Dariush Mozaffarian: Nutrition science history

Dariush Mozaffarian: Nutrition science history


Thank you very much to Swiss Re for hosting
this event, and to Fiona and the BMJ for really the vision for doing this. Anita and I, I guess maybe now two years ago,
started having these conversations with Fiona about doing something on food, and I think
this is really exciting. And I will say that our input from the beginning
was that this series of paper and like this conference, should not be sort of book chapters
that just kind of repeat one point of view, but really bring together co-authors that
may not agree with each other, and really talk about what we don’t know in addition
to what we do know. The paper I’m going to talk about I wrote
with Ricardo Uauy and Irwin Rosenberg, who are really thought leaders for many decades
in nutrition. I want to talk a little bit about the story
of I think how we got where we are today, in terms of nutrition science. I think that as Swiss Re knows and has highlighted,
that we really are facing a global nutrition crisis, and I don’t use the word crisis lightly
here. I think if you really just look at the numbers,
this is one of the biggest issues facing the globe. Poor diet is now the single leading cause
of poor health in the world, exceeding tobacco smoking. That’s mostly from chronic disease, but also,
of course, from under-nutrition, and micronutrient deficiencies. So if you care at all about health, if health
is any of importance to your business or to you personally, food should be the top issue
you are thinking about. And contrast that to healthcare systems around
the world that are largely ignoring food. This is also a major issue for disparities. This isn’t the only issue driving disparities,
but this is a major issue for disparities. People who are poorest in every country in
the world have the least access to healthy food, and that drives a vicious cycle of disparities. I mentioned healthcare costs. This is in the United States, crushing businesses
and crushing government costs. And this is really important for economic
growth. A really nice Institute of Medicine report
a few years ago said that the rise of chronic disease is a huge challenge for middle income
countries because of crushing costs. And I think that the Chinese economy is going
to have enormous problems in the next 20, 30 years because of their rising chronic diseases. Sustainability and climate change, not a part
of this series, but incredibly important to our food system, I think is the number one
overall threat to sustainability and climate, water use, land use, CO2 equivalent production
and so forth. And also national security. This isn’t an issue that is discussed often,
but food and national security have been linked for millennia. Both the birth of the RDAs from the League
of Nations and the British Medical Association, and the IOM in the 1940s, the US National
School Lunch Program. All of those things in the 1940s were because
of national security around World War II, and we forget that. Now we have a new national security crisis
in Western countries because of chronic diseases. And there’s a group in the United States called
Mission Readiness. 700 retired admirals and generals who’ve been
writing about this and talking about this for a decade, that poor nutrition is causing
national security crises. So all of these things put together, I think
this is one of the single biggest challenges facing the globe. And in contrast to those other challenges
like violence or prejudice, we actually can figure out within a decade how to fix most
of this. We have the science actually to fix most of
this, so I’m incredibly optimistic that we can move forward. The public gets this in a deep, deep way,
in a way that I haven’t seen in my entire career, and this is across the world. And so there’s incredible passion, but there’s
also confusion. This is an opportunity for moving forward. And the science has exploded. This is kind of what our piece is about, is
that modern nutrition science is less than a hundred years old, and if you look at the
science of diet and chronic diseases, obesity, cardiovascular disease and so forth, the science
is doubling every decade. This is the list of publications every decade,
and orange is just the first half of this decade. So the science is moving remarkably quickly,
and we know so much more now than we did just 20 or 30 years ago. And we have to be sure that the science intersects
with policy. At Tufts, our school is the Friedman School
of Nutrition Science and Policy. That’s not accidental. We think that science without policy is just
kind of stale knowledge, from bench to bookshelf. And policy without science is dangerous, and
so these things really have to be brought together. Right now, nutrition policy around the world
doesn’t always link and often doesn’t link with the best science. I’ll just give you a couple of examples. These are brand new policies. The UK front-of-pack traffic light label,
just a few years old, and the Chile black box warning labels, just less than a year
old. Very, very reductionist focus on foods, picking
single nutrients. Both of them have calories, they focus on
very reductionist approaches to defining health. And I think this is actually not the best
approach. This is also the current global paradigm for
addressing obesity, count your calories. It’s all about energy in, energy out. It’s all about energy balance and just people
should be moving more and eating less. Also I think, actually deeply flawed and potentially
harmful. So why are we so infatuated with these reductionist
approaches? We sort of go through this in our paper. We talk about modern nutrition science again
is so new, we don’t really realize how new this is. The first isolation and synthesis of a vitamin
was in 1932 with vitamin C. That was the first time a vitamin was isolated and synthesized. And that was the first time then that you
could prove that a vitamin cured or caused a disease. And in this case, the disease was scurvy. It was just less than a hundred years ago. We just have to remember how recent that was
that we actually showed that a dietary compound could cure or prevent a disease in a very
objective, rational way. And over the next 20 years, there was this
explosion of discovery and isolation, synthesis of all the known major vitamins. And the accident of history was the Great
Depression and World War II, which led to huge attention on food shortages and deficiency,
right? So this combination of science and geopolitics
led to this massive idea about we got to get enough nutrients into people to prevent these
diseases. And that led to this idea of food as a delivery
system. The idea of commodity crops, exploding commodity
crops to get calories to people. Fortification. And then when chronic disease started to be
considered in the 1950s and ’60s as I’ll talk about, the reductionist approach continued. Is it fat, is it sugar? That was the debate of the ’50s and ’60s. It was a real debate at that time. The reductionist approach works very well
for single nutrient deficiency diseases. It works perfectly well for scurvy or beriberi
or pellagra. But what we’ve learned since 2000 is that
the reductionist approach doesn’t work for obesity, for diabetes, for cancer, for cardiovascular
diseases. It falls apart for chronic disease. And so understanding that this is really just
the entire first half of the last century, explains a lot about how we got where we are. The next 20, 30 years continued this reductionist
approach. So when we started thinking about heart disease
and coronary heart disease in the 1970s, people said, “Well what’s the nutrient that’s causing
coronary heart disease? And it must be fat, unsaturated fat, and dietary
cholesterol. That’s what’s causing cardiovascular disease,
and if we get rid of that, we can eliminate it.” And that reductionist approach is continuing
now, as I mentioned, with our focus on obesity. It’s all about calories. You just have to count calories rather than
thinking about complexity. In developing countries, there was a huge
debate in the ’70s about whether malnutrition was due to a protein problem or a calorie
problem. And this was actually maybe forgotten now,
but a lot of debate back and forth. But while it was going on, the protein folks
were sort of winning the day, and industry followed. So industry made an enormous number of complementary
foods and infant formulas that were high in protein and high in vitamins, and flooded
the markets of those low income countries with these protein-enriched, fortified foods. And the history of this, as people may know,
has not always been so ethical in how those companies marketed and promoted those foods. And then of course, the dietary guidelines
continued these reductionist approaches. In 1980, the first dietary guidelines in the
US to really focus on chronic disease, it was largely nutrient focused. In low income countries around the same time,
1980s and 1990s, people started thinking about poverty and economic advancement, but somehow
that reductionist focus wasn’t forgotten. And people still thought, “It’s all about
getting enough calories to people and getting micronutrients into them through pills or
through food fortification.” And of course industry has followed this. And when I say food industry, we think about
manufactured foods, but we should remember food industry is agribusiness, multinational
supermarkets and retailers, multinational restaurants and food manufacturers. And I don’t blame industry for doing this. This is what we told them to do, right? This is what science and public health told
them to do. Industry followed what we asked them to do. They made a plethora of foods that were rich
in calories, starch and sugar, that were shelf stable, and were fortified with vitamins. And so Special K is kind of the classic example,
and that’s one of the older cereal boxes. Right? It’s cornstarch. It’s just cornstarch with a bunch of vitamins. And people think of it as a healthy cereal. Baked potato chips, chocolate skim milk, lowfat
turkey sausage, fat-free salad dressing. That’s an oxymoron, right? Salad dressing must have oil in it. So if it’s fat-free, what’s in it, right? Starch, salt and sugar. Right? So we’re putting starch, salt and sugar on
our salads instead of some of the healthiest fruit and nut oils that we can imagine. So what have we learned since then? Why am I saying these are all a mistake? Well I think we’ve learned an enormous amount
about chronic diseases really since the 2000s. And of course there was decades of foundational
science before this that was important. I mean if we didn’t have the studies of Ancel
Keys and others in the ’80s and the ’90s, we wouldn’t have been able to get where we
are today. But much of what we know, I think has really
accumulated since 2000. And what we know now, is for chronic diseases,
chronic diseases are not a single nutrient deficiency diseases. They’re complicated. They’re multi-factorial. And the influence of diet on them is complex
and multi-factorial. We have to think about foods and their complex
matrices. So instead of thinking about saturated fat,
we have to think about all the food sources that fat comes from. And instead of thinking about dairy as a class,
we have to say, “Well there’s yogurt, there’s cheese and there’s milk, and they’re all actually
very different foods.” And even among those foods, it may make a
difference if the milk is homogenized or not homogenized in terms of milk fat globule membrane
and bioactive phospholipids. It may make a difference if it’s a hard cheese,
it’s fermented, or a soft cheese that’s not fermented. There’s enormous complexity, and so that complexity
is crucial to understand. And at the same time in developing countries,
right, we shouldn’t just talk about the industrialized world, the complexity of food has finally
gotten to the international stage where it’s not just about starch and micronutrients anymore. It’s about diet quality and trying to assess
diet quality. Diet diversity. And addressing the double burden. As you know, the double burden is the presence
of chronic diseases like obesity and diabetes and hunger, in the same communities, in the
same family, and most often, in the same people, in the same individuals in those low income
countries. So that’s kind of where we are now, is this
complexity of foods and diet patterns and how to address the double burden globally. And this is kind of my sort of cartoon about
what I think we know right now about what the dietary priorities should be, what the
policies should be focused on. There’s foods that are really good for us,
and we should be trying to flood our bodies and the food supply with those foods. There’s foods that are kind of neutral, a
little bit better, a little bit worse for different reasons. Cheese is a little bit better because of its
links to lower diabetes. Unprocessed red meat’s a little bit worse
because of its links to higher risk of diabetes. And there it’s likely the heme iron, not the
fat. It’s about the heme iron in the meat that’s
likely the problem. And then the worst thing in the food supply
is grain, starches, sugars, processed meats, and foods with very high additives like sodium
and trans-fat. So everything in moderation is absolutely
the wrong message for the globe. The foods in the middle we should eat in moderation. I agree with that. The foods at the top, we should eat in excess. And the foods at the bottom, we should minimize. Right? That’s the approach to solving our global
crisis. So where are we going? Where do we think that the future of nutrition
science is going, and how will that influence policy? I think these are kind of five big areas that
we talk about. First is all of the complex interactions and
inter-relationships of our foods that we’re just starting to scratch the surface of and
I think are going to incredibly important. Probably, maybe most important is diet in
the microbiome. Maybe everything we eat in a sense is either
a prebiotic or a probiotic, and we’re really feeding our gut for health. Also related to that but also for their own
biologic effects, the effects of trace compounds in foods that we haven’t really paid attention
to. Like specific fatty acids, flavonoids, the
effects of fermentation that I mentioned. The effect of diet composition rather than
calories, on weight gain. And the powerful influence which we’re again,
just scratching the surface of, of social influences, like place, where you’re born,
and you’re social status, how that links to your food and to your diet and to future health. Second big bullet, quality not quantity. For preventing obesity or for solving the
obesity challenge that’s facing the world, we have to stop counting calories and focus
on diet quality. That means defining diet quality, which is
also something that’s not straightforward, but we know enough to start to do that, and
I think that’s really crucial. Processing and additives? I mean the public talks about processed foods
being bad for you. I don’t think processing per se is bad for
you, but there’s got to be optimal processing and harmful processing. And I don’t think we really quite understand
of all of the things that the food industry is doing, what are the things that are really
actually meaningful and important that’s optimal or not? Is oil deodorization a bad thing? Is homogenization of milk a bad thing? And answering and understanding these questions. Also additives. And when we think about processing and additives,
I don’t just mean again, food manufacturers. All the ways we breed our crops and the way
our crops have changed over time. Does it really make a difference if beef is
grass fed or not? I don’t think so. I don’t think that evidence to suggest it
makes a difference for health, whether beef is grass fed or not, but there’s just not
that much science yet. Diet risk pathways. I’ll show you a slide. I think this is another area for the future. I’ll come back to that. And then public health, I’ll come back to
that in a minute as well. So again, just a summary of some of the trials
that have been done in humans, showing that when it comes to longterm risk of obesity,
it’s not about energy, it’s about quality of the diet. That the types of foods we eat influence through
really interesting, complex, unconscious mechanisms, all of the pathways related to weight control. Not just hunger. We think about hunger, but that’s just the
tip of the iceberg. Glucose and insulin and hormone responses,
fat synthesis in the liver, brain reward and craving, the gut microbiome, and even metabolic
expenditure. Now there’ve been at least a couple of trials
showing that diet composition may influence metabolic expenditure. So all calories are not the same when it comes
to longterm risk of obesity. Complex pathways, I mentioned this. Almost every aspect of foods and diets affects
a range of risk factors, and if you put it all together, all of these have been documented
in human trials. Food affects almost every major pathway you
can think of related to health in the body. And we had blinders on in the ’80s and ’90s,
and were focused on blood lipids, because we were worried about middle aged men getting
heart attacks, and that led to the lowfat, low saturated fat focus. Now I think we have blinders on and we’re
just focused on obesity, so we just talk about calories. And I think food is much more complex, and
its effects are much more complex. The future’s going to be kind of putting all
of this together to think about effects of foods. I think the areas of research I mentioned
are incredibly important. I went over these already. These are I think major areas for the future. And I think also when we think about research,
I think that we have to understand how to put the evidence together. And I think we’re still at the earliest stage. I very strongly believe, from all of my training,
that thinking that randomized controlled trials are the pinnacle of evidence is a flawed approach. And that’s still kind of the current approach,
and I think Jon Ioannidis is going to speak this evening, I’m sure that’s what
he’s going to say. That is flawed. Randomized controlled trials have key strengths,
they also have key limitations. Every line of research inquiry has strengths
and limitations, and those are complementary. And so really, evidence based medicine, evidence
based policy, should say, “Look at all the evidence. Understand the strengths and limitations of
every single kind of study designed, put it together in a thoughtful and informed way.” Don’t just say, “Let’s do mega randomized
trials,” and assume that’s going to give us the answers. I think this is an area for the future. And then lastly, I think one of the major
areas for science is the science of behavior change. For too long, we’ve focused on nutrition in
terms of chronic disease risk, and said it’s about behavior change at the individual level,
it’s about knowledge, it’s about education. We have to explain to people what to eat. How do we get people to understand all of
the focus we have on labeling, on education, on guidelines. It’s sort of shocking to me, this is the only
major part of the globe’s economy that we leave up to the individual to determine whether
or not to do something safe. Right? The building we’re in has enormous numbers
of codes, right? If we walk into this building, we assume it’s
safe. We assume that it has fire codes, earthquake
codes. The cars you drive, right? You assume there’s a minimum level of safety. The toys we buy for our children. Imagine if all the toy stores in the world
had really, really unsafe toys that everybody knew were unsafe, sort of average toys that
were a little bit unsafe, and then safe toys. And we said, “Look. We have to … ” and there were thousands
and thousands of kids per day getting injured or dying from these toys, and all we did was
say, “Well, we have to explain to the parents which toys are safe so they go and buy the
safe toys.” Right? And tell them to shop at the toy section around
the outside of the toy section. Don’t go in the middle aisles of the toy section,
right? The stuff we do for food is just sort of mind-blowing,
right? All food should be healthy. All food should be safe, from a disease perspective. And I think to do this, it’s going to be about
policy, it’s going to be about innovation, and it’s going to be about culture. And the food industry is absolutely a part
of the solution, right? They’re not the enemy, they’re part of the
solution. We have to trust, but verify. And we have a list of “Best Buy” policies
that we’re working on, mostly focused on the United States. We have a Food is Medicine initiative, working
with the US government. There’s now a working group in the US House
called the Food is Medicine Working Group, which is really exciting that there’s a group
of congressmen in the House talking about Food is Medicine, and its influence. These are the kind of the spectrum of domains
that I think will work. It may be a little bit different in low income
countries, but I think this would also be very appropriate for middle income countries. I just want to end and say that it’s really
important to just look back at the last hundred years of history and sort of see how we got
to where we are today. It’ll really helps us know where we’re going. As Carl Sagan said, “You have to know the
past to understand the present.” And as Martin Luther King, Jr. said, “We are
not makers of history. We are made by history.” So thank you very much. I look forward to the discussion in the breaks
and to a panel that I’m on tomorrow.