Analysis: fruit and vegetables are an excellent source of both macro and micronutrients whcih are key to a healthy digestive system

By Muireann Egan, Teagasc

Every cell in our body requires fuel to function. When we eat food, we get energy from carbohydrates, fats and proteins – these are called macronutrients. On top of that, food, especially fruit and veg, have a number of other micronutrients, such as vitamins and minerals that help the immune system and give us healthy skin, hair and bones. The digestive system is responsible for breaking down food to release these nutrients, so that they can be absorbed into the bloodstream and delivered to where they are needed.

Fruit and vegetables are an excellent source of both macro- and micronutrients and are also key to a healthy digestive system. Fibre from fruit and vegetables such as oranges and carrots stimulate the movement of food through the gastrointestinal tract. Meanwhile, vegetables such as chickpeas and spinach are good sources of protein, which are the building blocks of our cells and muscles.

At Dr André Brodkorb's lab at Teagasc, food scientists and PhD students study the digestive tract in detail, in order to understand the body’s physiological response to different foods and how the food matrix affects digestion.

However, studies on the digestive system can require invasive, difficult or sometimes unsuitable methods. Alongside the worldwide Infogest network, Teagasc researchers have developed a lab-based experiment of food digestion. This allows them to study the digestion of various food types and analyse end-products such as amino acids, fatty acids and sugars, all while using common lab equipment and chemicals.

Once the food is digested, the nutrients must pass from the digestive system into the bloodstream. This process is called absorption and it mostly takes place in the small intestine. The gut barrier is the gatekeeper between the digestive tract and the bloodstream. In the small intestine, this barrier is paper thin, but the cells are tightly packed together so large food molecules, toxins and bacteria cannot enter the bloodstream. The junction between cells is called the tight junction and its effectiveness can be affected by the food we eat.

At Dr Linda Giblin's lab at Teagasc, scientists are studying the response of the gut barrier to digested food samples, including proteins from plant-based sources. If the tight junction acts like a sieve, letting the food molecules through, then it indicates that the food has had a negative effect on the gut barrier. However, foods like probiotic yoghurts, broccoli, carrots and strawberries are examples of those that strengthen the tight junction and promote gut health.

Sustainable, Nutritious and Delicious- What’s New in Fruit and Veg? is an online event which takes place on Thursday, November 11th as part of Teagasc’s Festival of Farming and Food for Science Week 2021.

Dr Muireann Egan is Communications Officer at the Teagasc Food Research Programme.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ