9 replies to this topic

[Brett Black]

This study reviewed pooled/meta-analyses and systematic reviews regarding diet-related chronic disease (DRCD) that were published between 1950 and 2013. The level of scientific evidence for what constitutes best dietary patterns isn't great in general, and collecting masses of studies together like this doesn't necessarily bring any more certainty, but it may be the best we have for now. (note: the authors seemed a little loose in their use of the term "grains", with positive effect attributed to *unrefined* grains and negative to *refined* grains, without this qualifier always being mentioned.) I've quoted some of the main points:
 

"...The exhaustive literature did not provide strong evidence of the protective
effects of fruits and vegetables, which contradicts the general widespread
belief that fruits and vegetables are very healthful: an almost equal number
of references were found for a protective effect and a neutral effect...

...More conclusive results have been obtained with grain-based food groups,
which appear to be protective against overweight/obesity, type 2 diabetes,
CVD, and cancers...

...The mechanisms behind the health protectiveness of
whole-grain cereals have already been thoroughly discussed.[70] If
whole-grain cereals tend to be protective, refined cereals appear to be
either neutral or harmful, especially toward type 2 diabetes. Legumes appear
to be a promising food group, although there are still only a few studies
available...

...Except for the deleterious effect of very hot tea on the prevalence of
esophagus cancer,[37] tea is globally either neutral toward or protective
against DRCD occurrence...

...In contrast to high/regular intakes of tea, coffee, milk, and
wine, a high/regular consumption of sweetened beverages (aka soft drinks)
appears to have deleterious effect on weight gain and type 2 diabetes and a
rather neutral effect on cancer risk....

...The protective effect of nuts and seeds
against CVD risk and, to a lesser extent, diabetes risk, is rather
convincing...

...the
results from the present analysis showed that regular and/or high
consumption of milk has a rather neutral effect, i.e., it is not associated
with major DRCD risks...

...Compared with plant-based food groups, animal-based food groups appear to be
less protective in the highest-level consumers as indicated by the highest
percentages of references reporting significant increased DRCD risks (27%
versus 7% for plant-based food groups)...

...Therefore, the results of this analysis
are, overall, in agreement with food-based pyramids, except that all grain
products should probably be emphasized over fruits and vegetables, rather
than the reverse...

...This exhaustive and holistic review also confirms that consumption of tea
and unrefined plant-based food groups should continue to be highly
recommended. In contrast, the consumption of refined cereal products,
red/processed meat, eggs, very hot tea (but not tea in general), sweetened
beverages, pickled vegetables, and fermented soy foods clearly should be
limited, while consumption of poultry and milk and dairy products appears to
have a rather neutral effect on DRCD risk. Therefore, on the basis of these
results, greater emphasis should be placed on grain products in food
pyramids, first on whole-grain cereals and leguminous seeds, and then on
nuts and seeds."

---

 

1. Nutr Rev. 2014 Dec;72(12):741-62. doi: 10.1111/nure.12153. Epub 2014 Nov 18.

Associations between food and beverage groups and major diet-related chronic
diseases: an exhaustive review of pooled/meta-analyses and systematic reviews.

Fardet A(1), Boirie Y.

Author information:
(1)Unité de Nutrition Humaine, INRA de Theix & Université d'Auvergne, 63122,
Saint-Genès-Champanelle, Auvergne, France.

Comment in
Nutr Rev. 2014 Dec;72(12):737-40.

Associations between food and beverage groups and the risk of diet-related
chronic disease (DRCD) have been the subject of intensive research in preventive
nutrition. Pooled/meta-analyses and systematic reviews (PMASRs) aim to better
characterize these associations. To date, however, there has been no attempt to
synthesize all PMASRs that have assessed the relationship between food and
beverage groups and DRCDs. The objectives of this review were to aggregate PMASRs
to obtain an overview of the associations between food and beverage groups (n =
17) and DRCDs (n = 10) and to establish new directions for future research needs.
The present review of 304 PMASRs published between 1950 and 2013 confirmed that
plant food groups are more protective than animal food groups against DRCDs.
Within plant food groups, grain products are more protective than fruits and
vegetables. Among animal food groups, dairy/milk products have a neutral effect
on the risk of DRCDs, while red/processed meats tend to increase the risk. Among
beverages, tea was the most protective and soft drinks the least protective
against DRCDs. For two of the DRCDs examined, sarcopenia and kidney disease, no
PMASR was found. Overweight/obesity, type 2 diabetes, and various types of
cardiovascular disease and cancer accounted for 289 of the PMASRs. There is a
crucial need to further study the associations between food and beverage groups
and mental health, skeletal health, digestive diseases, liver diseases, kidney
diseases, obesity, and type 2 diabetes.

© 2014 International Life Sciences Institute.

PMID: 25406801 [PubMed - in process]
http://nutritionrevi...ntent/72/12/741

[Mind]

Strange result, considering the voluminous data in favor of vegetables. Makes one wonder about the methodology. Wonder what the sample size of the true "whole grain" people was? Did they have 2 people who ate Ezekiel bread their whole life. Or, did the people who tended to eat true whole grain products (which are hard to find without some refinement) also have a "clean" diet with a lot of vegetables. I suspect the people who live very healthy probably avoided refined grain products (desserts, white bread, donuts, noodles, etc...). Even if the healthiest subjects ate jut one portion of whole grain products in a day or a week, it would skew this meta-analysis (most likely). Knowing the frequency and caloric content (as a percentage of the diet) of the grain consumption would shed more light on the situation

 

Then you also have high sugar content fruits that are probably negative for health if you eat too many. Bananas, mangoes, pears, apples, etc... Especially preserved ones with added sugar.

 

Leafy green and cruciferous vegetables are better than some others. Many things to consider.

[TheFountain]

My girlfriend is Asian and she eats about 5 apples a day, usually the green ones.

 

She is super healthy and has the skin of a new born baby. She is 24 years old. 

 

The problem with sugar is not fruit. The problem with sugar is table sugar and HFCS. Crap like that. 

 

Sugar coexists in fruits because fruits have natural, nutritional co-factors that balance the sugar content, probably with some natural anti-glycation nutrients. 

I have never seen a person who eats a lot of fruit be obese or have health problems. Not sure where this myth originated. 

[niner]

I agree with Mind.  Something seems a little screwy here, like maybe the fruit / vegetable eaters were more likely to be heavy consumers of meat and dairy, or something like that.  I think that all whole grains have been tarred with the same brush as (usually refined) wheat, and have gotten a worse rap than they deserve in parts of our community.  There are of course some people for whom gluten is not a great idea, and a few for whom it is lethal (I have a relative like that), but most people tolerate it.  For the majority of people, whole grains are a net positive.

[ceridwen]

To the Fountain you clearly don't know my husband. He eats an excessive amount of fruit and is obese

[12 String]

To the Fountain you clearly don't know my husband. He eats an excessive amount of fruit and is obese

Excessive? How much? Does he eat mostly fruit? Most vegans and fruitarians I've seen on youtube seem to be lean. 

[deeptrance]

I'm skeptical about this type of meta-analysis of dietary studies because of the inconsistencies that exist across studies. The most glaring problem that comes to mind is in how the various researchers delineate categories such as "fruits" and "vegetables." In the past, many researchers have counted such patently harmful garbage as "canned fruit in heavy corn syrup" as fruit, and everything from "potatoes au gratin" to "peas in cream sauce" goes into the vegetable category. 

 

Of course the same problem can occur with classifying whole grains, so maybe the effect washes out, but the whole process by which this is done seems very ambiguous and unconvincing to me.

[StevesPetRat]

Haven't we learned not to trust meta-analyses yet?

[niner]

It's not the meta-analysis methodology that's the problem, it's the underlying nutritional research using free-living humans.  It's just really difficult to do that at all well.  There are tons of confounders, people exaggerate, forget, mis-remember, and lie about what they've eaten, and the inclusion/exclusion criteria for patients or subjects can wildly change results.  Nutrition is hard enough on a metabolic ward.  With humans in "the wild", it's insanely difficult to get really good data.

[DAMI]

As far as I am aware whole grains mostly appear healthful in observational studies.

 

In the DART trial for example people who were instructed to eat more whole grains had INCREASED mortality compared to those without any dietary advice:

http://wholehealthso...ns-learned.html

http://www.nature.co...1342a.html#tbl4