One of the best guides to food variety is colour. And for colour, it is a group of natural plant chemicals called anthocyanins that are getting a lot of attention for their beneficial effects on our brain. Anthocyanins are the pigments that give red, purple, and blue plants their rich colouring. They’re responsible for putting the ‘blue’ into blueberries and a bunch of other berries as well as some foods with bright red-orange colouration. In this podcast, I’ll look at the science behind how these anthocyanins can help keep your brain healthy and functioning well throughout life.
Welcome to the Thinking Nutrition podcast. My name is Tim Crowe and I'm a career researcher, educator and science communicator with most of this spent in the field of nutrition. How do you make sense of so much conflicting information in the field of nutrition? While I don’t profess to have all the answers in an area that is continually changing as research changes, you can count on what is covered in this podcast to be based on the whole field of nutrition science, not just selective areas that support a particular way of thinking. And this podcast will always be free from any commercial product tie ins, endorsements or advertisements. Just credible nutrition science presented in plain and simple language and then translating this into what it means for your health. So on with today’s show.
There is so much to be gained from having plenty of plant-based foods in your diet. While it may be tempting to stake your claim that health is all about the superfood du jour, it is the variety of foods you eat that are key to good health. But there may just be something to the claims made about berries, in particular, the humble blueberry and similar foods like it, that are rich in a group of natural plant chemicals called anthocyanins.
Anthocyanins are abundant in berries and give these foods their bright blue, red and purple colours depending on the pH of the food. You’ll also find anthocyanins in purple corn, red cabbage, purple grapes, blackcurrants, blackberries, black raspberries and cherries.
Anthocyanins have been getting a lot of attention because of their antioxidant and anti-inflammatory properties. So how could the anthocyanins in berries be of benefit for the brain? The high amounts of antioxidants in berries may be one way they help protect brain cells from damage. In cell and animal models, berries change the way that neurons in the brain communicate in pathways involved in inflammation and cell survival. Yet more research has shown that in humans, berries can also improve cognition, motor control and enhance neuroplasticity.
An ageing population means a greater number of diseases linked to older age such as dementia. There is no certain way to prevent dementia, but scientists have been looking closer at the role that diet can play in reducing the risk of developing it and foods like blueberries rich in anthocyanins have attracted their interest.
However, in ageing Western populations, the dietary intake of anthocyanins is declining while the risk of neurodegenerative diseases is rising. Consequently, supplementation with anthocyanins could be helpful to sustain or even improve cognitive function. What does the evidence say?
One clinical trial that attracted a lot of media attention used a concentrated form of blueberry juice that was high in anthocyanins. The trial involved 26 healthy adults aged between 65 and 77. And I’ll link to the study in the show notes https://pubmed.ncbi.nlm.nih.gov/28249119
Half of the people drank a concentrated blueberry juice drink each day for 12 weeks. The blueberry concentrate was equal to eating 230 grams of whole blueberries each day. The other half of the volunteers drank a placebo drink that had a blackcurrant taste, but no anthocyanins in it. After 12 weeks, people drinking the blueberry juice showed improvements in cognitive function, blood flow to the brain and activation of brain areas linked with cognitive function. There was also evidence suggesting an improvement in working memory too.
Several other studies have also found that blueberries may have benefits for the brain by keeping it active and improving mood with improved mood and mental sharpness seen within a few hours of drinking a blueberry drink compared to a placebo drink.
And to illustrate this research field, a just-published systematic review has analysed 49 randomised controlled trials that examined the effects of anthocyanin supplementation on cognitive performance as well as cardiometabolic risk factors. Many of the risk factors for dementia are related to metabolic disease so anthocyanins could be helping out here too.
The finding from the review was that anthocyanins improved cognitive performance in specific areas such as memory and, in some cases, attention, psychomotor speed and executive function as well. There was also consistent evidence that anthocyanins improved vascular function and blood pressure. And I’ll link to the review in the show notes https://pubmed.ncbi.nlm.nih.gov/34204250
The studies in the review used berry extracts with doses of anthocyanins ranging from 10 up to 500 mg. For perspective, 100 grams of blueberries will give you several hundred milligrams of anthocyanins so you can see how just by eating a variety of berries and other foods rich in anthocyanins you can get plenty of these in your diet from whole foods alone.
If you caught my recent podcast on the MIND diet and brain health back in episode 76, it was all about the sorts of eating patterns that may reduce the risk of brain diseases like dementia which in this case is a variant of a Mediterranean-style diet with a bit of tweaking. A key food present in the diet and is specifically profiled is berries. Now you know why.
Fresh blueberries are great, but for convenience and price and when they are out of season, you can’t go past having frozen blueberries on hand. And as a bonus for choosing frozen, because they are processed and frozen soon after picking, the nutrient losses are small and the drying and freezing process has no impact on the antioxidant activity of anthocyanin extracts over several months of storage. In fact, the ice crystals that form during freezing can disrupt the structure of the plant tissue, making the anthocyanins more available. This may not be such a surprise when you consider that blueberries thrive under very cold overnight temperatures as part of their yearly growth and flowering cycle.
An ageing population means a greater number of diseases linked to older age and brain decline such as dementia. There is no certain way to prevent dementia, but scientists are looking closely at the role that diet can play in reducing the risk of developing it. Choosing a diet high in a variety of fruits and vegetables and including some delicious blueberries and other berries may go some way to reducing the risk of declining brain function in older age. And when it comes to blueberries, this is a case where the superfood hype may have a bit of solid science to support it.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.