The purpose of this feasibility study is to investigate the role of a dietary supplement in modulating the gut microbiota and improving pain outcomes in children with sickle cell disease (SCD).

Sickle cell disease (SCD) is associated with significant morbidity and mortality. Acute pain is the most frequent cause of hospitalization in children. Pain in sickle cell disease is inflammatory driven. Recent data has shown that gut dysbiosis is present in individuals with sickle cell disease. Gut dysbiosis has been linked to inflammation in certain diseases. Our preliminary study showed that gut dysbiosis is linked to pain.

Omega -3-fatty acids (fish oil) has been shown to improve pain outcomes in individuals with SCD. Acceptance of fish oil varies given its fishy smell and taste. Flaxseed is a plant-based omega-3-fatty acid which has antioxidant and anti-inflammatory properties.

This study aims to conduct a feasibility trial on the use of flaxseed to modulating the gut microbiome and improving inflammatory markers and pain outcomes in children with SCD.

Inclusion Criteria:

- Children 5-18 years with SCD at steady state. Steady state will be defined as not requiring an acute care visit for pain in the last 28 days.

Exclusion Criteria:

• current use of antibiotics except prophylactic penicillin
• current use of pre-or probiotic supplements
• current use of PPI therapy
• pregnant or lactating females
• individuals with known allergy to Flaxseed