Fructooligosaccharides (FOS) and Lactulose: Key Prebiotics Explained

Common Food Sources of FOS

• Asparagus
• Bananas (particularly those that are less ripe)
• Barley and Rye
• Wheat and Chicory Root
• Garlic, Onions, and Leeks

Health Benefits of FOS

1. Enhanced Mineral Absorption
   Research suggests FOS may improve calcium absorption, supporting bone density and skeletal health.
2. Possible Lipid and Cholesterol Management
   Several trials point to FOS having a mild cholesterol-lowering effect, although this is not universally observed. Still, for those aiming to maintain healthy lipid levels, FOS-rich foods can be a supportive element.
3. Skin and Immune Health
   Correcting gut flora imbalances through FOS supplementation has been used in some instances to help manage skin conditions such as atopic eczema.
4. Increased Resistance to Pathogens
   Growing levels of Lactobacillus and Bifidobacterium can discourage the proliferation of harmful bacteria in the gut, improving overall resilience against infections.

Side Effects of FOS

• Flatulence, Bloating, and Borborygmi: These are most common in higher doses and often diminish as your system adapts.
• Abdominal Discomfort: Typically dose-dependent and reduces over time.

Lactulose: The Disaccharide Prebiotic

Lactulose: The Disaccharide Prebiotic

What Is Lactulose?

Lactulose is a synthetic disaccharide made from fructose and galactose. Like FOS, it resists digestion and travels to the colon, where beneficial microbes ferment it into short-chain fatty acids, hydrogen, and other by-products.

Key By-Products of Lactulose Fermentation

• SCFAs (Short-Chain Fatty Acids): Help acidify the colon, preventing harmful bacteria from thriving, while offering various metabolic benefits.
• Hydrogen: Implicated in reducing the growth of certain gram-negative bacteria, as it can interfere with their metabolic processes.
• Lactic Acid & Carbon Dioxide: Contribute to maintaining a beneficial gut environment.

Uses of Lactulose

1. Preventing Urinary Tract Infections (UTIs)
   By reducing gut-based pathogens, lactulose minimises the bacteria available to move into the urinary tract.
2. Endotoxemia Reduction
   Lactulose helps lower endotoxins produced by certain harmful bacteria, which can otherwise be absorbed into the bloodstream and cause systemic inflammation.
3. Managing Hepatic Encephalopathy
   In individuals with liver disease, lactulose decreases the production of ammonia—a substance implicated in this serious condition—thereby lessening the risk or severity of encephalopathy.
4. Constipation Relief
   Lactulose draws water into the bowel, softening stools, and encouraging more regular bowel movements.
5. Colon Cancer Prevention Research
   Studies show potential for lactulose to decrease secondary bile acids and reduce the creation of carcinogenic compounds, thus lowering risks associated with colorectal polyp growth.

Typical Doses and Side Effects

• Effective Range: As little as 3 g may not be enough for therapeutic benefits, with 10 g twice daily often recommended.
• Higher Doses (e.g. 35 g or more): Commonly used for liver disease management.
• Side Effects: Include bloating, flatulence, and diarrhoea, especially with high or abrupt dosing.

Combining FOS and Lactulose for Optimal Gut Health

Because FOS and lactulose both feed beneficial microbes, they can complement each other. If you decide to supplement with either or both:

1. Begin Slowly: Minimise gastrointestinal upset by starting with a lower dose.
2. Monitor Your Response: Track any digestive changes and adjust dosage if needed.
3. Stay Hydrated: Adequate water intake helps the body manage increased fermentation in the colon.

Fructooligosaccharides and lactulose are two well-studied prebiotics, each offering a unique set of health benefits, from improved mineral absorption and cholesterol management to enhanced immune defences and digestive comfort. As with any dietary supplement or health strategy, it is wise to discuss specific concerns with a healthcare professional, especially if you have pre-existing conditions or are on medication. By thoughtfully incorporating FOS and lactulose into your nutrition plan—through diet or supplementation—you can unlock significant gut health benefits to support holistic well-being.