "Does an apple a day keep away diseases? Evidence and mechanism of action." Food Science & Nutrition (2023). [2023-06-20]