Diet & Fitness

Olive leaf contains a number of active constituents, including flavonoids and other phenolic compounds, that have positive health effects, and has been used traditionally to support respiratory, digestive, immune, and cardiovascular health. Among its many positive metabolic effects, olive leaf has been shown to lower high blood pressure.⁹ An uncontrolled pilot trial with 663 pre-hypertensive subjects found taking a supplement providing 240 mg of compounds found in olive leaves and fruit (200 mg of oleuropein and 40 mg of hydroxytyrosol) daily for two months was associated with a 13 mmHg drop in systolic blood pressure and 7.1 mmHg drop in diastolic blood pressure.¹⁰ Another uncontrolled trial that enrolled ten volunteers with hypertension or pre-hypertension found treatment with 1,600 mg of olive leaf extract (providing 240 mg of oleuropein and 16 mg of hydroxytyrosol) daily for 28 days lowered systolic and diastolic pressures, and the effect was stronger in those with higher baseline blood pressure.⁹ In a randomized, double-blind, placebo-controlled, crossover trial (in which all participants receive placebo during one phase and treatment during another phase, in random order) that included 60 participants with borderline high blood pressure, six weeks of treatment with olive leaf extract providing 136 mg of oleuropein and 6 mg of hydroxytyrosol per day resulted in small (approximately 3 mmHg) reductions in systolic and diastolic pressures.¹² In a double-blind trial, the blood pressure-lowering effect of 500 mg of olive leaf extract twice daily for eight weeks was nearly as great as that of captopril, a drug used to treat hypertension: systolic pressure was 11.5 mmHg lower and diastolic pressure was 4.8 mmHg lower in those who received olive leaf extract, versus drops of 13.7mmHg and 6.4 mmHg in those who received captopril.¹³

Hydroxytyrosol, a phenolic compound present in olive leaf and extra-virgin olive oil, has anti-inflammatory activity. In a double-blind trial, treatment with 50 mg per day of olive leaf extract (providing 10 mg per day of hydroxytyrosol) for 4 weeks significantly improved pain, compared with a placebo, in people with osteoarthritis of the knee.¹³

In a placebo-controlled trial, 79 subjects with type 2 diabetes received 500 mg per day of olive leaf extract or placebo. After 14 weeks, those who received the olive leaf extract had lower fasting blood insulin levels and HbA1c, but no difference in post-meal insulin levels was seen.¹⁴ The same researchers also reported finding olive leaf extract inhibited starch digestion and glucose absorption in animals with experimental diabetes. On the other hand, 100 mg per day of olive leaf extract, in combination with fenugreek and bergamot extracts, was no better than placebo at restoring healthy glucose metabolism in a trial with 100 participants with prediabetes.¹⁵ Another trial included people with prediabetes who received either olive leaf tea of a control tea three times per day for 12 weeks. Olive leaf tea reduced fasting blood glucose levels and improved lipid levels.¹⁶ In overweight men at risk for developing type 2 diabetes, a high-polyphenol olive leaf extract (providing 51.1 mg of oleuropein and 9.7 mg of hydroxytyrosol per day) improved insulin sensitivity and pancreatic function after 12 weeks.¹⁷ More research in subjects with type 2 diabetes is needed.

Olive leaf extract has been shown to reduce oxidative stress, inflammatory signaling, and autoimmune activity, and to improve glucose metabolism and protect pancreatic cells in animal models of type 1 diabetes.^18,19,20 These results have not yet been reproduced in human clinical trials.

 

Herbs that directly attack microbes include the following: chaparral, eucalyptus, garlic, green tea, lemon balm (antiviral), lomatium, myrrh, olive leaf, onion, oregano, pau d’arco (antifungal), rosemary, sage, sandalwood, St. John’s wort, tea tree oil, thyme, and usnea.