Health benefits are found in Rooibos Tea due to it having antioxidants, though the increase has been noted to be small.
Structure-antioxidant relationship of flavonoids from fermented rooibos: https://www.ncbi.nlm.nih.gov/pubmed/19156714
Aspalathin and Nothofagin from Rooibos (Aspalathus linearis) inhibits high glucose-induced inflammation in vitro and in vivo: https://www.ncbi.nlm.nih.gov/pubmed/25338943
Free Radicals, Antioxidants in Disease and Health: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614697/
Bioavailability and antioxidant potential of rooibos flavonoids in humans following the consumption of different rooibos formulations: https://www.ncbi.nlm.nih.gov/pubmed/25212140
Bioavailability of C-linked dihydrochalcone and flavanone glucosides in humans following ingestion of unfermented and fermented rooibos teas: https://www.ncbi.nlm.nih.gov/pubmed/19534535
There have been studies that suggested that Rooibos Tea can help with heart health.
Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study: https://www.ncbi.nlm.nih.gov/pubmed/8105262
Selective bronchodilatory effect of Rooibos tea (Aspalathus linearis) and its flavonoid, chrysoeriol: https://www.ncbi.nlm.nih.gov/pubmed/17080260
Effects of green tea, black tea and Rooibos tea on angiotensin-converting enzyme and nitric oxide in healthy volunteers: https://www.ncbi.nlm.nih.gov/pubmed/20144258
This study included 40 overweight adults who were at high risk of heart disease. It suggested that consuming six cups of Rooibos Tea daily for six weeks decreased “bad” LDL cholesterol. There was also a boost in “good” HDL cholesterol.
Effects of rooibos (Aspalathus linearis) on oxidative stress and biochemical parameters in adults at risk for cardiovascular disease: https://www.ncbi.nlm.nih.gov/pubmed/20833235
Antioxidants quercetin and luteolin which are in Rooibos Tea was shown to kill cancer cells and prevent tumor growth.
Blockade of the epidermal growth factor receptor tyrosine kinase activity by quercetin and luteolin leads to growth inhibition and apoptosis of pancreatic tumor cells: https://www.ncbi.nlm.nih.gov/pubmed/12168845
Food-derived polyphenols inhibit pancreatic cancer growth through mitochondrial cytochrome C release and apoptosis: https://www.ncbi.nlm.nih.gov/pubmed/11920648
Animal studies have shown that antioxidant aspalathin may have diabetic effects. This tea may help balance blood sugar levels and reduce insulin resistance.Aspalathin improves hyperglycemia and glucose intolerance in obese diabetic ob/ob mice: https://www.ncbi.nlm.nih.gov/pubmed/23238530