Fruits and Vegetables Offer Little Protection Against Cancer
The dynamic duo of the food world may not have as many superpowers as once thought.
A massive 478,000 subject prospective study (where subjects are picked and followed), found that for every 2 servings of fruits and vegetables eaten per day, an individual's risk of cancer fell by a paltry average 3%.
And, the news gets worse...
It's bad enough that fruits and veggies made such a scanty difference in cancer rates, but to add to the disappointment, researcher's point to other factors such as exercise, lower smoking rates, and less red meat consumption, which may also explain the reduced rates of cancer.
The study's lead researcher, Dr. Paolo Boffetta, offered this explanation:
Diet is a complex pattern and lifestyle. Cancer is a complex disease. It's unlikely that one thing will explain the other. (Source)
There are some questions that remain unanswered however, when it comes to the diet/cancer link, namely:
- It's likely that certain vegetables and fruits are especially protective. The study didn't discriminate as to what kind of produce was consumed. Says prominent researcher, Dr. Walter Willett:
A very weak or undetectable association between fruits and vegetables and risk of cancer, does not exclude the possibility that one, or a small group of fruits or vegetables ... has an important protective effect. (source)
- While diet is considered a less prominent factor in terms of overall cancer prevention, vegetable and fruit intake appears to be more highly protective of cancers such as mouth, throat, and esophageal.
- The study didn't examine the role of fruit and vegetable consumption during adolescence.
- It would also be unwise to ignore the role of fruits and veggies in weight control - a definite factor in cancer rates.
Another hopeful bit of news is, that the same individuals who showed no difference in cancer rates, showed a 30% reduced risk of coronary heart disease or stroke (for those who ate 5 servings of fruits and vegetables vs. less than 1.5).
Bottom line:
Fruits and veggies may not offer as much cancer protection as once thought, but there are other very good reasons to keep eating them. To bolster cancer protection, throw in some exercise, stop smoking, and quit going to tanning salons.
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Created / Updated: April 30, 2010
Did they expect fruits ad vegetables to be the only way to reduce your cancer risk?
ReplyA flawed study. I think the real point is that you need synergy with everything you do. Eat right, exercise, don't smoke, keep stress levels down, don't get too much UV exposure, breath clean air and don't use too many toxic chemicals in the house. You know if eating vegetables helps prevent one cancer at 55, but not one 20 years later that's a good bargain.
ReplyI read about this study somewhere else and I think it's a little misleading. How were they defining "fruits and vegetables"? Considering that, according to the oh-so-knowledgable-FDA, a Manwich is a "full serving of vegetables", I could see the data being slightly skewed. Even though not smoking, tanning, or eating a lot of red meat will decrease your cancer risk, eating fruits and veggies can't hurt.
I thought they had done a study several years ago that said that increased fruit and veggie consumption decreased people's risk of colorectal cancer, which makes sense to me. All the internal scrubbing that the fiber does has to have some sort of benefit. Plus, it's probably better to have your fecal matter in contact with your intestines for as short of a time period as possible so it doesn't just sit there and rot.
ReplyI think I big reason why particularily americans do not benifit as much from vegetables is that they never add any healthful fats to the vegetables. All those great fat soluble vitamins like the carotinoids and vitamin E do nothing unless they can be absorbed, so that fat-free salad for lunch does people no good.
ReplyEither that or they smother the veggies in a crapload of cheese, butter, sauces, etc. and the fruit is in the form of pies or covered in sugar. In general, the American palate is pretty averse to most unadorned fruits and veggies. I happen to LOVE roasted broccoli tossed with a bit of extra-virgin olive oil, but a lot of people probably aren't so adventurous.
Replycheese butter sauces french healthy wonderful life
ReplyI think part of Leigh's point, Spectra, is that veggies should be paired with butter or something of the sort or they provide less nutritional benefit. Carotenoids do need fat to be converted to real Vitamin A (retinol).
You can also lacto-ferment the veggies into sauerkraut or kimchi and that is also healthful. However, I rarely eat raw veggies, because I don't think the human body is equipped to deal with that.
ReplyRyan, Leigh said "healthful fats" which I would imaging includes more olive oil than butter. As for the human body being equipped/not equipped to eat raw veggie I'd say it probably depends on the veggie itself - some are more digestable than others. Raw cucumber.. yum... raw potato... i feel ill...
ReplyI don't think butter counts as a "healthful fat" - think avocado, nuts, olives, or olive oil.
ReplyI don't reject the idea that veggies should be paired with fats to get more of the benefit they offer, but the key is monounsaturated fats...olive oil, nuts, avocados, etc. I'm saying that the way most Americans get veggies is probably not optimal. Most of my relatives are from the South and the way they eat veggies is usually smothered in bacon grease and/or cheese, butter, etc.
ReplyThis is replying to all three of you, not just Spectra. If you listed the fats that I use in my kitchen, I would consider extra-virgin olive oil the last healthy.
In this country, we should all be wary of linoleic acid (Omega-6) toxicity. Olive oil, nuts, avocados, and many vegetable oils all have a high amount of this. In excess, linoleic acid will cause the liver and brown fat to become resistant to T3 and T4 hormone.
The myth of saturated fat being dangerous has been busted, and we've found that the ratio of Omega-3 to Omega-6 is more important than getting a lot of them. In fact, getting a ton of Omega fats may not be a good idea. In addition, the ALA type of Omega-3 found in plant foods is only converted to usable DHA/EPA at about a 3% rate, so you can't use plant oils for Omega-3 anyways.
Given the data, I would place grass-fed animal fats above all else.
ReplyHi Ryan,
Couple of thoughts...
1. As with anything else - we need to look at context. I've never been a fan of trying to pit foods vs. food in terms of "healthyness". In the case of oils, they all have different properties/compounds/health benefits and one may be more warranted than another in any given circumstance. We have to look at the context of an entire diet rather than trying to label oils as healthy or unhealthy.
2. Pertaining to the above - if you look at the foods as a whole (olives/olive oil, nuts, avocados) they are have healthful properties to them and are staples of healthy traditional mediterranean diets.
3. Insofar as your concern about n-6's (which may or may not be well-founded in the first place - I'll get to that), olive oil is only 11% n-6 and avocados are similar. Nuts have moslty monos as well (depending on the nut).
4. n-6 acids in and of themselves have not been shown to be harmful. Again I'll wave the flag for context here. Give this review a read.. http://www.ncbi.nlm.nih.gov/pubmed/11590994
Also, could you elaborate on your last point "given the data"... which "data" are you refering to?
ReplyMike, I realize that olive and avocado fat is "only" about 10% n-6. However, I still consider it too high for a staple oil. I use mainly grass-fed butter and tallow and very little coconut oil; those are more in the range of 2-3%. I use olive oil for that rare time I want to eat my sourdough bread with oil and balsamic vinegar.
Olive oil may have other compounds in it, but the same is true of grass-fed butter. Olive oil also has a very high n-6 to n-3 ratio, compounded by the fact that ALA isn't very usable. When I say "given the data", I'm talking about the T3/T4 resistance and n-6/n-3 ratio. Olive oil presents no unique benefit to me other than it's liquid at room temperature.
ReplyWhat I'm saying Ryan is if you are going to be concerned (or cause concern for others) over a relatively low amount of n-6 - you'd better have some good data to back it up.
n6 to n3 ratio shouldn't be a concern if you aren't mainlining high-n6 oils and getting some fatty fish and/or supplementing with n-3's (something I do recommend).
I do agree that the disparity of n6-n3 is high in our society, but I think avoiding olive oil and avocadoes because of a little n-6 is way over the top in the paranoia dept.
ReplyI don't even understand why they did this study... Did anyone actually think that overall rate of vegetable consumption (with no question as to what the veggies are) would significantly impact overall cancer risk (with no question as to which cancer it is) even more than things like smoking and exercise? I think a 3% decline for two servings a day is actually pretty good considering how broadly the study was looking. "Cancer" is not a single disease - every type of cancer is a different disease with different risk factors, different treatments, etc. Anything that lumps them all together isn't going to get big results.
ReplyStaying out of the sun or tanning beds is not a solution for preventing cancer. The vitamin D3 you get from exposure to the sun's or tanning bed rays, has shown to significatly reduce almost all forms of cancer. Foods don't have enough vitamin d, so either get in the sun for moderate amounts of time, or take a vitamin d3 supplement to help prevent cancer.
ReplyHi Alan,
I don't think there is any one "solution" for preventing cancer either. I didn't tell anyone to stay out of the sun - I think sensible exposure is a good thing. Tanning beds, however have recently been declared carcinogenic to humans by the International Agency for Research on Cancer.
I won't take my chances on fake-n-bake to get my vitamin D.
ReplyWhile a litte off track, but relevant nontheless, it should also be pointed out that cancer thrives in a sugary environment. Sugar, and any substance that can be broken down into sugar (starchy foods, and yes, even whole grains), actually feeds cancer cells(1).
There have been studies done on the value of a ketogenic diet in treating cancer and it is compelling stuff.
1 http://www.sciencedaily.com/releases/2009/08/090817184539.htm
ReplyFunny, sugar also feeds normal cells.
Your link does not support anything to do with diet at all. There is currently very little research supporting a ketogenic diet for curing cancer - what research that exists is mostly case studies. A true ketogenic diet is not something to take lightly, and even if it works for cancer treatment, I can't imagine that it would ever be suggested for the average person for cancer prevention, which is what this study was about.
ReplyMy bottom line? Who funded this study and what is their agenda. Nutritional and drug studies are almost always biased for the bennefit of their sponsors.
You want to prevent cancer? Incredibly enough, studies show that if everyone had optimal levels of vitamin D, the rate of cancer would drop by as much as 70% — almost immediately! But do you see the American Cancer Society or Susan B. Komen broadcasting this? NO! Why is that? Follow the money!
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