British researchers believe that certain plant substances can influence the amount of body fat.
There is this simple rule: If you consume fewer calories than you burn, you lose weight. That’s why weight loss programs are all about saving calories. Nevertheless, the rule is too simple because today, one assumes that not only the food or calorie quantity affects weight. Individual food components also have influence. A current study from Great Britain, for instance, allows us to assume that certain plant products could help us to remain slim.
Flavonoids are so-called secondary plant substances (or phytochemicals) that are only produced by plants but are not used or metabolized by them; they give many types of fruit and vegetables their red, blue, light yellow, or violet color. They are found, for example, in apples and onions, soya or tea. The most common flavonoids include flavonols, flavanols, flavanones, flavones, anthocyanins, and isoflavonoids. Scientists have known for a long time that these substances can do more than make our food colorful.
They assume that these natural substances can have a positive effect on health. Since plants do not need them but store them, they are ingested with food and fed into the human (and animal) metabolism. There is evidence that flavonoids provide some protection against intestinal or breast cancer and/or help prevent cardiovascular disease. However, there is another way in which flavonoids can improve health: via weight.
To test this, researchers led by Amy Jennings of Norwich Medical School analyzed the dietary habits of 2734 healthy female twins aged between 18 and 83 years (1). From the information they received, they calculated how much of the different flavonoids the women consumed daily. The researchers also measured body fat using dual X-ray absorptiometry, a method used to measure bone density.
The scientists observed that women who ate a lot of flavonoid-rich foods had a lower percentage of body fat than women who ate less. The amount of abdominal fat also differed significantly between the two groups. It is important to note that abdominal fat is an important risk factor for diseases such as type 2 diabetes and heart problems. The correlation remained even when the scientists considered other influences such as the participants’ enjoyment of exercise, the total amount of calories they consumed, or the amount of fruit and vegetables.
They, therefore, assume that these effects are not only due to a low-calorie diet or sufficient exercise, but also to ingredients such as flavonoids. In this case, two groups of phytochemical seem to have the greatest effect: anthocyanins, which can be found in berries and red grapes, and flavones, which give parsley or celery their color. Those who ate a particularly large amount of these two substances had about nine percent less belly fat. In contrast, the researchers measured a lower proportion of body fat in people who, in contrast to the comparison group, ate 2 to 3 times more anthocyanin-rich or flavone-rich foods a day, i.e. instead of 100 grams of berries, 170 grams of peaches, 80 grams of grapes, 120 grams of oranges, or 80 grams of peppers, they ate twice to three times as much.
In addition, the scientists looked at the connection between flavonoid uptake and body fat specifically in monozygotic pairs of twins, which fed very differently on flavonoids. They wanted to find out whether the results they had measured were independent of genetic influences. In fact, in genetically almost identical pairs, if one twin accessed flavonoid-rich foods frequently, it had less abdominal fat than the other, which ate flavonoids relatively infrequently, making this characteristic almost independent of genes.
This is part 30 of a series covering twin health provided by Paul Enck from the Tübingen University Hospital and science writer Nicole Simon. Further studies in twin research can be found at TwinHealth website. Translation was done with the assistance of DeepL translator.
- Jennings A, MacGregor A, Spector T, Cassidy A. Higher dietary flavonoid intakes are associated with lower objectively measured body composition in women: evidence from discordant monozygotic twins. Am J Clin Nutr. 2017 Mar;105(3):626-634.