Whether tea or coffee are beneficial depends on the root cause. Candida is often but not always down to consuming excess carbs or poor diet. The causes can be complex and multifactorial.
I've had candida overgrowth due to an impaired immune system caused by mercury poisoning and having joint hypermobility syndrome, which causes excess histamine release and increased permeability of mucosal linings.
I've eliminated candida overgrowth through avoiding all grains and legumes apart from white rice. Starch isn't a problem. Lectins, phytic acid and foods high in certain types of yeasts and molds are, and fructose to a lesser extent.
Caffeine is a powerful anti-histamine so it can be beneficial for those prone to autoimmune problems. I use it predominantly to keep my blood pressure up to a healthy level and as an antihistamine. I have excellent insulin sensitivity and never had any issues with blood sugar levels. I avoid black tea as that is histamine promoting, but find green tea very beneficial.
F 5 ft 3. HW: 196 lbs. Primal SW (May 2011): 182 lbs (42% BF)... W June '12: 160 lbs (29% BF) (UK size 12, US size 8). GW: ~24% BF - have ditched the scales til I fit into a pair of UK size 10 bootcut jeans. Currently aligning towards 'The Perfect Health Diet' having swapped some fat for potatoes.