The side effects of eating Canadian pond weed, which do not occur until approximately 48-72 hours after consumption, include diarrhea, discomfort, dizziness and sweating from the mix of chlorophyll with stomach acids.
Eating tissues or meat of any animal has possible cardiovascular effects. The main issue with eating tissues is that they contain saturated fats that clog arteries and make it difficult for blood to be carried to and from the heart.
From what I can understand... you can have bad side effects if you're allergic to them... or if you eat to many the seeds may cause kidney stones. Of course with most fruits eating too much of them causes diarrhea. Though strawberries have many good health factors as well, just don't over do them.