Blueberries every day – could it ease low mood in the elderly?

Blueberries are already loved for their sweet taste and all their health benefits – and now researchers are investigating whether they can also lift your mood! A new small study from Harvard points to a possible link between blueberries, gut flora and fewer low moods in older people.

Photo: Joanna Kosinska/Unsplash The small blue berries have long had a good reputation. They contain fibre, vitamin C and anthocyanins, the pigments that give blueberries their deep blue hue and which have antioxidant properties. Now a research team affiliated with Harvard Medical School and Beth Israel Deaconess Medical Center in Boston has investigated whether blueberries can also affect how we feel mentally.

The results are published as a pilot study in the scientific journal The Journal of Nutrition, Health and Aging . It is small, and the researchers themselves are careful to call the findings preliminary – but it opens up exciting questions about how the food we eat may be linked to our mood.

Blueberry powder for three months The study involved elderly people over 65 who led a fairly sedentary life and who had mild depressive symptoms, i.e. not a diagnosed depression. A total of 18 participants completed the study. Participants were randomly assigned to two groups.

One group received 48 grams of freeze-dried blueberry powder every day, which corresponds to roughly two cups of fresh blueberries. The other group received a placebo powder with the same number of calories, but without blueberries. Neither the participants nor the researchers knew who received what.

After three months, the researchers measured the participants' depressive symptoms using an established questionnaire. Both groups felt better Both the blueberry group and the placebo group had fewer depressive symptoms after three months. However, the improvement appeared to be greater and more consistent among those who had eaten blueberry powder.

But – and this is an important but – the difference between the groups was not statistically significant. This means that one cannot rule out that the difference is due to chance. The blueberries also did not affect anxiety or sleep quality compared with placebo.

The gut flora may be a piece of the puzzle Perhaps the most interesting part of the study concerns the gut. The researchers analysed the participants' stool samples and saw that some bacterial genes changed in those who ate blueberries, but not in the placebo group. One of the genes can be linked to a process that, by extension, may contribute to the formation of GABA, a signalling substance that calms the nervous system and has previously been associated with depression.

The researchers themselves describe this link as speculative: it concerns a minor pathway for GABA formation, and they were unable to confirm it with other measurements. The number of different bacterial species and the levels of short-chain fatty acids in the gut did not change. The connection between the gut and the brain is nevertheless one of the hottest research areas right now.

The gut bacteria form substances that can affect inflammation and nerve signals in the body, and fibre-rich food such as blueberries is important nutrition for the good bacteria. Read also: 30 plants a week – the health trend that's easier than it sounds Important things to know about the study The researchers themselves highlight several limitations.

There were few participants, and most were women, white and highly educated, which makes it difficult to know whether the results apply more broadly. The symptoms were also very mild, which makes it harder to see a clear effect. The placebo powder, maltodextrin, may also have affected the gut flora in itself.

It is also good to know that the blueberry powder was donated by a trade organisation for blueberry growers. This doesn't mean the results are wrong, but it is a reason to wait for larger and independent studies before drawing any conclusions. Blueberries are no treatment – but a tasty addition The study therefore doesn't show that blueberries can treat depression.

However, there's little reason to avoid the blue berries. They're nutritious, high in fibre and delicious, and frozen blueberries are available in the supermarket all year round. Sprinkle them over porridge, blend them into a smoothie or add them to yoghurt.

A handful a day is a simple way to get more colour and more fibre on your plate. If you feel low for a longer period, or worry about someone close to you, it is important to seek help. At 1177 you will find advice about low mood and depression, as well as information about where you can get support.

A vårdcentral is often a good first step. Also read: Ultra-processed food linked to silent damage in the brain – new study