Chia seeds contain significant amounts of omega-3 fatty acids and fiber. According to WebMD, they are believed to aid in miminizing risks for heart disease and stroke, but research results are to date inconclusive.
Possible side effects accompanying the use of chia seeds include increasing blood triglyceride levels and cholesterol, which are already very high in some individuals. A type of chia seed called Salba does not appear to have this effect. High alpha-linolenic acid content in chia also may increase the risk of prostate cancer.
Pregnant or nursing women should avoid using chia seeds, as not enough research has been done to determine any potential risks.