Nutrigenomics is one application of the exciting new field of Epigenetics.
OK, for the rest of this article, I'm going to speak about science in plain English. I'm not going to talk about GLUT-4, sirtuin, or APO-E. I'm not even going to distinguish between saturated and un-saturated fats (gasp!). The science should be done, and available to all who want to know it. I just think we who understand the science have a responsibility to translate it into plain English, so normal people can take action on it in their own lives. So, instead of the technically-correct term “Nutrigenomics”, let's just call it.. Signaling.
It's a fact. I'm not saying we don't have souls (in fact, I believe we do), but science has discovered a lot of interesting stuff, and we can use some of it to make our lives better. Based on findings from the field of Evolutionary Biology, we can identify 4 phases of the human species, nutritionally-speaking: Pre-Hunter-Gatherer, Hunter-Gatherer, Agriculture, and of course, Junk Food.
From before our last common ancestor with our nearest genetic relative, chimpanzees – about 5 million years ago – our ancestors probably ate what was readily available in the forest/jungle, the foods modern chimps get most of their calories from: leaves and fruit (and some bugs – yum!).
The Hunter-Gatherer phase began when our ancestors moved onto the plains, and began scavenging; the addition of animal food gave them vitamin B-12, protein, zinc, iron, and omega-3's. These nutrients spurred further evolution of our species, making humans larger, stronger, and smarter. Thus began pack-hunting, enabling the ancestors to target bigger game, from which they got not only more protein, but FAT. (Gathering would have included not only plant foods, but slugs, worms, and shellfish.)
Grains, of course – wheat, oat, rice. Nuts; as Jared Diamond noted in Guns, Germs, and Steel, a culture has to have been farming an annual crop for many years before developing nut-producing trees. Potatoes; actually, all non-leafy vegetables belong in this category. Wild-growing veggies were much less abundant and much tougher to eat; modern veggies are all the result of thousands of years of selective breeding. (Although one could say the same for lettuce and fruit, for signaling purposes they are similar enough to the wild versions; wild fruits even today are bright and sweet.)
Also, all non-leafy vegetables are much healthier cooked than not - to the point that eating non-leafy veggies raw could be considered un-healthy.
Duh. (Note: fruit JUICE is junk food; liquid fruit = liquid sugar.)
This also includes the so-called “vegetable oils”, none of which are even from vegetables (not that it matters): corn oil (corn is a grain), soybean oil, canola (a seed), etc. No human consumed more than trace amounts of these oils – which require industrial tech to extract – before the 20th century.
The first two were such long periods of human history, millions of years each, those foods – the Leaves and Fruit category, and the Animal Food category – send signals to your DNA which turn on the genes that make your body function properly. Because the latter two are so recent, eating foods from those categories – Agriculture and Junk food – fails to send those signals.
What To Do
Leaves (aka lettuce) and fruit (don't forget the berries): 30% of calories (those who need to eat less carbs/more fat for hormonal reasons can have more of the fruit fats: olive/oil, coconut/oil, and avacado/guacamole). Radicchio, though red on your plate, is green as it grows, and is then blanched to turn it red; so throw some of that in with your romaine. Most fruits are healthier raw than cooked, the exceptions mainly being the nightshade fruits: tomato and bell peppers/capsicum; summer squash (e.g. zucchini) can be eaten raw, but winter squash (e.g. pumpkin) should be cooked. Frozen fruit is great (may even be healthier than “fresh”, which is usually picked before ripe and ripens on the truck on its way to your store); canned acidic fruit is completely unacceptable (acidic food makes the phthalate and BPA leach out of the plastic liner of the can and into the food).
Animal food (fat and pro): 30% of calories. (Animals store pollution in fat cells, so if you can't afford to eat organic all the time, target your organic dollars on animal fat.)
Agriculture: 30% of calories. (Again, if needing to eat LC/HF, you could get cals in this category more from nuts than grains or beans.)
Junk food: up to 10% of calories. Not a requirement, I just don't think it's realistic to expect most Americans to eat zero junk food.
Now we see the mechanism by which the modern diet is wrecking the health of most Americans: by supplying most calories from agriculture and junk food, the body is deprived of the essential signals.
UPDATE April 8 2013
"Eating your greens may be even more important that previously thought, with the discovery that an immune cell population essential for intestinal health could be controlled by leafy greens in your diet. ...
Dr Belz said that the proteins in green leafy (cruciferous) vegetables are known to interact with a cell surface receptor that switches on T-bet, and might play a role in producing these critical immune cells. “Proteins in these leafy greens could be part of the same signalling pathway that is used by T-bet to produce ILCs,” Dr Belz said. “We are very interested in looking at how the products of these vegetables are able to talk to T-bet to make ILCs, which will give us more insight into how the food we eat influences our immune system and gut bacteria.”
Source: Walter and Eliza Hall Institute of Medical Research
(via Bill Lagakos/CaloriesProper)