Strawberries could help against dementia
A new study shows that eating strawberries every day could reduce the risk of developing dementia in old age. Apparently you don't even have to eat fresh fruit for this, the test subjects were given powder. Blueberries are said to have a similar effect. However, healthy suspicion is appropriate.
Strawberries are not only delicious, but also healthy. According to the Federal Center for Nutrition, they are full of vitamins and minerals. They also contain secondary plant substances that can protect against cardiovascular diseases, kill germs and have an anti-inflammatory effect. According to the federal authority, this applies above all to organically produced fruit grown outdoors.
However, strawberries can apparently also have a great effect in powder form. According to a new peer-reviewed study by scientists at the University of Cincinnati, daily consumption can reduce the risk of dementia in overweight, middle-aged people.
"Dementia is an umbrella term that encompasses many different diseases for which there is no cure," quotes"EurekAlert" study leader Robert Krikorian. "It's not clear when or if an effective therapy will be available; prevention and mitigation through diet and lifestyle choices are currently the best approach we have."
Participants overweight and middle-aged
A total of 30 overweight people aged 50 to 65 with mild cognitive decline (including memory impairment) took part in the study, including 25 women and five men. "We wanted to work with an overweight middle-aged population, as dementia is a disease that is likely to develop over a period of decades. Furthermore, inflammation is likely to be a factor associated with metabolic disorders such as overweight/obesity, prediabetes and type 2 diabetes," explains Krikorian.
The test subjects were divided into two groups. One half received a strawberry powder made from freeze-dried ground whole fruit over a period of twelve weeks, the other half an identical looking and tasting placebo.
On the trail of antioxidants
The strawberry powder was equivalent to 130 grams of fresh fruit and contained around 37 grams of anthocyanins. They give the berries their red color, but are also considered powerful antioxidants that have anti-inflammatory properties, among other things. During the study, the participants were not allowed to eat any berries or drink any juices that may contain the same or similar substances.
The group that received strawberry powder consisted exclusively of women. The paper states that there were no differences between the participating men and women in terms of demographic factors or cognitive abilities before the start of the study.
Improved memory, less depressive
At the end of the twelve weeks, the scientists observed a reduction in the impairment of verbal learning and memory in the group that consumed strawberry powder. Specifically, they made fewer errors in a word list test than the placebo group. Such tests can be used for the early detection of Alzheimer's/dementia. One example is the DemTect test, in which participants have to repeat words read aloud, among other things.
The researchers also found that the test subjects who consumed strawberry powder also exhibited fewer depressive symptoms. They concluded that the relative improvement in mood "indicates an improved ability to cope emotionally and a lower level of stress".
Metabolism not affected
The subjects who received strawberry powder showed no improvement in metabolic function, which the scientists had expected to be the reason for the positive cognitive and mood effects. "Our results can probably be attributed to the anti-inflammatory effect of the anthocyanins contained in strawberries," suspects Krikorian instead.
The lack of metabolic response may be due to the lower dose of antioxidants compared to similar studies, the scientists write. Among other things, the proportion of the active ingredient in strawberries is significantly lower than in blueberries.
Funded by interest groups
Krikorian and colleagues have in fact conducted comparable studies with blueberry powder in the past, most recently in 2022. The study design and conduct were similar, as were the results. However, the researchers also found improved metabolic function in the non-placebo group.
How meaningful such studies are is generally disputed. One reason for this is that they are often funded by vested interests. In the case of the Krikorian research, these were the California Strawberry Commission and the US Highbush Blueberry Council, both of which also donated the powders administered. Both organizations have funded numerous studies, an overview can be found here and here.
This is not a US-American phenomenon; lobbyists are funding nutritional studies worldwide. At the beginning of 2022, for example, Karls supported a research study by the University of Rostock on the health-promoting effects of strawberries, which produced"astonishing results".
RCT or cohort study?
This does not mean that Krikorian's work is dubious, especially since, according to the introduction, these are so-called randomized, double-blind, placebo-controlled studies (RCTs). In nutrition research, on the other hand, cohort studies are often carried out in which participants are regularly examined and asked about their eating habits. This allows possible statistical associations to be established between certain dietary habits, such as regular consumption of strawberries, and important endpoints such as improved cognitive abilities.
According to Cochrane Germany, RCTs are considered the "gold standard", especially in medicine. In nutrition research, however, RCTs are difficult to implement, according to an article by the organization. Among other things, study participants would have to change their diet over a period of years in order to track down long-term effects.
Elderberry juice beats blueberries and strawberries
The results of cohort studies often differ only slightly from RCTs, writes Cochrane with reference to a study by the Institute for Evidence in Medicine at Freiburg University Hospital. However, it is questionable whether the twelve-week strawberry study provides the long-term observations required in both cases. In any case, a healthy dose of suspicion can do no harm.
And if you want to consume large quantities of anthocyanins, you don't necessarily have to eat strawberries or blueberries. There are 1900 to 6600 milligrams (mg) in 100 milliliters (ml) of elderberry juice and up to 1000 mg in 100 grams of berries. Blackcurrant juice provides 1300 to 4000 mg of anthocyanins, 100 grams of blackberries up to 350 mg and the skin of eggplants 700 mg. Blueberries provide 10 to 515 mg, strawberries only 7 to 50 mg.
Source: www.ntv.de
