You are thinking incorrectly about this and probably because of the misinformation posted on this forum by certain people.
Leaky Gut is not actually the gut ie colon but the stomach! It does also affect the colon but the source is the stomach.
Candida is also stomach based. That is why most people fail to defeat it and struggle for years. It's not even candida that needs defeating, it is a gram negative bacteria. Candida likes to shack up with these bacteria as it protects them with a biofilm. They can then seed/spore from the biofilm spreading throughout the digestive system.
Check your stomach acid production and you will probably find it is low. Poor food breakdown and diminished stomach function causes many problems for the body including poor protein utilization, poor vitamin and mineral absorption and the risk of parasites as the protective function of the stomach is compromised.