“Two glasses of tomato juice a day strengthens bones and can ward off osteoporosis,” The Daily Telegraph reported. It said scientists have found that an ingredient in the drink, called lycopene, slows down the breakdown of bone cells, protecting against the disease.
This news story is based on a small pilot study that compared the effects of lycopene supplements and tomato juice on chemical signs of bone loss in postmenopausal women. Women taking lycopene from either juice or pills had lower levels of the chemical by-product associated with osteoporosis.
The findings of this study highlight an avenue for further research. However, it is too soon to conclude that tomato juice will help fight bone disease. The researchers, though optimistic, make it clear that their study is a pilot and that larger studies that measure actual bone loss or fractures, rather than the signs of the disease, will provide better evidence.
The study was carried out by researchers from St Michael’s Hospital in Toronto and the University of Toronto, Canada.
The study was funded by tomato juice manufacturers, the makers of the lycopene supplements and various other organisations. These included the Canadian Institutes of Health Research, the research and development departments of Genuine Health Inc., the HJ Heniz Co, Millennium Biologix Inc., Kagome Co (Japan) and LycoRed Ltd (Israel).
The study was published in the peer-reviewed medical journal Osteoporosis International.
The Telegraph covered the research well, although it is important to highlight some of the study’s shortcomings including its small size and the fact that it measured a surrogate marker of bone loss, rather than actual bone loss or fractures.
The researchers enrolled 60 women who had been postmenopausal for at least a year and who were aged between 50 and 60 years. Women were excluded if they were smokers or if they were taking any medications that might affect their bone metabolism or have antioxidant properties (for example, treatments for heart disease, high blood pressure or diabetes). They were asked not to consume any vitamins that may contain antioxidants or foods containing lycopene, such as grapefruit and watermelon, for the duration of the study.
The researchers compared the levels of N-telopeptide in the three lycopene supplementation groups with those in the placebo group. They also merged the three lycopene supplementation groups into one group to compare it separately against placebo. This was the main analysis they presented. The analyses were adjusted for factors that might affect the relationship between lycopene and bone health, such as BMI, age, blood pressure, years since menopause and levels of antioxidants and bone-loss markers at the start of the study.
The total amount of lycopene absorbed by the body was the same for both women taking supplements and those taking tomato juice. As expected, women taking supplements had more lycopene in their blood than those on placebo at the two- and four-month follow-ups.
After two months, blood levels of N-telopeptide were reduced in the supplementation group, while the placebo group showed increased levels. This difference between the treatment and placebo groups was significant and present at four months. The blood levels of other substances also increased, such as beta-carotene (a pro-vitamin also found in tomato juice and a product of lycopene metabolism).