12 January - 20 June 2016

Higher flavonoid intake may be associated with lower depression risk

A study published in the American Journal of Clinical Nutrition has investigated the association between intake of dietary flavonoids and depression risk in midlife and older women. Dietary flavonoids are a group of polyphenolic compounds that occur naturally in plant foods and are commonly consumed in fruit, vegetables, grains, herbs and beverages. High intake of flavonoids has been associated with lower risk health outcomes.

A study published in the American Journal of Clinical Nutrition has investigated the association between intake of dietary flavonoids and depression risk in midlife and older women.  Dietary flavonoids are a group of polyphenolic compounds that occur naturally in plant foods and are commonly consumed in fruit, vegetables, grains, herbs and beverages.  High intake of flavonoids has been associated with lower risk health outcomes. 

In this current study Chang et al. examined data from 82,643 women who at baseline were depression free and involved in the Nurses’ Health Study (NHS) (aged 52-80 years) and the Nurses’ Health study II (NHSII) aged 36-55 years.  Every two to four years, dietary intake was recorded using food frequency questionnaires.   Flavonoid rich foods were split into different subclasses.  The team focused on flavonols, flavones, flavanones, flavan-3-ols monomers, anthocyanins, and polymers.  Total flavonoids were defined as the sum of these subclasses.  Proanthocyanidins were examined separately. Depression was defined as diagnosed depression or antidepressant use and was self-reported in response to periodic questionnaires.

During the 10 years of follow up 10,752 incident depression cases were identified.  Chang et al. state that at baseline participants who had higher total flavonoid intake had a healthier lifestyle behaviour, with polymer (proanthocyanidins, theaflavins and peonidin) and flavone (luteolin and apigenin) subclasses contributing most and least respectively to total flavonoid intakes.  Compared to those with the lowest amounts of flavonoids in their diet (quintile 1), those who were in the highest quintile (5) have a significant 7-10% reduction in depression risk.  High intake of total polymers and proanthocyanidins were associated with a lower risk of depression in the NHS, although these results were not seen in the NHSII.  Again only seen in the NHS study, a greater intake of total flavonoids was associated with lower depression risk.  After taking into account other nutrients (omega-3 fatty acids, vitamin C, vitamin B6, vitamin B12 and folate) in flavonoid rich food that may be linked with depression, Chang et al. report that their findings remained unchanged.

Compared to citrus intake of <1 serving/wk, intake of ≥ 2 servings/d were associated with an 18% reduction in depression risk.  This finding was the same for both cohorts. Compared to those who consumed either none or little tea, consuming ≥ 4 cups of tea per day was significantly associated with 12% lower risk of depression.

In discussion the scientists state that their results are “in line with evidence of favourable relations of flavonoids to other later life brain outcome, including cognitive decline and Parkinson disease.”  They note that although the link between flavonoid consumption and depression are unclear, mechanisms may include “modulating signalling pathway responsible for maintain neuron survival and inducing synaptic plasticity.”  Chang et al. also suggest indirect mechanisms such as improving blood flow and reducing oxidative stress.  In conclusion the authors reiterate their findings that higher flavonoid intake may be associated with lower depression risk although further studies are needed to confirm these associations.   

RSSL can carry out simple flavonoid screens. For more information please contact Customer Services on +44 (0) 118 918 4076 or email enquiries@rssl.com

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