Prebiotics
Your gut bacteria are only as good as the food you give them. Prebiotics are the fibre that feeds the good ones — and most people in India don't get enough.
Prebiotics are non-digestible fibres that feed beneficial bacteria in your gut. When these bacteria eat prebiotic fibre, they produce short-chain fatty acids (especially butyrate) that strengthen your gut lining, reduce inflammation, and improve digestion.
Good for you if: You have irregular digestion, bloating after meals, take antibiotics often, or want to support your immune system from the inside.
Dive deeper into the researchCommon side effects
- Gas and bloating when starting (usually settles in 1–2 weeks)
- Loose stools at high doses
- Mild cramping if you increase too fast
What do prebiotics do?
Your gut has trillions of bacteria. Some are helpful, some are not. Prebiotics are special types of fibre that you can't digest — but your good bacteria can. When they eat this fibre, they produce short-chain fatty acids (SCFAs), especially butyrate, which is like fuel for the cells lining your gut.
The result: a stronger gut barrier, less inflammation, better nutrient absorption, and a healthier immune system. About 70% of your immune cells live in your gut, so feeding them well has effects far beyond digestion.
What can you expect?
- Better digestion — more regular bowel movements, less constipation
- Less bloating — once your microbiome adjusts (give it 1–2 weeks)
- Stronger immunity — fewer minor infections over time
- Better mineral absorption — especially calcium and magnesium
- Improved blood sugar — fibre slows glucose spikes after meals
How to take prebiotics
Start with 3–5 g/day and build up to 10–15 g over 2–3 weeks. Get as much as you can from food. If supplementing, take with a meal and plenty of water.
If you get a lot of gas, back off to a lower dose and increase more slowly. Your gut bacteria need time to adjust.
Best food sources in India: Raw or cooled rice and potatoes (resistant starch), green banana flour, garlic, onion, whole wheat, barley, lentils (dal), and chicory root.
Supplement options: Partially hydrolysed guar gum (PHGG) is one of the best-tolerated. Inulin and FOS powders are also widely available and affordable.
Which type of prebiotic?
| Type | Best for | Found in |
|---|---|---|
| Inulin | Bifidobacteria growth | Chicory root, garlic, onion |
| FOS | Bifidobacteria, easy to find | Banana, onion, wheat |
| GOS | Broad-spectrum gut support | Lentils, chickpeas, dairy |
| Resistant starch | Butyrate production | Cooled rice/potatoes, green banana |
| PHGG | IBS, low gas | Supplement (guar gum) |
If you're not sure, start with resistant starch — it's the easiest to get from Indian food (just eat your leftover rice or potatoes) and produces the most butyrate.
Want to see how your gut health is improving?
eterni tracks your inflammation markers and gut-related labs over time — so you can see if prebiotics are making a difference.
Get early accessFrequently Asked Questions
What's the difference between prebiotics and probiotics?
Probiotics are live bacteria you swallow. Prebiotics are the fibre those bacteria eat. Think of probiotics as seeds and prebiotics as fertiliser. You need both — but prebiotics are arguably more important because they feed the trillions of bacteria already living in your gut.
What are the best Indian food sources of prebiotics?
India has excellent options: raw or cooled rice and potatoes (resistant starch), raw banana or green banana flour, garlic, onion, whole wheat, barley, lentils (dal), chicory root, and jackfruit. Fermented preparations like idli and dosa batter also develop prebiotic compounds during fermentation.
Can prebiotics cause bloating?
Yes, especially when you start at a high dose. Gas and bloating happen because your gut bacteria ferment the fibre, producing gas as a byproduct. This usually settles within 1–2 weeks as your microbiome adapts. Start low (3–5 g/day) and increase gradually to minimise discomfort.
Which prebiotic type is best?
No single type wins. Inulin and FOS preferentially feed Bifidobacteria; GOS supports a broader range of species; resistant starch produces the most butyrate. A diverse mix from whole foods is ideal. If supplementing, partially hydrolysed guar gum (PHGG) is one of the best-tolerated options.
How prebiotics work in your body
Prebiotics pass through your stomach and small intestine undigested. In the colon, specific bacteria (mainly Bifidobacteria and Lactobacilli) ferment them, producing short-chain fatty acids — butyrate, propionate, and acetate. Butyrate is the primary energy source for colonocytes (cells lining the colon), maintaining the gut barrier. Propionate travels to the liver and helps regulate cholesterol and glucose metabolism. Acetate enters systemic circulation and influences appetite signalling.
This fermentation also lowers colonic pH, which inhibits pathogenic bacteria and improves mineral absorption (especially calcium and magnesium). The downstream immune effects come from SCFAs modulating T-regulatory cells and reducing pro-inflammatory cytokines.
What the studies show
- Microbiome: Inulin and FOS consistently increase Bifidobacteria counts by 0.5–1.0 log units within 2 weeks
- Immunity: Meta-analyses show prebiotic supplementation reduces incidence and duration of common infections
- Blood sugar: Resistant starch lowers post-meal glucose response by 20–30% in controlled feeding studies
- Mineral absorption: Inulin-type fructans increase calcium absorption by 20% in adolescents (key meta-analysis)
- IBS: PHGG at 5 g/day improves both constipation-predominant and diarrhoea-predominant IBS symptoms
Side effects & safety
Prebiotics are food-derived fibre and very safe, but the adjustment period can be uncomfortable:
- Gas and bloating — The most common issue, especially in the first 1–2 weeks. Your bacteria are adjusting to the new fuel source. Start low and build up slowly.
- Loose stools — High doses (above 15 g/day) can draw water into the colon. Reduce dose if this happens.
- Cramping — Increasing too fast causes abdominal discomfort. Slow down the ramp-up.
- FODMAP sensitivity — If you have IBS triggered by FODMAPs, choose low-FODMAP options like resistant starch or PHGG rather than inulin or FOS.
Who should be careful: People with SIBO (small intestinal bacterial overgrowth) should consult their doctor first — prebiotics can worsen symptoms by feeding bacteria in the wrong location.
Which labs to check
Prebiotics don't have a single blood marker, but these can help you track gut-related improvements:
- hsCRP — general inflammation marker that often improves with better gut health
- Fasting glucose / HbA1c — resistant starch can improve blood sugar over time
- CBC — look for normalising white blood cell counts as a sign of reduced low-grade inflammation
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