Eating six serves of vegetables a day is a good way to feed your microbiome but are there better choices ? Actually it depends on what is going on with your gut so lets look at six different types of prebiotic fibres from vegetables. They all have different roles so the activity should give you an idea of what may be helpful for you and then you can determine if you may need to increase your consumption of one of these groups.
Six types of prebiotic fibres are inulin, pectin, galactooligosaccharides (usually referred to as GOS) , arabinoxylan, resistant starch and proanthocyanidins.
Inulin is found in artichokes, asparagus, garlic, onions and leeks, bananas, grapefruit and peaches. Inulin as a prebiotic fibre decreases the desire for sweet and fatty food and increases the feeling of fullness after a meal. A small study reported by the American Journal of Clinical Nutrition showed a 3.8 fold increase in the beneficial Bifidobacterium from consuming inulin for 3 weeks. (Vol 109, Iss 6, June 2019, pp1683-1695).
Pectin is found is peas, beans, carrots, potato, beetroot, tomato, eggplant, lentils and pumpkin as well as fruits such as banana, apples, berries, pears, apricots, lemons and kiwifruit. Increasing foods containing pectin is associated with an increase in the range of bacterial species in the gut as well as a specific increase in beneficial strains such as F praausnitzii which is anti-inflammatory. It is also considered a marker for good gut health.
Galactooligosaccharides (GOS) are found in most legumes such as green peas, lentils chickpeas and beans as well as nuts like hazelnuts, cashews and pistachio. GOS has a role in reducing IBS symptoms in particular bloating and flatulence and it also increases the level of beneficial bacteria. (2).
Arabinoxylan is found in almonds, bamboo shoots, brown and white rice, flaxseeds and sorghum. It is anti-inflammatory, reduces cholesterol and improves insulin sensitivity as well as increasing the beneficial levels of Bibfidobacterium Longum.
Resistant starch is found in most legumes as well as potato, sweet potatoes, taro, plantains, greenish bananas, sorghum and brown rice. The levels of resistant starch are also higher if root vegetables such as potato are allowed to cool and then served as a potato salad. Resistant starch is so called because it doesn’t get broken down in the small intestine but is partially broken down further in the bowels and serves as a useful food for bacteria in the large intestine. Its primary role seems to be to feed bacteria so they can produce butyrate. Butyrate is a useful fuel for the cells so it helps them stay healthy and resistant starch may also assist in the maintenance of healthy cholesterol.
Proanthocyanidins are found in almonds, pecans, hazelnuts peanuts, pistachios, pecans, cinnamon, sorghum, berries, cranberries and plums as well as dark chocolate. Proanthocyanidins have a number of health benefits due to their anti-oxidant status however the impact on the microbiome may also explain some of this benefit. These nutrients have an anti-microbial impact which may reduce problematic species such as helicobacter pylori (known for its role in causing gastric ulcers) and also through their prebiotic effect they increase beneficial bacteria such as Lactobacilli and Bifidobacterium (3)
Generally speaking ensuring you are eating a range of vegetables as well as a small serve of nuts and some berries may be the optimal approach for maintaining a healthy gut.
Christine Pope is a Naturopath and Nutritionist based at Elemental Health at St Ives. You can make appointments with her on (02) 8084 0081 or online at her website www.elementalhealth.net.au .
1. Prebiotics , Definitions, Types, Sources , Mechanisms and Clinical
applications. Accessed. at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463098/
2. The effects of a trans-galactooligosaccharide on faecal microbiota and symptoms in IBS. Accessed at https://pubmed.ncbi.nlm.nih.gov/19053980/https://pubmed.ncbi.nlm.nih.gov/19053980/
3. The Gastrointenstinal Tract as a key organ for the Health Promoting effects of Proanthocyanidins accessed at https://www.frontiersin.org/articles/10.3389/fnut.2016.00057/full#h1