Food is much more than energy and nutrients!

The phrase "eat to live" covers much more than just putting energy in your mouth. When we look at our daily intake of food and drink, we see it primarily as sources of fat, carbohydrates, proteins, vitamins and minerals - that is, the classic nutrients. It's just more complex than that! There are thousands of other chemical compounds in food that are also absorbed by the body.

While vitamins, minerals and dietary fiber have for many years been considered the most important health compounds in vegetables and fruits, the importance of the other substances has probably been greatly underestimated. Here we need to take a closer look at some of the substances that can affect our intestinal flora and thus also our health.

Phytochemicals? Is it really healthy?

Although chemicals may sound like something you scrub the bathroom in, it can also cover substances found in plants. In i.a. vegetables and fruits there is a large group of substances that are collectively referred to as phytochemicals. Phyto comes from Greek (phyton) and means plant. Chemical really just means element or compound of elements. So the possible negative connotation of the word is probably mostly because we are used to talking about chemicals as something that is produced in laboratories and is mostly toxic. Many people do not want chemicals in their food, but in reality, something as simple as table salt is a chemical. Sodium chloride is the element salt consists of which has been refined at a factory. So simplified, phytochemicals are natural plant substances. The phytochemicals sit for the most part in the peel of plants and often give the plant its color and taste. Phytochemicals have several functions, but they protect i.a. the plant against harmful UV radiation and the more and thicker the peel, the more phytochemicals.

As with all other substances, one cannot just say that all phytochemicals are healthy. Most of the phytochemicals are beneficial, but there are also harmful varieties in, for example, fungi. Furthermore, when we talk about food and chemicals, it is about the fact that their good / bad properties depend on frequency and quantities.

The phytochemicals sit for the most part in the peel of plants and often give the plant its color and taste.

Where are phytochemicals used?

Phytochemicals have been used throughout human history to prevent or cure diseases. It is estimated that approx. 10% of known plant species with different phytochemical properties can be used as medicine (1). Despite the continuous development of modern medicine, phytochemicals are still used as a first choice in some countries due to their low cost. So in countries where large sections of the population are poor and medical care is not free, nature's medicine plays a big role. In addition to the fact that price and availability play a role in the choice of means to prevent and remedy diseases, culture also plays a role. China and India are the countries that mostly use phytochemicals as part of their cultural customs. They are mainly used as functional foods for daily use, but are also used and recognized as pharmaceutical preparations. So in summary, phytochemicals in the form of fruits, vegetables and plant parts such as roots, leaves or seeds have thus been used and are used as food and medicine. A relatively new discovery, however, is how the phytochemicals work, as it can now be shown that various chemical plant compounds can affect our intestinal bacteria and thus also our health. (1).

How do phytochemicals affect the gut?

As mentioned earlier, phytochemicals are a large group of substances, and when it comes to influencing intestinal bacteria, it seems that polyphenols in particular play a role. We can get polyphenols through foods such as berries, cocoa powder, beans and nuts, but they are also available as dietary supplements. Polyphenols are loaded with antioxidants and therefore have potential health benefits. In the gut, it appears that the gut bacteria and the polyphenols interact with each other. The intestinal bacteria enzymatically transform the polyphenols so that they can be better absorbed from the diet, while the polyphenols affect the composition of the intestinal bacteria so that it is more resistant to pathogens (disease-causing bacteria). Specific polyphenols are able to inhibit or increase the growth of specific bacteria, resulting in changes in the composition of intestinal bacteria. For example, ingestion of different polyphenols results in different ratios of the healthy gut bacteria (2). That the composition of bacteria in our gut is healthy is important because it can have a major impact on our health, as several diseases can be linked to dysbiosis (imbalance in the gut bacteria, which is linked to disease).

Specific polyphenols are able to inhibit or increase the growth of specific bacteria, resulting in changes in the composition of intestinal bacteria.

So what should I eat?

Basically, the understanding of phytochemicals, including polyphenols, does not change the current official dietary guidelines. You are advised to eat varied and pay particular attention to the recommended 600 g of fruits and vegetables daily. Knowing that the peel parts have a high health value, it is especially coarse vegetables such as legumes, root vegetables, onions and cabbage as well as lots of berries and fresh fruit. Many fruits can easily be eaten with peel, so feel free to buy organic vegetables so you can eat, for example, kiwi, orange and lemon peels. Of course, always remember to wash / scrub fruit and vegetables free of soil, but otherwise you should eat them as unprocessed as possible to get the good phytochemicals.

References:

1. Martinez et al. (2020) Role of the Phytochemical Compounds like Modulators on Gut Microbiota and Oxidative Stress. Current Pharmaceutical Design
2. Filosa et al. (2018) Polyphenols-gut microbiota interplay and brain neuromodulation. Neural regenaration research