Comments on Palaeo diets; especially in regard to modern fruits and vegetables

 

 

 

If science is honest, it must be admitted that the “best” diet to eat for a long and healthy life is still unknown. Although studies have given some clues, hardly a decade goes by in which some previously promulgated message is not greatly questioned, and sometimes completely overturned.

 

However, a few things we know for certain: that evolution is an incredibly powerful force that has ruthlessly shaped human metabolism by “survival of the fittest” for approximately 6 million years since we separated from the chimpanzees; that for 99.8% of that time (until 10,000 years ago) neither we, nor the livestock that we eat, consumed as much grain or seed as we now do (although both consumed some); and that for 99.9% of that time (until 5,000 years ago) none of us consumed dairy food (and therefore modern quantities of calcium). So it is highly likely that most people’s DNA is still adapted to thrive on a diet considerably different from the modern Western one. I say “most” people, because some groups and individuals undoubtedly carry DNA that is in fact well adapted to particular aspects of modern diet, such as high dairy, or high grain, and so there could be a lucky few who are well adapted to all aspects of the modern diet. But, in general, the great majority must be ill adapted to the modern high fat, high sugar, high grain, high dairy, low fibre diet, and must still carry many genes attuning them to various aspects of the pre-agricultural (“Palaeo”) diet, from before 10,000 years ago, and certainly to the pre-dairy diet. Indeed, we in fact already know this for certain, due to to the otherwise inexplicable prevalence of ailments like lactose intolerance and gluten intolerance even amongst genetic populations that have consumed large quantities of dairy and/or gluten-bearing grains for thousands of years. These two are relatively “visible” ailments, but it is very unlikely that there are not other, as yet unrecognised, genetic mismatches to modern diets, carried by significant numbers of people.

 

The nature of Palaeo diets probably varied significantly across locations and time, so it is difficult to specify one overall diet. But, where choice permitted, it usually seems to have included such things as shellfish, crustaceans, reptiles, insects, eggs, certainly fruits, fungi and tubers (although how much of the latter compared to fruits is unclear), with still-uncertain amounts of mammals, finfish, birds, and grains and other seeds (although usually some of all of these). In addition, it can be stated with great confidence that basically all the animal flesh was not very fatty, and that those animal fats were not grain-derived; that all seeds, of any kind, were smaller, more fibrous and less carbohydrate rich; and that all fruits were smaller, less sweet, and more sour and/or bitter. Reading of any anthropological descriptions of hunter-gatherers’ diets will easily confirm these facts.

 

So there certainly should be no surprise if a significant number of people suffer adverse effects from excess calcium, or gain benefit from employing hunter-gatherer levels of Vitamin D, or from ingesting a relatively “unimproved” fruit like cranberry which is much less sweet, and more bitter, than essentially all other commercial fruits.

 

Most other aspects of Palaeo issues (re dairy, grains, vitamin D, meats etc) are heavily covered on the internet. But the changes which have occurred to fruits and vegetables over time are less well discussed. Most dietary authorities tend to accept all fruit and vegetable consumption as a good thing. But the fact is that modern fruits and vegetables bear no resemblance to ancient versions. Virtually without exception they are much larger, more carbohydrate-packed, sweeter, less fibrous, less sour and less bitter. This trend continues rapidly.

 

The polyphenols, proanthocyanidins, antioxidants and other phytonutrients which provide the great benefits of fruits and vegetables are bitter components, now substantially bred out of modern varieties compared to wild ones. Here is a 1992 quote from a respected food scientist, who wasn’t trying to be the least bit humorous or ironic, discussing fruits under the heading “Evaluating Taste”: “There are some wild fruits, notably plum and apple species, which are so high in polyphenols as to be inedible due to their bitterness and astringency. Cultivated varieties however, do not have these disadvantages” [1]. But the ridiculous fact is, those wild varieties were and are the original varieties, end of story. They are all that our ancestors had available for six million years! He might say “inedible”, but the truth is he means poor tasting in his own opinion. All of our ancestors found them highly edible! And the "inedible" levels of polyphenols are really something to think about when contemplating modern fruits!

 

A few examples:

 

Apples: Consider what crab apples (wild-type apples) are like. Besides being much smaller and much more sour and bitter, numerous scientific analyses show that they are often dozens of times more enriched in micronutrients like polyphenols, proanthocyanidins and antioxidants [2].

 

Carrots: Were a thin, bitter, fibrous, white root until the 1600’s.

 

Grapes: Even wine grapes, in which the flavour is all-important for that market, not the fruit size or appearance, have developed far from the wild fruit. But they are relatively small, and dominated by relatively sour and bitter skin and seed flavours, compared to the incredibly sweet modern table grapes.

 

Brussel Sprouts: I recall, just a few years ago, specifically reading of the “success” in developing new low-bitterness varieties.

 

Cranberry: A relatively unaltered fruit because it has not been a mass-produced commercial fruit for very long -- the very first farm began in 1816. They are much more like the small, sour and/or bitter berries that are the main fruits encountered in all descriptions of hunter-gatherer societies. (But how long will plant breeders allow this to continue?)

 

Sour components, and bitter components especially, have been consistently bred out of nearly all commercial fruits and vegetables over the 10,000 years since agriculture began. Is it the least bit implausible that in some cases, and/or for some individuals, they are still highly beneficial?

 

At the end of the main text, I state: “Predisposing genetic variations are known to be involved in particular individuals’ susceptibility to LAF. Indeed, numerous candidate genes have already been identified. It seems likely to eventuate that these genetic variations cause some percentage of the population to be more sensitive to the factors raised on this site.” It is also not at all implausible that modern deviations from humans’ multi-million-year genetically fine-tuned lifestyle, ie dramatically changed intakes of calcium, vitamin D and bitter components of fruits and vegetables, are also likely to be having other serious but unrecognised adverse health effects across the whole population. Some obvious possible areas for consideration are discussed later, in Link L.

 

 

 

 

[1] Lea, A.G.H. (1992) Flavour, Colour and Stability in Fruit Products: The Effect of Polyphenols. Plant Polyphenols – Synthesis, Properties and Significance. Edited by Hemingway, R.W and Laks, P.E. Plenum Press New York p. 827-847.

 

[2] Andre, C. M., Greenwood, J. M., Walker, E. G., Rassam, M., Sullivan, M., Evers, D., ... & Laing, W. A. (2012). Anti-inflammatory procyanidins and triterpenes in 109 apple varieties. Journal of agricultural and food chemistry,60(42), 10546-10554.