Forget about an apple a day. When it comes to saving your bones, research suggests a dose of tomato juice might keep brittle bones at bay.
Calcium researchers at the University of Toronto examining the link between nutrition and osteoporosis in post-menopausal women say as little as 30 milligrams of lycopene found in tomatoes — the equivalent of two glasses of tomato juice — significantly increases the presence of cell-protecting antioxidants and reduces the risk of osteoporosis.
The brittle-bone disease affects one in four women Canadian women over the age of 50, with two million Canadians at risk of serious fractures in their lifetime. The burden to the Canadian health care system is estimated at $1.9 billion a year.
Tomato juice
In the U of T study, post-menopausal women aged 50 to 60 were initially restricted for a month from consuming anything containing lycopene, a bright red phytochemical found in tomatoes, watermelons and papayas. For the rest of the four-month investigation, they were split into four groups. Twice a day, participants either consumed a 15 milligram lycopene supplement, a glass of Heinz tomato juice naturally containing 15 mg of lycopene, a gourmet Japanese tomato juice with 35 mg of lycopene or a placebo.
By the end of the lycopene-free month, researchers measured bone turnover markers to assess bone metabolism, antioxidant capacity to measure antioxidants in blood, and oxidative stress parameters to determine cell damage. In every participant, lycopene and antioxidants had dropped significantly, while oxidative stress associated with cell damage dramatically rose.
“There was an increased resorption of bone. In other words, within a month, the participants were more prone to the risk of osteoporosis,” says Leticia Rao, director of the Calcium Research Laboratory, who conducted the study with Erin Mackinnon. For the next phase, during which participants consumed tomato juice or supplements, “the results were the opposite. We found increased antioxidant capacity, decreased oxidative stress parameters and decreased bone resorption markers.”
Researchers found no difference between the groups taking the supplements, regular juice or gourmet tomato juice from Japan. “So there is a certain maximum of lycopene you can take for it to be clinically effective” of between 30 mg and 70 mg daily, Rao says.
Not all individuals might exhibit the same benefits to lycopene intervention. As a corollary to the study, the researchers assessed participants for paraoxonase-1, an enzyme responsible for removing oxidative stress from molecules. The study showed that some women with a specific gene mutation responded better to lycopene than others.
Tomato juice
Although there have been no population studies to assess how widespread the paraoxonase-1 mutation is, focus on genetic studies is increasing.
According to Rao, the growing field of nutrigenomics — research that links nutrition to genetic expression — is advancing knowledge of osteoporosis-fighting essentials, such as vitamin D and polyphenols, chemical compounds found in plants. A recently released study by McMaster University found that half of osteoporosis patients are vitamin D deficient, even though more than 40 per cent were taking supplements. The study also found that in 47 per cent of patients with known deficiencies, physicians did not prescribe supplementation.
“In Canada, everyone should be on vitamin D,” says McMaster’s Dr. Jonathan Adachi, who conducted the study of 16 specialists and 36 primary care practitioners in Ontario and Quebec. “Osteoporosis Canada says we should be taking between 800 (international units) and 2000 IU daily. It’s pennies a day, and it’s a therapy with known benefit. It can reduce hip fractures. There are studies to suggest it can protect against breast and prostate cancer. It may prevent falls, infection and osteoarthritis.”
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“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.
Where did the story come from?
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.
What kind of research was this?
This small randomised controlled trial investigated whether levels of a substance called N-telopeptide, a marker of bone loss, in the body could be affected by lycopene supplementation in pill form and from tomato juice. Lycopene is a type of antioxidant. It is found in fruit and and levels of lycopene are especially high in tomatoes. Antioxidants in general are thought to help prevent damage to cells by neutralising substances called “reactive oxygen species” (ROS), which are byproducts of the metabolic process (how the body breaks down food).
The researchers enrolled early postmenopausal women, aged 50 to 60 years old. Women at this age lose bone at an accelerated rate and according to the researchers, some studies have shown that the rate of bone loss and damage to bone cells is increased by rising levels of ROS.
In this study, the researchers wanted to see whether lycopene supplementation would reduce evidence of bone loss in women at high risk.
What did the research involve?
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 women were randomly allocated to one of four groups: 15mg of lycopene from regular tomato juice, 35mg of lycopene from lycopene-rich tomato juice, 15mg of lycopene from a capsule, and a placebo capsule containing no lycopene.
All the women were asked to refrain from eating foods that contained lycopene for one month before the start of the study. Height, weight, blood pressure and a blood sample for analysis were also taken before the study started.
The women took the supplement twice a day with meals. Further blood samples were taken for analysis after two and four months of supplementation. For the seven days prior to a blood test, the women kept a daily food diary to record the other food and drinks they consumed during this period. The study lasted for four months. The researchers were mainly interested in blood levels of the substance N-telopeptide. This is one of several substances whose concentration in the blood will increase if bone is being broken down. The researchers also measured a number of other substances in the blood including proteins and enzymes, and also tested blood samples for antioxidant capacity.
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 is the main analysis they present. 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.
What were the basic results?
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).
How did the researchers interpret the results?
The researchers concluded that the levels of reduction in N-telopeptide in the groups receiving lycopene are comparable to those seen in postmenopausal women who are supplemented with calcium and vitamin D, both of which are recommended for preventing osteoporosis.
Conclusion
This was a small randomised controlled trial which the researchers themselves called a pilot study. It provides preliminary evidence of an effect, but must be followed by larger, more robust studies that have clinically meaningful outcomes.
The researchers delivered an in-depth and insightful report of their research,highlighting the main shortcomings of their study. While they are optimistic about their findings, reporting that the size of the reduction in N-telopeptide was similar to that seen as a result of calcium and vitamin D supplementation, they admit that they did not measure bone mineral density (BMD) or follow the participants for long enough to observe any significant changes in BMD.
This means we do not know what effect the reduction in N-telopeptide has on BMD or other outcomes like fracture rates which are the important clinical ones for women at risk of osteoporosis. As such, the research does not provide evidence that lycopene has a clinically important benefit for postmenopausal women. Longer studies would be needed to determine whether lycopene has a role in preventing of osteoporosis.
Importantly, giving the women supplements with greater concentrations of lycopene did not affect the total amount absorbed by the body. This suggests that the body may only absorb what it needs and does not take in more simply because it is given more.
The relationship between beta-carotene and lycopene may also need further research, as it is not clear which of these antioxidants (or both) might be responsible for the changes seen. The potential harms of taking too much of either substance need further investigation.
Two glasses of tomato juice a day strengthens bones and can ward off osteoporosis, say scientists.
The key ingredient is thought to be lycopene, the antioxidant already credited with cutting the risk of prostate cancer in men and protecting against heart disease.
Osteoporosis affects around three million people in the UK.
Researchers at the University of Toronto in Canada asked 60 post-menopausal women, aged 50 to 60, to cut out all tomato products from their diet for a month.
This led to a significant increase in blood levels of N-telopeptide, a chemical released into the bloodstream when bone is being broken down.
Then, for four months, the women were given a daily dose of standard tomato juice containing 15mg of lycopene, an enriched version with 35mg of lycopene, lycopene capsules or dummy capsules.
This led to a significant drop in levels of N-telopeptide in women drinking either type of juice or taking the capsules. But there was no benefit in women taking the dummy capsules.
Standard supermarket juice was just as good as the lycopene-enriched one, said researchers.
Two glasses a day of tomato juice containing 15mg of lycopene could be enough to strengthen brittle bones, the journal Osteoporosis International reported.