Tomato consumption may protect against osteoporosis
MedWire News: Restricting dietary lycopene intake for a period of only 1 month results in increased bone resorption and oxidative stress, Canadian researchers report.
Therefore, "consumption of tomatoes and tomato products, as a source of lycopene in the daily diet, may be beneficial in maintaining overall health and decreasing the risk for age-related chronic diseases, particularly osteoporosis, which is associated with oxidative stress," they say.
Lycopene is a carotenoid that acts as a powerful antioxidant, explain Leticia Rao (St Michael's Hospital, Toronto, Ontario) and colleagues in the Journal of Nutrition Health and Ageing.
Previous research by Rao and team, reported by MedWire News, revealed that lycopene supplementation may decrease the risk for osteoporosis in postmenopausal women.
In the present study, the team investigated the effects of a lycopene-restricted diet on oxidative stress parameters and bone turnover markers in 23 healthy postmenopausal women aged 50-60 years.
The women were asked to avoid lycopene-containing foods, including tomatoes and tomato products, vegetable juice, watermelon, Chinese orange, pink guava, red grapefruit, and rosehip, for a period of 1-month.
The researchers report that after 1-month of lycopene restriction, serum lycopene levels were, on average, a significant 54.9% lower than at baseline (before the diet began), while levels of the carotenoids α/β-carotene and lutein/zeaxanthin were 22.8% and 12.8% lower, respectively.
Furthermore, concentrations of the endogenous antioxidant enzymes catalase and superoxide dismutase were significantly reduced by a mean 8.4% and 9.3%, respectively. In contrast, the concentration of glutathione peroxidase significantly increased by 114.7% on average.
There was also a marginal increase in oxidative stress as demonstrated by non-significantly increased lipid and protein oxidation.
Finally, bone resorption, as measured by crosslinked N-telopeptide of type I collagen, increased by 20.6%, whereas bone formation, measured by bone alkaline phosphatase remained stable.
Rao and co-authors note that although their findings suggest that the daily consumption of lycopene may be important as it acts as an antioxidant to decrease bone resorption in postmenopausal women, it is also possible that other carotenoids present in tomatoes and tomato products have an impact on the parameters studied.
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By Laura Dean