Diet rich in tomatoes may lower breast cancer risk
A tomato-rich diet may help protect at-risk postmenopausal women from breast cancer, according to new research in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism.
Breast cancer risk rises in postmenopausal women as their body mass index climbs. The study found eating a diet high in tomatoes had a positive effect on the level of hormones that play a role in regulating fat and sugar metabolism.
“The advantages of eating plenty of tomatoes and tomato-based products, even for a short period, were clearly evident in our findings,” said the study’s first author, Adana Llanos, PhD, MPH, who is an Assistant Professor of Epidemiology at Rutgers University. Llanos completed the research while she was a postdoctoral fellow with Electra Paskett, PhD, at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute. “Eating fruits and vegetables, which are rich in essential nutrients, vitamins, minerals and phytochemicals such as lycopene, conveys significant benefits. Based on this data, we believe regular consumption of at least the daily recommended servings of fruits and vegetables would promote breast cancer prevention in an at-risk population.”
The longitudinal cross-over study examined the effects of both tomato-rich and soy-rich diets in a group of 70 postmenopausal women. For 10 weeks, the women ate tomato products containing at least 25 milligrams of lycopene daily. For a separate 10-week period, the participants consumed at least 40 grams of soy protein daily. Before each test period began, the women were instructed to abstain from eating both tomato and soy products for two weeks.
When they followed the tomato-rich diet, participants’ levels of adiponectin – a hormone involved in regulating blood sugar and fat levels – climbed 9 percent. The effect was slightly stronger in women who had a lower body mass index.
“The findings demonstrate the importance of obesity prevention,” Llanos said. “Consuming a diet rich in tomatoes had a larger impact on hormone levels in women who maintained a healthy weight.”
The soy diet was linked to a reduction in participants’ adiponectin levels. Researchers originally theorized that a diet containing large amounts of soy could be part of the reason that Asian women have lower rates of breast cancer than women in the United States, but any beneficial effect may be limited to certain ethnic groups, Llanos said.
Eating Tomatoes Lowers the Risk of Stroke
Eating tomatoes and tomato-based foods is associated with a lower risk of stroke, according to new research published in the October 9, 2012, print issue of Neurology®, the medical journal of the American Academy of Neurology. Tomatoes are high in the antioxidant lycopene.
The study found that people with the highest amounts of lycopene in their blood were 55 percent less likely to have a stroke than people with the lowest amounts of lycopene in their blood.
The study involved 1,031 men in Finland between the ages of 46 and 65. The level of lycopene in their blood was tested at the start of the study and they were followed for an average of 12 years. During that time, 67 men had a stroke.
Among the men with the lowest levels of lycopene, 25 of 258 men had a stroke. Among those with the highest levels of lycopene, 11 of 259 men had a stroke. When researchers looked at just strokes due to blood clots, the results were even stronger. Those with the highest levels of lycopene were 59 percent less likely to have a stroke than those with the lowest levels.
"This study adds to the evidence that a diet high in fruits and vegetables is associated with a lower risk of stroke," said study author Jouni Karppi, PhD, of the University of Eastern Finland in Kuopio. "The results support the recommendation that people get more than five servings of fruits and vegetables a day, which would likely lead to a major reduction in the number of strokes worldwide, according to previous research."
The study also looked at blood levels of the antioxidants alpha-carotene, beta-carotene, alpha-tocopherol and retinol, but found no association between the blood levels and risk of stroke.
Health benefits of eating tomatoes
Eating more tomatoes and tomato products can make people healthier and decrease the risk of conditions such as cancer, osteoporosis and cardiovascular disease, according to a March, 2011 review article the American Journal of Lifestyle Medicine, (published by SAGE).
Of all the non-starchy vegetables, Americans eat more tomatoes and tomato products than any others. Researchers Britt Burton-Freeman, PhD, MS, and Kristin Reimers, PhD, RD of the National Center for Food Safety & Technology, Illinois Institute of Technology and ConAgra Foods, Inc., looked at the current research to discover the role tomato products play in health and disease risk reduction.
The researchers found that tomatoes are the biggest source of dietary lycopene; a powerful antioxidant that, unlike nutrients in most fresh fruits and vegetables, has even greater bioavailability after cooking and processing. Tomatoes also contain other protective mechanisms, such as antithrombotic and anti-inflammatory functions. Research has additionally found a relationship between eating tomatoes and a lower risk of certain cancers as well as other conditions, including cardiovascular disease, osteoporosis, ultraviolet light–induced skin damage, and cognitive dysfunction.
Tomatoes are widely available, people of all ages and cultures like them, they are cost-effective, and are available in many forms. "Leveraging emerging science about tomatoes and tomato products may be one simple and effective strategy to help individuals increase vegetable intake, leading to improved overall eating patterns, and ultimately, better health." write the authors.
"Tomatoes are the most important non-starchy vegetable in the American diet. Research underscores the relationship between consuming tomatoes and reduced risk of cancer, heart disease, and other conditions," the authors conclude. "The evidence also suggests that consumption of tomatoes should be recommended because of the nutritional benefits and because it may be a simple and effective strategy for increasing overall vegetable intake."
Tomato-broccoli combo shown to be effective against prostate cancer
A new University of Illinois study shows that tomatoes and broccoli--two vegetables known for their cancer-fighting qualities--are better at shrinking prostate tumors when both are part of the daily diet than when they're eaten alone.
"When tomatoes and broccoli are eaten together, we see an additive effect. We think it's because different bioactive compounds in each food work on different anti-cancer pathways," said University of Illinois food science and human nutrition professor John Erdman.
In a study published in the January 15, 2007 issue of Cancer Research, Erdman and doctoral candidate Kirstie Canene-Adams fed a diet containing 10 percent tomato powder and 10 percent broccoli powder to laboratory rats that had been implanted with prostate cancer cells. The powders were made from whole foods so the effects of eating the entire vegetable could be compared with consuming individual parts of them as a nutritional supplement.
Other rats in the study received either tomato or broccoli powder alone; or a supplemental dose of lycopene, the red pigment in tomatoes thought to be the effective cancer-preventive agent in tomatoes; or finasteride, a drug prescribed for men with enlarged prostates. Another group of rats was castrated.
After 22 weeks, the tumors were weighed. The tomato/broccoli combo outperformed all other diets in shrinking prostate tumors. Biopsies of tumors were evaluated at The Ohio State University, confirming that tumor cells in the tomato/broccoli-fed rats were not proliferating as rapidly. The only treatment that approached the tomato/broccoli diet's level of effectiveness was castration, said Erdman.
"As nutritionists, it was very exciting to compare this drastic surgery to diet and see that tumor reduction was similar. Older men with slow-growing prostate cancer who have chosen watchful waiting over chemotherapy and radiation should seriously consider altering their diets to include more tomatoes and broccoli," said Canene-Adams.
How much tomato and broccoli should a 55-year-old man concerned about prostate health eat in order to receive these benefits? The scientists did some conversions.
"To get these effects, men should consume daily 1.4 cups of raw broccoli and 2.5 cups of fresh tomato, or 1 cup of tomato sauce, or ½ cup of tomato paste. I think it's very doable for a man to eat a cup and a half of broccoli per day or put broccoli on a pizza with ½ cup of tomato paste," said Canene-Adams.
Erdman said the study showed that eating whole foods is better than consuming their components. "It's better to eat tomatoes than to take a lycopene supplement," he said. "And cooked tomatoes may be better than raw tomatoes. Chopping and heating make the cancer-fighting constituents of tomatoes and broccoli more bioavailable."
"When tomatoes are cooked, for example, the water is removed and the healthful parts become more concentrated. That doesn't mean you should stay away from fresh produce. The lesson here, I think, is to eat a variety of fruits and vegetables prepared in a variety of ways," Canene-Adams added.
Another recent Erdman study shows that rats fed the tomato carotenoids phytofluene, lycopene, or a diet containing 10 percent tomato powder for four days had significantly reduced testosterone levels. "Most prostate cancer is hormone-sensitive, and reducing testosterone levels may be another way that eating tomatoes reduces prostate cancer growth," Erdman said.
Erdman said the tomato/broccoli study was a natural to be carried out at Illinois because of the pioneering work his colleague Elizabeth Jeffery has done on the cancer-fighting agents found in broccoli and other cruciferous vegetables. Jeffery has discovered sulfur compounds in broccoli that enhance certain enzymes in the human body, which then act to degrade carcinogens.
"For ten years, I've been learning how the phytochemicals in tomatoes affect the progression of prostate cancer. Meanwhile Dr. Jeffery has been investigating the ways in which the healthful effects of broccoli are produced. Teaming up to see how these vegetables worked together just made sense and certainly contributes to our knowledge about dietary treatments for prostate cancer," said Erdman.
Fighting prostate cancer with a tomato-rich diet
Men who eat over 10 portions a week of tomatoes have an 18 per cent lower risk of developing prostate cancer, new research suggests.
To assess if following dietary and lifestyle recommendations reduces risk of prostate cancer, researchers at the Universities of Bristol, Cambridge and Oxford looked at the diets and lifestyle of 1,806 men aged between 50 and 69 with prostate cancer and compared with 12,005 cancer-free men.
The NIHR-funded study, published in the medical journal Cancer Epidemiology, Biomarkers and Prevention, is the first study of its kind to develop a prostate cancer 'dietary index' which consists of dietary components – selenium, calcium and foods rich in lycopene – that have been linked to prostate cancer.
Men who had optimal intake of these three dietary components had a lower risk of prostate cancer.
Tomatoes and its products – such as tomato juice and baked beans - were shown to be most beneficial, with an 18 per cent reduction in risk found in men eating over 10 portions a week.
This is thought to be due to lycopene, an antioxidant which fights off toxins that can cause DNA and cell damage. Vanessa Er, from the School of Social and Community Medicine at the University of Bristol and Bristol Nutrition BRU, led the research.
She said: "Our findings suggest that tomatoes may be important in prostate cancer prevention. However, further studies need to be conducted to confirm our findings, especially through human trials. Men should still eat a wide variety of fruits and vegetables, maintain a healthy weight and stay active."
The researchers also looked at the recommendations on physical activity, diet and body weight for cancer prevention published by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR).
Only the recommendation on plant foods – high intake of fruits, vegetables and dietary fibre - was found to be associated with a reduced risk of prostate cancer. As these recommendations are not targeted at prostate cancer prevention, researchers concluded that adhering to these recommendations is not sufficient and that additional dietary recommendations should be developed.