An increased intake of blueberries may prevent the weakening of bones that occurs
after menopause, suggests a new study with lab animals.
Researchers from Florida State University and Oklahoma State University looked
at the effects of blueberries on bone loss in rats that had had their ovaries
removed (ovariectomised). This animal model is designed to represent menopausal
osteoporosis, or the bone-wasting condition that affects the elderly, as it
combines both hormone deficiency with chronic inflammation. One group of the
animal’s diet was supplemented with blueberries (5%) for 100 days. The
rats not supplemented with blueberries lost about 6% of the bone mineral densities
at the femoral neck (where the hip breaks), at the tibia (the shin bone), in
the lumbar spine and throughout their whole body. Supplementing the diet with
blueberries prevented thinning of bone throughout the body, but had an intermediary
effect at preserving bone at the femoral neck and tibia. The researchers published
their study online ahead of print in The Journal of Nutritional Biochemistry.
Ellagitannin-rich pomegranate extract inhibits prostate cancer viability
and spread
Angiogenesis is the formation of blood vessels between a tumor and surrounding
tissue so the tumor can be nourished. Studies have found that prostate cancer
tumors suffer from hypoxia, a condition where there is a lack of oxygen reaching
the tissue despite the presence of oxygenated blood. Thus the tumor must apparently
create a greater blood supply (angiogenesis) to get more oxygen. The cellular
hypoxia triggers angiogenesis via the induction of two chemical messengers;
hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth
factor (VEGF) which both work at a cellular level.
Scientists at the Center for Human Nutrition in Los Angeles write that Pomegranate
juice and extracts are rich sources of Ellagitannins, phytochemicals that are
converted to Ellagic Acid. They have been shown to have chemopreventive potential
against prostate cancer. So far there have been no studies on the effects of
an Ellagitannin-rich pomegranate extract on angiogenesis. Human prostate cancer
cells were incubated with a pomegranate extract standardized to Ellagitannin
content, under normal and hypoxic conditions. Human prostate cancer cells (LAPC4)
were also injected into mice with severe immunodeficiency and the effects of
oral administration of Pomegranate on tumor growth, microvessel density, and
HIF-1alpha and VEGF expression were determined after 4 weeks of treatment. Ellagitannin-rich
Pomegranate extract inhibited the proliferation of prostate cancer cells significantly
under both normoxic and hypoxic conditions. HIF-1alpha and VEGF protein levels
were also reduced by Ellagitannin-rich Pomegranate extract under hypoxic conditions.
The extract decreased prostate cancer graft size, tumor vessel density, VEGF
peptide levels and HIF-1alpha expression after 4 weeks of treatment in SCID
mice. These results demonstrate that an Ellagitannin-rich Pomegranate extract
can inhibit tumor-associated angiogenesis as one of several potential mechanisms
for slowing the growth of prostate cancer in chemopreventive applications.
