DNS traffic over port 53 is plaintext so any requests made will be visible to your ISP (For more background on
DNS, check out the RFCs, start with 883 and then go to 7626 "DNS Privacy Considerations")
Therefore, in order to prevent eavesdropping between your client and the DNS service you would need to either use a secure-
DNS extension or tunnel your regular
DNS traffic through a VPN or proxy. However, if you are using your ISPs DNS servers than this is a moot point.
Depending on your circumstance you may want to use a VPN for all traffic or you may want to consider using something like Tor or a simple web based HTTP privacy proxy like AnonyMouse. However, if you are worried about DNS requests you might not want your ISP seeing you use privacy services.
Some options include:
Note: DNSSEC does not provide confidentiality:
DNSSEC does not provide confidentiality of data; in particular, all DNSSEC responses are authenticated but not encrypted.
Also consider, that if you have prefetch (see also) (predictive loading) enabled your browser will load the page and do more than the DNS lookups. You may want to disable this and due some research on the best secure browser configuration and addons to meet your needs.
If you are worried about inappropriate content you are not expecting, try enabling Safe Search.