DOES SOIL HEALTH AFFECT HUMAN HEALTH?
Dr. David Montgomery’s book, “What Your Food Ate” explores the connection between soil health and human health.
HART HAGAN: Does soil health affect human health? And how does that work?
DAVID MONTGOMERY: It's a great question that gets at the heart of what Ann Bickle and I tried to cover in our book “What Your Food Ate.”
We divided the book into four sections,
1) how farming practices affect soil health,
2) how soil health affects crop health,
3) how crop health affects livestock or animal health, and
4) how all that integrates up into human health.
At the risk of trying to oversimplify the book, there's a couple things that are pretty clear: That agricultural practices influence the soil. That then translates to differences in what's in our food. And that boils down to things like mineral micronutrients and vitamin contents. How we treat the soil affects those. We looked at the studies that looked at that, synthesized the research in our book and did some our own measurements.
There are also things called phytochemicals, plant-made chemicals that plants make to do things like protect their own bodies from ultraviolet radiation, or to fend off insect pests. We tend to think of them as antioxidants and anti-inflammatories, things that actually help keep our bodily systems running well. There are a lot of studies that have looked at how the style of farming and/or the way we treat the soil impacts the provisioning of phytochemicals, particularly in fruits and vegetables.
And then there's also a connection in terms of the fat profile of meat and dairy products. For example, 100% grass-fed meat and dairy typically has high omega-3 oil content, whereas grain-fed meat and dairy tend to have high omega-6 fat contents.
HART HAGAN: Which one is better omega-3 or omega-6?
DAVID MONTGOMERY: You actually need both in your diet, but the one that we lack in the western diet is our omega-3’s. Omega-3’s are the reason that doctors will tell you to eat more salmon. It's full of omega-3 fats. It's a good fat, a so-called healthy fat. There are studies that have looked at how that helps to prevent chronic illnesses in particular.
But it turns out that salmon are not the only good source of omega-3s on the planet.
Leafy green plants are also a good source of omega-3’s. The reason for that is that omega-3 fats are involved in photosynthesis. So the leaves and photosynthetic parts of plants tend to have a lot of omega-3s, not as many as salmon do. But salmon get them from marine plants that they eat, as well as plankton in the ocean.
The closer you are to photosynthesis in terms of the functional part of a plant, the higher the omega-3 content of it is. Omega-6, on the other hand, are fats that are very rich in seeds and seed oils because seeds serve a very different purpose in a plant than the leafy green parts.
Seeds are meant for storage. They're meant for shelf life. They're meant to be consumed later to help feed a plant in its early growth and fuel that growth.
So when we look at our livestock and meat and dairy products, what those animals ate really captures what those fats are in their diet.
Omega-3 and -6 fats are so-called essential fats. We can only get them from our diet. Our bodies can't make them out of other things. We can't synthesize them ourselves. What we eat is what determines what our body has to work with in terms of omega-3’s and omega-6’s.
It turns out that what our food ate--in terms of livestock and meat and dairy products--is what sets the fat balance, the abundance and balance of fats. It seems to me that what you want is a diverse abundance. You want a balance between the two, but you need enough of them for them to serve their purposes in your body.
Omega-6 in the human body is an integral part of initiating the process of inflammation, whereas omega-3s are integral to the process of ending or quelling inflammation.
You want inflammation. You want your body to be able to get inflamed when it needs to. You cut your finger in the kitchen. It turns red as your body is fighting off the bacteria that are getting in from the knife.
You want inflammation to work when you need it. But then you want it to stop when it's over. There's a lot of chronic diseases that are affecting more and more people in the US today that are rooted in inflammation that has some tie to diet. And so that's where the omega-6 and -3 balance really comes in, in our diet.
We want our bodies to be provisioned with what it takes to start inflammation. But we also need them to be provisioned with what it takes to shut it off and turn it down.
If we have a diet that is awash in omega-6 fats, then that's what our body has to work with. Those omega-6 and omega-3 fats share a lot of biochemical pathways in the human body. So if our diet is 2-to-1 omega-6 versus omega-3s, we've really helped our body start inflammation, and we're really challenged in terms of turning it off.
That could be at the root of many chronic diseases. Omega-6 to -3 ratio is not the only thing that influences those, obviously. There's a lot of things that influence the health of an individual human being. There's what we choose to eat. There's whether we get any exercise. There's our family genetics. All have a huge impact.
But I argue in “What Your Food Ate” that there's another dimension in terms of provisioning our bodies with what it takes to help manage and prevent chronic illnesses in the long run.
Some of this relates to the flavor of our food. The flavor of that tomato is strongly influenced by how we farm. And as I'm sure people have noticed those flavors in whole natural foods give our bodies clues as to the micronutrient and phytochemical and fat profile and amino acid profiles of the food that we're eating.
A lot of this is fairly recent science and we've tried to synthesize that in the book (“What Your Food Ate”) to try and make it digestible for people who don't happen to read in four or five different disciplinary journals the way that we had to, to research the book.
For the entire interview, please click on the link.