Q&A with Mark Pettus
What do you consider to be the most exciting development in the field of nutrition?
I think the most exciting development right now in the nutritional sciences is this burgeoning field of nutrigenomics, which essentially is generating unprecedented understanding and insight into how the food that we eat can influence—in such a fundamental way—how our genes express themselves.
We’ve left behind the genetic perspective in which everything is sort of preordained; the belief that "Whatever the translation of your genetic coding is, will manifest over the course of your life, and ultimately, there’s very little you can do about it." Research with nutrigenomics is suggesting a very, very different picture, in which food can take that genetic predisposition and influence whether or not a gene will ultimately express itself for better or for worse.
It’s a much more dynamic, plastic system than I think anyone ever anticipated, and it’s shedding a whole new light on how our relationships with food, at many levels, can so profoundly influence health.
What’s a good example of a nutrigenomic finding?
One is high-glycemic foods. These are mostly the refined grains, refined carbohydrates, high-fructose corn syrup, sugar-sweetened soft drinks, and many other processed foods. We now have some data to suggest that those high-glycemic foods will actually turn on or stimulate the expression of what are known to be dozens of genes that somehow play a role in turning on our immune system and promoting inflammation.
We also have data showing that low-glycemic foods (brown rice, whole fruits and vegetables) can turn off the same dozens of genes that promote this inflammatory response. So we now know that the biologic interpretation of those foods at a genetic level has a polar opposite effect. The message here is that food really is “information” that our bodies “translate.” And depending on the nature of that information, the translation can be an unbelievably positive one, or it could be a woefully horrible one.
Is this exciting information to be able to pass along to your patients?
Very exciting. It’s enormously empowering. And although people hear about it a lot, and it’s talked about a lot, I’m not sure the real magnitude of these effects are often well communicated or well appreciated or understood.
Where does food rank, as one of many contributors to overall health?
Take someone who is eating poorly but exercises regularly. Let’s say that she sleeps well and consistently each night and that she has a very supportive social network and environment. How a poor diet might manifest in that circumstance could be very different than someone who’s eating poorly who also is very sedentary, who also has disrupted sleep patterns.
Generally, the negative effects of unhealthful eating can have the same magnitude as the positive effects. But how that ultimately contributes to the overall health experience for the individual will also be influenced by many other factors.
What general changes should people make to their diets?
The low-hanging fruit for so many people would fall into the categories of refined carbohydrates, or high-glycemic foods. And they’re so prevalent in the standard American diet, from desserts to chips to bagels, to so many processed foods that have refined grains.
This has been one of the major changes in the American diet over the last generation, and clearly, it correlates significantly with some of the changes in the health patterns that we’ve seen.
The other change would be eating less unhealthful saturated fats from mostly animal protein sources: red meat, dairy, processed foods of any kind. Even when people cut back in moderation, they can see significant health benefits.
What are the chronic diseases linked most strongly to diet?
Although not everyone considers obesity a disease, I would categorize it as the most important public health problem that we confront. So, I would say that obesity, heart disease, diabetes, cancer, and autoimmune diseases all have clearly been connected to changes in the types of foods that we eat. And many of these conditions are reversible through diet.
Of course, other factors, like environmental toxins, stress levels, and genetic risk play a role, but the suggestion is clearly that the majority of the “age-related” diseases are preventable, and in some instances reversible, by virtue of changes in one’s dietary intake.
What else plays a significant role in disease prevention?
I would add sleep patterns to the list. Disruptive sleep patterns are right up there with risks like sedentary lifestyle, poor eating, and stress. Environmental toxins are a major contributor.
And then the other one that comes to mind, which I think is really important and very underappreciated, is this issue of meaning. Connection, meaning, purpose in one’s work, in one’s love, in one’s play, is a major health contributor.
What are some of the biggest misconceptions about nutritious foods?
There are certain myths, like “all low-fat foods are healthy,” since many low-fat foods have very high amounts of refined carbohydrates in them. You think you’re eating something healthy, and in fact, you’re undermining your health, since we know that many of these refined carbohydrates go right to your waistline.
I think another myth for people is that if you’re not adding salt to your food with a salt shaker, that you’re not getting much salt. People very much underestimate the amount of sodium in processed foods, like meat and canned soups.
And in general, I think people very much underappreciate the potential harm that dairy can cause. T. Colin Campbell has gone a long way to try to alter that perception, and to challenge the notion. As you well know, it’s almost un-American to suggest that dairy’s not good for you.
What can people do to take charge of their health?
With respect to food, it would be to cut back on the refined carbohydrates, and all sugar. Any decrement in the amount of sugar one is eating will have big benefits.
Definitely move more. Most people just need to move more—and I don’t even mean exercise, because, you know, I think people sometimes equate exercise with jogging, or going to lift weights for an hour. Movement of any kind, like dancing or just walking, is beneficial.
And a third thing would be greater mindfulness, in whatever form that might take—from taking soft, deep breaths to forms of meditation and prayer. And yoga.