In the conventional nutrition world, the answer to seemingly every nutritional ill is to eat more fruitsandvegatables (written as one word as they are communicated as effectively being the same thing and having the same health properties), whilst decreasing your intake of red meat and its associated animal fat (which if you have too much of it, will rot your gut, give you diabetes, block your arteries, and before all that takes place, you'll grow horns and be insatiably randy...). It was only recently that one of New Zealand's most vociferous obesity campaigners, Robin Toomath, was lamenting the losing battle she has been fighting and claimed reduced taxes and/or subsidies on fruits and vegetables (alongside fat taxes) were part of the answer.

I remember debates from the early 2000's over whether the common 5+ serves of fruits and vegetables per day were enough. Perhaps it needed to be seven... or nine? And food companies, in their propaganda marketing like to suggest that you can consume whatever brand of syrup they are pedaling as long as you a) do plenty of exercise and b) eat plenty of fruitsandvegetables, thereby making the syrup part of your balanced lifestyle.

But just what is the evidence that fruits and vegetables are your beta cells, arteries, and immune system's knight in shining apple skin? The analysis often goes something like this;
  • One group gets to eat Krispie Cremes, deep-fried Mars bars, white bread, saveloy's, margarine, and four litres of fizzy drink, every day (we'll call them the "Red Meat/High Fat" group).
  • The other group does away with all those high-fat meat-based foods above, and replaces it all with plenty of steamed vegetables, a few pieces of fruit, and some poached fish, and for eating those foods, they get signed autographs of T. Colin Campbell.
  • Get each group to eat their respective diets for a few years and see which one is closest to extinction.
Obviously, because we all know what a serial-killer red meat and animal fat is, we can deduct from the above groups that fruits and vegetables protect us from disease. WTF?

Whilst being obviously facetious, I don't think I've stretched the truth too far with my example above. In my mind, the vast majority of studies that show the "benefits" of fruitsandvegetables when it comes to disease prevention, are actually showing the effects of the relative absence of refined grains, sugars, and vegetable oils - our wild horsemen of the apocalypse. Don't get me wrong... I do actually think that fruits and vegetables (more so the vegetables than the fruit), do offer benefits to our health. I just don't believe that, on their own, they will be the saviours of the human race. A study abstract that I came across today, tends to reinforce this belief;

Few favorable associations between fruit and vegetable intake and biomarkers for chronic disease risk in American adults
Using 24-hour dietary recall data from the National Health and Nutrition Examination Survey 1999 to 2006, the possible link between fruit and vegetable intake and chronic disease risk was assessed.

C-reactive protein (CRP), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), fasting plasma glucose (FPG), total cholesterol, and glycosylated hemoglobin were selected as biomarkers for chronic disease risk. It is hypothesized that individuals who consume more fruits and vegetables will have reduced chronic disease risk because of the healthful benefits of these foods. The objective of this study was to examine the relationship between fruit and vegetable consumption on selected biomarkers for chronic disease risk.

Although some associations were significant for FPG, HDL-C, and low-density lipoprotein cholesterol in some of the models, no trend was present.

After adjusting for demographic factors, socioeconomic factors, lifestyle factors, body mass index, total energy intake, and the presence of at least 1 of our 5 predetermined comorbidities, no associations of reduced or increased risk were observed in any quartiles of combined fruit and vegetable intake.

Fruit and vegetable intakes were weakly associated with an increased HDL-C level and decreased FPG, glycosylated hemoglobin, and C-reactive protein levels in some of the models; however, no association was observed in the final model.

Because selected biomarkers of future disease risk remained in reference ranges at both high and low intake and no significance was observed in the final model, no protective association was observed between fruit and vegetable intake and biomarkers for chronic disease risk.

However, fruit and vegetable consumption is recommended as part of an overall healthy diet and to displace other energy-dense foods for weight maintenance, which can lead to a decrease in future disease risk.
Just to repeat, no associations were seen with any of the commonly held biomarkers of disease across any range of fruit and vegetable intake. Perhaps our biomarkers are a bit rubbish? I agree with the last statement in this abstract - that fruit and vegetable consumption is part of a healthy eating template; not necessarily in the amounts commonly recommended, but healthy nonetheless. And I mean healthy in a broad sense... in the sense that these plant-based foods provide nutrients useful in maintaining a healthy physiology, but also healthy in that many plants are enjoyable to eat, providing different tastes, textures, and making eating good food the incredibly satisfying experience that it should be.

I also agree that these plant-based foods will contribute toward displacing "other energy-dense foods", which, if these energy-dense foods happen to be based on some Frankenfood mixture of grains, sugar, vegetable oil, and soy protein, will appear to decrease chronic disease risk. But I remain skeptical that they offer the degree of protection that they have been positioned to hold in conventional nutrition wisdom.

Speaking of plants... another fascinating paper drifted onto the radar this morning -

Exogenous plant MIR168a specifically targets mammalian LDLRAP1: evidence of cross-kingdom regulation by microRNA
Our previous studies have demonstrated that stable microRNAs (miRNAs) in mammalian serum and plasma are actively secreted from tissues and cells and can serve as a novel class of biomarkers for diseases, and act as signaling molecules in intercellular communication. Here, we report the surprising finding that exogenous plant miRNAs are present in the sera and tissues of various animals and that these exogenous plant miRNAs are primarily acquired orally, through food intake.

MIR168a is abundant in rice and is one of the most highly enriched exogenous plant miRNAs in the sera of Chinese subjects. Functional studies in vitro and in vivo demonstrated that MIR168a could bind to the human/mouse low-density lipoprotein receptor adapter protein 1 (LDLRAP1) mRNA, inhibit LDLRAP1 expression in liver, and consequently decrease LDL removal from mouse plasma.

These findings demonstrate that exogenous plant miRNAs in food can regulate the expression of target genes in mammals.
MicroRNAs (miRNAs) are a class of nucleotide and are part of the genetic coding mechanism which includes DNA and RNA. From Wikipedia;
MiRNAs are post-transcriptional regulators that bind to complementary sequences on target messenger RNA transcripts (mRNAs), usually resulting in translational repression or target degradation and gene silencing. The human genome may encode over 1000 miRNAs, which may target about 60% of mammalian genes and are abundant in many human cell types.

The function of miRNAs appears to be in gene regulation.
What is totally fascinating from this study, is that these gene regulators that are present in all animals, are also present in plants, AND, the little buggers can survive digestion, entering circulation and various organs. From the paper...
Microvesicles (MVs) are small vesicles that are shed from almost all cell types under both normal and pathological conditions. They bear surface receptors/ligands of the original cells and have the potential to selectively interact with specific target cells and mediate intercellular communication by transporting bioactive lipids, mRNA, or proteins between cells. Our recent results demonstrated that MVs from human plasma are a mixture of microparticles, exosomes, and other vesicular structures and that many types of MVs in human plasma contain miRNAs.

Our further studies demonstrated that miRNAs could be selectively packaged into MVs and actively delivered into recipient cells where the exogenous miRNAs can regulate target gene expression and recipient cell function. Thus, secreted miRNAs can serve as a novel class of signaling molecules in mediating intercellular communication.
So there seems to be a potential mechanism for exogenous plant miRNAs to regulate gene expression within the animal that has consumed the plant. This could have some pretty big implications for both health and disease. A Science Daily alert on this research offers more;
The finding is obviously very thought-provoking; for instance, it would indicate that in addition to eating "materials" (in the form of carbohydrates, proteins, etc), you are also eating "information" (as different miRNAs from distinct food sources could well bear different consequences on the regulation of host physiology once taken by the host due to potential regulation of different target genes as determined by the "information" contained within the miRNA sequence), thus providing a whole new dimension to "You are what you eat."
The researchers provide an example of miRNA from rice being found in Chinese subjects...
MIR168a is abundant in rice and is one of the most highly enriched exogenous plant miRNAs in the sera of Chinese subjects. Functional studies in vitro and in vivo demonstrated that MIR168a could bind to the human/mouse low density lipoprotein receptor adapter protein 1 (LDLRAP1) mRNA, inhibit LDLRAP1 expression in liver, and consequently decrease LDL removal from mouse plasma. These findings demonstrate that exogenous plant miRNAs in food can regulate the expression of target genes in and thus physiology of mammals.
So in mice, and possibly humans, miRNA from the grain, rice, can survive digestion and bind to a receptor for LDL cholesterol in the liver, downgrade the expression of that receptor, decreasing the removal of LDL from circulation. Leaving LDL building up in circulation could potentially increase the likelihood of that LDL becoming glycated and/or oxidised - not a good thing.

So, whilst plants don't have legs, some of them are still sneaky little bastards and are not to be trusted!