Mysql slow queries?

[welkin]

My mysql server has about 130 slow queries. I know what slow queries are, but how does this value affect my mysql server? what can i do to lower these slow queries? or do i even have to lower these queries or is this just a "normal" value?
Zabbix is monitoring 2754 items on 89 hosts and stores 49.318 new values per second,

thanks in advance

welkin