Guidelines and Precautions. The jury is still out on melatoninâs effects on blood pressure. If you have high or low blood pressure, or take medications to control your blood pressure, it is best to avoid the supplement unless advised otherwise by your doctor.uidelines and Precautions. The jury is still out on melatoninâs effects on blood pressure. If you have high or low blood pressure, or take medications to control your blood pressure, it is best to avoid the supplement unless advised otherwise by your doctor.
1 This can cause the can to bulge or rust.  Use canned tuna by the expiration date on the can. If the can doesn't have a best by date, mark it with the date of purchase and use the tuna within 12 to 24 months of purchase.
Tips. 1  Immediately refrigerate leftover canned tuna in a glass or plastic container. Do not leave the tuna in the opened can, as it may become rusty once open. 2  If you are storing your canned tuna in an unheated garage, ensure that it does not freeze during the winter months. This can cause the can to bulge or rust.