HSA | FSA CARDS ARE NOW ACCEPTED

Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

How SI Gene Variants Affect Sugar Digestion and Digestive Symptoms

The SI gene makes the sucrase-isomaltase enzyme, which helps break down sucrose (table sugar) and certain starch fragments into simple sugars your body can absorb. Variations in SI can reduce enzyme activity, leaving more sugars in the small intestine to be fermented by gut bacteria. Fermentation can cause gas, bloating, abdominal pain, and other symptoms commonly addressed by a FODMAPs diet.

Why this matters

The standard FODMAPs diet limits certain fermentable carbohydrates such as wheat, onions, some fruits, and dairy. It does not specifically restrict sucrose or many refined starches. If your SI gene reduces sucrase-isomaltase activity, limiting typical FODMAPs may not fully relieve symptoms. Understanding your SI genotype can help you tailor a dietary and lifestyle approach that targets the specific carbohydrates that may be causing symptoms.

Genetic Interpretations

2 effect alleles (CC) — Reduced enzyme activity

Your CC genotype at rs147207752 is associated with reduced sucrase-isomaltase enzyme activity. This can make it harder to digest sucrose and some starch fragments. Undigested sugars can remain in the gut and be fermented by bacteria, producing gas, bloating, and abdominal discomfort.

What to consider

  • Limit added sugars and sugary beverages, including sodas, fruit juices with added sugar, candy, and desserts.
  • Reduce refined starches such as white bread, many pastries, and some processed snack foods. Choose whole grains cautiously and monitor tolerance.
  • Prefer smaller carbohydrate portions at meals to reduce the load on sucrase-isomaltase.
  • Consider targeted enzyme supplements that contain sucrase or combinations for carbohydrate digestion if recommended by a healthcare provider.
  • Eat slowly, chew thoroughly, and manage stress to support digestion.
  • Track symptoms and food intake to identify specific triggers and improvements.
1 effect allele (CT) — Moderately reduced enzyme activity

Your CT genotype at rs147207752 is associated with moderately reduced sucrase-isomaltase activity. You may digest sucrose and some starches less efficiently than average, which can lead to fermentation and symptoms similar to those seen with FODMAP intolerance.

What to consider

  • Moderate consumption of added sugars and sweetened beverages. Swap high sugar items for lower sugar alternatives when possible.
  • Limit refined starches and monitor portion sizes of carbohydrate-rich foods. Try pairing carbs with protein, fat, or fiber to slow digestion.
  • If symptoms persist after general dietary changes, consider a trial of enzyme supplementation with guidance from a clinician.
  • Practice lifestyle measures that support digestion, including mindful eating, regular physical activity, and stress management.
  • Keep a symptom and meal diary to help identify which foods or patterns worsen symptoms.
0 effect alleles (TT) — Typical enzyme activity

Your TT genotype at rs147207752 is associated with expected sucrase-isomaltase function. Sugars like sucrose and common starch fragments are likely broken down and absorbed normally. If you experience bloating or gas, those symptoms may be driven by other fermentable carbohydrates or unrelated causes.

What to consider

  • A standard FODMAPs approach can be appropriate for investigating persistent symptoms that suggest sensitivity to fermentable carbs like fructans, lactose, polyols, or fructose.
  • Maintain balanced carbohydrate intake and avoid excessive added sugars for general health and blood sugar control.
  • Use symptom tracking to help identify triggers and share findings with your healthcare team.

Dietary Recommendations

  • Limit added sugars and sugar-sweetened beverages. Focus on whole foods and use natural flavorings like herbs and spices.
  • Choose carbohydrate sources with more fiber and structure, such as whole fruits in moderation, legumes if tolerated, and minimally processed grains. Introduce these slowly and watch symptoms.
  • Prefer smaller, balanced meals combining carbohydrates with protein, healthy fats, and fiber to slow carbohydrate absorption and reduce fermentation risk.
  • If you follow a low FODMAP plan and still have symptoms, try a trial reduction in sucrose and refined starches while tracking effects.

Supplement and Testing Considerations

  • Enzyme supplements that include sucrase or broader carbohydrate-digesting enzyme blends may help symptom management for some people. Discuss options and dosing with your healthcare provider before starting.
  • Breath tests that measure hydrogen and methane can help identify carbohydrate malabsorption related to fermentation. Talk with a clinician about whether breath testing is appropriate for you.
  • Your clinician may recommend other tests if symptoms are severe or persistent, such as stool studies, nutrient assessments, or imaging, tailored to your history and exam.

Lifestyle Strategies to Support Digestion

  • Eat slowly and chew thoroughly to reduce the size of food particles and give your small intestine more time to work.
  • Manage stress using techniques such as deep breathing, meditation, gentle yoga, or regular physical activity. Stress can worsen digestive symptoms.
  • Stay hydrated, but avoid drinking large amounts of fluid during meals which can dilute digestive enzymes in some people.
  • Regular physical activity supports gut motility and overall digestive health.

How to Use This Information

Use your genotype information to guide focused changes in diet and habits. If you have reduced SI activity, target sucrose and refined starches in addition to the usual FODMAPs approach. Keep a food and symptom diary for several weeks to see patterns and share those findings with your healthcare provider or a registered dietitian. If you try enzyme supplements, coordinate with a clinician and evaluate benefits and any side effects.

When to See a Healthcare Provider

  • If symptoms are severe, persistent, or causing weight loss or nutritional problems.
  • If over-the-counter or lifestyle strategies do not improve symptoms after a reasonable trial.
  • If you are considering long term restriction of major food groups or starting new supplements, especially if you have other health conditions or take medications.

Important disclaimer

PlexusDx provides educational information about genetic predispositions only. This content is not medical advice. Always consult your healthcare provider or a registered dietitian before making significant changes to your diet, starting supplements, or pursuing diagnostic testing.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About FODMAPS Diet and SI rs147207752

How can SI gene variants affect sugar digestion and symptoms like gas or bloating?

The SI gene helps produce the sucrase-isomaltase enzyme, which breaks down sucrose (table sugar) and some starch fragments into absorbable sugars. If your SI variant is associated with reduced enzyme activity, more sugars may remain in the small intestine and get fermented by gut bacteria, which can contribute to gas, bloating, abdominal pain, and other digestive symptoms.

Does an SI-related reduction in sucrase-isomaltase mean I should follow a FODMAPs diet differently?

Possibly. The standard FODMAPs diet limits many fermentable carbohydrates (like wheat, onions, some fruits, and dairy) but does not specifically target sucrose or many refined starches. If your SI genotype suggests reduced sucrase-isomaltase activity, limiting typical FODMAPs may not fully relieve symptoms; you may need to also trial changes to sucrose and refined starches while tracking results.

What dietary and lifestyle strategies can help if my SI genotype suggests reduced enzyme activity?

If you have reduced or moderately reduced sucrase-isomaltase activity, strategies commonly include limiting added sugars and sugary beverages, reducing refined starches (and monitoring tolerance of whole grains), and keeping carbohydrate portions smaller. Other helpful approaches include eating slowly and chewing thoroughly, managing stress, staying hydrated, and using symptom/food tracking. In some cases, clinicians may discuss targeted enzyme supplements or other testing if symptoms persist.

What tests can help me learn more about FODMAPS Diet and SI rs147207752?

The Optimal Diet and Weight Loss Genetic Test delivers over 295 genetic insights related to nutrition response, body composition, metabolism, and fitness. The Diet and Nutrition Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.