Fruits and vegetables provide only modest protection from cancer?

vegetables

 

You’ve probably seen these headlines on the internet or television recently, claiming that fruits and vegetables provide very little protection against cancer. Of course something like this makes big news – it makes eaters of the typical Western diet feel validated in their unhealthy choices. But is it true? Do fruits and vegetables really offer only weak protection against cancer? Let’s look at the details of the study.

Researchers analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC), a large study of over 400,000 people. Subjects reported dietary intakes and were followed for approximately 8 years. The researchers reported the associations between fruit and vegetable intake and risk of total cancer. Two-hundred grams of combined fruits and vegetables (approximately 2 servings) offered a 3% decrease in risk that was statistically significant.1 

According to the lead scientist, Dr. Paolo Boffetta, from Mount Sinai Medical Center, “The bottom line here is that, yes, we did find a protective effect of fruit and vegetable intake against cancer, but it is a smaller connection than previously thought. However, eating fruits and vegetables is beneficial for health in general and the results of this study do not justify changing current recommendations aiming at increasing intake of these foods.”2

A tiny amount of plant food offers a tiny amount of benefit.

Yes, 3% is a tiny reduction in risk – but 200 grams is also a tiny amount of fruits and vegetables! One medium apple is approximately 180 grams, one cup of blueberries is 150 grams, and 1 cup of chopped raw broccoli is 90 grams. So keep in mind all these people did is eat the standard cancer-causing diet and add one apple or two cups of vegetables with dinner, they did not follow a vegetable-centered diet. They were still eating all the cancer-causing processed foods and animal products as their major source of calories.

The median daily intake in this study was 335 grams of fruits and vegetables combined per day – only about three servings. According to the CDC, only one-third of U.S. adults eat two or more servings of fruit per day, and only one-quarter of adults eat three or more servings of vegetables per day.3 These minimal amounts cannot be expected to provide disease protection. I recommend a far more substantial intake of fruits and vegetables with 90 percent of calories coming from nutrient rich plant material, lots of it raw and green. I recommend about two pounds of vegetables per day (approximately 900 grams) and at least 4 fresh fruits per day (which adds another 600 grams). Most importantly, attention should be paid to the highly cancer-protective plant foods, greens, onion, berries, beans and seeds. 

The more fruits and vegetables the subjects ate, the more cancer protection they got.

Many of the news stories on this subject neglected to mention the fact that the researchers found a dose-response relationship between fruit and vegetable intake and cancer risk – this means that as the number of servings increased, rates of cancer decreased. Those eating five servings per day reduced their risk by 9% compared with those eating 2.5 or less, and those eating more than eight servings per day reduced their risk by 11%.4 The benefits of lifestyle changes are proportional to the changes made. As we add more vegetable servings, we increase our phytochemical intake and leave less room in our diet for harmful foods, enhancing cancer protection even further. 

Different fruits and vegetables offer different levels of protection.

In this study, all fruits and vegetables were lumped together in one category – this could have diluted the results. Leafy greens and potatoes have nutrient profiles that are quite different, but in this study, they are both treated the same.   The participants did not eat an extra 200 grams of raw greens - French fries and ketchup counted as a vegetable.

Cruciferous vegetables, such as kale, cabbage, collards, and broccoli, contain potent chemopreventive compounds called isothiocyanates (ITCs). ITCs have a variety of anti-cancer actions including inhibition of angiogenesis (blood vessel formation; important for tumor growth), detoxification or removal of carcinogens, inhibition of cancer cell growth, promotion of cancer cell death, and prevention of DNA damage by carcinogens. Epidemiological studies suggest that cruciferous vegetables, onions, and mushrooms are far more protective against cancer than vegetables overall - inverse relationships between cruciferous vegetable intake and breast, prostate, lung, and colorectal cancers have been found.5  For example, in one prospective study, one or more servings per week of cabbage reduced the risk of pancreatic cancer by 38%.6 And that was just one serving a week, demonstrating dramatic protection is available and real when a diet is ideally designed. The regular consumption of mushrooms has been demonstrated to decrease risk of breast cancer by over 60 percent.7 Onions, berries, seeds and beans also have dramatic beneficial effects.8 In other words, high nutrient plant foods work synergistically and a well designed diet can offer dramatic protection against not just cancer, but heart disease, strokes and dementia.

Healthful eating is a lifetime commitment

The EPIC study followed adult subjects for 8 years, but the foundation of adult cancers was very likely laid down in childhood or early adulthood.9   These researchers missed the most important tenet of nutritional research and that is—childhood diets are the major cause of adult cancers. I wrote a book about this—Disease-Proof Your Child, with all the supporting scientific references. The protective substances contained in fruits and vegetables are more effective if they are consistently present in the diet since childhood.  Making moderate changes later in life, like adding a serving of fruit and vegetables, is not likely to make much of an impact on cancer risk. For later life changes to dramatically reduce cancer risk a total dietary makeover is required, that is one of the purposes of my nutritarian diet-style, to offer people real protection from an ideally designed diet that is adopted later in life.

Conclusion

Most people are confused about nutrition, and results like these can add to the confusion. There is clear evidence that unrefined plant foods protect against chronic disease, but modest nutritional improvements offer only modest health benefits. Cutting back on cigarettes does not offer much protection against lung cancer either.  It is the total package of a well-designed, nutrient-dense diet, regular exercise, and a healthy weight that offers optimal benefit. We can win the war on cancer.

 

References:

1. Boffetta P, Couto E, Wichmann J, et al. Fruit and Vegetable Intake and Overall Cancer Risk in the European Prospective Investigation Into Cancer and Nutrition (EPIC). J Natl Cancer Inst. 2010 Apr 6.[Epub ahead of print]

2. Mount Sinai Study Shows Only a Weak Link Between Fruit and Vegetable Intake and Reduced Risk of Cancer. http://mountsinai.org/about-us/newsroom/press-releases/mount-sinai-study-shows-only-a-weak-link-between-fruit-and-vegetable-intake-and-reduced-risk-of-cancer

3. U.S. Centers for Disease Control. Fruit and Vegetable Consumption Among Adults --- United States, 2005. Morbidity and Mortality Weekly Report March 16, 2007 / 56(10);213-217

4. NewScientist. Short Sharp Science: Five fruit and veg a day won't keep cancer away. http://www.newscientist.com/blogs/shortsharpscience/2010/04/five-fruit-and-veg-a-day-wont.html

5. Higdon JV et al. Cruciferous Vegetables and Human Cancer Risk: Epidemiologic Evidence and Mechanistic Basis. Pharmacol Res. 2007 March ; 55(3): 224–236

6. Larsson SC, Hakansson N, Naslund I, Bergkvist L, Wolk A. Fruit and vegetable consumption in relation to pancreatic cancer: a prospective study. Cancer Epidemiol Biomarkers Prev 2006;15:301–305.

7. Zhang M, et al. Dietary intakes of mushrooms and green tea combine to reduce the risk of breast cancer in Chinese women. Int J Cancer. 2009;124:1404-1408

8. Powolny AA, Singh SV. Multitargeted prevention and therapy of cancer by diallyl trisulfide and related Allium vegetable-derived organosulfur compounds. Cancer Lett. 2008 Oct 8;269(2):305-14.

Stoner GD, Wang LS, Casto BC. Laboratory and clinical studies of cancer chemoprevention by antioxidants in berries. Carcinogenesis. 2008 Sep;29(9):1665-74.

Aune D, De Stefani E, Ronco A, et al. Legume intake and the risk of cancer: a multisite case-control study in Uruguay. Cancer Causes Control. 2009 Nov;20(9):1605-15.

Jenab M, Ferrari P, Slimani N, et al. Association of nut and seed intake with colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition. Cancer Epidemiol Biomarkers Prev. 2004 Oct;13(10):1595-603.

9. Maynard M, Gunnell D, Emmett P, Frankel S, Davey Smith G. Fruit, vegetables, and antioxidants in childhood and risk of adult cancer: the Boyd Orr cohort. JEpidemiol Community Health. 2003 Mar;57(3):218-25. Erratum in: J Epidemiol Community Health. 2007 Mar;61(3):271.

Fuemmeler BF, Pendzich MK, Tercyak KP. Weight, Dietary Behavior, and Physical Activity in Childhood and Adolescence: Implications for Adult Cancer Risk. Obes Facts. 2009;2(3):179-186.

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Comments (17) Read through and enter the discussion with the form at the end
kls - April 19, 2010 10:31 PM

Yes, several people at my work checked their daily news sites during lunch and found the results of this article and came down on those of us nutritarians with much ridicule and laughter. "We told you, ha, all the good food you have been missing out on for nothing. Fruits and veggies are overrated." The banter hasn't stopped and now the article has been blown-up and posted in several areas of my work...the lunch room, bathrooms, waiting areas, staff meeting rooms, etc...to top it off, several areas of the article are highlighted about how fruits/veggies do little to prevent cancer.

Heather - April 19, 2010 11:13 PM

Does organic vs. non-organic play a role in subsequent cancers?

Greg - April 20, 2010 1:07 AM

Great leg work on this post... now how do we get as many people who read the other version of this article to read this one as well?

Zach - April 20, 2010 9:21 AM

kls - you work with some real jerks. You need to find a less hostile work environment.

Stephanie - April 20, 2010 10:11 AM

kls--You should totally print out this blog post fifty times and put it up everywhere in response. Seriously.

I really think this article highlights how little most people know about nutrition. It's really very sad....Even people who want to be healthful don't know how to go about it. The dining halls where I go to college just instituted a new thing, Meatless Mondays--for the sake of the environmental impact eating meat has--and along with all the griping about the lack of meat, a lot of people were complaining, "Where am I going to get my protein? I need protein!" Meanwhile, I was sitting there with a HUGE salad including lots of beans, thinking, "Duh. Vegetables." I kept my mouth shut this time, though; I didn't think people were in a mood to be argued with.

J. Rodriguez - April 20, 2010 10:42 AM

Just another example of how research can be manipulated for agendas. Critical thinking when reading this sort of research - or even watching the news - is essential.

Kat - April 20, 2010 12:28 PM

As I read the article a few days ago, I did notice that the vegetables and fruits were simply added to a standard diet.

The articles written on this seem to imply that since adding a small amount of fruit and veg to someone's diet makes little positive impact, eating processed food and burgers doesn't have much NEGATIVE impact. We really need to learn to read research much more carefully.

I hoping Dr. Fuhrman would comment on this and he did. Bravo.

Michelle - April 20, 2010 2:22 PM

Saw this article a week ago and was fuming... and waiting for it to appear on Diseaseproof ;) Great job!

carfree - April 20, 2010 3:48 PM

All the headlines said that vegetables don't help, but reading the article shows that even a small amount of vegetables does help. So if people only read the headline, that's the conclusion they'll get. No wonder people are confused.

colleen - April 21, 2010 6:14 AM

I think this makes so much sense!!!!!!!!!! Fruits and veggies were put on this earth for a reason to help humans live!!!! All this man made garbage that people are shoveling in was not made for our bodies to breakdown. I have had so many disagreements with nutritionist they get so angry when I tell them it better to eat Dr Furhman way. I just think it so sad that these studies come out and misinform people as they continue down the same nutritional road and head for disaster. Thank God for Dr's like you Dr Furhman!!!!

Kat - April 21, 2010 6:22 PM

Thank you so much for this article..it is so very interesting to read. I am passing it on to all my friends!

Monty - April 22, 2010 8:37 AM

Minimizing fruits and vegetables will not protect against cancer, but it will protect the cancer industry from loss of profits.

John - December 22, 2010 5:00 PM

I still haven't found any reason to believe that a diet rich in beans, brown rice, oatmeal in the morning, seeds, berries, cruciferous vegetables, onions, fruit like oranges and lemons and apples and watermelon and pineapple and avacado, roots and small amounts of meat/fish once or at most twice a week is bad. In fact, the more I learn the more I think this is the ideal diet.

I think our enemy is the processed food industry (snacks, softdrinks, donuts, etc) and the agricultural industry that wants people gulping down 3 pound burgers and bacon and eggs and the coal power industry that wants us to ignore increased cancer rates and the cities and municipal powers that want us to ignore the missions from cars and industry. Etc. I just get so tired of all this.

I haven't eaten well in the past 10 years because of little money, but I know as clearly as I know what I"m sexually attracted to that our diet in this country SUCKS BIGTIME.

Scott - March 17, 2011 10:27 AM

If you are smart enough to continue a commitment to F & v consumption and have kids, take a look at "The ABC's of Fruits & Vegetables and Beyond." Many classes using it

Vivek - May 1, 2011 1:03 PM

I agree heartily that reports on this study underrate the protective effect of fruits and vegetables, and the study has little bearing on a nutritarian diet, but I'd like to correct one point in the post. Potatoes were not in fact counted as vegetables. "Fresh fruits comprised approximately 90% of the total fruit intake. This category also included dried and canned fruits but not fruit juices. Fruit juices are nutritionally different from fresh fruits (eg, added sugars and vitamins could be diluted or prepared from concentrate) and are quantified in the liquid form, whereas total fruit and vegetable intake is expressed primarily as solid foods. Potatoes, other tubers, legumes, and vegetable juices were not included in the category of total vegetables." (http://jnci.oxfordjournals.org/content/102/8/529.long)

I am not sure how processed vegetable products such as ketchup would be counted by the EPIC researchers.

I was curious about the dose-response relationship mentioned by Dr.Fuhrman and wanted to forward the data to my scientifically minded but skeptical friends. In case anyone else wants a pointer to that data, here it is: http://jnci.oxfordjournals.org/content/102/8/529/T2.expansion.html

Truthseeker - July 20, 2011 2:34 AM

It is my understanding that there is no scientific basis underpinning the recommendation to eat large quantities of grains, fruits and vegetables. We are simply told to eat these foods because it makes big bucks for agribusiness. Fruit contains copious amounts of fructose - a sugar which is directly implicated in obesity. Veges are ok, but why eat more than you need to i.e. maybe a couple a week? Grain, nuts and legumes cause a host of health problems.

Peter - October 24, 2011 5:35 AM

I hate hearing bad news about my good habits. Also, people don't realize that you cannot be healthy simply just by adding vegetables to your diet. Ever seen those dietitians telling you that ice-cream mixed with fruit is healthy because it has fruit on it? To be healthy, you need to take all the "crap" out of your diet, and replace it with anything that would naturally grow out of the ground in it's whole form. Try this: Smell your feces, and if it smells bad, then it means you really need to clean out your body. Nothing is more disgusting than having pipes in your body that are clogged with rotten crap.

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