Prebiotics supplement health benefit, dosage, safety, side effects and various types
March 25 2018 by
Ray Sahelian, M.D.


There is increasing awareness that the human gut bacteria play a critical role in maintaining health both within the gastrointestinal tract and throughout the rest of the body through the absorption of metabolites. The prebiotics concept, which was launched in 1995, concerns nondigested and selectively fermented carbohydrate food ingredients. It is thought that their effect in the colon could reduce risk for disease in the rest of the body.
   One can increase the number of good bacteria in the body in several ways: By taking probiotic supplements (the actual bacteria), eating yoghurt and other foods that have such bacteria, or by ingesting prebiotics which help stimulate the growth of good bacteria that are already in the colon.


Fructooligosaccharide (FOS), Galactooligosaccharide (GOS), inulin, dietary carbohydrates, and xylooligosaccharide (XOS) are some of the most studied prebiotics in humans.


What are they?
Prebiotics are food ingredients, mostly complex carbohydrates that are not digested, that stimulate the growth or activity of certain bacteria in the colon. The types of bacteria most often stimulated are bifidobacteria and lactic acid bacteria. These are considered good bacteria and can provide various health benefits.


Br J Nutrition. 2016. Oatmeal porridge: impact on microflora-associated characteristics in healthy subjects. Oatmeal porridge has been consumed for centuries and has several health benefits. We aimed to investigate the effect of oatmeal porridge on gut microflora functions. A total of ten healthy subjects ingested 60 g oatmeal porridge daily for 1 week. The following microflora-associated characteristics were assessed before and after the intervention: intestinal gas production following lactulose ingestion, faecal excretion of SCFA and faecal levels of urease and β-galactosidase. In addition, rectal levels of PGE2 were measured. Microbial fermentation as evaluated by intestinal gas production and excretion of SCFA did not change significantly following the dietary intervention. However, faecal levels of β-galactosidase and urease decreased after eating oatmeal porridge. Host inflammatory state, as measured by rectal levels of PGE2, also decreased, but the change was not significan. The results suggest that oatmeal porridge has an effect on gut microbial functions and may possess potential prebiotic properties that deserve to be investigated further.


Adv Nutr. 2016. Prebiotics, Fermentable Dietary Fiber, and Health Claims. Since the 1970s, the positive effects of dietary fiber on health have increasingly been recognized. The collective term "dietary fiber" groups structures that have different physiologic effects. Since 1995, some dietary fibers have been denoted as prebiotics, implying a beneficial physiologic effect related to increasing numbers or activity of the gastrointestinal microbiota. Given the complex composition of the microbiota, the demonstration of such beneficial effects is difficult.


Benefit of prebiotics
In addition to colon health, they can improve the immune system and reduce the incidence of allergies.



There are various types of prebiotics. Typical sources of prebiotics are unrefined wheat, oat, barley, soybeans, and Jerusalem artichokes (which contain inulin). Other prebiotics include fructo-oligosaccharides used as an alternative sweetener.

Inulin fiber is a prebiotic fiber available as a supplement for sale.


Fructo-oligosaccharides (FOS) are are dietary fibers that help keep the stomach and bowels healthy. they are extracted from fruits, grains, vegetables, and herbs such as bananas, barley, wheat, asparagus, garlic, onions, tomatoes, burdock, and chicory root. Fructo-oligosaccharides can also be produced by degradation of inulin. The Jerusalem artichoke and its relative, yacón, have very high concentrations of fructo-oligosaccharides. FOS can also be produced by degradation of inulin.
   FOS nourish and promote the naturally present friendly bacteria (Bifidobacteria and Lactobacilli in particular) capable of reducing the risk of infection in the digestive system.


Anaerobe 2015. Pomegranate ellagitannins stimulate growth of gut bacteria in vitro: Implications for prebiotic and metabolic effects.


Prebiotics and Probiotics in disease prevention or treatment
Probiotics (usually lactobacilli and bifidobacteria) and prebiotics (non-digestible oligosaccharides) have been shown to be useful in preventing certain disease conditions as well as possibly promoting specific aspects of health. Both may be helpful in malnutrition, particularly in lactose intolerance and calcium absorption, in treating constipation, and reducing the risk for traveler's diarrhea and reducing the risk for gastrointestinal infections.
   An "optimal" gut microflora establishes an efficient barrier to the invasion and colonisation of the gut by disease producing bacteria. These bacteria in the gut produce a range of metabolic substrates which in turn are utilized by the host (e.g. vitamins and short chain fatty acids) and stimulate the immune system in a non-inflammatory manner. Although little is known about the individual species of bacteria responsible for these beneficial activities, it is generally accepted that the bifidobacteria and lactobacilli constitute important components of the beneficial gut microflora. A number of diet-based microflora management tools have been developed and refined over recent decades including probiotic, prebiotic and synbiotic approaches. Each aims to stimulate numbers and/or activities of the bifidobacteria and lactobacilli within the gut microflora.


Eczema help

Infant formulas containing a mixture of prebiotic oligosaccharides may protect against the development of eczema or dermatitis in babies at high risk for allergic skin conditions. The research was conducted by Dr. Guenther Boehm from Numico Research Germany, Friedrichsdorf. Human breast milk contains natural prebiotics that promote the development of a healthy immune system, which can help prevent allergies. Boehm's team developed an infant formula based on the prebiotic content of human breast milk and tested its ability to reduce the incidence of skin allergy in a group of newborns whose mothers were unable to start or continue breastfeeding. These infants were at high risk for skin allergy because they had a parent with the condition. A total of 102 infants were fed a prebiotic -enriched infant formula and 104 were fed a normal formula. The children were seen on a monthly basis until the age of 6 months. Only 10 infants fed the prebiotic formula had signs of atopic dermatitis after six months, compared with 24 infants fed the normal formula. Tests on stool samples from 98 infants showed that the prebiotic group had significantly higher levels of the beneficial gut microbes bifidobacteria compared to the other group. Prebiotics can favorably affect development of the immune system of infants by altering the bacteria in the bowel and in so doing reduce the chances of skin allergy developing in at-risk infants. Archives of Disease in Childhood 2006.


Gastrointestinal infections
Healthy infants were enrolled and randomized to a formula with a mixture of galacto- and fructo-oligosaccharides or to a control formula. Prebiotic administration reduce intestinal and, possibly, respiratory infections in healthy infants during the first year of age. Clin Nutr. 2009. A formula containing galacto- and fructo-oligosaccharides prevents intestinal and extra-intestinal infections: an observational study.


Heart disease and cholesterol, metabolic syndrome
The combination of soy and prebiotics may lower cholesterol and boost heart health. A study included 23 adults with high lipid levels who were an average age of 58 years. The participants were randomly assigned to one of three groups: One group received a soy food containing diet, providing 30 grams per day of soy protein, and 61 milligrams per day of isoflavones plus maltodextrin (placebo); the second group received the soy food diet plus prebiotic (oligofructose); the final group received a low-fat dairy diet plus the prebiotic. The combination of soy and prebiotics lowered LDL cholesterol levels more than either soy or prebiotics alone. Wong JM, Kendall CW, deSouza R. The effect on the blood lipid profile of soy foods combined with a prebiotic: a randomized controlled trial. Metabolism. 2010.


Int J Food Sci Nutrition 2014. Interactions between prebiotics, probiotics, polyunsaturated fatty acids and polyphenols: diet or supplementation for metabolic syndrome prevention? The metabolic syndrome can be prevented by the Mediterranean diet, characterized by fiber, omega-3 polyunsaturated fatty acids and polyphenols. However, the composition of the Mediterranean diet, which can be viewed as a natural multiple supplement, is poorly controlled, and its beneficial effects poorly predictable. The metabolic syndrome is associated with intestinal dysbiosis and the gut microbioma seems to be the main target and player in the interactions occurring between probiotics, prebiotics, omega 3 polyunsaturated fatty acids, and polyphenols. From the reviewed evidence, it is reasonable to manage growth and metabolism of gut microflora with specific prebiotics and polyphenols. Even though the healthy properties of functional foods and nutraceuticals still need to be fully elucidated, available data suggest that well-designed supplements, containing the better ratio of omega-3 polyunsaturated fatty acids and antioxidants, specific probiotic strains, and selected polyphenols and prebiotics, could be useful in metabolic syndrome prevention and treatment.


Inflammatory bowel disease
Perhaps use can be of benefit in those with ulcerative colitis.


Immune system
A double-blind study of 419 college students sought to find out the health benefits of prebiotic supplements. The students were randomized to receive 0, 2.5 or 5.0 grams of a galactooligosaccharide prebiotic product for eight weeks before, during and after final exams. Those who took the supplements had fewer symptoms of gastrointestinal problems, including diarrhea, constipation, indigestion and abdominal pain. The ones receiving the 5 gram prebiotic supplement experienced a 40 percent reduction in days with cold or flu although no effect was observed in overweight or obese participants. These findings suggest that galactooligosaccharide prebiotics may provide beneficial protection during times of increased stress. Hughes C, Davoodi-Semiromi Y. Galactooligosaccharide supplementation reduces stress-induced gastrointestinal dysfunction and days of cold or flu: a randomized, double-blind, controlled trial in healthy university students. Am J Clin Nutr. 2011.


Human milk oligosaccharides
Human milk contains prebiotic oligosaccharides which stimulate the growth of intestinal bifidobacteria and lactobacilli. The development of intestinal microflora in newborns is strictly related to the kind of feeding. Breast-fed infants, unlike the bottle-fed ones, have an intestinal ecosystem with a strong prevalence of bifidobacteria and lactobacilli. Among the numerous substances present in human milk, oligosaccharides have a clear prebiotic effect. They are quantitatively one of the main components of human milk and are only partially digested in the small intestine, so they reach the colon, where they stimulate selectively the development of bifidogenic flora.

Are supplements of homeostatic soil organisms preferable to prebiotics for gastrointestinal disorders?
   Since I have not seen any independent published studies with homeopathic soil organisms, and none comparing homeopathic soil organisms to a prebiotic supplement, it is not possible to say.


Does the body naturally extract FOS (the dietary fiber) found in bananas, oat, barley, wheat, soy beans etc., when I eat these types of foods? Does one have to eat them in a particular fashion or cook them in a certain way to avail benefits of the prebiotics? Also, are FOS supplements more effective than ingesting them naturally through foods?
   The body does make use of the prebiotics present in foods that are ingested. Each food or plant is different in terms of its ideal preparation for best prebiotic benefits, but the matter is too complicated and impractical to go out of one's way in terms of ideal ingestion and preparation. Rather, one should focus on consuming a number of healthy foods from a variety of sources. Little is known about the benefits of prebiotics in supplement form compared to the benefits obtained from eating foods that have them. Until more is known, it would seem reasonable to consume prebiotic supplements a few times a week or a few times a month.


I'm currently on probiotics medication, I wanted to understand how I should take prebiotics along with probiotics to maximize their effect. In what quantity (and when) should they be taken to maximize benefit of the probiotic bacteria?
   There is no reason to be concerned about the timing. Just take them when at any time of the day that you remember.