Research Highlights Podcast
October 24, 2024
Agricultural productivity and chronic disease
Sheetal Sekhri discusses the impact of the Green Revolution on long-term health outcomes in India.
Source: alisa24
A half a century ago, new high-yield varieties of crops were introduced to India, and it transformed the country's farming. This so-called “Green Revolution” significantly boosted agricultural output, allaying concerns about famine and food security. But it may have had some unanticipated consequences for long-term health outcomes.
In a paper in the American Economic Journal: Applied Economics, authors Sheetal Sekhri and Gauri Kartini Shastry show that the areas where agricultural productivity accelerated the most also saw the highest rates of diabetes among men later in life. The authors argue that substantial changes to the diets of mothers and young children, in the form of higher levels of rice consumption, likely increased the risks of chronic diseases.
The findings suggest that dietary diversification should accompany efforts to promote agricultural production.
Sekhri recently spoke with Tyler Smith about how the Green Revolution changed diets in India and why it led to a rise in diet-related diseases like diabetes.
The edited highlights of that conversation are below, and the full interview can be heard using the podcast player.
Tyler Smith: First, I'd like to just lay some groundwork on what the Green Revolution was and maybe what spurred it. Can you give us some background?
Sheetal Sekhri: Like most developing countries, India, after its independence, was food insecure. It was also grappling with importing food. So they wanted to support the production of food grains in India to make it self-reliant. They were looking at various ways to improve their productivity and tried things like irrigation infrastructure, crop rotation, and fertilizers, which did result in higher productivity, but the gains were very slow. Because this was also happening in other parts of the world, some foundations were funding research to try and boost productivity at the seed level. In particular, the Ford Foundation and Rockefeller Foundation were sponsoring research in the Philippines and Mexico to try and boost food production through the crossbreeding of seeds. When the Indian government came to know about this, they invited the architect of the Green Revolution, Norman Borlaug, to come to India. The invitation was extended in 1963 to provide consultation to help the government improve agricultural productivity by bringing in these newer seeds, which are called the high-yielding varieties. These seeds are very sensitive to where they're grown and the timing of irrigation, so the initial stage was just to experiment with them and see if they would be a good fit for the Indian environment. In 1966, the seeds were first distributed to be grown by the farmers. And from there on, it ushered in a food revolution in the country. Their production of high-yielding varieties dramatically increased in the decades from the inception year of 1966.
Smith: This seems like such an unambiguously positive thing. What made you think that it might be connected to chronic diseases and bad health outcomes?
Sekhri: These chronic diseases and obesity are usually thought of as diseases of plenty. And the conventional wisdom is that they are only prevalent in developed countries. But if you look at recent trends, worldwide obesity and chronic diseases are growing. On the one hand, you have stunting and malnutrition among children. But at the same time, obesity and chronic diseases are growing. For example, in India, in the decades after the Green Revolution, malnourishment dropped significantly. But in the decades following, the obesity rates dramatically increased. If you look at diabetes prevalence from 1971 to 2014, it increased fourfold. That was a big puzzle for us.
Smith: Can you describe a little bit about how the Green Revolution and high-yielding crops changed the diets of Indians?
Sekhri: It has had a very substantial effect on their diets. Prior to the Green Revolution, the population was reliant on ancient grains and complex carbohydrates, such as millets, barley, and sorghum. But then, after the Green Revolution, white rice and wheat became the staples. And there's a very sharp increase in consumption of these food groups or derivatives of those foods. People were not consuming as much of the ancient grains, and the new diets are very rich in these newer grains.
Smith: How did you isolate the impact of the Green Revolution and these dietary changes on long-run health?
Sekhri: In my previous research, I had observed that there were areas that have rich historical endowments of groundwater. And those were the areas where, in1966, when the high-yielding seeds arrived, the Green Revolution really accelerated. The reason is that these seeds are very sensitive to the timing of irrigation. Where the groundwater was abundant, the farmers were able to irrigate the seeds in a timely manner. They didn't have to rely on the uncertainties of either rainfall or surface water availability. In those areas, you see a very steep increase in the production of these new crop varieties. That gave me this idea that spatially what we can do is harness these differences in the rates of acceleration of the Green Revolution. So we compared the areas that were very water abundant historically to the areas that were less abundant. And then we also look at the cohort of males born before 1966, when the seeds were not available, and after 1966, when the seeds were available. Looking at changes over time across this very specific period at the beginning of the Green Revolution, we compare these before and after changes across areas.
Smith: When you compare these areas that are more suitable for the high-yield crops with less suitable areas, what do you find? What impact did the Green Revolution have on health outcomes in India?
Sekhri: What we find is that the rate of diabetes prevalence among the cohorts that were born right after the Green Revolution, that is 1966, in areas with high-water endowment, where the Green Revolution was really accelerating, are much higher relative to both the cohorts born right before and the cohorts born in the less water-abundant areas. The areas that were experiencing the full rush of the Green Revolution are where the rate of prevalence of diabetes in later life for males aged 49 and above is much higher.
Increasing agricultural productivity is a great agenda because it reduces poverty and increases food security. But we should also be very mindful of the staple whose production and access is increasing. We have to prioritize diversification of the diet as well.
Sheetal Sekhri
Smith: Which groups in particular were affected the most?
Sekhri: We are able to see this for males. We don't see this effect for females and there could be several reasons for that. For example, it could be that the time gradient over which women develop diabetes is different than men. There is research showing that they tend to develop diabetes after menopause. So, it's possible that our data is from a period when women haven't aged enough. It could also be that diets affect men and women differently, but our evidence shows that it's the males. We also have heterogeneity in the results, which helps us to corroborate the fact that the diet is a driving mechanism for this. We found that the results are driven by areas where rice was the staple that increased a lot. Medical research does show that eating white rice is associated with higher diabetes risk in animal studies. It's also shown to increase the risk of mortality from diabetes. Rice-eating areas are the ones that are experiencing differentially higher risks of increase in diabetes.
Smith: How should governments in developing countries address the rise of these chronic diseases caused by high-yield agricultural techniques?
Sekhri: Increasing agricultural productivity is a great agenda because it reduces poverty and increases food security. There is a lot of focus on different types of ways to increase agricultural productivity by giving subsidies for machines or increasing market access or improving distribution channels for food. What we find in our paper is that while we should pursue that agenda, we should also be very mindful of the staple whose production and access is increasing. We have to prioritize diversification of the diet as well. We could focus on information campaigns around eating vegetables. Otherwise you can have very substantial health risks later in life, the biggest one being an increase in the likelihood of getting diabetes. So dietary diversification has to accompany the promotion of agricultural production to improve health outcomes.
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“The Curse of Plenty: The Green Revolution and the Rise in Chronic Disease” appears in the October 2024 issue of the American Economic Journal: Applied Economics. Music in the audio is by Podington Bear.