Anthocyanins are associated with reducing the risk of cognitive decline as we age. According to the WHO, around 50 million people are currently living with dementia. A rapidly growing public health challenge, the WHO has estimated that the number of people affected will grow to around 82 million by 2030. Although age is the most important risk factor for cognitive decline, dementia is not an inevitable outcome of our aging process. Recent research has shown there is a relationship between several of our lifestyle choices and the development of cognitive decline including lack of exercise, unhealthy diet and harmful use of alcohol and tobacco. The good news is that we can modify these risk factors with the aim of delaying or slowing cognitive decline and dementia.
Diet is one of the most important risk factors that can be modified. For example, doctors from Harvard Medical School have recommended we eat five foods which have been linked to slowing cognitive decline and achieving “better brainpower”. They are green vegetables, fatty fish, berries, tea/coffee and walnuts.
There is growing research evidence to suggest a diet containing anthocyanins may help reduce the risk of cognitive decline as we age. A large population study published in 2012 in the Annals of Neurology assessed cognition and diet in 16,010 female participants age 70 or older. Women who had consumed a higher anthocyanin diet (from berries) showed a delay in cognitive aging by up to two and a half years.
A recent study recently published by scientists from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Massachusetts, showed that older adults who regularly ate higher amounts of anthocyanin-rich foods (such as berries) had a significant four-fold reduction in developing Alzheimer’s Disease and Related Dementias (ADRD). (Many studies have looked at the association between anthocyanin intake and cognition over the short term, however this study focused on the role of dietary anthocyanins and the risk of developing ADRD over a 20-year period.)
The research published in the American Journal of Clinical Nutrition followed 2,800 adults aged over 50 for twenty years. The participants were part of the Framingham Heart Study, a long-term study exploring cardiovascular and other disease risk factors in residents of the city of Framingham, Massachusetts. The researchers examined the long-term relationship between eating flavonoid-rich foods and the risks of developing ADRD. The researchers looked at six main flavonoid subclasses consumed in the American diet, including anthocyanins (found in berries and red wine), flavonols (in apples and pears), and flavonoid polymers (in tea). The study participants filled in detailed food frequency questionnaires completed as part of 4 yearly medical assessments. The researchers analyzed the long-term intake of these six flavonoid subclasses and the number of ADRD diagnoses in the study participants. They found that lower consumption (15th percentile or lower) of three of the flavonoid subclasses was linked to a higher risk of dementia than the highest intake (greater than 60th percentile).
The most striking results were associated with anthocyanins. Low intake of anthocyanins (no berries per month) was associated with a four-fold risk of developing ADRD, compared to those with the highest anthocyanin intake (equivalent to 7.5 cups of berries per month or 16.4mg anthocyanins per day). Low intake of flavonols (one and a half apples per month) and flavonoid polymers (no cups of tea) were each associated with twice the risk of developing ADRD compared to the highest intakes (8 apples and pears or 19 cups of tea per month). The same pattern of associations was specifically seen with Alzheimer’s disease for flavonols and anthocyanins but not for flavonoid polymers.
It is thought flavonoids exert their beneficial neuroprotective effects by a combination of actions. These include protecting our brain cells from neurotoxins, combating neuroinflammation, improving brain blood flow, and also via their antioxidant activity.
The study concludes that higher long-term dietary intakes of flavonoids are associated with lower risks of ADRD in American adults. Anthocyanins were associated with the most significant risk reduction.
One of the leading researchers, Dr. Paul Jacques, says that the good news is that 50 years old is not too late to make positive dietary changes.
“The risk of dementia really starts to increase over age 70, and the take-home message is, when you are approaching 50 or just beyond, you should start thinking about a healthier diet if you haven’t already.”
THE HASKAP RESEARCH
The first pilot clinical study on Haskap berries was published by a team from the University of Reading in the European Journal of Nutrition, December 2018: A pilot dose–response study of the acute effects of haskap berry extract (Lonicera caerulea L.) on cognition, mood, and blood pressure in older adults
The study had a double-blind crossover design and looked at the acute effects of three Haskap berry doses and a sugar matched placebo on 20 older adults, age 62-81 years. Results showed improvements in cognition (word recall and recognition i.e. episodic memory effects) and diastolic blood pressure, with higher doses appearing more effective. The researchers wrote that the positive blood pressure result was probably caused by dilation of blood vessels, as observed in previous anthocyanin research.
- Risk reduction of cognitive decline and dementia: WHO guidelines. Geneva: World Health Organization; 2019. Licence: CC BY-NC-SA 3.0 IGO.
- Dietary intakes of berries and flavonoids in relation to cognitive decline. Devore EE, Kang JH, Breteler MM, Grodstein F.Ann Neurol. 2012 Jul;72(1):135-43.
- Paul F Jacques, Rhoda Au, Jeffrey B Blumberg, Gail T Rogers, Esra Shishtar. Long-term dietary flavonoid intake and risk of Alzheimer’s disease and related dementias in the Framingham Offspring Cohort. The American Journal of Clinical Nutrition, 2020; DOI: 1093/ajcn/nqaa079
- A pilot dose–response study of the acute effects of haskap berry extract (Lonicera caerulea) on cognition, mood, and blood pressure in older adults. Bell, L. & Williams, C.M. Eur JNutr (2018). https://doi.org/10.1007/s00394-018-1877-9