Evidence supporting the use of: Flavan-3-ols
For the health condition: Colds (prevention)

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Synopsis

Source of validity: Scientific
Rating (out of 5): 2

Flavan-3-ols, a subclass of flavonoids found in foods such as tea, cocoa, apples, and berries, have been studied for their potential role in the prevention of colds and upper respiratory tract infections (URTIs). The evidence for their effectiveness is limited but growing. A key source is a 2022 Cochrane systematic review (Cochrane Review, 2022) which analyzed several randomized controlled trials examining polyphenol-rich flavan-3-ol supplements (including green tea extracts) for URTI prevention. The review found a modest reduction in the number of people experiencing one or more URTIs, and a slight decrease in the duration of symptoms, compared to placebo. However, the quality of evidence was rated as low to moderate due to small sample sizes, risk of bias, and heterogeneity between studies.

Mechanistically, flavan-3-ols are thought to support immune function through their antioxidant and anti-inflammatory effects, and by promoting beneficial changes in gut microbiota that may modulate immunity. Despite these plausible mechanisms, the clinical impact appears modest, and the evidence is not strong enough to recommend flavan-3-ols as a primary preventive measure for colds. There is no substantial tradition of using isolated flavan-3-ols for cold prevention, though teas rich in these compounds have traditional use. In summary, there is emerging scientific evidence, but it remains limited in quality and consistency.

More about flavan-3-ols
More about Colds (prevention)

Other ingredients used for Colds (prevention)

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bamboo
basil
berry flavor
beta-pinene
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black cumin
black currant
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phenolic acids
pineapple
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Products containing flavan-3-ols

We currently have no products on Vitabase that contain this ingredient.