Fruits, Vegetables, Biomarkers, and just how sneaky can plants be...

That Paleo Guy: Fruits, Vegetables, Biomarkers, and just how sneaky can plants be...

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 pedalling 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.