Earlier this month, we reported on a recently published United Kingdom study indicating that regularly consuming berries may reduce the risk of developing Parkinson’s disease. A more recently published study by clinical researchers at the Harvard Medical School supports these findings, concluding that women who eat blueberries and strawberries may slow their rate of mental decline in later life.

The mental health and cognitive benefits of berries may be due to their flavonoid content, according to the medical researchers. Flavonoids can be defined as phytonutrients in plant-based foods that typically contribute to the color of the actual food. Most flavonoids act as antioxidants. More specifically, they assist in neutralizing overly reactive oxygen containing molecules and prevent them from damaging parts of other healthy cells.

Delaying Cognitive Decline in Women by 2.5 Years

During the study, Harvard researchers including Dr. Elizabeth Devore examined the health data of 16,000 women whose average age was 74. All of the women had been involved in the Nurses’ Health Study, a collaborative survey which has been ongoing since 1976. The study participants responded to questionnaires regarding their lifestyle choices and health, and had their cognitive functioning tested by the researchers every two years between 1995 and 2001.

The researchers concluded that the women who consumed larger quantities of strawberries and blueberries slowed their cognitive decline. In fact, test scores in areas such as thinking and memory indicated that these women delayed the mental aging process by as many as 2.5 years, according to the researchers.

Dr. Devore describes her study as the “first epidemiologic evidence” showing that berries may slow the progress of cognitive decline in older women. She hopes the findings will significantly benefit public health since increasing berry intake is such a simple lifestyle modification.

How do Berries Prevent Cognitive Decline?

According to the researchers, the mental health benefits of berries may be explained by their flavonoid content. Flavonoids are antioxidant compounds found in especially high concentrations in strawberries, blueberries and other berries. Since inflammation is one of the causes of cognitive impairment and flavonoids are known to reduce inflammation, it stands to reason that increased berry consumption would delay cognitive decline.

In previous studies, examinations of flavonoids and especially a subgroup of flavonoids called anthocyanins indicated they could improve cognitive function. However, those studies relied on animal testing or human testing with significantly smaller subject pools in comparison to the new Harvard study.

Limitations of the Study

The study was limited in that the researchers only confirmed a link of association, not necessarily of causation. The researchers said that the subjects who displayed increased cognitive functioning may have done so as a result of other lifestyle factors, such as additional exercise or brain-training activities like crossword puzzles.

The researchers said that additional work will be required in order to confirm the findings, though there’s no reason not to eat additional berries in the meantime. There’s also no reason to believe that the findings of the study won’t apply to men, despite the study including only women.

Other Sources of Flavonoids

Blueberries and strawberries aren’t the only food sources that contain flavonoids, although they are among the most concentrated. Other foods rich in flavonoids include the following:

• Cherries

• Cranberries

• Raspberries

• Cabbage

• Tea

• Citrus fruits

• Parsley

• Onions

• Beans

In general, the highest concentrations of flavonoids are found in the colorful parts of a given food, such as in the skin of fruit. One known exception to this is the orange, whose flavonoids reside in the white pulpy material under the skin as opposed to the skin itself.

Brain Foods for Women: The Bottom Line

A recent study by Harvard Medical School indicates that consuming berries can help to prevent or delay symptoms of cognitive decline in older adults. The researchers behind the study believe that compounds found in berries and other foods known as flavonoids may be responsible.

The full text of the study can be found online in the medical journal Annals of Neurology.