In Praise of (Plant-based) Dietary Diversity

[Dean Pomerleau]

In his latest video (embedded below), everyone's favorite ☺ nutrition expert, Dr. Michael Greger talks about a topic near and dear to my own heart - dietary diversity when it comes to plant foods. He cites several studies including [1] which found different specific fruits and vegetables were protective against the development of cancer in different regions of the colon (i.e. proximal vs. distal). Study [2] found variety of fruits & vegetables consumed (independent of quantity) was associated with reduced risk of lung cancer in smokers. 

 

But study [3] was perhaps the most interesting. Researchers followed 7000 people for 11 years to see how their reported (via 7-day food diary) dietary quantity and variety of fruits and vegetables correlated with the development of type 2 diabetes (T2D). They found eating more quantity of F&V was associated with a 21% reduced risk of subsequent T2D. But eating a greater variety of F&V trumped the benefits of quantity - being associated with a 39% reduction in subsequent risk of T2D. Every different kind of F&V a person ate per week was associated with a 4% reduction in T2D. Since I eat almost 50 different F&Vs at every meal, I should have low enough risk to protect both me and anyone standing nearby☺.

 

Dr. G. points to the fact that the body appears to have receptors specifically (and perhaps serendipitously?) tuned to bind with specific phytochemicals in different fruits & vegetables, as an explanation for why eating a greater variety of F&V conveys health benefits. He doesn't mention the other important motivation in my book for eating a wide variety of fruits, vegetables, and other healthy plant foods. Namely, you minimize the risk of detrimental effects from eating too much of any one of them, be it a result of pesticides, contaminants, or unknown anti-nutrients.

 

--Dean

 

 

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[1] J Am Diet Assoc. 2011 Oct;111(10):1479-90. doi: 10.1016/j.jada.2011.07.008.

 

Fruit and vegetable consumption and the risk of proximal colon, distal colon, and

rectal cancers in a case-control study in Western Australia.

 

Annema N(1), Heyworth JS, McNaughton SA, Iacopetta B, Fritschi L.

 

Author information: 

(1)Western Australian Institute for Medical Research, Australia.

 

Comment in

    J Am Diet Assoc. 2011 Oct;111(10):1476-8.

    J Am Diet Assoc. 2011 Oct;111(10):1472-5.

    J Acad Nutr Diet. 2012 May;112(5):610; author reply 610-1.

 

BACKGROUND: Fruits and vegetables (F/V) have been examined extensively in

nutrition research in relation to colorectal cancer (CRC). However, their

protective effect is subject to debate, possibly because of different effects on 

different subsites of the large bowel.

OBJECTIVE: To determine whether any association between F/V consumption and risk 

of CRC differed by subsite of the bowel (proximal colon, distal colon, and

rectum).

DESIGN: The Western Australian Bowel Health Study is a population-based,

case-control study conducted between June 2005 and August 2007. Complete food

frequency questionnaire data were analysed from 834 CRC cases and 939 controls.

Logistic regression analysis was used to estimate the effects of quartiles of F/V

intake on risk of CRC at different subsites. Odds ratios (OR) and 95% confidence 

intervals (CI) were calculated for CRC overall and for the three separate

subsites.

RESULTS: Risk of proximal colon cancer and rectal cancer was not associated with 

intakes of total F/V, total vegetable, or total fruit. Brassica vegetable intake 

was inversely related with proximal colon cancer (Q4 vs Q1 OR 0.62; 95% CI 0.41

to 0.93). For distal colon cancer, significant negative trends were seen for

total F/V, and total vegetable intake. Distal colon cancer risk was significantly

decreased for intake of dark yellow vegetables (Q4 vs Q1 OR 0.61; 95% CI 0.41 to 

0.92) and apples (Q4 vs Q1 OR 0.51; 95% CI 0.34 to 0.77). An increased risk for

CRC was found to be associated with intake of fruit juice (Q4 vs Q1 OR 1.74; 95% 

CI 1.24 to 2.45).

CONCLUSIONS: Our results suggest that different F/V may confer different risks

for cancer of the proximal colon, distal colon, or rectum. Future studies might

consider taking into account the location of the tumor when examining the

relation between F/V consumption and risk of CRC.

 

Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All

rights reserved.

 

PMID: 21963014

 

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[2]  Cancer Epidemiol Biomarkers Prev. 2010 Sep;19(9):2278-86. doi:

10.1158/1055-9965.EPI-10-0489. Epub 2010 Aug 31.

 

Variety in fruit and vegetable consumption and the risk of lung cancer in the

European prospective investigation into cancer and nutrition.

 

Büchner FL(1), Bueno-de-Mesquita HB, Ros MM, Overvad K, Dahm CC, Hansen L,

Tjønneland A, Clavel-Chapelon F, Boutron-Ruault MC, Touillaud M, Kaaks R,

Rohrmann S, Boeing H, Nöthlings U, Trichopoulou A, Zylis D, Dilis V, Palli D,

Sieri S, Vineis P, Tumino R, Panico S, Peeters PH, van Gils CH, Lund E, Gram IT, 

Braaten T, Sánchez MJ, Agudo A, Larrañaga N, Ardanaz E, Navarro C, Argüelles MV, 

Manjer J, Wirfält E, Hallmans G, Rasmuson T, Key TJ, Khaw KT, Wareham N, Slimani 

N, Vergnaud AC, Xun WW, Kiemeney LA, Riboli E.

 

Author information: 

(1)National Institute ofPublicHealth and the Environment, Bilthoven, The

Netherlands. frederike.buchner@rivm.nl

 

BACKGROUND: We investigated whether a varied consumption of vegetables and fruits

is associated with lower lung cancer risk in the European Prospective

Investigation into Cancer and Nutrition study.

METHODS: After a mean follow-up of 8.7 years, 1,613 of 452,187 participants with 

complete information were diagnosed with lung cancer. Diet diversity scores (DDS)

were used to quantify the variety in fruit and vegetable consumption.

Multivariable proportional hazards models were used to assess the associations

between DDS and lung cancer risk. All models were adjusted for smoking behavior

and the total consumption of fruit and vegetables.

RESULTS: With increasing variety in vegetable subgroups, risk of lung cancer

decreases [hazard ratios (HR), 0.77; 95% confidence interval (CI), 0.64-0.94

highest versus lowest quartile; P trend = 0.02]. This inverse association is

restricted to current smokers (HR, 0.73; 95% CI, 0.57-0.93 highest versus lowest 

quartile; P trend = 0.03). In continuous analyses, in current smokers, lower

risks were observed for squamous cell carcinomas with more variety in fruit and

vegetable products combined (HR/two products, 0.88; 95% CI, 0.82-0.95), vegetable

subgroups (HR/subgroup, 0.88; 95% CI, 0.79-0.97), vegetable products (HR/two

products, 0.87; 95% CI, 0.79-0.96), and fruit products (HR/two products, 0.84;

95% CI, 0.72-0.97).

CONCLUSION: Variety in vegetable consumption was inversely associated with lung

cancer risk among current smokers. Risk of squamous cell carcinomas was reduced

with increasing variety in fruit and/or vegetable consumption, which was mainly

driven by the effect in current smokers.

IMPACT: Independent from quantity of consumption, variety in fruit and vegetable 

consumption may decrease lung cancer risk.

 

©2010 AACR.

 

PMID: 20807832

 

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[3] Diabetes Care. 2012 Jun;35(6):1293-300. doi: 10.2337/dc11-2388. Epub 2012 Apr 3.

 

A prospective study of the association between quantity and variety of fruit and 

vegetable intake and incident type 2 diabetes.

 

Cooper AJ(1), Sharp SJ, Lentjes MA, Luben RN, Khaw KT, Wareham NJ, Forouhi NG.

 

Author information: 

(1)MRCEpidemiology Unit, Institute of Metabolic Science, Addenbrooke’s Hospital, 

Cambridge, U.K.

 

OBJECTIVE: The association between quantity of fruit and vegetable (F&V) intake

and risk of type 2 diabetes (T2D) is not clear, and the relationship with variety

of intake is unknown. The current study examined the association of both quantity

and variety of F&V intake and risk of T2D.

RESEARCH DESIGN AND METHODS: We examined the 11-year incidence of T2D in relation

to quantity and variety of fruit, vegetables, and combined F&V intake in a

case-cohort study of 3,704 participants (n = 653 diabetes cases) nested within

the European Prospective Investigation into Cancer and Nutrition-Norfolk study,

who completed 7-day prospective food diaries. Variety of intake was derived from 

the total number of different items consumed in a 1-week period. Multivariable,

Prentice-weighted Cox regression was used to estimate hazard ratios (HRs) and 95%

CIs.

RESULTS: A greater quantity of combined F&V intake was associated with 21% lower 

hazard of T2D (HR 0.79 [95% CI 0.62-1.00]) comparing extreme tertiles, in

adjusted analyses including variety. Separately, quantity of vegetable intake

(0.76 [0.60-0.97]), but not fruit, was inversely associated with T2D in adjusted 

analysis. Greater variety in fruit (0.70 [0.53-0.91]), vegetable (0.77

[0.61-0.98]), and combined F&V (0.61 [0.48-0.78]) intake was associated with a

lower hazard of T2D, independent of known confounders and quantity of intake

comparing extreme tertiles.

CONCLUSIONS: These findings suggest that a diet characterized by a greater

quantity of vegetables and a greater variety of both F&V intake is associated

with a reduced risk of T2D.

 

PMCID: PMC3357245

PMID: 22474042

 

[Guest mike colella]

Thanks Dean! This is a very impressive resource. I was especially thrown off balance by his take on extra virgin olive oil which I use. I am careful to purchase the real stuff that is lab tested. There is so much phoniness going on in this industry that I have to wonder if the data is reliable. IAC, it got me wondering if I should simply follow your lead on this and my own intuition that eating whole food sources from plants to get my fats is the best approach-avocados and nuts!  Oils, even genuine  extra virgin olive oil, are not whole foods and are suspect and his take on it was a bit sobering.