Berries

Berries and Alzheimer's

Berries are commonly thought of as a small, pulpy edible fruit. The culinary definition of berry includes what most people think of as berries, such as blueberries, strawberries and raspberries. The botanical definition of berry is a fleshy fruit that usually has many seeds and includes tomatoes, cucumber and bananas but excludes common berries such as strawberries and raspberries. Here we’ll be referring to the common (culinary) definition of berries.1

The Many Benefits of Berries

Berries are part of the MIND diet and Baltic Sea diet. They have a low glycemic index and small amounts can be eaten and are recommended for a ketogenic diet. Berries have are filled with minerals (phosphorus, calcium, iron, potassium, magnesium, manganese, sodium and copper) and vitamins (vitamins A, C and E). In addition, berries are a rich source of polyphenols. A particular type of polyphenol, anthocyanins, is common to berries and it is what gives berries its blue, purple or red color. Anthocyanins have been shown to have positive effects on many medical ailments including cognitive impairment, inflamed and arduous joints, cardiovascular diseases, and obesity. Anthocyanins can cross the blood brain barrier but have low bioavailability. Berries have other polyphenols as well which may contribute to neuroprotective effects.2,3

Studies have shown that berry consumption may be associated with decreased risk in disorders that are caused, at least in part, by reactive oxygen species (ROS), such as cancer, cardiovascular disorders and Alzheimer’s disease. Data from one randomized clinical trial showing that berries have a positive effect on cognitive function. The study provided subjects with a mixed berry (blueberries, blackcurrants, elderberries, lingonberries, and strawberries) and tomato beverage daily over a period of five weeks. The treatment group performed better on working memory test compared to the control group. A similar study provided a berry smoothie (containing equal parts strawberry, raspberry, and blackberry) to young healthy adults. Executive function was tested through the day and the treatment performed better on executive function tests over the course of six hours.2,3,4,5

Now, let’s take a look at how specific berries help fight Alzheimer’s disease. For the sake of brevity, we’ll keep the discussion focused on berries with cognitive data from randomized clinical trials.

Blueberries

A systematic review examined 12 randomized clinical trials looking at blueberries and cognition. Of the 12 studies, 8 studies reported improvements in cognition. Long term, short term and spatial memory in particular improved. The authors pointed out that the differences in study design (such as age and health of subjects, blueberry dose, and anthocyanin content) between the 12 studies hindered direct comparison, however, based on the evidence the authors concluded that based on the evidence available, blueberries may have a positive effect on cognition.7

In three randomized clinical trials that looked at the effect of blueberries on older cognitively impaired adults and both showed a neurocognitive benefit from blueberry consumption.8,9,10

Black Chokeberries

One randomized clinical trial used 113 healthy adults to show that black chokeberries improved cognition and blood pressure. The study divided participants into two treatment groups and one control group who was given placebo. Of the treatment groups, one group was administered 150 mg of black chokeberries per day for 24 weeks, the other group was given 90 mg. Blood pressure increased with the lower dosage of black chokeberries but decreased with the higher dosage. Psychomotor speed was improved with the low dose of black chokeberries, but placebo performed better than the higher dose. No changes were observed in attention, cognitive flexibility, mood, and serum brain-derived neurotrophic factor (BDNF) levels. Brain-derived neurotrophic factor is very important for cognition and will be discussed in detail in the supplements section.11

Haskap Berry

A pilot randomized clinical trial with 20 elderly subjects examined the effect of haskap berry on cognition, mood and blood pressure after 1.5 hours. There were three dosage groups, haskap berry extract containing 100 mg, 200 mg, and 400 mg anthocyanins. Higher doses appeared to have more of an effect with 400mg dose eliciting significantly lower diastolic blood pressure and improving episodic memory tasks. Subjects with 200 mg or 400 mg doses performed better on word recall tests.12