Plant polyphenols: are they the new magic bullet?

Area of Science:

• Nutritional Science
• Molecular Biology
• Epidemiology

Background:

• Epidemiological studies link fruit and vegetable consumption to reduced risk of mortality from cancer and heart disease.
• The specific bioactive components responsible for these health benefits and their mechanisms of action remain largely undetermined.
• Marketing claims for plant-based health products, particularly those containing polyphenols, often outpace scientific evidence.

Purpose of the Study:

• To critically evaluate the scientific evidence supporting the health claims of plant-based compounds, specifically polyphenols.
• To discuss the uncertainties surrounding the protective roles and mechanisms of action of fruit and vegetable components.
• To provide guidance for consumers regarding the interpretation of health claims associated with plant-based supplements.

Main Methods:

• Review of epidemiological evidence on fruit and vegetable intake and mortality.
• Analysis of scientific literature on the properties, bioavailability, and metabolism of plant polyphenols.
• Examination of in vitro studies on polyphenol toxicity and mutagenicity.

Main Results:

• While epidemiological data suggest benefits, the specific protective components in fruits and vegetables are not fully identified.
• Plant polyphenols exhibit variable bioavailability and extensive metabolism, complicating direct health benefit assessments.
• Some polyphenols demonstrate toxicity and mutagenicity in cellular systems, warranting cautious interpretation of their health effects.

Conclusions:

• Increased intake of whole fruits and vegetables is recommended over reliance on specific plant compounds.
• Consumers should exercise caution regarding exaggerated marketing claims for plant-based 'health elixirs'.
• Further research is needed to elucidate the precise biological activities and metabolic fate of polyphenols for accurate health assessments.