Researchers were shocked to learn that these undigested foods actually served as nourishment for the probiotics in the gut, those beneficial microbes that perform useful biological functions and are a critical component of a healthy immune system.
According to Dhekhar K. Chalia MD, author of Probiotics for Dummies, the important properties of prebiotics, found only in plants, are threefold:
- Healthy bacteria building potential
- Starch and sugar replacement capabilities
- Improving gut health as fiber
Prebiotics Encourage Building Up of Healthy Bacteria
In essence, prebiotics are a type of dietary fiber that encourages the growth of favorable intestinal flora. They do this by acting as a functional food for these organisms.
It is important to note that prebiotics are not alive like probiotics are. Prebiotics are a functional food, whereas probiotics are living organisms.
By nourishing these helpful microbes known as probiotics, a prebiotic effect occurs where there is an increase in the activity of healthy bacterial colonies such as bifidobacteria and lactobacilli. This strengthens the gut environment and provides resistance to invading pathogens thereby shoring up the immune system.
The great news is that prebiotics are heat resistant, and so, to a large extent, remain unaltered during the cooking or baking process. It also ensures that they will reach the intestines unaffected by the digestive process in order to trigger the beneficial prebiotic effect.
The top ten foods that contain prebiotics are as follows. Remember that cooking generally does not diminish the prebiotic effect. In fact, researchers report that cooking onions actually slightly increases the prebiotic value of this functional food.
- Chicory root
- Jerusalem artichoke
- Dandelion greens
- Garlic
- Leek
- Onion
- Asparagus
- Wheat bran
- Wheat Flour
- Bananas
Prebiotics Show Promise for Blood Sugar and Weight Control
A specific type of prebiotic known as resistant starch is showing much promise far and beyond gut health benefits.
Not only is it turned into energy boosting, inflammation squashing short-chain fatty acids by probiotic bacteria, but resistant starch is also proving helpful for stabilizing blood glucose levels, increasing insulin sensitivity, reducing appetite by increasing satiation, and encouraging weight loss that is easier to maintain.
Be wary as all forms of resistant starch are not the same, however! Note that some resistant starch is industrialized and should be avoided, the types you want are types 1-3 below.
- Type 1 – This type of resistant starch that is bound by fibrous cell walls and therefore resists digestion, such as beans/ legumes, grains, and seeds.
- Type 2 – Indigestible due to it’s high amylase content when in its raw form, such as found in potatoes, plantains, and green bananas. Heating or over-ripening these foods renders a portion of the resistant starch to no longer be indigestible.
- Type 3 – This type of resistant starch is the result of a process called retrogradation- when starches are cooked and then immediately cooled, which allows the digestible starch in some foods like rice, potatoes, and beans to be more resistant to digestion.
- Type 4 – Industrialized resistant starch that does not occur in nature. It is man made via a chemical process and should be avoided.
Resistant starch can be obtained either through food or supplements. Most common sources include:
- Retrograded potatoes (cooked and then cooled)
- Green bananas (unripe)
- Plantains
- Legumes (cooked and cooled)
- Parboiled (partially cooked) rice
- Some grains such as teff (gluten free) and wheat.
- Potato starch (healthier than potato flour)
- Plantain flour
- Green banana flour
- Cassava powder and tapioca starch (where to find)
If the potential of using resistant starch as a prebiotic for blood sugar and weight control is appealing to you, be aware that it needs to be added slowly to your diet until your body becomes used to it. Otherwise, you may end up experiencing painful and embarrassing episodes of gas and bloating!
Also be aware that if you are already grappling with gut imbalance issues or suffer from IBS, colitis, Crohn’s disease or other GI illnesses or infections, resistant starch should really be avoided until you are at least in partial remission. You can try experimenting with low amounts of resistant starch to see how it goes, but be aware that it may add to the problem rather than help the situation until you are further along in your healing journey.
Prebiotics Present in Breast Milk
Breastfeeding is known to benefit a baby’s developing immune system, so it’s no surprise that prebiotics have been identified via research to be present in human breastmilk.
Specifically, the prebiotics known as oligosaccharides (HMOs) are highly abundant in and unique to human breastmilk.
HMOs are anti-adhesive antimicrobials that prevent pathogen attachment to infant mucosal surfaces (ear, nose, throat, gut etc) and lower the risk for viral, bacterial and protozoan parasite infections.
HMOs may even make your baby smarter as they provide the infant with sialic acid which shows potential as an essential nutrient for brain development and cognition!
How Much Prebiotics Should Be Consumed Each Day?
There is currently no broad consensus on an ideal amount of prebiotics to include in the diet on a daily basis either via food or supplements. Recommendations range from 4 g/.14 oz up to 8 g/.28 oz for general digestive health support. Therefore, if your gut is in good shape, try a little bit at a time and increase slowly to observe how it works for you.
Those with digestive disorders may require much more (up to 15 g/.53 oz per day) to support the growth and development of healthy flora, but it would be wise to consult with a holistic healthcare practitioner on the best type of prebiotics to incorporate without exacerbating your particular medical condition.
Another good idea is to check to see that the probiotic you take has some prebiotics in there to nourish the microflora once it reaches your gut. Note that this is not completely necessary if you are eating prebiotic foods already. The probiotic brands I recommend are: Prescript Assist, Innate Response, Custom Probiotics, Bio-Kult, and Metagenics.
Sarah, The Healthy Home Economist
Sources and More Information
Human milk oligosaccharides: every baby needs a sugar mama
The Best Resistant Starch
Why Fermented Foods are Not Enough to Heal the Gut (and the probiotic boost they need)
Gluten Free Teff a Powerhouse of Nutrition
Choosing the Best Probiotic and Prebiotic Supplement
How to Take Probiotics for Maximum Benefit
Foods Containing Prebiotics
Doctor Approved Remedies for Eczema Treatment
Sarah – do you have any thoughts on those who are unable to supplement with prebiotics? I have tried both potato starch and FOS with the result being extreme joint pain and fatigue. I do not have any symptoms of SIBO, and in fact feel pretty great. I have used a number of the probiotics you recommend for about a year and a half, in addition to a lot of fermented foods. I did some gut testing and was told that my microbiota is healthy. I love the idea of benefiting from prebiotics, but am not inclined to use them based on my experience so far.
Do others have this issue?
Thanks so much. Love your blog.
Heather
Have you tried some of the more gentle prebiotics as food, not in supplement form? I would suggest soaked teff porridge, cooked plantains, onions, garlic etc. You don’t have to supplement to get the wonderful benefits of prebiotics.
Sarah, do you have a cooked plaintain recipe or two that you could share?
Hi Beth, this recipe for banana fritters that I posted a few years back works beautifully with plantains as a substitute for the bananas. https://www.thehealthyhomeeconomist.com/to-die-for-no-grain-banana-fritters/
Thanks!
Just FYI, there’s a typo in that recipe, I think, because bananas aren’t listed (although it’s obvious you need them, it just would be helpful to know how many). Coconut oil isn’t listed in the ingredient list either. 🙂
Thanks .. will fix that recipe. From the blogging early days 🙂
Hi Sarah – Yes I eat a lot of food that qualifies as prebiotic (although I haven’t learned to love Teff yet). It sounds like some people are also supplementing pretty heavily with good results, and so I had hoped to try it. But it isn’t worth those side effects. I wonder how common the joint pain is, I really can’t find where people are having issues with anything other than potato starch. Thanks for the reply!
do retrograded potatoes need to be consumed cold? i cook whole potatoes in a sous vide water bath at 158 degrees F for 3-4 hours. this does completely change the texture of the potato.
then i peel them, coarsely grate them and fry or add to soups/stews. am i defeating the purpose?
Sarah,
I have been taking Garden Of Life: Primal Defense Ultra in addition to four tablespoons daily of potato starch. Do you have any opinion on Primal Defense?
Does Retrograded potatoes, legumes (cooked and then cooled) mean you can cook them anyway (boiled, freed with onions, baked in the oven) and just eat them after they cool. I keep reading people who say to cook and cool but no one really explains.
Hello Sarah,
I think i have some Form of leaky gut so therefore i drink kefir everyday.
I usually do a second fermentation with prebiotics/RS like Onions or plátano/banana starch to give the probiotics a head start on consuming them before they arrive the small intestines in csse i have SIBO.
Does this make sense?
4 tablespoons of potato starch? Not sure this is the smartest choice. Starch is a highly processed food with poor nutritional value and a high glycemic index. It can also glue to your intestines and slow down your bowel movements.
Just make sure you consume a variety of whole fruits, veggies, legumes, grains, seeds and nuts. These are the favorite food of your probiotic bacteria.
Cheers!
I guess you’ve never heard of resistant starch? It feed probiotics in the gut, is indigestible and studies are showing it reduces belly fat. The Standard American Diet, while high in starch, is very LOW in resistant starch. Might want to read up some more as your views are not up to date.
Sarah, do you know if you can have chicory root while breastfeeding? I’m struggling to find legitimate answers.