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.