Raisins have been the object of phytonutrient research primarily for their unique phenol content, but these delicious dried grapes are also a top source of the trace mineral, boron.
The phenols found in fruit have repeatedly been show to have antioxidant activity and to help prevent oxygen-based damage to cells in the body. The total antioxidant activity of many fruits and vegetables has been found to be exactly parallel to their total phenol content, and raisins take their place in this list right alongside prunes and apricots as an antioxidant-rich fruit. The flavonols (one type of phenol belonging to the flavonoid family) in raisins appear to be least affected by the grape-drying process.
Boron is a mineral critical to our health, and is of special interest in women in relationship to bone health and osteoporosis (bone softening). Boron is a trace mineral required to convert estrogen and vitamin D to their most active forms (17-beta-estradiol and 1,25-(OH)2D3 respectively). Estrogen levels drop after menopause causing osteoclasts to become more sensitive to parathyroid hormone, which signals them to break down bone. Studies have shown that boron provides protection against osteoporosis and reproduces many of the positive effects of estrogen therapy in postmenopausal women. Raisins are among the top 50 contributors to total dietary boron in the U.S. diet.
Eating 3 or more servings of fruit per day may lower your risk of age-related macular degeneration (ARMD), the primary cause of vision loss in older adults, by 36%, compared to persons who consume less than 1.5 servings of fruit daily. Surprisingly, intakes of vegetables, antioxidant vitamins and carotenoids were not strongly related to incidence of either form of ARMD but fruit intake was definitely protective against the severe form of this vision-destroying disease.